A neutral atom fully connected quantum computing system

Abstract

The application relates to the technical field of quantum computing, and provides a neutral atom full-connection quantum computing system, which comprises a double-layer cross-chip structure and a static neutral atom array; the double-layer cross-chip structure comprises a first chip and a second chip which are oppositely stacked, the first chip comprises a first microwave resonant cavity array extending along a first direction, the second chip comprises a second microwave resonant cavity array extending along a second direction, and the first direction intersects with the second direction; the static neutral atom array is arranged in a gap between the first chip and the second chip, and each neutral atom in the static neutral atom array is located in an intersection region of the first microwave resonant cavity array and the second microwave resonant cavity array, so as to form a two-dimensional addressable cavity-atom coupling network. The technical scheme fundamentally eliminates the millisecond-level delay and the atom loss risk caused by mechanical rearrangement, and provides a hardware basis with high clock frequency and high array integrity for large-scale fault-tolerant quantum computing.

Description

Technical Field

[0001] This invention relates to the field of quantum computing, and more particularly to a fully interconnected quantum computing system of neutral atoms. Background Technology

[0002] Quantum computing is at a critical stage of evolution from physical experimental platforms to large-scale fault-tolerant computing systems. Realizing a practically valuable fault-tolerant quantum computer typically requires integrating tens of thousands of physical qubits, encoding multiple physical qubits into a single logical qubit using quantum error-correcting codes, and continuously and stably performing a large number of checkpoint measurements during algorithm execution. This places stringent demands on the hardware platform: it not only needs high-fidelity single-qubit gates, two-qubit gates, measurement and reset capabilities, but also requires efficient quantum interconnects in both space and time according to the checkpoint structure of the error-correcting codes.

[0003] Neutral atom quantum computing platforms have become an important hardware approach for quantum computing and quantum simulation due to their advantages such as naturally identical atoms, scalable array size, and strong parallel optical manipulation capabilities. These platforms typically use optical tweezers or optical lattices to trap atoms, storing quantum information in long-lived ground states or hyperfine levels. When executing two-qubit gates, entanglement is achieved by exciting atoms to Rydberg states and utilizing Rydberg blocking or dipole interactions. However, the topology of neutral atom arrays does not natively support efficient interconnections between any two atoms. Achieving high-speed, deterministic quantum entanglement between distant atoms in a static atom array, while avoiding compromise to array integrity and clock frequency, is one of the core challenges in realizing large-scale fault-tolerant quantum computing.

[0004] Existing technical solutions to address this challenge can be mainly divided into the following two categories: (i) Neutral atom interconnection scheme based on optical tweezers movement rearrangement The closest prior art to this invention is a neutral atom quantum computing scheme based on optical tweezers movement and array rearrangement to achieve nonlocal interconnection. The apparatus for this type of scheme typically includes: a spatial light modulator or a fixed optical tweezers array for generating a static atom array; an acousto-optic deflector or other dynamic beam control module for generating movable optical tweezers; an atom library or loading region for storing spare atoms; a laser excitation system for executing Rydberg gates; and a control electronics system for planning transport paths, controlling optical tweezers power, and synchronizing quantum gate operations. Kim et al. demonstrated single-atom array rearrangement based on dynamic holographic optical tweezers in Nature Communications 7, 13317 (2016), laying the foundation for this type of technology.

[0005] The general steps of this type of method are as follows: First, an initial neutral atom array is formed using static optical tweezers or an optical lattice, and the positions of vacancies or target atoms are identified through imaging. Second, based on the quantum circuit to be executed or the error correction and verification requirements, the sets of atom pairs or checker-data bits that need to interact are calculated. Third, the target atom is picked up from the static potential well using AOD or other dynamic optical tweezers and transported along a planned path to a position adjacent to another target atom or within the Rydberg interaction radius. Subsequently, a local Rydberg two-qubit gate or multi-qubit operation is performed. Finally, the atom is returned to its target position or the next transport, vacancy filling, rearrangement, and gate operation is performed. For high-weighted checks or long-range connections, this process needs to be repeated on a large number of target atoms within one error correction cycle.

[0006] (II) Photon-mediated interconnection scheme based on optical cavity The second type of existing technology closest to this invention is a photon-mediated interconnection scheme based on optical cavities. Such devices typically include a Fabry-Perot cavity, microcavity, or other optical resonant cavity operating in the optical band; neutral atoms or an array of atoms located in the cavity mode; an optical control system for exciting and reading out atomic states; and a detection system for detecting photons or performing post-selection decisions. The basic idea is to enable distant atoms or different processing units to establish entanglement through a common optical cavity mode, photon emission, photon absorption, photon interference, or photon detection events, thereby reducing dependence on the mechanical transport of atoms.

[0007] The general steps of this type of method are as follows: First, the target atom or processing unit is coupled to an optical cavity mode; second, an atom-photon interaction is induced by an excitation pulse, allowing the cavity photons to carry information about the quantum state of the atom; third, a success event signal is obtained through photon transmission, interference, or detection; finally, the success event is retained based on the detected heralding result, or the failure event is discarded, waited for, reset, or retried. Borregaard et al. proposed an optical cavity post-selection quantum gate with integrated error detection in Phys. Rev. Lett. 114, 110502 (2015); Ramette et al. proposed an arbitrary interconnect cavity-mediated architecture for Rydberg arrays or ion arrays in PRX Quantum 3, 010344 (2022). These schemes show that cavity modes can serve as nonlocal interconnect mediators, thus providing a feasible direction for circumventing the mechanical movement of atoms.

[0008] Both of the above-mentioned existing technical solutions have significant drawbacks: Problems with the first type of solution (optical tweezers movement and rearrangement): First, there is a significant bottleneck in clock speed. When executing long-range quantum gates, the system must first transfer atoms from a static potential well to a dynamic potential well. This "dynamic-to-static conversion" process requires smooth adjustment of the relative power of the two laser beams, taking approximately 0.05 ms. To prevent atoms from heating up or even escaping due to violent shaking during the movement, AOD optical tweezers must employ an optimal control trajectory of acceleration followed by deceleration, rather than uniform or infinitely accelerated motion. Theoretically, the movement time... With distance traveled It is proportional to the square root ( ). Using a sample containing 1000 atoms with a spacing of 5... Taking a one-dimensional array as an example, a single rearrangement takes about 13ms, far exceeding the microsecond-level operation time of a Rydberg gate. A single error correction cycle typically requires tens or even hundreds of rearrangements, with the total time reaching the order of seconds. This drawback is not only due to the slow speed of a single transport, but more fundamentally, the mechanical transport time is directly incorporated into the error correction clock, limiting the clock frequency of the entire quantum computer.

[0009] Secondly, frequent mechanical rearrangement increases the probability of atoms escaping from optical tweezers, leading to frequent vacancies in the array, which disrupts the integrity of the computing array and forces the system to introduce complex dynamic reconstruction processes or additional error correction overhead.

[0010] Problems with the second type of scheme (optical cavity photon-mediated): First, low coupling strength leads to slow gate speed. Most existing schemes use microcavities operating in the optical band (such as Fabry-Perot cavities). Due to the relatively large mode volume of optical cavities and the limited dipole moment of optical transitions, the coupling strength g between photons and individual atoms within the cavity is low, which directly limits the speed of the mediated two-qubit entanglement gate.

[0011] Secondly, they lack fault tolerance and are extremely dependent on post-selection. Existing optical microcavity schemes typically use conventional photon states (such as Fock states or ordinary coherent states) as information carriers, making them highly susceptible to spontaneous emission, photon scattering, and cavity mirror leakage (i.e., photon loss errors). Due to the lack of underlying hardware bias noise or error suppression mechanisms, many schemes require a post-selection mechanism to screen successful events in order to achieve high-fidelity entanglement—the gate operation is only considered successful when the detector receives the correct number of photon signals within a specific time window; events where no photons are detected are discarded. This nondeterministic operation, which trades data for fidelity, undermines the continuous execution capability of quantum circuits.

[0012] In summary, existing technologies, such as optical tweezers rearrangement schemes, are limited by millisecond-level delays in mechanical handling and the risk of atom loss, making it difficult to support the high clock frequencies and array integrity requirements of large-scale fault-tolerant computing architectures. Optical cavity photon-mediated schemes, on the other hand, are limited by low coupling strength and post-selection dependence, failing to provide deterministic high-speed entanglement operations and lacking underlying error suppression mechanisms. Therefore, a novel quantum computing architecture is urgently needed that can achieve deterministic, high-speed, long-range entanglement connections between arbitrarily distant atoms in a static neutral atom array without mechanically moving atoms, while maintaining high clock frequencies and long-term array integrity, thus providing a feasible hardware foundation for large-scale fault-tolerant quantum computing. Summary of the Invention

[0013] To address the aforementioned problems, the present invention aims to provide a fully interconnected quantum computing system based on neutral atoms. Through a two-dimensional addressable cavity-atom coupling network formed by the intersection region of a microwave resonant cavity array extending along the intersecting direction and a static neutral atom array in a two-layer cross-chip structure, long-range entangled interconnections of static atoms can be achieved without mechanical movement. This fundamentally eliminates the millisecond-level latency and atom loss risk caused by mechanical rearrangement, providing a hardware foundation with high clock frequency and high array integrity for large-scale fault-tolerant quantum computing.

[0014] The above-mentioned objective of this invention is achieved through the following technical solutions: A fully interconnected quantum computing system of neutral atoms includes: a two-layer cross-chip structure and a static neutral atom array; The dual-layer cross-chip structure includes a first chip and a second chip stacked opposite each other. The first chip includes a first microwave resonant cavity array extending along a first direction, and the second chip includes a second microwave resonant cavity array extending along a second direction. The first direction and the second direction intersect. The static neutral atom array is disposed in the gap between the first chip and the second chip. Each neutral atom in the static neutral atom array is located in an intersection region of the first microwave resonant cavity array and the second microwave resonant cavity array to form a two-dimensional addressable cavity-atom coupling network.

[0015] Furthermore, the first microwave resonant cavity array and the second microwave resonant cavity array are configured to respectively turn on or off the coupling relationship with the neutral atom.

[0016] Furthermore, each microwave resonator in the first microwave resonator array and the second microwave resonator array is configured to encode its internal single-mode electromagnetic field into boson qubits through a boson encoding method, and to serve as a quantum bus for controlled entanglement interaction with multiple neutral atoms located in the cavity mode of the same microwave resonator, so as to mediate long-range entanglement between the neutral atoms that are spatially far apart. The boson encoding method is selected from any one of cat-state encoding, GKP code, binomial code, rotationally symmetric boson code, or other oscillator error correction code; When the boson encoding method employs cat-state encoding, each microwave resonant cavity is configured to stabilize its internal single-mode electromagnetic field in two coherent states through a nonlinear stabilization mechanism. and In Zhang Cheng's boson cat state subspace, cat bits are formed.

[0017] Furthermore, the static neutral atom array comprises a plurality of trapped neutral atoms; The static neutral atom array is confined by a two-dimensional optical lattice, a static optical tweezers array, a three-dimensional optical lattice, a nanophotonic confinement structure, or other confinement methods that can fix the neutral atom positions for a long time during quantum gate execution and error correction cycles. Independent loading and gap-filling mechanisms are used during atom initialization, loading, or pre-arrangement stages, but no mechanical handling of atoms via optical tweezers is required during computational execution to achieve nonlocal connections. Each neutral atom is located at a corresponding confinement position and simultaneously within the spatially overlapping region of a cavity mode of the first microwave resonant cavity and a cavity mode of the second microwave resonant cavity. Each neutral atom has four energy levels, including a first hyperfine level and a second hyperfine level for storing quantum information, and a first Rydberg level and a second Rydberg level for resonant coupling with the microwave resonant cavity.

[0018] Furthermore, the present invention also includes a first addressing beam system projected along the first direction and a second addressing beam system projected along the second direction; when the first addressing beam and the second addressing beam irradiate the neutral atom, the energy level of the irradiated neutral atom is shifted; the energy level shift of the neutral atom under the action of a single first addressing beam or a single second addressing beam is configured to be greater than the equivalent coupling strength of the subsequent global excitation, so that the neutral atom located only on a single beam path does not satisfy the resonance condition of the global excitation; at the intersection of the first addressing beam and the second addressing beam, the neutral atom is subjected to a dual energy level shift and is adjusted to satisfy the resonance condition of the global excitation, so as to achieve selective addressing of the target atom; by generating multiple intersections simultaneously, multiple target atoms are selected in parallel within the same physical operation cycle.

[0019] Furthermore, the microwave resonant cavity is coupled to the neutral atom that is addressed inside it; the microwave resonant cavity and the addressed neutral atom achieve controlled interaction through coherent coupling between the electromagnetic field mode of the microwave resonant cavity and the Rydberg level of the addressed neutral atom; after the microwave resonant cavity is stabilized into the cat bit, the controlled interaction is equivalently mapped to controlled coupling between the Pauli operator of the cat bit and the Pauli operator of the addressed neutral atom, and the cat bit acts as a quantum bus to mediate entanglement between the addressed neutral atoms; the residual nonideal coupling terms in the controlled interaction are exponentially suppressed as the coherent amplitude of the boson cat state increases.

[0020] Furthermore, the following timing operations are performed to implement the entanglement gate between the cat bit and at least one of the addressed neutral atoms: Addressing is performed on at least one of the addressed neutral atoms; The at least one addressable neutral atom after addressing is excited from the computational ground state to the Rydberg state; The controlled coupling between the target microwave resonant cavity and the at least one addressed neutral atom is initiated, and conditional evolution is performed within a preset time period to form controlled entanglement between the cat bit and the at least one addressed neutral atom. The at least one addressed neutral atom is de-excited from the Rydberg state back to the computational ground state; Perform local phase compensation on the at least one addressed neutral atom; Wherein, when the number of the at least one addressed neutral atom is multiple, the entanglement gate acts on multiple neutral atoms in parallel within the same operation cycle, and the preset duration is determined by the coupling parameter and the coherent state amplitude of the cat bit, and is independent of the number.

[0021] Furthermore, the cat bit also serves as an intermediate quantum bus to mediate parallel entanglement gates between the first neutral atom and multiple target neutral atoms; The first neutral atom and the plurality of target neutral atoms are all addressed and located within the same cavity mode of the microwave resonant cavity; The first neutral atom interacts in a controlled manner with the cat bit, and the cat bit interacts in a controlled manner with multiple target neutral atoms, so that the parallel entanglement gate between the first neutral atom and the multiple target neutral atoms is completed in a single physical time step; After the parallel entanglement gate is executed, the cat bit is unentangled with the first neutral atom and the plurality of target neutral atoms. The quantum state of the cat bit is used to indicate whether an error occurred during the execution of the parallel entanglement gate.

[0022] Furthermore, the total error rate of a single operation of the controlled interaction is composed of the phase error contribution of the microwave resonant cavity and the energy level decay error contribution of the neutral atom, and the microwave resonant cavity supports configuring the coherent state amplitude of the cat bit to an optimal operating state in which the phase error contribution and the energy level decay error contribution tend to be balanced. The value of the coherent state amplitude under the optimal operating state is determined by the coupling strength between the neutral atom and the microwave resonant cavity, the loss characteristics of the microwave resonant cavity, and the energy level decay characteristics of the neutral atom, so as to minimize the total error rate of the single operation.

[0023] Furthermore, the parallel entanglement gates between the cat bits and the multiple addressed neutral atoms achieve low crosstalk operation by confining the microwave resonant cavity within a large-amplitude boson cat state manifold. The field operator of the microwave resonant cavity is mapped to the logical diagonal operator of the cat bits within the boson cat state subspace, enabling the ideal controlled evolution terms between the multiple addressed neutral atoms and the same cat bit to commutate with each other, thereby realizing multiple entanglement gates in parallel within the same gate time. The dynamic evolution of the parallel entanglement gates is equivalent to the action of multiple independent two-bit entanglement gates. The non-diagonal, non-commutative residual crosstalk terms caused by the finite cat state amplitude decrease exponentially with the overlap between the two coherent states of the boson cat state, thereby suppressing gate crosstalk between the multiple addressed neutral atoms.

[0024] Compared with existing technologies, the architecture of this invention utilizes stable single-mode Bose cat states in a superconducting microwave cavity as a quantum bus to mediate long-range interactions between any two atoms within the cavity, thereby achieving fully connected quantum entanglement within a neutral atom array. This architecture differs from traditional pure superconducting quantum bus systems (where both bits and the bus are implemented using superconducting circuits). This architecture uses Rydberg atoms as core computing nodes and a superconducting microwave cavity as the bus medium, combining the long coherence of atoms with the efficient information transmission advantages of a microwave cavity. This invention fundamentally eliminates millisecond-level latency and the risk of atom loss caused by mechanical rearrangement, and utilizes the bias noise characteristics of cat-state encoding to provide underlying error suppression, aiming to construct a large-scale fault-tolerant quantum computing system with high clock frequency, high fidelity, and low error correction overhead. Specifically, this invention can achieve the following beneficial effects: (1) Significantly improves computing speed and long-term system stability This invention employs a two-dimensional addressable cavity-atom coupling network formed by the intersection region of a microwave resonant cavity array extending along the intersecting direction and a static neutral atom array in a dual-layer cross-chip structure. This allows for fully connected long-range entangled interconnections of static atoms without mechanical movement. The invention utilizes a Schrödinger cat-state bus to mediate the interconnection between stationary atoms. Information transmission essentially occurs at the speed of light, and the time of quantum gate operations depends only on the gate operation itself (microseconds), eliminating the mechanical delay (milliseconds) of traditional mechanical rearrangement schemes and fundamentally eliminating the millisecond-level delay caused by mechanical rearrangement. Simultaneously, since there is no need to move atoms, atoms remain at static lattice points trapped in a two-dimensional optical lattice throughout the entire computation process, eliminating the need for any physical handling by optical tweezers and completely avoiding the risk of atom loss due to movement. This design fundamentally eliminates the risks of atomic heating, oscillation, or even escape loss caused by atomic transfer, acceleration / deceleration, and potential well switching during dynamic potential well transfers in traditional schemes. Since atoms no longer undergo physical movement, there will be no errors caused by failed transport, such as missing atoms, nor will there be any idle errors caused by other atoms during transport. This avoids additional error correction overhead, ensures the long-term integrity and operational stability of the quantum computing array, and provides a solid hardware foundation for large-scale, long-term, and continuous fault-tolerant quantum computing.

[0025] (2) Error suppression at the hardware level This invention stabilizes each microwave resonant cavity into a boson cat bit through a nonlinear stabilization mechanism and uses it as a quantum bus. Utilizing the bias noise characteristics of the Schrödinger cat state, bit-flipping errors can be suppressed exponentially. Compared to traditional optical cavity schemes that are extremely sensitive to photon loss, this invention enhances the error resistance of the quantum bus by using stable boson cat state encoding, achieving more robust long-range interconnects.

[0026] (3) High efficiency and low error correction overhead The microwave cavity cat-state bus of this invention supports a "one-to-many" parallel gate operation mode. The entanglement gate between the cat bit and at least one addressed neutral atom acts in parallel on multiple neutral atoms in the same operation cycle, and the gate operation time is independent of the number of target atoms acting in parallel. At the same time, the cat bit can also be used as an intermediate quantum bus to mediate the parallel entanglement gate between one atom and multiple target atoms, and complete it in one step in a single physical time step. This greatly optimizes the depth and execution efficiency of quantum circuits, thereby significantly reducing the physical resource overhead of fault tolerance and error correction. Attached Figure Description

[0027] Figure 1 The diagram shows the structure of the double-layer orthogonal chip and static atom array of the present invention, wherein (a) is a schematic diagram of the microwave resonant cavity encoded as boson cat bits, (b) is a schematic diagram of the X-cavity and Y-cavity distributed in a grid pattern, and (c) is a schematic diagram of the structure of the four energy levels (storage energy level and Rydberg energy level) of the neutral atom. Figure 2 In this invention, a single microwave cavity cat bit is used as a control bit to execute multiple addressed atoms in parallel. Door operation diagram; Figure 3 This invention utilizes microwave cavity cat bits to mediate the pairing of atom 0 to atom 1. Parallel execution The diagram shows a comparison of the circuits of the gate. The left side represents the traditional serial circuit, and the right side represents the parallel circuit of this invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0030] The terminology involved in this invention is explained as follows: (1) Schrödinger Cat States / Cat Qubits This refers to a special class of boson quantum states that are actively stabilized in a microwave resonant cavity through the introduction of a two-photon dissipation mechanism or the Kerr nonlinear effect. These quantum states manifest in phase space as two macroscopically distinguishable coherent states (i.e., and The quantum superposition of the superposition state. Due to the physical properties of this superposition state, when used as a qubit (i.e., a cat bit), it can exponentially suppress bit flip errors (X errors), thus exhibiting significant biased noise characteristics, that is, phase flip errors are much stronger than bit flip errors.

[0031] (2) Cat Bus This invention proposes a microwave cavity-based quantum bus architecture. Specifically, this bus encodes the electromagnetic field modes within the microwave cavity into Schrödinger's cat states. These cat states serve as a medium for information and interaction, mediating the deterministic quantum entanglement of stationary neutral atoms at long distances (or even across the entire cavity) within the cavity space, without requiring physical movement. The cat-state bus combines the advantages of high-speed photonic communication with hardware-level error suppression.

[0032] The present invention relates to the following known technical content that forms the basis of the present invention: (1) Fault-tolerant quantum computing Fault-tolerant quantum computing (FTQC) encodes a logical qubit into multiple physical qubits using quantum error-correcting codes and suppresses physical errors through periodic error extraction, decoding, and feedback. Building a fault-tolerant quantum computer capable of solving complex real-world computational problems typically requires tens of thousands of physical qubits to provide sufficient redundancy. This necessitates hardware that not only possesses high-fidelity single-qubit and two-qubit gates, measurement and reset capabilities, but also the ability to continuously and stably perform a large number of checksum measurements during algorithm execution, according to the checksum structure of the error-correcting code.

[0033] (2) Neutral atom (Rydberg atom) platform Neutral atom quantum computing platforms typically use optical tweezers or optical lattices to trap atoms and store quantum information in long-lived ground states or hyperfine levels. When executing two-qubit gates, atoms can be briefly excited to Rydberg states, and entanglement gates can be achieved using Rydberg blocking or dipole interactions. This platform has advantages such as naturally identical atoms, scalable array size, and strong parallel optical manipulation capabilities, and has become an important hardware approach for quantum computing and quantum simulation.

[0034] (3) Clock rate bottleneck caused by mechanical rearrangement While neutral atom quantum computers theoretically possess the potential for all-to-all connectivity, currently, achieving two-qubit entanglement between any two widely separated atoms primarily relies on optical tweezers for physical movement (mechanical rearrangement), bringing one atom into the Rydberg interaction radius of the other. To prevent the atom from escaping due to heating during the movement, there is a physical lower limit to the duration of this mechanical movement. In the currently optimized scheme, the movement time... With distance traveled It is proportional to the square root ( This results in long-range interconnects typically requiring milliseconds ( ). The time interval is on the order of 1 / 2000, which is much longer than that of microseconds. The operation time of a Rydberg gate is on the order of magnitude of a quantum computer. Every thousand-fold increase in the system's operating speed significantly reduces the physical resource overhead for fault tolerance and correction. Therefore, reducing or even eliminating the mechanical delay caused by physically transporting atoms is a bottleneck problem in realizing large-scale fault-tolerant quantum computers.

[0035] (4) Cavity quantum electrodynamics (cQED) Cavity quantum electrodynamics (cQED) studies the interaction of light and matter within a confined space. It has been demonstrated that a stationary array of atoms placed within a resonant cavity can mediate long-range interactions between distant atoms using electromagnetic field modes within the cavity as a medium (data bus), providing a theoretical basis for avoiding mechanical movement.

[0036] (5) Bosonic Cat code In quantum information science, "boson cat state encoding" refers to encoding quantum information into the electromagnetic field modes of quantum resonators such as microwave resonant cavities. Specifically, Schrödinger's cat state typically manifests as two macroscopically distinguishable coherent states (e.g., and The quantum superposition of electromagnetic fields. Electromagnetic field modes can be stabilized using nonlinear dissipation or Kerr nonlinear mechanisms. and In Zhang Cheng's cat-state subspace, a cat bit is thus formed, in which... Corresponding bit state, Corresponding bit Cat states exhibit a strong bias against physical noise, meaning they can exponentially suppress bit-flipping errors. In some literature, the term "cat state" sometimes refers to the Greenberger-Horne-Zeilinger state based on multi-qubit entanglement. To avoid confusion, all references to "cat state" in this patent refer to the single-mode boson cat state.

[0037] (6) Quantum Bus Concept A quantum bus is a medium in quantum computing architecture used to transfer quantum state information or mediate long-range interactions between physical qubits. In many static qubit architectures, the quantum bus is a core component for achieving nonlocal connections. In known technologies, a quantum bus can be implemented using photonic modes (such as optical microcavities), phonon modes (such as collective vibrational modes in trapped ion systems), or superconducting resonators. Its core physical function is to act as an intermediary, enabling geometrically non-adjacent qubits to achieve controlled entanglement through coupling with the bus mode.

[0038] The technical problem that this invention aims to solve is: Current neutral atom quantum computing processors rely on optical tweezers to physically move atoms to achieve nonlocal connections between qubits, which introduces extremely high mechanical latency. The mechanical latency leading to atomic decoherence errors and the risk of atom loss during movement are bottlenecks in realizing large-scale scalable fault-tolerant quantum computers. This invention provides a fully connected high-speed quantum computing architecture that eliminates the need for mechanical atom movement, fundamentally eliminating millisecond-level latency, atom heating, and loss risks associated with mechanical rearrangement. It significantly improves the execution speed of quantum error correction cycles and the long-term stability of the system, and provides a hardware foundation for building large-scale fault-tolerant quantum computers with both high clock frequencies and low error correction resource overhead.

[0039] The technical solution of the present invention will be described below through specific embodiments: like Figure 1 The present invention provides a fully interconnected quantum computing system for neutral atoms, comprising: a two-layer cross-chip structure and a static neutral atom array; The dual-layer cross-chip structure includes a first chip and a second chip stacked opposite each other. The first chip includes a first microwave resonant cavity array extending along a first direction, and the second chip includes a second microwave resonant cavity array extending along a second direction. The first direction and the second direction intersect. The static neutral atom array is disposed in the gap between the first chip and the second chip. Each neutral atom in the static neutral atom array is located in an intersection region of the first microwave resonant cavity array and the second microwave resonant cavity array to form a two-dimensional addressable cavity-atom coupling network.

[0040] In this embodiment, the microwave resonant cavity may be a coplanar waveguide resonant cavity, a three-dimensional superconducting microwave cavity, a stripline resonant cavity, a microstrip resonant cavity, a lumped parameter LC resonator, or other microwave resonant structures that can achieve coherent coupling or strong coupling with microwave transitions between the Rydberg states of neutral atoms.

[0041] like Figure 1 As shown in (b), the core of this invention lies in constructing a two-dimensional addressable cavity-atom coupling network by spatially combining a dual-layer cross-chip structure with a static neutral atom array.

[0042] Specifically, the system includes a first chip and a second chip stacked opposite each other. The first chip has a first microwave resonant cavity array extending along a first direction (e.g., the X direction), and the second chip has a second microwave resonant cavity array extending along a second direction (e.g., the Y direction). The first and second directions intersect (exemplarily, they may be orthogonal to each other). In the gap between the first and second chips, an array of static neutral atoms trapped in a two-dimensional optical lattice is disposed. Each neutral atom is precisely positioned at a lattice point of the two-dimensional optical lattice and simultaneously located within the spatially overlapping region of a cavity mode of the first microwave resonant cavity and a cavity mode of the second microwave resonant cavity, thereby forming a two-dimensional mesh-like cavity-atom coupling network.

[0043] Based on the above structure, the system requires no physical handling of atoms during operation. When entanglement needs to be established between any two distant neutral atoms, the system selects a microwave resonant cavity in a common direction (either the first or second direction) and uses the stable electromagnetic field mode within that cavity as the information transmission medium to mediate controlled entanglement interactions between the two atoms. Since the atoms are always confined to static optical lattice points, interconnection requirements can be met simply by selecting the appropriate microwave resonant cavity bus, and the topology of the atom array remains constant throughout the computation.

[0044] In this embodiment, the first direction and the second direction are exemplaryly set to be orthogonal to each other. When the polarization directions of the electromagnetic fields generated by the microwave resonators in the first and second directions are orthogonal to each other, crosstalk between the cross-distributed cavity modes is further suppressed, and the system can turn the coupling between the target microwave resonator and the atom on or off as needed. It should be understood that the angle between the first direction and the second direction is not limited to 90°, and can also be other intersecting angles, as long as they are spatially cross-distributed and can form a grid-like cavity-atom coupling network. In an exemplary embodiment, the first chip and the second chip can use high-purity single-crystal silicon or sapphire as substrate materials, the microwave resonator can be a superconducting coplanar waveguide resonator (CPWR), the optical lattice can be formed by a far-infrared laser standing wave field, and the atom can exemplaryly be an alkali metal atom (such as rubidium or cesium atom).

[0045] Based on the spatial combination of the aforementioned dual-layer cross-chip structure and static neutral atom array, the system can achieve at least the following technical effects: Since atoms are statically confined on optical lattice points, interconnection is achieved through information transmission at the speed of light via microwave resonant cavity buses, fundamentally eliminating the millisecond-level atom transport time in traditional schemes, thereby eliminating the bottleneck of mechanical rearrangement delay; at the same time, since atoms do not need to undergo dynamic potential well transfers, acceleration and deceleration movements, and potential well switching during the entire computation process, the risk of atom loss due to transport is completely avoided, and there will be no vacancies in the array due to transport failures, ensuring the long-term integrity and operational stability of the quantum computing array; in addition, the two-dimensional grid-like cavity-atom coupling network supports multiple microwave resonant cavities in different directions to mediate parallel entanglement operations of multiple pairs of atoms in the same operating cycle, providing a high-clock-frequency hardware foundation for large-scale fault-tolerant quantum computing that requires continuous and rapid execution of a large number of checker measurements.

[0046] As a specific example, such as Figure 1As shown in (b), the first chip and the second chip are arranged in a stacked configuration with the top chip and the bottom chip stacked opposite each other. For ease of description, the microwave resonant cavity array on the bottom chip (i.e., a specific instance of the first chip) is referred to as the X-cavity array (i.e., a specific instance of the first microwave resonant cavity array), and its resonant cavities are arranged at equal intervals along the X direction (i.e., a specific instance of the first direction); the microwave resonant cavity array on the top chip (i.e., a specific instance of the second chip) is referred to as the Y-cavity array (i.e., a specific instance of the second microwave resonant cavity array), and its resonant cavity is arranged at equal intervals along the Y direction (i.e., a specific instance of the second direction). The top chip and the bottom chip are stacked in parallel, so that the Y-cavity array and the X-cavity array form a grid-like cross-distribution in spatial projection. In this embodiment, the first direction (X direction) and the second direction (Y direction) are exemplarily set to be mutually orthogonal. The polarization directions of the electromagnetic fields generated in each X-cavity and Y-cavity are configured to be mutually orthogonal, thereby ensuring no crosstalk between the cross-distributed electromagnetic fields from the physical level, so that the system can turn the coupling relationship between the target microwave resonant cavity and the neutral atom on or off as needed. It should be understood that the angle between the first direction and the second direction is not limited to 90°, and can also be other intersecting angles, as long as the two are spatially intersecting and can form a grid-like cavity-atom coupling network.

[0047] In one specific embodiment, the first microwave resonant cavity array and the second microwave resonant cavity array are configured to respectively turn on or off the coupling relationship with the neutral atom.

[0048] Specifically, the system achieves this function by independently controlling the microwave resonators in the two directions. Taking the microwave resonator in the X direction (first direction) and the microwave resonator in the Y direction (second direction) as examples, the system's control logic is as follows: When the microwave resonator in the X-direction needs to mediate entanglement between specific atoms, the system only activates the coupling between that X-cavity and the corresponding atom, while simultaneously deactivating the coupling between the microwave resonator in the Y-direction and that atom. Similarly, when the microwave resonator in the Y-direction needs to be used, the system only activates the corresponding Y-cavity coupling, while simultaneously deactivating the X-direction cavity coupling. If a microwave resonator in a certain direction does not need to participate in the current operation, the system can completely shut it down or keep it detuned from all atoms.

[0049] To achieve the aforementioned independent control of "turning on or off separately," this embodiment provides safeguards from both hardware structure and operation method perspectives: At the hardware level, the microwave resonant cavities in the X and Y directions are configured such that the polarization directions of their internal electromagnetic fields are orthogonal. Because the cavity modes in the two directions have different polarization directions, direct electromagnetic crosstalk between the X and Y cavities is effectively suppressed at the physical level, and the cavity in one direction will not affect the cavity in the other direction through electromagnetic field leakage when it is turned on.

[0050] At the manipulation level, the system selectively turns the coupling between the cavity and specific atoms on or off by addressing and manipulating atomic energy levels. Combined with the aforementioned cross-point addressing scheme, the system only uses addressing light at the cross-point location of the target atom to adjust its energy level to resonate with the target microwave resonant cavity, thus establishing effective coupling between the atom and the target cavity. Atoms that are not addressed, due to their significantly detuned energy levels, do not effectively couple with the cavity even if they are in the same cavity mode. Therefore, the system can select coupling channels both in the directional dimension (between X and Y cavities) and in the atomic dimension (between multiple atoms), thereby achieving independent, on-demand control of arbitrary cavity-atom coupling relationships.

[0051] Based on the above configuration, this embodiment can achieve at least the following technical effects: Due to the orthogonal polarization design of the X and Y cavities, there is no mutual interference between the cavity modes in the two directions. Within the same operating cycle, the system can simultaneously utilize multiple cavities in different directions to mediate entanglement operations of multiple pairs of atoms without crosstalk, thus achieving highly parallel quantum operations. Simultaneously, since the system can independently turn on or off the coupling between any cavity and any atom, when a cavity is not needed for the current operation, it will not introduce additional decoherence channels into the atomic array, ensuring the system's coherence performance during long-term operation. Furthermore, this independent switching capability ensures that all microwave cavities are in a closed state during localized operations (such as single-qubit gates or measurements), avoiding interference from the cavity field to the atomic quantum state and ensuring flexible switching and compatible operation of the system between different operating modes.

[0052] In one specific embodiment, each microwave resonator in the first microwave resonator array and the second microwave resonator array is configured to encode its internal single-mode electromagnetic field into boson qubits through a boson encoding method, and to serve as a quantum bus for controlled entanglement interaction with multiple neutral atoms located in the cavity mode of the same microwave resonator, so as to mediate long-range entanglement between the spatially distant neutral atoms. The boson encoding method is selected from any one of cat-state encoding, GKP code, binomial code, rotationally symmetric boson code, or other oscillator error correction codes; however, when a non-cat-state boson code is used, its stabilization mechanism, logic gate implementation method, readout method, and error model should be replaced accordingly. This type of alternative solution is an extended implementation of the "boson-encoded microwave cavity bus," and is not necessarily equivalent to the bias noise protection mechanism of the cat-state bus.

[0053] When the boson encoding method employs cat-state encoding, each microwave resonant cavity is configured to stabilize its internal single-mode electromagnetic field in two coherent states through a nonlinear stabilization mechanism. and In Zhang Cheng's boson cat state subspace, cat bits are formed.

[0054] In addition, the cat-state stabilization mechanism in this embodiment can be an engineered two-photon dissipation, a Kerr-cat stabilization mechanism formed by combining Kerr nonlinearity with two-photon drive, an auxiliary nonlinear dissipation, parametric pump feedback stabilization, or other equivalent stabilization methods that can confine the microwave cavity field to the two-phase coherent cat-state subspace and maintain bias noise characteristics.

[0055] Specifically, when using cat-state encoding, the single-mode electromagnetic field within each microwave resonant cavity is not in a typical Fock state or coherent state during operation, but is stabilized in a special boson cat-state subspace. This subspace consists of two coherent states with equal amplitude and opposite phase. and Thus, the electromagnetic field within the cavity forms a quantum superposition between these two coherent states, constituting a "cat bit". To achieve this stable process, a nonlinear stabilization mechanism is introduced into the microwave resonant cavity, such as through engineered two-photon dissipation or Kerr nonlinearity, so that the evolution of the electromagnetic field within the cavity is confined within this two-dimensional cat-state subspace and does not escape to other states outside the subspace. Therefore, the microwave resonant cavity is no longer merely a passive medium for transmitting photons, but becomes an active element with qubit properties—a cat bit.

[0056] Each catbit in a microwave resonant cavity exhibits controlled interactions with the multiple neutral atoms contained within its cavity mode. When entanglement needs to be established between two relatively far-away neutral atoms within a cavity mode, the system utilizes the cavity's catbit as an intermediate quantum bus: the catbit first engages in a controlled interaction with one atom, then with the other, thereby establishing entanglement between the two atoms without physically moving the atoms closer together. Since the catbit is an electromagnetic field mode, its propagation as an information carrier within the cavity occurs at the speed of light, and a cavity mode can simultaneously cover multiple atoms located within that mode. Therefore, a single catbit bus can mediate entanglement connections between multiple atoms on the same timescale.

[0057] Based on the above configuration, this embodiment can achieve at least the following technical effects: Due to the bias noise characteristics of cat-state encoding, when the microwave resonant cavity is used as a quantum bus, it has an exponential suppression capability for bit flip errors in environmental noise, which enhances the robustness of long-range interconnection and solves the problem of photon loss error sensitivity in traditional optical cavity schemes; at the same time, since each microwave resonant cavity can be used as an independent cat bit bus, multiple cavities in the system can mediate atomic entanglement in different directions in the same operating cycle, realizing efficient parallel operation of the fully connected architecture; in addition, since atoms do not need to move physically, long-range entanglement is completed by transmitting at the speed of light through the cavity bus, which fundamentally eliminates the millisecond-level delay in traditional mechanical rearrangement schemes and provides a high clock frequency hardware foundation for large-scale fault-tolerant quantum computing.

[0058] For example, Figure 1 As shown in (a), each microwave resonant cavity is encoded as an independent boson cat bit. This is achieved by introducing a rate of... The two-photon dissipation mechanism strictly confines the evolution of the electromagnetic field within the cavity to two coherent states. Zhang Cheng's two-dimensional cat-state manifold In the middle. Under the large amplitude limit ( The overlap between two coherent states It is suppressed exponentially, making and Asymptotic orthogonality is achieved. Thus, the intracavity optical field evolves into a high-quality qubit, whose orthogonal computational basis is defined as... .

[0059] In one specific embodiment, the static neutral atom array includes a plurality of said neutral atoms that are trapped; The static neutral atom array is confined by a two-dimensional optical lattice, a static optical tweezers array, a three-dimensional optical lattice, a nanophotonic confinement structure, or other confinement methods that can fix the neutral atom positions for a long time during quantum gate execution and error correction cycles. Independent loading and gap-filling mechanisms are used during atom initialization, loading, or pre-arrangement stages, but no mechanical handling of atoms via optical tweezers is required during computational execution to achieve nonlocal connections. Each neutral atom is located at a lattice point corresponding to its confinement position and simultaneously within the spatially overlapping region of a cavity mode of the first microwave resonant cavity and a cavity mode of the second microwave resonant cavity. Each neutral atom has four energy levels, including a first hyperfine level and a second hyperfine level for storing quantum information, and a first Rydberg level and a second Rydberg level for resonant coupling with the microwave resonant cavity.

[0060] Specifically, as an example, this embodiment uses a two-dimensional optical lattice as a means of trapping atoms. For instance, a periodic array of potential wells is formed in space using a far-infrared laser standing wave field, with each potential well lattice trapping a neutral atom. Since the optical lattice potential wells are static, the atoms are always locked at their respective lattice positions during the calculation process and will not move. Simultaneously, the atom array is precisely placed in the gap between the top and bottom chips, so that each atom is exactly located within the cavity mode coverage of a first microwave resonator and a second microwave resonator, i.e., in the overlapping region of the two directional cavity modes. This spatial configuration ensures that each atom can be covered by the microwave resonators in the first and second directions, thus providing the physical conditions for coupling with cavity buses in any direction.

[0061] In terms of energy level structure, each neutral atom has four energy levels for quantum operations. Among them, the first hyperfine level and the second hyperfine level are two long-lived energy levels in the atom's ground state manifold, used to stably store quantum information, i.e., as the atom's computational ground state. and These two energy levels have extremely long lifetimes (ranging from seconds to minutes) and extremely low decoherence rates, making them suitable as storage carriers for quantum information. The first and second Rydberg levels are highly excited states of atoms with large electric dipole moments, enabling strong resonant coupling with the electromagnetic field of the microwave resonant cavity. This provides a channel for coherent interaction between the atom and the cavity during quantum gate operations. During a gate operation, the atom is briefly excited from the hyperfine level to the Rydberg level, interacting with the cavity to complete entanglement. After the operation, the atom is de-excited back to the hyperfine level, returning to its stable storage state. Through this "storage-interaction separation" energy level design, quantum information is stored in the noise-insensitive hyperfine level for the vast majority of the time, only briefly transferred to the Rydberg level to participate in coherent evolution during gate operations, thus minimizing the interference of environmental noise on quantum information.

[0062] Based on the above configuration, this embodiment can achieve at least the following technical effects: atoms are statically trapped by a two-dimensional optical lattice and do not need to move during the entire calculation process, thereby completely eliminating the risk of loss caused by atom transport in traditional schemes and ensuring the long-term integrity of the array and the stability of the system; each atom is located in the overlapping region of the X cavity and the Y cavity at the same time, so that any atom can be covered by the microwave resonant cavity in any direction, providing a physical basis for two-dimensional full connectivity; the four-level structure realizes the functional separation of quantum information storage and coherent interaction. During the storage stage, the atom is in a hyperfine level that is insensitive to noise, and only during the interaction stage is it coupled to the cavity through the Rydberg level, reducing the interference of environmental noise on quantum information, and avoiding unnecessary disturbances to the atom caused by the electromagnetic field in the cavity during non-operation time, providing an energy level basis for high-fidelity quantum gate operation.

[0063] As a concrete example, a neutral atom array confined by a two-dimensional optical lattice is placed in the gap between the top-level chip and the bottom-level chip. Each atom is located on a lattice point of the optical lattice and also in a spatially overlapping region of a Y-cavity mode and an X-cavity mode. To achieve separation of storage and interaction, such as... Figure 1 As shown in (c), each neutral atom has four energy levels, which are long-lived hyperfine levels used for the stable storage of quantum information. and And high-excitation Rydberg levels specifically involved in microwave cavity resonant coupling and .

[0064] In one specific embodiment, the system further includes a first addressing beam system projected along the first direction and a second addressing beam system projected along the second direction; when the first addressing beam and the second addressing beam irradiate the neutral atom, the energy level of the irradiated neutral atom is shifted; the energy level shift of the neutral atom under the action of a single first addressing beam or a single second addressing beam is configured to be greater than the equivalent coupling strength of the subsequent global excitation, so that the neutral atom located only on a single beam path does not satisfy the resonance condition of the global excitation; at the intersection of the first addressing beam and the second addressing beam, the neutral atom is subjected to a dual energy level shift and is adjusted to satisfy the resonance condition of the global excitation, so as to achieve selective addressing of the target atom; by generating multiple intersections simultaneously, multiple target atoms are selected in parallel within the same physical operation cycle.

[0065] Specifically, the system is configured with a first addressing beam projected along a first direction (e.g., the X direction) and a second addressing beam projected along a second direction (e.g., the Y direction). Each addressing beam is a focused laser beam, the frequency of which is selected to produce an AC Stark effect with specific energy level transitions in the atom. When one addressing beam irradiates an atom, the atom's energy level shifts; when two addressing beams irradiate simultaneously, the shift in the atom's energy level is the superposition of the contributions from each beam.

[0066] The system employs specific parameter configurations for the addressing light intensity and the Rabi frequency of the subsequent global excitation pulse. The atomic energy level shift caused by the single-direction addressing light is set to be significantly greater than the equivalent coupling strength corresponding to the subsequent global Rydberg excitation pulse. Therefore, atoms illuminated only by the single-direction addressing light, while experiencing energy level shifts, do not reach the resonance condition with the subsequent global excitation pulse and will not respond to it. However, for atoms located at the intersection of the first and second addressing beams, the simultaneous illumination by both beams results in a double shift in their energy levels, precisely shifting them to the frequency position that satisfies the resonance of the subsequent global excitation pulse. Consequently, they are accurately excited to the Rydberg state under the global excitation pulse. In this way, the system achieves selective addressing of target atoms—only atoms located at the intersection of the two addressing beams are selected.

[0067] When multiple target atoms need to be selected in parallel within the same operation cycle, the system generates multiple intersection points simultaneously using beam modulation devices (such as spatial light modulators or acousto-optic deflectors). These intersection points can be distributed at different positions in the two-dimensional array, and each intersection point selectively addresses the atoms at its location according to the aforementioned principle, thereby completing the parallel selection of multiple target atoms within the same physical operation cycle.

[0068] Based on the above configuration, this embodiment can achieve at least the following technical effects: by utilizing the combination of the AC Stark effect and the global excitation pulse, precise selective addressing of a single target atom is achieved, and the positioning accuracy depends only on the focusing size of the addressing beam; by generating multiple intersection points simultaneously, parallel selection of multiple target atoms can be completed within the same physical operation cycle, and the addressing efficiency is independent of the array size; the addressing operation is completed through optical means, without any mechanical movement, and the addressing speed is only limited by the optical modulation speed and the atomic energy level response time, supporting high repetition frequency fast operation; intersection point addressing is not limited by the atomic spacing, and simultaneous selection can be achieved through beam path design regardless of the distance between target atoms, fundamentally breaking through the distance limitation of atoms being within the Rydberg interaction radius to establish a connection in traditional schemes, providing key support for flexible parallel manipulation in large-scale atomic arrays.

[0069] As a specific example, this invention employs a cross-point addressing protocol, which can simultaneously address multiple target atoms in a two-dimensional array. The specific implementation mechanism and steps of this scheme are as follows: The system is equipped with an orthogonal laser beam system that projects independently along the X and Y axes. When the addressing laser beam irradiates an atom, it induces an atom through the AC Stark effect. Energy level shift. The system sets the energy level shift caused by a single-direction laser beam ( or The magnitude is much greater than the subsequently applied global Rydberg excitation. Pulse (in) Figure 1 (c) is written as The corresponding Rabi frequency Only atoms located at the intersection of two orthogonal laser beams, X and Y, have... The energy level is doubly modified and shifted to a specific frequency to precisely match the subsequent global excitation pulse. The resonance condition. Atoms not located at a crossover point or only on a single laser beam path will not respond to the excitation pulse due to the significant detuning of their energy levels. To address multiple target atoms in the array in parallel, multiple crossover points can be generated simultaneously. These crossover points also exhibit a geometric product structure, meaning that the number of crossover points in each row or column is the same.

[0070] In one specific embodiment, the microwave resonant cavity is coupled to the neutral atom that is addressed inside it; the microwave resonant cavity and the addressed neutral atom achieve controlled interaction through coherent coupling between the electromagnetic field mode of the microwave resonant cavity and the Rydberg level of the addressed neutral atom; after the microwave resonant cavity is stabilized into the cat bit, the controlled interaction is equivalently mapped to controlled coupling between the Pauli operator of the cat bit and the Pauli operator of the addressed neutral atom, and the cat bit acts as a quantum bus to mediate entanglement between the addressed neutral atoms; the residual nonideal coupling terms in the controlled interaction are exponentially suppressed as the coherent amplitude of the boson cat state increases.

[0071] Specifically, after the addressed neutral atom is excited to a Rydberg state, the transition frequency between its first and second Rydberg levels is configured to match the resonance frequency of the microwave resonant cavity. At this point, coherent coupling occurs between the atom and the microwave cavity through the Jaynes-Cummings interaction, that is, the Rydberg state of the atom resonates with the electromagnetic field mode within the cavity, exchanging energy. The atom can absorb or emit photons that resonate with the cavity mode, thereby forming entanglement with the cavity field.

[0072] After the microwave resonant cavity is stabilized into a catbit state, the electromagnetic field within the cavity is confined to two coherent states. and In Zhang Cheng's two-dimensional cat-state subspace, under this condition, the original Jaynes-Cummings interaction is equivalently mapped to a new controlled coupling form: controlled coupling between the Pauli Z operator of the cat bit and the Pauli X operator of the addressed atom. This means that the state of the cat bit will control the state evolution of the atom, and vice versa. By controlling the duration of the interaction, the system can establish a deterministic entanglement gate between the cat bit and the atom. Since a cavity mode can simultaneously couple with multiple atoms located in the same cavity mode, the cat bit bus can establish this controlled coupling with multiple atoms sequentially or in parallel, thereby transmitting entanglement information between multiple atoms and mediating entanglement between any two distant atoms.

[0073] In real physical systems, due to the coherent state amplitude of the cat bits For finite values, two coherent states and The atoms are not perfectly orthogonal, exhibiting a slight overlap. This imperfect orthogonality introduces residual non-ideal coupling terms, potentially leading to undesirable crosstalk between atoms. However, with the amplitude of the coherent state... The increase of , the overlap between two coherent states It decreases exponentially. Under the large amplitude limit, the overlap... Approaching zero, the two coherent states become asymptotically orthogonal, and the residual non-ideal coupling terms are exponentially suppressed and almost completely disappear as the amplitude of the coherent state of the boson cat state increases. This property ensures that when the cat bit bus mediates entanglement between multiple atoms, gate crosstalk between atoms is effectively suppressed at the physical level.

[0074] Based on the above configuration, this embodiment can achieve at least the following technical effects: by stabilizing the microwave resonant cavity into a cat bit, the electromagnetic field within the cavity is transformed from a susceptible ordinary photon state to a cat state with bias noise characteristics. The error channels of controlled interactions are restricted to phase errors as the main cause, while bit flip errors are exponentially suppressed, enhancing the error resistance of the quantum bus and solving the problem of photon loss error sensitivity in traditional optical cavity schemes. Controlled interactions are mapped to deterministic controlled coupling between Pauli operators, enabling the system to complete entanglement operations in a deterministic manner without relying on a post-selection mechanism, ensuring the continuous execution capability of the quantum circuit. The residual non-ideal coupling terms are exponentially suppressed as the coherent amplitude of the boson cat state increases, effectively suppressing gate crosstalk between atoms when multiple atoms operate in parallel within the same cavity mode, ensuring high fidelity of parallel operations, and providing a reliable underlying physical mechanism for large-scale fault-tolerant quantum computing.

[0075] In this embodiment, as a specific example, the microwave cavity and its internally located... The coupling of atoms, described by the Jaynes-Cummings (JC) interaction, is as follows:

[0076] in, and Representing the addressed number The ascending and descending operators of a Rydberg manifold with 1 atom, The coupling coefficient is proportional to the intensity of the microwave electric field and the electric dipole moment between the two Rydberg states. and These are the annihilation operator and the generation operator for microwave cavity photons, respectively. By applying enhanced two-photon dissipation to the microwave cavity, the evolution of the optical field within the cavity is stably confined within a cat-state manifold, mathematically equivalent to applying a projection operator:

[0077] in, , , and There are two coherent states. For the amplitude of the coherent state, The average number of photons in the coherent state; Under the action of this projection operator, the original Jaynes-Cummings interaction is equivalently mapped to the Cat Bus Hamiltonian. Its form is:

[0078] in, For the first Pauli X operator of 1 atom The Z operator for the cat bits encoded by the microwave cavity. Two coherent states and The degree of overlap between them This represents a higher-order small quantity proportional to the degree of overlap, in the coherent state amplitude. It is exponentially suppressed.

[0079] The basic entanglement gate in this invention is not limited to the CZ gate, but can also be implemented as a controlled phase gate, a CNOT gate, a controlled rotation gate, or other two-bit entanglement gates. The gate used to stabilize the sub-error correction circuit is preferably a CZ, CNOT, or a Clifford entanglement gate equivalent to it after a local single-bit gate transformation. For general quantum computing, a non-Clifford controlled rotation gate compatible with the selected error correction code and compilation scheme can also be used. The aforementioned alternative gate types should ensure that the microwave cavity bus can de-entangle with the target atom after gate execution, and maintain the corresponding error detection or error suppression mechanism.

[0080] In one specific embodiment, the following timing operations are performed to implement an entanglement gate between the cat bit and at least one addressed neutral atom: Addressing is performed on at least one of the addressed neutral atoms; The at least one addressable neutral atom after addressing is excited from the computational ground state to the Rydberg state; The controlled coupling between the target microwave resonant cavity and the at least one addressed neutral atom is initiated, and conditional evolution is performed within a preset time period to form controlled entanglement between the cat bit and the at least one addressed neutral atom. The at least one addressed neutral atom is de-excited from the Rydberg state back to the computational ground state; Perform local phase compensation on the at least one addressed neutral atom; Wherein, when the number of the at least one addressed neutral atom is multiple, the entanglement gate acts on multiple neutral atoms in parallel within the same operation cycle, and the preset duration is determined by the coupling parameter and the coherent state amplitude of the cat bit, and is independent of the number.

[0081] In this embodiment, the preset duration can be exemplarily set to... ,in The coupling coefficient between the neutral atom and the microwave resonant cavity is given. The coherent state amplitude of the cat bit is given. This preset duration is independent of the number of target atoms involved in parallel operations; that is, the required conditional evolution time is exactly the same regardless of whether the number of atoms in parallel operations is 1 or n. Here, "constant time" is explicitly defined as: under the same coupling parameters, the gate operation time does not increase linearly with the number of target atoms involved in parallel operations, rather than being absolutely independent of any physical parameters. This timing can realize entanglement gates between a single cat bit and a single atom, or parallel entanglement gates between a single cat bit and multiple atoms. A parallel entanglement gate between a single cat bit and multiple target atoms is explicitly defined as... That is, a single cat bit is associated with multiple target atoms. The execution of a star-shaped multi-target entanglement gate.

[0082] With controlled phase gate As a specific example, the above embodiments can be executed in two different scenarios: (1) Performing controlled phase gates between the microwave cavity and individual atoms Specifically: The two-bit spatial basis composed of a single atom and a microwave cavity cat bit is ,in and The computational state of the atom, and These are two coherent states of a microwave cavity cat bit. For coherent state amplitude; in order to achieve the ideal Gate Evolution The system completes this through a timing sequence consisting of the following four high-speed control steps: Step 1: After establishing the addressing crossover point, a global Rydberg excitation pulse is applied to the system. This makes the addressed atom Precise transition of state components to high-Rydberg states ; Step 2 Conditional Evolution: Simultaneously activate the corresponding X-cavity or Y-cavity coupling, while keeping the orthogonal cavities closed, allowing atoms in the Rydberg state to resonate with the microwave cavity and achieve Hamiltonian coupling. Next evolution; set the evolution duration to ,in The coupling coefficient is... The amplitude represents the coherent state; within this evolution time, the system completes conditional interactions and achieves state mapping. ; Step 3: Rydberg de-excitation: After the evolution is complete, the system applies a return global excitation. Pulse, which will affect the position of the atom Component mapping back At this point, the atom exits the Rydberg manifold and returns to the state of... Zhang Cheng's computational subspace; Step 4: Local Phase Compensation: Apply a local phase gate operation to the addressed atom. The corresponding operator is... Then the addressing light is turned off.

[0083] (2) Perform parallel controlled phase gate between the microwave cavity and multiple atoms ,like Figure 2 As shown, a single microwave cavity cat bit, acting as a control bit, can simultaneously execute parallel operations on multiple addressed atoms within it. The operation steps are the same as the single-atom scheme described above, the only difference being: in step one, a gate is simultaneously generated. Addressing intersections, and in step two using the included The evolution of the Hamiltonian of the cat-state bus of each atom is the same. Time, thus completing a one-to-many star-shaped entanglement within a constant time. Specifically: A single microwave cavity cat bit serves as a control bit, simultaneously executing commands on multiple addressable atoms within it in parallel. The gate is completed through a time sequence consisting of the following four steps: Step 1: Parallel State Preparation: Simultaneous Generation Each addressing intersection, in establishing the aforementioned After each addressing intersection, the system applies a global Rydberg excitation pulse. This makes all the addressed One atom Precise transition of state components to high-Rydberg states ; Step 2: Parallel Conditional Evolution: Simultaneously activate the corresponding X-cavity or Y-cavity coupling, while keeping the orthogonal cavities closed, thus ensuring that the cavities in the Rydberg state are in the correct position. Individual atoms resonate with the microwave cavity and, within the... The Hamiltonian of the cat-state bus of atoms Next evolution; set the evolution duration to ,in The coupling coefficient is... This represents the amplitude of the coherent state; within this evolution time, the system completes conditional interactions, realizing the state mapping for each addressed atom. ; Step 3: Parallel Rydberg de-excitation: After the evolution is complete, the system applies a return global excitation. Pulse, to all The position of each atom Component mapping back At this point, all atoms have exited the Rydberg manifold and returned to the state where all atoms are in the Rydberg manifold. Zhang Cheng's computational subspace; Step 4: Parallel local phase compensation: For all addressed... Each atom is subjected to a local phase gate operation, and the corresponding operator is... Then the addressing light is turned off; Through the above steps, at a constant time It completes a one-to-many star-shaped entanglement within the system.

[0084] In one specific embodiment, the cat bit also serves as an intermediate quantum bus to mediate parallel entanglement gates between a first neutral atom and multiple target neutral atoms; The first neutral atom and the plurality of target neutral atoms are all addressed and located within the same cavity mode of the microwave resonant cavity; The first neutral atom interacts in a controlled manner with the cat bit, and the cat bit interacts in a controlled manner with multiple target neutral atoms, so that the parallel entanglement gate between the first neutral atom and the multiple target neutral atoms is completed in a single physical time step; After the parallel entanglement gate is executed, the cat bit is unentangled with the first neutral atom and the plurality of target neutral atoms. The quantum state of the cat bit is used to indicate whether an error occurred during the execution of the parallel entanglement gate.

[0085] Specifically, such as Figure 3 As shown, it still uses a controlled phase gate. As an example, consider the microwave cavity inside... Each of the addressed atoms is labeled as an atom. , Figure 3 The lines on the left represent the desired atomic implementation. For atoms Simultaneously execute Gate operations; in traditional architectures that rely on optical tweezers for mechanical rearrangement, these two-bit... Gates must be queued sequentially and cannot be executed simultaneously. In this architecture ( Figure 3 The right-side circuit utilizes cat bits encoded in a microwave cavity as a medium, enabling efficient communication of atoms. For atoms Simultaneously execute The door, marked by the dashed box. Gates can be completed in a single physical time step, thus compressing the execution depth of quantum circuits; Furthermore, this scheme possesses native fault tolerance characteristics. Under ideal conditions where the line is noise-free, the cat bit will complete the execution of the last... Behind the door, there will be all When all atoms are completely de-entangled, the cat bit is measured on the X substrate, and the measurement result will inevitably be 0. During this process, the cat bit acts as a built-in flag bit in the system. If the measurement result is 1, it directly reflects an error that occurred during circuit execution. By feeding this flag information back to the error correction decoder, or combining it with a post-selection mechanism, the system can support high-fidelity fault-tolerant parallelism at the hardware level. The gate; among which, the methods for feeding back the flag information to the error correction decoder include: expanding the spatiotemporal decoding graph topology or dynamically adjusting the prior weights. In the invention, the system architecture is... The gate also includes fidelity analysis and optimal parameter configuration: (1) The quantum gate operation control unit performs the following: The faulty channel of the gate inherits the bias noise characteristics of the cat-state bus, specifically: In actual operation, the system mainly faces two types of physical noise: Rydberg state decay of atoms and single-photon loss of the microwave cavity; among them, Rydberg state decay leads to errors leaking out of the computation space, and its decay rate is denoted as... and And satisfy The attenuation rate of single-photon loss in a microwave cavity is denoted as . ; An open system dynamics model was established using the Lindblad master equations for analysis. The gate's erroneous path inherits the biased-noise characteristic of the cat-state bus, which manifests at the physical layer as bit flipping of the boson cat bits. Errors are suppressed exponentially, and the total operational errors of the system are almost entirely concentrated on the phase flips of the boson cat bits. Errors and atomic leakage / loss errors; incoherent errors can be eliminated using the Pauli Twirling technique.

[0086] (2) In the boson cat-state encoded microwave cavity unit, the coherent state amplitude of the boson cat state is... Adjust to the optimal operating point, specifically: The total error rate of a single operation of the controlled interaction is composed of the phase error contribution of the microwave resonant cavity and the energy level decay error contribution of the neutral atom, and the microwave resonant cavity supports configuring the coherent state amplitude of the cat bit to an optimal operating state that balances the phase error contribution and the energy level decay error contribution. The value of the coherent state amplitude under the optimal operating state is determined by the coupling strength between the neutral atom and the microwave resonant cavity, the loss characteristics of the microwave resonant cavity, and the energy level decay characteristics of the neutral atom, so as to minimize the total error rate of the single operation.

[0087] As a specific example, according to the theoretical error model, the system executes a single... The total error probability of a gate is expressed as:

[0088] in, The probability of a cat bit phase flip error. This represents the probability of atomic leakage error. The coupling coefficient is... The single-photon loss attenuation rate of the microwave cavity. The decay rate of the Rydberg state. The amplitude of the coherent state; To achieve the highest fidelity in hardware operation, the microwave cavity module measures the coherent amplitude of the boson cat state. Adjust to the optimal operating point When the system configuration coherent state amplitude is at or near At this point, the microwave cavity phase error and atomic leakage error reach physical equilibrium, and the total system error rate reaches its theoretical minimum. ,in This is a parameter representing the degree of synergy between the microwave cavity and matter. The optimal parameter configuration provides a direct implementation path for the calibration and operation of actual hardware.

[0089] (3) Parallel execution in the quantum gate operation control unit The gate has extremely low crosstalk suppression, specifically: The parallel entanglement gates between the cat bits and multiple addressed neutral atoms achieve low crosstalk operation by confining the microwave resonant cavity within a large-amplitude boson cat state manifold. The field operator of the microwave resonant cavity is mapped to the logical diagonal operator of the cat bits within the boson cat state subspace, enabling the ideal controlled evolution terms between multiple addressed neutral atoms and the same cat bit to commutate with each other, thereby realizing multiple entanglement gates in parallel within the same gate time. The dynamic evolution of the parallel entanglement gates is equivalent to the action of multiple independent two-bit entanglement gates. The off-diagonal and non-commutative residual crosstalk terms caused by the finite cat state amplitude are exponentially suppressed as the coherent state amplitude of the boson cat state increases, thus suppressing gate crosstalk between multiple addressed neutral atoms.

[0090] As a specific example, consider parallel processing mediated by a microwave cavity involving multiple atoms. Gate, due to the cat-state bus Hamiltonian The non-commutation terms in the coherent state are exponentially suppressed as the amplitude increases, and the conditional evolution process of multiple atoms in the microwave cavity is approximately decoupled in terms of physical mechanism. The parallel The dynamic evolution of the gate is equivalent to A completely independent atom-microwave cavity dual-bit The linear superposition of gates means that inter-atomic gate crosstalk can be effectively suppressed and approximately ignored at the physical level. This characteristic enables complex parallel operations to be precisely decomposed into independent two-bit error models when designing and analyzing large-scale fault-tolerant quantum circuits, thereby ensuring high fidelity of parallel control and reliability of decoding.

[0091] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

[0092] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A neutral atom fully connected quantum computing system, characterized in that, include: Dual-layer cross-chip structure and static neutral atom array; The dual-layer cross-chip structure includes a first chip and a second chip stacked opposite each other. The first chip includes a first microwave resonant cavity array extending along a first direction, and the second chip includes a second microwave resonant cavity array extending along a second direction. The first direction and the second direction intersect. The static neutral atom array is disposed in the gap between the first chip and the second chip. Each neutral atom in the static neutral atom array is located in an intersection region of the first microwave resonant cavity array and the second microwave resonant cavity array to form a two-dimensional addressable cavity-atom coupling network.

2. The neutral atom fully connected quantum computing system according to claim 1, characterized in that... The first microwave resonant cavity array and the second microwave resonant cavity array are configured to respectively turn on or off the coupling relationship with the neutral atom.

3. The neutral atom fully connected quantum computing system according to claim 1, characterized in that... Each microwave resonator in the first microwave resonator array and the second microwave resonator array is configured to encode its internal single-mode electromagnetic field into boson qubits through a boson encoding method, and to serve as a quantum bus for controlled entanglement interaction with multiple neutral atoms located in the cavity mode of the same microwave resonator, so as to mediate long-range entanglement between the neutral atoms that are spatially far apart. The boson encoding method is selected from any one of cat-state encoding, GKP code, binomial code, rotationally symmetric boson code, or other oscillator error correction code; When the boson encoding method employs cat-state encoding, each microwave resonator is configured to stabilize its internal single-mode electromagnetic field in two coherent states through a nonlinear stabilization mechanism. and In Zhang Cheng's boson cat state subspace, cat bits are formed.

4. The neutral atom fully connected quantum computing system according to claim 1, characterized in that, The static neutral atom array comprises a plurality of trapped neutral atoms; wherein the trapping method of the static neutral atom array is achieved by a two-dimensional optical lattice, a static optical tweezers array, a three-dimensional optical lattice, a nanophotonic trapping structure, or other trapping methods that can fix the position of neutral atoms for a long time during quantum gate execution and error correction cycle operation; an independent loading and missing mechanism is adopted in the atom initialization, loading, or pre-arrangement stage, but there is no need to mechanically transport atoms with optical tweezers to achieve non-local connection during the computation operation stage; Each neutral atom is located at a corresponding confinement position and simultaneously within the spatially overlapping region of a cavity mode of the first microwave resonant cavity and a cavity mode of the second microwave resonant cavity; each neutral atom has four energy levels, including a first hyperfine level and a second hyperfine level for storing quantum information, and a first Rydberg level and a second Rydberg level for resonant coupling with the microwave resonant cavity.

5. The neutral atom fully connected quantum computing system according to claim 1, characterized in that, It also includes a first addressing beam system projected along the first direction and a second addressing beam system projected along the second direction; when the first addressing beam and the second addressing beam irradiate the neutral atom, the energy level of the irradiated neutral atom is shifted; the energy level shift of the neutral atom under the action of a single first addressing beam or a single second addressing beam is configured to be greater than the equivalent coupling strength of the subsequent global excitation, so that the neutral atom that is only in a single beam path does not satisfy the resonance condition of the global excitation; At the intersection of the first addressing beam and the second addressing beam, the neutral atom is subjected to a dual energy level shift and is tuned to satisfy the resonance condition of the global excitation, so as to achieve selective addressing of the target atom. By generating multiple intersection points simultaneously, multiple target atoms are selected in parallel within the same physical operation cycle.

6. The neutral atom fully connected quantum computing system according to claim 1, characterized in that... The microwave resonant cavity is coupled to the neutral atom that is addressed inside it; the microwave resonant cavity and the addressed neutral atom achieve controlled interaction through coherent coupling between the electromagnetic field mode of the microwave resonant cavity and the Rydberg level of the addressed neutral atom; after the microwave resonant cavity is stabilized into the cat bit, the controlled interaction is equivalently mapped to the controlled coupling between the Pauli operator of the cat bit and the Pauli operator of the addressed neutral atom, and the cat bit acts as a quantum bus to mediate entanglement between the addressed neutral atoms; the residual nonideal coupling term in the controlled interaction is exponentially suppressed as the coherent state amplitude of the boson cat state increases.

7. The neutral atom fully connected quantum computing system according to claim 6, characterized in that... Perform the following timing operations to implement the entanglement gate between the cat bit and at least one of the addressed neutral atoms: Addressing is performed on at least one of the addressed neutral atoms; The at least one addressable neutral atom after addressing is excited from the computational ground state to the Rydberg state; The controlled coupling between the target microwave resonant cavity and the at least one addressed neutral atom is initiated, and conditional evolution is performed within a preset time period to form controlled entanglement between the cat bit and the at least one addressed neutral atom. The at least one addressed neutral atom is de-excited from the Rydberg state back to the computational ground state; Perform local phase compensation on the at least one addressed neutral atom; Wherein, when the number of the at least one addressed neutral atom is multiple, the entanglement gate acts on multiple neutral atoms in parallel within the same operation cycle, and the preset duration is determined by the coupling parameter and the coherent state amplitude of the cat bit, and is independent of the number.

8. The neutral atom fully connected quantum computing system according to claim 6, characterized in that... The cat bits also serve as an intermediate quantum bus to mediate parallel entanglement gates between the first neutral atom and multiple target neutral atoms; The first neutral atom and the plurality of target neutral atoms are all addressed and located within the same cavity mode of the microwave resonant cavity; The first neutral atom interacts in a controlled manner with the cat bit, and the cat bit interacts in a controlled manner with multiple target neutral atoms, so that the parallel entanglement gate between the first neutral atom and the multiple target neutral atoms is completed in a single physical time step; After the parallel entanglement gate is executed, the cat bit is unentangled with the first neutral atom and the plurality of target neutral atoms. The quantum state of the cat bit is used to indicate whether an error occurred during the execution of the parallel entanglement gate.

9. The neutral atom fully connected quantum computing system according to claim 6, characterized in that... The total error rate of a single operation of the controlled interaction is composed of the phase error contribution of the microwave resonant cavity and the energy level decay error contribution of the neutral atom. The microwave resonant cavity supports configuring the coherent state amplitude of the cat bit to an optimal operating state that balances the phase error contribution and the energy level decay error contribution. The value of the coherent state amplitude under the optimal operating state is determined by the coupling strength between the neutral atom and the microwave resonant cavity, the loss characteristics of the microwave resonant cavity, and the energy level decay characteristics of the neutral atom, so as to minimize the total error rate of the single operation.

10. The neutral atom fully connected quantum computing system according to claim 7, characterized in that... The parallel entanglement gates between the cat bits and multiple addressed neutral atoms achieve low crosstalk operation by confining the microwave resonant cavity within a large-amplitude boson cat state manifold. The field operator of the microwave resonant cavity is mapped to the logical diagonal operator of the cat bits within the boson cat state subspace, enabling the ideal controlled evolution terms between multiple addressed neutral atoms and the same cat bit to commutate with each other, thereby realizing multiple entanglement gates in parallel within the same gate time. The dynamic evolution of the parallel entanglement gates is equivalent to the action of multiple independent two-bit entanglement gates. The non-diagonal, non-commutative residual crosstalk terms caused by the finite cat state amplitude decrease exponentially with the overlap between the two coherent states of the boson cat state, thereby suppressing gate crosstalk between multiple addressed neutral atoms.

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