Quantum computer system

Abstract

The present invention relates to a high-throughput remote entanglement generation system between atomic qubits in separate quantum information modules, using an atom-light interface such as optical cavities in the presence of slow auxiliary operations. More particularly, the invention provides techniques for mitigating the effect of slow operations on the overall entanglement generation rate by parallelizing the auxiliary operation and the entanglement generation operation, as well as a method for optimizing the cavity parameters to achieve higher operation rates. The method can be applied to high rates and to the interconnection of multiple quantum information processing units comprising atomic qubits. Figure for abstract: Figure 1

Description

Title of the invention: Quantum computer system FIELD OF INVENTION

[0001] Quantum computing is a type of computing that uses quantum mechanics to perform certain tasks more efficiently than classical computing. In classical computing, bits can exist in one of two states, either 0 or 1, but in quantum computing, qubits can exist in a superposition of states 0 and 1. This phenomenon and other effects of quantum mechanics, such as entanglement, allow quantum computers to perform certain calculations much faster than classical computers, such as factoring large numbers, optimization problems, and simulations of quantum systems.

[0002] However, quantum computing and the quantum repeater also have drawbacks. One of the main problems is that qubits are very sensitive to noise and decoherence, which can lead to errors in computation and repeater operations. Therefore, quantum computers and repeaters require meticulous error mitigation and correction techniques to maintain computational accuracy through precise control and detection of individual qubits on demand. In particular, error mitigation and correction operations often incur overhead costs when scaling a large-scale distributed quantum computing architecture.

[0003] It follows from the above that techniques for improving the scalability of error-correcting quantum computing and the quantum repeater are desired. Technological background

[0004] The following prior art documents are known: Reference 1: S. Barrett et al, Phys. Rev. A 71, 060310(R) (2005), Reference 2: W. Huie et al, Phys. Rev. Res. 3, 043154 (2021), Reference 3: G. Vasilev et al, New J. Phys. 12, 063024 (2010), Reference 4: T. Utsugi et al, Phys. Rev. A 106, 023712 (2022), Reference 5: J. Covey et al, US20240056711A1. Summary of the invention

[0005] The present invention proposes techniques generally related to quantum computing and quantum repeaters. In particular, the present invention proposes an optical tweezer system and method comprising a high-resolution imaging system for trapping and controlling atoms and a pair of reflectors for creating an optical cavity for a quantum computing and repeater device. In particular, the present invention proposes a method for generating entanglement at High-speed photon-mediated computing for distributed quantum computing. More specifically, the invention proposes techniques for efficiently collecting photons emitted by a large number of atoms in the presence of slow auxiliary operations such as qubit shuttle. By way of example, the invention can be applied to a variety of applications such as cryptography, drug discovery, optimization, machine learning and artificial intelligence, finance, weather forecasting, chemistry, mechanics, electricity, civil engineering, nuclear fusion and fission, economics, materials science, and any other complex human or non-human matter.

[0006] In one example, the present invention proposes a quantum computer system. The system comprises at least one quantum computer cell. In one example, the quantum computer cell system comprises an optical linking module including at least one pair of optical mirrors characterized by a mirror reflectivity > 90% and configured to form a cavity. In one example, the cavity has a length of 1 micrometer or more. In one example, the module comprises a plurality of qubits comprising a laser-coolable atom, such that the number of qubits, for example, is from one to 100,000. In one example, the module has an optical interconnect coupled to the linking module. In one example, the module includes a photon multiplexing device coupled to the optical interconnect.The photon multiplexing device is configured to transform at least two or more photons in one or more different spatial modes into two or more photons configured in a single spatial mode.

[0007] In one example, the quantum computer cellular system comprises a free-space computing module in a computing region, the computing module comprising a plurality of atoms. In one example, each of the atoms is coupled to an optical tweezer, the optical tweezer being configured to move in order to transport one or more atoms from a first spatial location to a second spatial location. In another example, the system comprises an array of dynamic tweezers configured to transport one or more qubits coupled to the cavity to the computing region and a detection system comprising a camera operationally coupled to the cavity or the computing region and configured to collect one or more fluorescence photons to be sent to the detection system with a quantum efficiency, for example, of 0.1 or more.In one example, the system includes an electrical computer system comprising an information processing unit configured to process information about the state of the qubit captured from the sensing system.

[0008] In one example, the electrical computer system is configured to identify a quantum state of one or more qubits and is configured to decode information quantum error from a measurement result of the syndrome using the information processing unit.

[0009] In one example, the present invention proposes a quantum computer system. The system comprises at least one quantum computer cell. In one example, the quantum computer cell system comprises an optical linkage module. In one example, the optical linkage comprises a pair of optical mirrors characterized by a reflectivity > 90% and configured with a facing reflective surface to form a cavity, the cavity having a length, for example, from 1 micrometer to 1 centimeter or more. In another example, the optical linkage consists of a high numerical aperture photon-collecting device. In one example, the system comprises a plurality of qubits including an atom, an ion, a laser-coolable nitrogen vacation center, a silicon color center, or qubit systems with optical control capability, such that the number of qubits ranges from one to 100,000, among others.In one example, the system has an optical interconnect coupled to the optical link module. In another example, the system includes a photon multiplexing device coupled to the optical interconnect. The photon multiplexing device is configured to transform at least two or more photons in one or more different spatial modes into two or more photons configured in a single spatial mode.

[0010] In one example, the system includes a free-space computing module in a computing region. The free-space computing module comprises a plurality of atoms, each atom being trapped in an optical clamp. In one example, the optical clamp is configured to move in order to transport one or more atoms from a first spatial location to a second spatial location. In another example, the system includes a detection system operationally coupled to the link and the computing region and configured to collect one or more fluorescence photons to be sent to a camera or detector with a quantum efficiency, for example, 0.1 or greater. In another example, the system includes an electrical computing system comprising an information processing unit configured to process information about the state of the qubit captured from the camera or detector.

[0011] In one example, the photon-based remote entanglement generation technique establishes entanglement between a pair of atomic qubits in separate modules by emitting a single photon for each of the qubits, which are detected by interference. The emitted photon covers the space of one qubit in possible encodings such as time, polarization, frequency, or others.

[0012] In one example, successful entanglement generation is predicted by photon detection models, so that only high-fidelity entangled qubits can to be selected for a subsequent calculation, a predicted entanglement generation (HEG) operation. Photon detection is performed at the address so that the two photon qubits are measured in the Bell basis, where the bases are covered by the maximally entangled states of two photon qubits.

[0013] In one example, the announced entanglement generation is efficient thanks to the use of an optical cavity, which increases the probability of successfully emitting a photon from an atom. For optimal parameters, the probability is greater than 90%. For time-efficient operation, the photon emission rate must be optimized, which corresponds to the ratio between the probability of photon generation and the pulse duration r. Since two photons are involved in the HEG operation, the optimization must be performed to maximize p(e) (2) / r.

[0014] In one example, the advertised entanglement generation rate is practically limited by auxiliary operations such as moving atoms from cavity mode to the free-space region, resulting in a time cost several orders of magnitude higher than that of a single-photon generation operation. This cost can be mitigated by performing the slow operation in parallel for a large number of atoms, for example, by moving several optical tweezers simultaneously using acousto-optic deflectors (AODs). This time-multiplexed operation is only efficient when the number of atoms N is high.

[0015] To make time-division multiplexing more efficient, the atoms in cavity mode can be divided into several regions with distinct operations occurring in parallel. One example is the two-zone operation, where one array of atoms generates photons while the other is transported simultaneously. This significantly reduces the N requirement in the presence of slow atom transport. Another advantage is that smaller HEG trial repetitions are sufficient to achieve the optimal HEG rate, thus improving the fidelity of the entangled atoms. Brief description of the drawings

[0016]

[0001] In order to better understand the present invention, reference is made to drawings accompanying it. It being understood that these drawings should not be considered as limitations of the scope of the invention, the embodiments currently described and the best embodiment of the invention currently understood are described in more detail with reference to the accompanying drawings in which:

[0017] [Fig.1] Fig.1 is a simplified diagram illustrating the implementation of a cellular quantum computing device according to an example.

[0018] [Fig.2] The [Fig.2] is a more detailed diagram illustrating a quantum computing cellular device according to an example of the present invention.

[0019] [Fig.3a] Fig.3a is a simplified diagram illustrating a network of clamps mobiles with acousto-optical deflectors.

[0020] [Fig.3b] Fig.3b is a simplified diagram illustrating a network of clamps mobiles with acousto-optical deflectors.

[0021] [Fig.4a] Fig.4a is a simplified diagram illustrating the generation procedure remote entanglement and the interface with the quantum computing region.

[0022] [Fig.4b] Fig.4b is a simplified diagram illustrating the generation procedure remote entanglement and the interface with the quantum computing region.

[0023] [Fig.4c] Fig.4c is a simplified diagram illustrating the generation procedure remote entanglement and the interface with the quantum computing region.

[0024] [Fig.4d] The [Fig.4d] is a simplified diagram illustrating the remote entanglement generation procedure and the interface with the quantum computing region.

[0025] [Fig. 5a] Fig. 5a is a simplified diagram illustrating efficient operation. of the cavity module according to an example.

[0026] [Fig. 5b] Fig. 5b is a simplified diagram illustrating efficient operation. of the cavity module according to an example.

[0027] [Fig.6] [Fig.6] is a simplified diagram illustrating a parallelized operation of the cavity module according to an example.

[0028] [Fig.7a] Fig.7a is a detailed diagram illustrating the photonic networking cavities and the functioning of a single cavity according to an example.

[0029] [Fig.7b] Fig.7b is a detailed diagram illustrating the photonic networking cavities and the functioning of a single cavity according to an example.

[0030] [Fig.8] [Fig.8] is a detailed diagram illustrating more precisely the operation of two cavities and the photon detection module according to an example.

[0031] [Fig.9a] Fig.9a shows the numerically simulated performance of the operation of the parallelized cavity module.

[0032] [Fig.9b] Figure [Fig.9b] shows the numerically simulated performance of the operation of the parallelized cavity module.

[0033] [Fig. 10a] The [Fig. 10a] illustrates the optimization of the cavity parameters in order to obtain a fast remote entanglement operation.

[0034] [Fig. 10b] The [Fig. 10b] illustrates the optimization of the cavity parameters in order to obtain a fast remote entanglement operation.

[0035] [Fig. 10c] The [Fig. 10c] illustrates the optimization of the cavity parameters in order to obtain a fast remote entanglement operation.

[0036] [Fig.lia] The [Fig.lia] shows a simplified diagram illustrating the scaling of the optimal cavity parameters for interconnection operation as a function of cavity quality.

[0037] [Fig. 11b] The [Fig. 11b] shows a simplified diagram illustrating the scaling of the optimal cavity parameters for interconnection operation as a function of cavity quality.

[0038] [Fig. 1] The [Fig. 1] shows a simplified diagram illustrating the scaling of the optimal cavity parameters for the operation of the interconnect as a function of the cavity quality. DETAILED DESCRIPTION

[0039] The present invention proposes techniques generally related to quantum computing and quantum repeaters. In particular, the present invention proposes a method for generating high-speed, photon-mediated entanglement for distributed quantum computing. More specifically, the invention provides techniques for efficiently collecting photons emitted by a large number of atoms in the presence of slow auxiliary operations such as qubit shuttle. By way of example, the invention can be applied to a variety of applications such as cryptography, drug discovery, optimization, machine learning and artificial intelligence, finance, weather forecasting, chemistry, mechanics, electricity, civil engineering, nuclear fusion and fission, economics, materials science, and any other complex matter, whether human or non-human.

[0040] Further details of the present system can be found throughout this specification and more particularly below.

[0041] Figure 1 is a simplified diagram illustrating a quantum computing cellular device according to an example. The system comprises an optical cavity composed of two mirrors, both having a high reflectivity of 90% or more, and which may have different reflectivities. The computing cellular device further comprises qubits with optical control and readout capabilities, such as neutral atoms trapped in an array of optical tweezers.

[0042] In one example, the quantum computing cellular device is equipped with a dynamic tweezer array. The dynamic tweezer array comprises acousto-optic deflectors (AODs) and a laser beam for trapping atoms, in which radio frequency (RF) signals applied to the AODs are modulated to induce movement of the focusing position of the optical tweezers, in order to transport the trapped atoms.

[0043] Figure 2 is a simplified diagram illustrating the quantum computing cell device according to an embodiment of the present invention. Two lenses are located above and below the linking and computing module, so that the field of view covers both the linking and computing modules. One of the lenses is used to focus an array of optical tweezers, coupled by a dichroic mirror to a system

[0044]

[0045]

[0046] High-resolution imaging is achieved through a high-quantum-efficiency camera and an addressable control laser beam to control the quantum state of atomic qubits. The other objective is used to focus an array of laser beams targeting each site of the clamp, with individual frequency control. Optical interconnects with other cavities and individual photon generators and detectors are also included. The array comprises link modules, an optical fiber, an optical router (optical switches), a photon detector, a polarization beam splitter, and other optical components. Figure 3a is a simplified diagram illustrating a dynamic gripper array system according to an embodiment of the present invention. Multitone RF signals are applied to two acousto-optic deflectors (AODs) for gripper movement in the x and y directions (AODx, AODy). The tones create a deflected beam of light that is focused by a lens to create optical grippers. By modulating the RF frequencies over time, the grippers are moved in two dimensions, either by a single gripper point or simultaneously by multiple points. of pliers, as illustrated. Figure 3b is a simplified diagram illustrating the dynamic clamp system for moving atoms in and out of cavity mode. The optical cavities, represented by a pair of mirrors surrounding the cavity mode and the atoms, are positioned on the focal plane (square) of the objective. The optical clamps are configured to move along the plane, such that the atoms are moved between the free-space region where coupling to cavity mode is negligible, and the cavity region where the atoms are coupled to cavity mode with a finite coupling force g, which is not negligible for typical operations of neutral atom qubits. Figures 4A-D are a simplified illustration of the announced photon-assisted entanglement generation (HEG) operation. a) Atom-photon entanglement is created by the emission of a photon from the atom depending on the state; here, the photon is in the time interval encoding (early>, late>) such that its state is correlated with the state of the atom. Thus, the sequential emission of photons for two internal states of an atom in a (10 + 11') / ^2' superposition results in an atom-photon Bell pair (10, early> + 11, late^ / ^T). Panel b) is a typical setup for HEG with atoms and an optical interface, illustrated here with free-space optical cavities. Two optical cavities in a separate module are connected by a fiber array to a Bell state analyzer consisting of a non-polarizing beam splitter and single-photon detectors (SPDs, semicircles). The photons are measured in the Bell basis (BS) (Bell state measurement, BSM), with a success probability of Bell basis projection limited to 50% (Reference 1). A Successful BSM projects the atom states into the maximum entanglement state, as illustrated by the equivalent quantum circuit in the dotted box. Panel c) illustrates an atom-light interface with an optical cavity and a three-level atom. A transition between one of the ground states (10,1>) and the excited state (10,1>) is coupled to the cavity with a coupling rate of g. The cavity is also characterized by three other rate constants: the internal loss rate, the external coupling rate, and the decay rate of the atom's state.

[0047] d) The photonic interface is integrated into the neutral atom QPU by transporting atoms into free space after successful entanglement generation, so that the remote transverse gate operation is performed by consuming n physical Bell pairs for physical gate teleportations, where n is the code block size.

[0048] Figures 5A-B are a simplified illustration of the time-multiplexed HEG operation. On the left, an optical cavity is shown, in which one or more atoms (dots) are coupled. A control laser beam (triangle) is applied to the atoms to induce the generation of single photons. The transport of the atoms in free space is achieved by moving the optical clamp, which allows the atoms in cavity mode to interface with the atoms in the computational region of free space. The cavity mode is coupled to an optical fiber, using a coupling system or by direct connection to the fiber, to emit photon pulses in a fiber array.

[0049] The diagram in Figures 5A, 5B illustrates the time-division multiplexed operation (Reference 2). Atom transport is interleaved by HEG trials, which consist of M repetitions of qubit initialization, qubit pulse (ir / 2 and ji pulses), and sequential single-photon generation operations. Panel b) illustrates time-division multiplexing with a reduced number of atoms. In this case, the time cost of atom transport dominates and significantly limits the trial rate.

[0050] Fig. 6 represents a zone-based operation of the time-multiplexed HEG. Here, the cavity mode is divided into two regions (separated by a horizontal dashed line), zones A and B. The number of zones can be two, as illustrated here, or more than two. Two zones alternately perform atom transport and HEG testing to minimize channel downtime, as illustrated in Figures 7A and 7B. This method is particularly effective when the atom transport time is significantly longer than the photon generation time, 't(photon)'.

[0051] In [Fig. 6], the cavity atom-photon interface module and the detection system are shown in dashed boxes. The structure of the internal state of the atom is also shown: the atoms contain two levels IO> and ll> for cover the qubit, as well as an excited state le> which is used to emit a photon at the wavelength corresponding to the separation of the transition IO>«-> le>, or ll><-> le>.

[0052] Figure 7b illustrates the optical connection enabling the generation of remote entanglement (Figures 5 and 6). Two cavities are connected to optical fibers, which are themselves connected to one or more detection modules comprising 50:50 beam splitters and single-photon detectors. One or more atoms in zones A and B of each cavity are configured to sequentially emit photons via single-atom excitation laser beams, so that the photon pulse train is directed to the detection module.

[0053] Figure 7b illustrates the detailed functioning of the atoms in the cavities for to perform the sequential emission of photons from several atoms in the cavity, which are divided into zones A and B. The operation begins with the initialization of the atoms in free space, then their transport to cavity mode. After initialization, the two zones operate a sequence including the transport of atoms out of the cavity, the preparation and initialization of the atoms in free space, the transport of the atoms into the cavity, and the resetting of the atoms to initialize the qubit state to a high-fidelity state such as 10...0>. Zones A and B are configured to avoid running photon emission simultaneously, so that the fiber array is used by only one of the zones at any given time. The photon detection module detects the photons emitted by the atoms in the cavities and provides conventional information on the success or failure of photon detections with the desired detection models. [Fig.Figure 8 illustrates the overall operation, including the photon detection module and the second cavity with zones A' and B'.

[0054] Figure 8 is a detailed description of the generation of atom-atom entanglement at The distance consists of two cavities, each divided into cavity mode zones A, B and A', B', such that each zone contains up to N atoms, where N is the number of atoms in the respective zones. The two cavities perform the operation illustrated in Figures 7a and 7B, with synchronized or different timing, so that the photons emitted by a pair of atoms in the two cavities arrive simultaneously at the 50:50 beam splitter of the photon detection module. The beam splitter of the photon detection module interferes with the photons emitted by two atoms in the two cavities and performs photodetection at the output ports of the beam splitter using single-photon detectors.Since the atoms are initialized in the equal superposition state of IO> and ll>, and photon generation is performed for each of the internal states on each trial, and since the photon generation operation is probabilistic, we often detect only a single photon in one of the two detectors. Such a detection result is the desired detection event. which we call a success. If photon detection for the labeled atomic pairs i in regions A and A' (or B and B') is successful for both the trials before and after the bit-inversion operation, then the entire entanglement generation for the labeled pair of atoms i is successful, and this classical information is sent to the cavity module such that during the next cycle of atom reset and photon generation, this pair of atoms is ignored in order to preserve the entanglement already generated. After M cycles of reset and photon emission and detection, the atoms are then transported out of cavity mode (as illustrated in Figures 3A-B), so that the entangled atom pair can be used for quantum information tasks. The process repeats until the entangled atom pairs are no longer needed, for example, when the quantum computation is complete.

[0055] Figures 9A-B represent the numerically simulated performance of the HEG success rate, for a particular parameter of single HEG success probability Pheg = 0.2 and single photon generation time tphoton = lus (panel a). The solid line represents the single-zone operation illustrated in Figures 5a, 5b, and the dashed lines represent the zone operation of [Fig. 6]. The vertical dashed line represents the typical atom capacity in a cavity, N = 200. The atom initialization time is 20 µs, and two atom transport times of 100 qs and 1000 qs are considered. Since AN > 100 for t^pon = 1000 qs and N > 10 for transport = 100 qs, the two-zone operation gives better performance. Panel b) also shows the number of repetitions M that optimizes the HEG rate, used in panel a. The zoned operation requires fewer repetitions M, thus reducing the source of decoherence for the qubits..

[0056] Figures 10A-C illustrate the optimization of the cavity parameters to obtain an optimal HEG generation rate as a function of the cavity and atom parameters (g, Kinet y). In panel a), we consider the pulse time tau and the external cavity coupling ratio K^s to be controllable parameters, as is the case for optical cavity implementations. Panel a) shows the configuration of the atomic levels and the cavity coupling. As shown on the left, the atom has three levels: lu>, lg>, le>. The atom-cavity coupling ratio is g, and can be detuned from the atomic transition le>«-> lg> by Ae. The lu>«-> le> transition, with a possible detuning Ae, is driven by a laser beam whose Rabi frequency Q(t) is time-dependent and controlled by the time-dependent intensity and phase of the laser.

[0057] The [Fig. 10a], panel a in the middle, represents a unilateral optical cavity with a left mirror having a reflectivity close to unity and a right mirror having a Lower reflectivity, for the extraction of directed photons. One or more atoms (dot in the middle) are coupled to the cavity. The light is confined within the cavity with an enhanced atom-light coupling γ, with finite dissipation Kinet coupling to the external propagation mode KeX.

[0058] Figure 10b illustrates the control pulse Q(t) for obtaining a Gaussian wave packet photon with the time-mode function w0(t) (References 3, 4), for pulse widths r = 1.5 rc (left) and r = 5 rc (right), shown in the lower panels, where rc is the typical cavity response time rc = max(l / K, K / g²), where k = Kin + Kex (Reference 3). Reversing the sign of Q(t) in the upper left panel can be achieved by adjusting the phase of the control laser pulse.

[0059] Figure 10c illustrates the probability of photon generation and the upper bound of the HEG pe2 / 2r success rate for a wide range of cavity parameters and photon pulses, K^ / g and kt, at two specific cavity qualities characterized by internal cooperativity Cin = g2 / 2Kin y = 200 (left) and 10 (right). Higher (internal) cooperativity gives a large region with a high pe, whereas a cavity with lower cooperativity requires a long pulse even for a modest pe. The upper bound of the HEG pe2 / 2r success rate shows an overall optimum near K^X ~ g and t ~ 1 / K for a cavity with high cooperativity, while the optimum for lower internal cooperativity is shifted towards larger kt, which requires long pulses.

[0060] Figures 11A-C illustrate the scale of the optimal pulse and cavity parameters, KeX / g and kt, for a cavity quality range Kin / g. The optimal values ​​are obtained by finding the parameter that gives the highest HEG rate pe2 / 2r, as shown in the lower panels of [Fig. 10c]. In panel a, the dots represent the optimal values ​​of kt for a given value of Kin / g, with exemplary values ​​of g / 2n = 5 MHz and y / 2n = 0.25 MHz, while the overall scale remains the same for the different parameters. The dots follow the scale t = 1 / g for Kin / g < 1, which indicates that the speed limit for efficient HEG operations is given by the atom-light coupling rate. Panel b shows the optimal rate K^ / g, which follows the scaling KeX = g + Kin. Panel c) shows the optimal pe2 / 2r ratio obtained for a range of Kin / g.

[0061] In one example, the present invention proposes a quantum computer system. The system comprises at least one quantum computer cell. In one example, the quantum computer cell system comprises an optical linking module comprising at least one pair of optical mirrors characterized by a mirror reflectivity > 90% and configured to form a cavity. In one example, the cavity has a length of 1 micrometer or more. In one example, the module comprises a plurality of qubits comprising a laser-coolable atom, so that the number of qubits, for example, is between one and 100,000. In one example, the module has an optical interconnect coupled to the link module. In another example, the module includes a photon multiplexing device coupled to the optical interconnect. The photon multiplexing device is configured to transform at least two or more photons in one or more different spatial modes into two or more photons configured in a single spatial mode.

[0062] In one example, the quantum computer cellular system comprises a free-space computing module in a computing region, the computing module comprising a plurality of atoms. In one example, each of the atoms is coupled to an optical tweezer, the optical tweezer being configured to move in order to transport one or more atoms from a first spatial location to a second spatial location. In another example, the system comprises an array of dynamic tweezers configured to transport one or more qubits coupled to the cavity to the computing region and a detection system comprising a camera operationally coupled to the cavity or the computing region and configured to collect one or more fluorescence photons to be sent to the detection system with a quantum efficiency, for example, of 0.1 or more.In one example, the system includes an electrical computer system comprising an information processing unit configured to process information about the state of the qubit captured from the sensing system.

[0063] In one example, the electrical computer system is configured to identify a quantum state of one or more qubits and is configured to decode quantum error information from a syndrome measurement result using the information processing unit.

[0064] In one example, the system also includes several pairs of electric coils to control a magnetic field and a magnetic field gradient at the location of the qubits.

[0065] In one example, = the pair of optical mirrors comprises at least one free-space mirror, one fiber-based mirror, one fiber-bragg grating (FBG) mirror or one photonic crystal mirror.

[0066] In one example, the cavity is characterized by a cavity mode coupled to a region of nanofibers such that one or more atoms are coupled to an evanescent field of the cavity mode in the vicinity of the nanofiber between the pair of mirrors which are two Bragg grating mirrors.

[0067] In one example, the plurality of qubits characterized as first qubits are coupled to a linking module and one or more second qubits are located in the computation region.

[0068] In one example, the optical interconnect is coupled to a second linking module in a second quantum computer cellular system.

[0069] In one example, the optical interconnect is coupled to at least one or more of the following devices: a single photon generator, a photon detector, an array comprising one or more identical optical cavities, a single photon source, a semiconductor single photon emitter, an optical router, an optical switch, a circulator, a photon detector, a homodyne or heterodyne optical detector, a polarization beam splitter, a coherent light source or a compressed light source, among other devices.

[0070] In one example, the system includes a photon detection device configured with optical interconnect. In one example, the photon detection device includes a beam splitter and a plurality of single photon detectors, such that one or more incoming photons are measured after interference at the beam splitter.

[0071] In one example, the system includes one or more focused lasers, for local control of a single qubit, which is subjected to one or more qubits selected by the spatial addressing of the focused laser, or by a magnetic field generated by a pair of coils to shift a resonant frequency of one or more qubits.

[0072] In one example, the quantum computing cell system is at least one of two quantum computing cell systems that are connected by optical interconnection to achieve remote entanglement generation between qubits in separate cell systems, assisted by optical linkage, to enable remote quantum gate operations for a concatenated quantum error correction operation.

[0073] In one example, remote entanglement generation is achieved (a) by generating a single photon from the plurality of qubits and detecting it in the optical interconnect, (b) in which remote entanglement generation is achieved by reflecting a photonic qubit with at least two cavities and measuring the qubit, (c) or in which remote entanglement generation is achieved by detecting photons transmitted through the cavity.

[0074] In one example, the system comprises one or more remote two-qubit gates between a pair of logic qubits from at least two quantum computing cell systems, including the quantum computing cell system, performing quantum gate teleportation or photon-assisted remote two-qubit gates.

[0075] In one example, the plurality of qubits is configured to be transported inside and outside the linking module such that the coupling of the electric field of an individual qubit to the cavity is controlled in intensity from 0 to g_max, where g_max is a maximum at the center of the cavity where an electric field of the cavity field has an amplitude at a maximum value, or that the qubits move out of a field of view of a photon collecting system.

[0076] In one example, the dynamic gripper network is configured to transport the atoms in parallel after a sequential entanglement generation operation. In another example, the dynamic gripper network is configured to initialize the atoms in parallel after a sequential entanglement generation operation.

[0077] In one example, the plurality of atoms is transported in and out of a region of the cavity while the other atoms perform a remote entanglement generation operation.

[0078] In one example, the reflectivity of a decoupling cavity mirror, characterizing an external coupling rate of the cavity, is adjusted to improve the efficiency of an entanglement generation rate.

[0079] In one example, the qubit(s) are characterized by an atomic state controlled by a laser beam whose amplitude and phase depend on time, in order to emit a photon according to a Gaussian distribution or a time probability distribution with a controllable duration.

[0080] In one example, at least one photon is characterized by a photon pulse duration that is adjusted to improve the entanglement generation rate and the fidelity of a generated entangled state.

[0081] In one example, the present invention provides an alternative quantum computer system. The system comprises at least one quantum computer cell.

[0082] In one example, the quantum computer cell system includes an optical linking module.

[0083] In one example, the module comprises at least one pair of optical mirrors characterized by a mirror reflectivity > 90% and configured to form a cavity, for example, the cavity has a length of 1 micrometer or more. In one example, the module comprises a plurality of qubits comprising a laser-coolable atom, such that the number of qubits, for example, is between one and 100,000. In one example, the module comprises an optical interconnect coupled to the linking module and a photon multiplexing device coupled to the optical interconnect, the photon multiplexing device being configured to transform at least two or more photons in one or more different spatial modes into two or more photons configured in a single spatial mode.

[0084] In one example, the quantum computer cellular system includes a free-space computing module in a computing region. In one example, the computing module comprises a plurality of atoms. In one example, each of the atoms is coupled to an optical tweezer. In one example, the optical tweezer is configured to to move in order to transport one or more atoms from a first spatial location to a second spatial location. In one example, the system includes a dynamic gripper array configured to transport one or more qubits coupled to the cavity to the computing region. In another example, the system includes a sensing system comprising a camera operationally coupled to the cavity or computing region and configured to collect one or more fluorescence photons to be sent to the sensing system with a quantum efficiency, for example, of 0.1 or greater. In another example, the system includes an electrical computing system comprising an information processing unit configured to process information about the state of the qubit captured from the sensing system. In yet another example, one or more qubits are configured for a remote entanglement generation operation.

[0085] Further details of the system can be found in common-owner patent applications described in U.S. Patent Application No. 18 / 347,121, filed July 5, 2023, commonly assigned, and incorporated by reference in this document. Other applications describe various aspects of the components described in U.S. Patent Applications No. 18 / 325,901, filed May 30, 2023, and 18 / 347,174, filed July 5, 2023, each of which is commonly assigned and incorporated by reference in this document.

[0086] Although the foregoing constitutes a complete description of the specific examples, various modifications, alternative constructions, and equivalents may be used. By way of example, the device may comprise any combination of elements described above, as well as those outside this specification. Furthermore, the terms first, second, third, and last do not imply any order in any of the examples presented. Therefore, the above description and illustrations should not be considered as limiting the scope of the present invention, which is defined by the appended claims.

Claims

Demands

1. A quantum computer system comprising at least one quantum computer cell system, the quantum computer cell system comprising: *an optical linking module comprising *at least one pair of optical mirrors characterized by a reflectivity > 90% and configured to form a cavity, the cavity having a length of 1 micrometer or more; *a plurality of qubits comprising a laser-coolable atom such that the number of qubits is between one and 100,000; *an optical interconnect coupled to the linking module; a photon multiplexing device coupled to the optical interconnect, the photon multiplexing device being configured to transform at least two or more photons in one or more different spatial modes into two or more photons configured in a single spatial mode;a free-space computing module in a computing region, the computing module having a plurality of atoms, each of the atoms being coupled to an optical clamp, the optical clamp being configured to move in order to transport one or more of the atoms from a first spatial location to a second spatial location; a dynamic clamp array configured to transport one or more qubits coupled to the cavity to the computing region; a detection system comprising a camera operationally coupled to the cavity or computing region and configured to collect one or more fluorescence photons to be sent to the detection system with a quantum efficiency of 0.1 or more; and an electrical computing system comprising an information processing unit configured to process information on the state of the qubit captured by the detection system.

2. The system of claim 1 wherein the electrical computing system is configured to identify a quantum state of one or more qubits and is configured to decode quantum error information from a measurement result of a syndrome using the information processing unit.

3. The system according to any one of claims 1 to 2 further comprises a plurality of pairs of electric coils to control a magnetic field and a magnetic field gradient at the location of the qubits.

4. The system according to any one of claims 1 to 3, wherein the pair of optical mirrors comprises at least one free-space mirror, one fiber-based mirror, one fiber-bragg grating (FBG) mirror, or one photonic crystal mirror.

5. The system according to any one of claims 1 to 4 wherein the cavity is characterized by a cavity mode coupled to a nanofiber region such that one or more atoms are coupled to an evanescent field of the cavity mode in the vicinity of the nanofiber between the pair of mirrors which are two Bragg grating (FBG) mirrors.

6. The system according to any one of claims 1 to 5 wherein the plurality of qubits characterized as first qubits are coupled to a linking module and one or more second qubits are located in the computation region.

7. The system according to any one of claims 1 to 6, wherein the optical interconnect is coupled to a second linking module in a second quantum computer cell system.

8. The system according to any one of claims 1 to 7 wherein the optical interconnect is coupled to at least one or more of the following: a single-photon generator, a photon detector, an array comprising one or more identical optical cavities, a single-photon source, a semiconductor single-photon emitter, an optical router, an optical switch, a circulator, a photon detector, a homodyne or heterodyne optical detector, a polarization beam splitter, a coherent light source or a compressed light source.

9. The system according to any one of claims 1 to 8 further comprises a photon detection device configured with optical interconnect, the photon detection device comprising a beam splitter and a plurality of single photon detectors (SPDs) such that one or more incoming photons are measured after interference at the beam splitter.

10. The system according to any one of claims 1 to 9 further comprises one or more focused lasers, for local control of a single qubit, which is subjected to one or more qubits selected by the spatial addressing of the focused laser, or by a magnetic field generated by a pair of coils to shift a resonant frequency of one or more qubits.

11. The system according to any one of claims 1 to 10 wherein the quantum computing cell system is at least one of two quantum computing cell systems that are connected by optical interconnection to perform remote entanglement generation between qubits in separate cell systems, assisted by optical linkage, to enable remote quantum gate operations for a concatenated quantum error correction operation.

12. The system of claim 11, wherein remote entanglement generation is achieved (a) by generating a single photon from the plurality of qubits and detecting it in the optical interconnect, (b) wherein remote entanglement generation is achieved by reflecting a photonic qubit with at least two cavities and measuring the qubit, (c) or wherein remote entanglement generation is achieved by detecting photons transmitted through the cavity.

13. The system according to any one of claims 1 to 12 further comprises one or more remote two-qubit gates realized between a pair of logic qubits of at least two quantum computing cell systems comprising the quantum computing cell system by realizing quantum gate teleportation or photon-assisted remote two-qubit gates.

14. The system according to any one of claims 1 to 13 wherein the plurality of qubits is configured to be transported in and out of the linking module such that the coupling of the electric field of an individual qubit to the cavity is controlled in intensity from 0 to g_max, where g_max is a maximum at the center of the cavity where an electric field of the cavity field has an amplitude at a maximum value, or the qubits move out of a field of view of a photon-collecting system.

15. The system according to any one of claims 1 to 14, wherein the dynamic gripper network is configured to transport the parallel atony after a sequential entanglement generation operation.

16. The system according to any one of claims 1 to 15, wherein the network of dynamic grippers is configured to initialize atoms in parallel after a sequential entanglement generation operation.

17. The system according to any one of claims 1 to 16 wherein the plurality of atoms is transported in and out of a region of the cavity while the other atoms perform a remote entanglement generation operation.

18. The system according to any one of claims 1 to 17, wherein the reflectivity of a decoupling cavity mirror, characterizing an external coupling rate of the cavity, is tuned to improve the efficiency of an entanglement generation rate.

19. The system according to any one of claims 1 to 18, wherein one or more qubits are characterized by an atomic state controlled by a laser beam whose amplitude and phase depend on time, in order to emit a photon according to a Gaussian or time-dependent probability distribution with a controllable duration.

20. The system according to any one of claims 1 to 19, wherein at least one photon is characterized by a photon pulse duration that is tuned to improve the entanglement generation rate and the fidelity of a generated entangled state.

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