Quantum computing method, device and equipment based on rydberg atoms and storage medium

Abstract

The present application relates to the field of quantum computing, and particularly relates to a quantum computing method, device and equipment based on Rydberg atoms and a storage medium, the method comprising: under a preset condition, controlling evolution of a Rydberg atom quantum bit through adiabatic geometric manipulation to obtain a first phase; obtaining a first control field phase corresponding to the adiabatic geometric manipulation under the preset condition; performing non-circuital operation on the first control field phase to obtain a second control field phase; under the condition of the second control field phase, controlling evolution of the Rydberg atom quantum bit through adiabatic geometric manipulation to obtain a second phase; and obtaining a target phase of the Rydberg atom quantum bit conforming to a two-bit gate controlled phase gate according to the first phase and the second phase. Through the joint action of non-circuital operation, adiabatic geometric manipulation and quantum adiabatic shortcut, the two-bit controlled phase gate with fast speed, higher robustness and arbitrary phase angle is realized by using Rydberg interaction.

Description

Technical Field

[0001] This invention relates to the field of quantum computing technology, and in particular to a quantum computing method, apparatus, device, and storage medium based on Rydberg atoms. Background Technology

[0002] In recent years, quantum computers have attracted much attention due to their ability to solve many problems that classical computers cannot. Neutral atom systems, with their advantages such as scalable atomic arrays, long coherence times, controllable interactions, and horizontal stability of the hyperfine structure of the ground state, are one of the strong candidate systems for realizing quantum computers. Significant experimental progress has been made in neutral atom systems in recent years, including deterministic loading of hundreds of single atoms, addressing and manipulating single atoms in two-dimensional and three-dimensional arrays, extending the coherence time of qubits, realizing two-qubit gates based on Rydberg states, and efficient readout of quantum states. Recently, quantum algorithms have begun to be used to solve some practical problems.

[0003] However, in neutral atom systems, improving the fidelity of a two-qubit gate to the quantum error correction threshold of 0.99 has always been a huge challenge. Existing gradient descent algorithms are not convenient for finding waveforms for controlled phase gates that require arbitrary rotation angles, and when the rotation angle is small, it is even more difficult to optimize the evaluation function to a very small value, which is very challenging in computation and has limited robustness to system noise. Summary of the Invention

[0004] One objective of this invention is to provide a quantum computing method, apparatus, device, and storage medium based on Rydberg atoms, to address the technical challenges of limited fidelity of current two-qubit gates and the difficulty of optimizing the evaluation function to a very low level for small-angle rotations when using gradient descent algorithms to construct waveforms.

[0005] In a first aspect, embodiments of the present invention provide a quantum computing method based on Rydberg atoms, comprising:

[0006] Under preset conditions, the Rydberg atomic qubits are evolved through adiabatic geometric manipulation to accumulate the first phase;

[0007] Obtain the first control field phase corresponding to the adiabatic geometric manipulation under preset conditions;

[0008] A non-circuit operation is performed on the first control field phase to obtain the second control field phase;

[0009] Under the conditions of the second control field phase, the Rydberg atom qubit is evolved through the adiabatic geometric manipulation to obtain the second phase;

[0010] Based on the first phase and the second phase, the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate is obtained.

[0011] In conjunction with the first aspect, in one possible implementation, the step of controlling the Rydberg atomic qubits to evolve under preset conditions through adiabatic geometric manipulation to accumulate a first phase includes: accelerating the adiabatic geometric manipulation through a quantum adiabatic shortcut under preset conditions to obtain an accelerated adiabatic geometric manipulation; and evolving the Rydberg atomic qubits through the accelerated adiabatic geometric manipulation to accumulate a first phase.

[0012] In conjunction with the first aspect, in one possible implementation, before the first phase is accumulated by controlling the Rydberg atom qubits to evolve under preset conditions through adiabatic geometric manipulation, the method includes: acquiring an initial control field phase; performing an adiabatic operation on the initial control field phase to obtain a first control field phase that satisfies the adiabatic geometric manipulation conditions.

[0013] In conjunction with the first aspect, in one possible implementation, the first phase includes a first dynamic phase and a first geometric phase, and the second phase includes a second dynamic phase and a second geometric phase; obtaining the target phase of the Rydberg atomic qubit conforming to a two-bit gate controlled phase gate based on the first phase and the second phase includes: superimposing the first dynamic phase and the second dynamic phase to obtain a third dynamic phase, wherein the third dynamic phase is 0; superimposing the first geometric phase and the second geometric phase to obtain a third geometric phase; and obtaining the target phase of the Rydberg atomic qubit conforming to a two-bit gate controlled phase gate based on the third dynamic phase and the third geometric phase.

[0014] In conjunction with the first aspect, in one possible implementation, the non-circuit operation is to perform a π flip on the control field.

[0015] In conjunction with the first aspect, in one possible implementation, the step of controlling the Rydberg atom qubit to evolve under the condition of the second control field phase through the adiabatic geometric manipulation to accumulate and obtain the second phase includes: accelerating the adiabatic geometric manipulation through a quantum adiabatic shortcut under the condition of the second control field phase to obtain an accelerated adiabatic geometric manipulation; and controlling the Rydberg atom qubit to evolve through the accelerated adiabatic geometric manipulation to accumulate and obtain the second phase.

[0016] In conjunction with the first aspect, in one possible implementation, the quantum adiabatic shortcut is to obtain the form of an auxiliary Hamiltonian through reverse engineering of the Hamiltonian, and to add an auxiliary Hamiltonian during the evolution process to perform the quantum adiabatic shortcut operation.

[0017] Secondly, embodiments of the present invention provide a quantum computing device based on Rydberg atoms, comprising:

[0018] The evolution unit is used to evolve the Rydberg atom qubit under preset conditions through adiabatic geometric manipulation, and accumulate to obtain the first phase;

[0019] The acquisition unit is used to acquire the phase of the first control field corresponding to the adiabatic geometric manipulation under preset conditions;

[0020] An operation unit is used to perform a non-circular operation on the first control field phase to obtain the second control field phase;

[0021] The evolution unit is further configured to evolve the Rydberg atom qubit under the condition of the second control field phase through the adiabatic geometric manipulation, and accumulate to obtain the second phase;

[0022] A determining unit is used to obtain the target phase of the Rydberg atom qubit that conforms to a two-bit gate controlled phase gate based on the first phase and the second phase.

[0023] In a third aspect, embodiments of the present invention provide a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the quantum computing method based on Rydberg atoms as described in the first aspect.

[0024] In a fourth aspect, embodiments of the present invention provide a computer device including a memory and one or more processors, the memory being connected to the one or more processors, the one or more processors being configured to execute one or more computer programs stored in the memory, and the one or more processors, when executing the one or more computer programs, causing the computer device to implement the method described in the first aspect above.

[0025] In the aforementioned scheme implemented using Rydberg atoms in quantum computing methods, devices, equipment, and storage media, firstly, under preset conditions, the Rydberg atom qubits are evolved through adiabatic geometric manipulation to accumulate a first phase. Secondly, a first control field phase corresponding to the adiabatic geometric manipulation under the preset conditions is obtained. Then, a non-circuit operation is performed on the first control field phase to obtain a second control field phase. Under the conditions of the second control field phase, the Rydberg atom qubits are evolved through the adiabatic geometric manipulation to accumulate a second phase. Finally, based on the first and second phases, the target phase of the Rydberg atom qubits conforming to a two-qubit controlled phase gate is obtained. This method, by using Rydberg atoms as qubits, enables efficient quantum state control. Furthermore, through the combined effects of non-circuit processing and adiabatic geometric manipulation, a fast, more robust, and arbitrarily phase-angle-controlled two-qubit phase gate is achieved. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the energy level structure of a Rydberg atom qubit according to an embodiment of the present invention;

[0028] Figure 2A This is a flowchart illustrating a quantum computing method based on Rydberg atoms.

[0029] Figure 2B A schematic diagram of the population and phase evolution trajectory of the initial state |11>.

[0030] Figure 2C A schematic diagram of the population and phase evolution trajectory for initial states of |10> or |01>;

[0031] Figure 2D This is a comparative diagram of the three schemes in terms of Rabi frequency bias;

[0032] Figure 2E A comparative diagram of the three schemes in terms of detuning frequency offset;

[0033] Figure 2F This is a schematic diagram illustrating the robustness of a non-circuitous geometric two-bit gate to random noise of different ranges.

[0034] Figure 2GThis is a schematic diagram illustrating the relationship between the total duration and fidelity of a non-circular geometric two-bit gate.

[0035] Figure 2H A comparative diagram showing the total time taken to complete the quantum Fourier transform using a non-circuitous geometric scheme and a time-optimal scheme;

[0036] Figure 3 This is a schematic diagram of the structure of a quantum computing device based on Rydberg atoms in one embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of a computer device according to an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0039] It should be noted that, unless otherwise specified, the various features in the embodiments of this invention can be combined with each other, all of which are within the protection scope of this invention. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this invention do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0040] In existing technologies, in 1984, Berry discovered that under adiabatic approximation conditions, after a period of evolution, a system not only accumulates a dynamic phase but also acquires an additional special phase, known as the Berry phase or geometric phase. The accumulation of the geometric phase is mainly determined by the solid angles during the evolution process. Later, Demirplak and Berry proposed the quantum adiabatic shortcut, which, by adding an auxiliary Hamiltonian, eliminates errors caused by non-adiabatic processes in rapid evolution, significantly increasing the speed of adiabatic evolution and laying the foundation for high-fidelity geometric operations.

[0041] In recent years, quantum computers have attracted much attention due to their ability to solve many problems that classical computers cannot. Neutral atom systems, with their advantages such as scalable atomic arrays, long coherence times, controllable interactions, and horizontal stability of the hyperfine structure of the ground state, are one of the most promising candidate systems for realizing quantum computers. Significant experimental progress has been made in neutral atom systems in recent years, including deterministic loading of hundreds of single atoms, addressing and manipulating single atoms in two-dimensional and three-dimensional arrays, extending the coherence time of qubits, realizing two-qubit gates based on Rydberg states, and efficient readout of atomic states. Recently, quantum algorithms have begun to be used to solve some practical problems. This work has greatly promoted the application of this system in quantum simulation and quantum computing. Simultaneously, quantum algorithms have also seen tremendous development. Shor proposed the Shor algorithm, the core of which is the quantum Fourier transform. The two most important quantum gates used in the quantum Fourier transform circuit are the single-qubit Hadamard gate and the two-qubit controlled-phase gate with a rotating phase.

[0042] However, achieving the fidelity of a two-qubit gate to the quantum error correction threshold of 0.99 has been a significant challenge in neutral atom systems. Recently, Evered et al. at Harvard University used gradient descent to find a suitable waveform, achieving a controlled Z-gate with a fidelity of 0.995 in a single-atom array for the first time. However, gradient descent is inconvenient for finding waveforms for controlled phase gates requiring arbitrary rotation angles, and optimizing the evaluation function to a very small value is computationally challenging, especially when the rotation angle is small. Furthermore, Evered et al.'s approach uses a global phase encompassing both dynamic and geometric phases, resulting in limited robustness to system noise. Therefore, employing non-circuitous geometric manipulation to achieve arbitrary phase angles, while incorporating quantum adiabatic shortcuts and non-circuitous manipulation to effectively eliminate the dynamic phase component and reduce gate manipulation time, has become a promising approach for achieving fast and robust two-qubit gates with arbitrary rotation angles.

[0043] With the rapid development of quantum computing, systems using Rydberg atoms as qubits have received increasing attention. The qubits mentioned in this article are typically obtained by encoding energy levels of an array of neutral atoms trapped in an optical trap or optical lattice. In single-atom quantum computing, alkali metal atoms... 87 Rb is a relatively common choice for qubits.

[0044] We typically encode energy levels as follows: |0>=|5S 1 / 2 F = 1 > |1 > = |5S 1 / 2 F = 2>Rydberg state can be encoded as |r>=|79D 5 / 2 >

[0045] See Figure 1 , Figure 1 This is a schematic diagram of the energy level structure of a Rydberg atom qubit provided in an embodiment of this application. In existing neutral atom two-qubit gate protocols, control pulses couple the |1> state and the |r> state, causing atom pairs in the |10> or |01> state to couple to the |r0> or |0r> state. However, if the atom pair is initially in the |11> state, when one atom is excited to the |r> state, due to the Rydberg interaction, it will inhibit the other atom from transitioning to the |r> state. Therefore, the |11> state will... State coupling.

[0046] In subsequent simulations, the main parameters used were alkali metal atoms. 87 Rb, energy levels are encoded as follows: |0>=|5S 1 / 2 F = 1 > , |1 > 1 = |5S 1 / 2 F = 2>, the Rydberg state encoding is |r> = |79D 5 / 2 The control pulse couples the |1> and |r> states, causing atom pairs in the |10> or |01> states to couple to the |r0> or |0r> states. However, if the atom pair is initially in the |11> state, when one atom is excited to the |r> state, the Rydberg interaction will inhibit the other atom from transitioning to the |r> state. Therefore, the |11> state will couple with... Because of the state coupling, the Rydberg atomic qubit can be approximated as a two-level system with three different initial states.

[0047] In view of this, this application proposes a quantum computing method based on Rydberg atoms to solve the above problems. The details are described below.

[0048] Please refer to Figure 2, which is a flowchart illustrating a quantum computing method based on Rydberg atoms provided in an embodiment of the present invention. The method includes the following steps:

[0049] S10. Under preset conditions, the Rydberg atomic qubits are evolved by adiabatic geometric manipulation to accumulate the first phase.

[0050] In one embodiment, before the first phase is accumulated by controlling the Rydberg atom qubits to evolve under preset conditions through adiabatic geometric manipulation, the method includes: obtaining an initial control field phase; performing an adiabatic operation on the initial control field phase to obtain a first control field phase that satisfies the adiabatic geometric manipulation conditions.

[0051] In this process, the evolution of Rydberg atomic qubits is controlled by adiabatic geometry manipulation. After evolving from the initial state, the atomic population returns to the initial state and accumulates the first phase.

[0052] The first phase includes a first dynamic phase and a first geometric phase.

[0053] Rydberg atoms are atoms in a highly excited state, where one or more electrons are excited to energy levels much higher than the ground state. Because their electrons are far from the nucleus, these atoms possess unique properties such as extremely large electric dipole moments, long coherence times, and strong electron-electron interactions.

[0054] The Rydberg blocking effect is a phenomenon observed in multi-atom systems where an atom excited to a Rydberg state prevents surrounding atoms from reaching the same excited state. When an atom is excited to a Rydberg state, due to the significant increase in its electron cloud and enhanced inter-electron interactions, it forms a "forbidden zone" around itself, making it difficult for other atoms to be excited to the same Rydberg state within this region.

[0055] The Rydberg blocking effect allows for precise control over the evolutionary states of atoms. By selectively evolving specific atoms, unique quantum state configurations can be created within a cluster of atoms. In this configuration, atoms evolved into Rydberg states can be considered as "1" states of qubits, while unexcited atoms are equivalent to "0" states.

[0056] Adiabatic geometric manipulation can be divided into two parts. The first part is adiabatic manipulation, where "adiabatic" means that the state of the quantum system changes slowly over time, so that the system always remains in its eigenstate. This manipulation method reduces non-adiabatic excitations caused by rapid changes, thereby improving the accuracy of the operation. The second part is geometric manipulation, which involves changing the parameters of the quantum system (such as the polarization or intensity of the laser field), so that the quantum state evolves along a specific path, thus producing the so-called geometric phase.

[0057] S20. Obtain the first control field phase corresponding to the adiabatic geometric manipulation under preset conditions.

[0058] The phase acquired by a qubit refers to the phase that the qubit wavefunction gains after undergoing adiabatic geometric manipulation. The magnitude of this phase is related to the phase of the control field.

[0059] S30. Perform a non-circuit operation on the first control field phase to obtain the second control field phase.

[0060] Non-circuitous operations refer to the process of changing the state of a quantum system, where the final state of the system is not a simple periodic repetition of the initial state (i.e., non-circuitous property). Such operations typically involve specific phase adjustments to the quantum state to give it new quantum properties.

[0061] The non-circuit operation is to perform a π flip on the control field.

[0062] Among them, π flip is a special non-circuit operation, which is actually flipping the control field vector by 180 degrees, equivalent to a semi-circular movement on the Bloch sphere.

[0063] S40. Under the condition of the second control field phase, the Rydberg atom qubit is evolved through the adiabatic geometric manipulation to obtain the second phase.

[0064] The second phase includes a second dynamic phase and a second geometric phase.

[0065] In this process, the evolution of Rydberg atomic qubits is controlled by adiabatic geometric manipulation. After evolving from the initial state, the atomic population returns to the initial state and accumulates the second phase.

[0066] Specifically, the control field couples the ground state and the Rydberg state. In other words, the control field excites the Rydberg atomic qubits to evolve. During the evolution, the qubits will pass through the Rydberg state, but eventually return to the initial state and accumulate phase.

[0067] S50. Based on the first phase and the second phase, obtain the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate.

[0068] Among them, the two-qubit gate allows non-trivial interactions between two qubits, thereby enabling quantum entanglement and logical operations.

[0069] In this method, the following three systems can be used: a vacuum system: the vacuum cavity is where the qubits are captured and evolved. An ion pump continuously extracts gas from the vacuum cavity to achieve an ultra-high vacuum, preventing qubit loss due to collisions between background gas atoms and the qubits. Rydberg atoms can be released inside the vacuum system (e.g., if rubidium rods are present, they will release rubidium atoms when energized); a laser system: generating lasers of various wavelengths and projecting them into the vacuum cavity through an optical path to capture Rydberg atoms as qubits, prepare the initial state of the qubits, and manipulate their evolution; and an imaging system: used to measure the quantum state of the qubits after their evolution is complete.

[0070] In one embodiment, the step of controlling the evolution of Rydberg atomic qubits through adiabatic geometric manipulation under preset conditions to accumulate a first phase includes: accelerating the adiabatic geometric manipulation through a quantum adiabatic shortcut under preset conditions to obtain an accelerated adiabatic geometric manipulation; and evolving the Rydberg atomic qubits through the accelerated adiabatic geometric manipulation to accumulate a first phase.

[0071] In one embodiment, the first phase includes a first dynamic phase and a first geometric phase, and the second phase includes a second dynamic phase and a second geometric phase; obtaining the target phase of the Rydberg atomic qubit conforming to a two-bit gate controlled phase gate based on the first phase and the second phase includes: superimposing the first dynamic phase and the second dynamic phase to obtain a third dynamic phase, wherein the third dynamic phase is 0; superimposing the first geometric phase and the second geometric phase to obtain a third geometric phase; and obtaining the target phase of the Rydberg atomic qubit conforming to a two-bit gate controlled phase gate based on the third dynamic phase and the third geometric phase.

[0072] In the non-circuit geometric manipulation, the phases accumulated by the qubits are such that the dynamic phases cancel each other out and the geometric phases superimpose each other, leaving only the geometric phases.

[0073] In one embodiment, the non-circuit operation is to perform a π flip.

[0074] In one embodiment, the step of controlling the Rydberg atom qubit to evolve through the adiabatic geometric manipulation under the condition of the second control field phase, and accumulating to obtain the second phase, includes: accelerating the adiabatic geometric manipulation through a quantum adiabatic shortcut under the condition of the second control field phase, to obtain the adiabatic geometric manipulation in an accelerated state; and controlling the Rydberg atom qubit to evolve through the adiabatic geometric manipulation in the accelerated state, and accumulating to obtain the second phase.

[0075] In one embodiment, the quantum adiabatic shortcut is obtained by reverse engineering the Hamiltonian to obtain the form of an auxiliary Hamiltonian, and an auxiliary Hamiltonian is added during the evolution process to perform the quantum adiabatic shortcut operation.

[0076] In quantum mechanics, the Hamiltonian is a crucial concept used to describe the total energy of a quantum system. It determines the dynamical behavior of the quantum system, that is, how the system changes over time.

[0077] Reverse engineering involves a detailed analysis of the target quantum state and the design of a specific Hamiltonian that enables the quantum system to rapidly evolve to the target state along a predetermined path. This method is similar to optimization problems in engineering design, where the process or conditions for the application are deduced from the desired final result.

[0078] The auxiliary Hamiltonian is specially designed to help the system transition from the initial state to the target state more quickly.

[0079] Among these, the adiabatic shortcut addresses the challenge of traditional adiabatic manipulation, which requires extremely slow changes in system parameters to prevent quantum states from transitioning to other eigenstates. However, this approach can be inefficient in practical applications. The adiabatic shortcut cleverly designs the Hamiltonian to achieve adiabatic evolution of states in a shorter time, thus increasing the speed of operations while maintaining the adiabatic principle. By using adiabatic shortcuts, faster quantum gate operations can be achieved in quantum computing while maintaining a low error rate. This is crucial for improving the computational speed and reliability of quantum computers.

[0080] It is evident that adiabatic geometric operations can be reverse engineered to design auxiliary Hamiltonians, thereby enabling fast and efficient state transformations in quantum systems.

[0081] Furthermore, the Rabi frequency, phase, detuned waveform, etc., can be easily modified under the non-circular geometric operation principle, and no unique limitation is made here.

[0082] As can be seen, by modulating the phase of the control field through adiabatic geometric manipulation and incorporating a quantum adiabatic shortcut, the qubit rapidly completes its adiabatic evolution, accumulating both dynamic and geometric phases. The magnitude of the accumulated geometric phase is related to the range of phase shift in the control field. A π-flip is then performed on the control field phase, implementing a non-circuitous operation. Finally, adiabatic geometric manipulation is performed again, modulating the control field phase once more based on the π-flip, with the modulation range identical to the first step. This time, due to the π-flip in the control field phase, the eigenstates flip, and the accumulated dynamic phase has the opposite sign to that of the first step, thus canceling each other out. The geometric phase, however, has the same sign as that of the first step, thus superimposing. Since the magnitude of the accumulated geometric phase is related to the modulation of the control field phase, only the adjustment range of the control field phase needs to be adjusted to achieve rotation at any phase angle. Furthermore, because the geometric phase is only related to the solid angle, it is less affected by system noise, while the dynamic phase, which is more affected by system noise, is canceled out. Therefore, this scheme has stronger robustness to system noise. Moreover, under the acceleration effect of hyperadiabatic and non-circuitous operations, this scheme also has a greater advantage in resisting decoherence.

[0083] In the aforementioned scheme implemented using Rydberg atoms in quantum computing methods, devices, equipment, and storage media, firstly, under preset conditions, the Rydberg atom qubits are evolved through adiabatic geometric manipulation to accumulate a first phase. Secondly, a first control field phase corresponding to the adiabatic geometric manipulation under the preset conditions is obtained. Then, a non-circuit operation is performed on the first control field phase to obtain a second control field phase. Under the conditions of the second control field phase, the Rydberg atom qubits are evolved through the adiabatic geometric manipulation to accumulate a second phase. Finally, based on the first and second phases, the target phase of the Rydberg atom qubits conforming to a two-qubit controlled phase gate is obtained. This method, by using Rydberg atoms as qubits, enables efficient quantum state control. Furthermore, through the combined effects of non-circuit processing and adiabatic geometric manipulation, a fast, more robust, and arbitrarily phase-angle-controlled two-qubit phase gate is achieved.

[0084] Based on the diagram, this solution can be implemented according to the above-mentioned implementation methods. The following examples are examples, but not the only examples.

[0085] We now use |↑> to represent the three upper energy levels |r0>, |0r>, Let |↓> denote the three upper energy levels |10>, |01>, and |11>. Then, in the basis vectors |↑> and |↓>, the Hamiltonian can be written as...

[0086]

[0087] Where Δ represents the detuning between the control field and the atomic energy level, and Ω is the Rabi frequency of the control field. When the initial state is |10> state or |01> state, ΩM = Ω; when the initial state is |11> state...

[0088] For this Hamiltonian, the eigenstate is: in The corresponding eigenenergy is in

[0089] Control field vector By setting the detuning to Δ = 0, i.e., in the resonant state, there will be θ = π / 2.

[0090] In this invention, a two-bit controlled phase gate can be achieved simply by adjusting the phase of the control field.

[0091] In order for the system to undergo adiabatic evolution, we need to satisfy the following conditions: The condition. Now we assume the initial phase of the control field is... For the eigenstate |λ +Overlapping initial states By thermally separating the phase from Adjust to The state will follow the eigenstate |λ + >Evolve and accumulate geometric phases and dynamic phase

[0092] Then, a π flip is instantaneously applied to the phase of the control field, causing the phase to change from... Become At this point, the evolutionary state and the eigenstate |λ - >Overlap, phase controlled by adiabatic control from Become This will cause the evolutionary state to follow the eigenstate |λ - >Evolve and accumulate a geometric phase and dynamic phase Then the time evolution operator Can write

[0093]

[0094] Time evolution operator Can write

[0095]

[0096] Therefore, the evolution operator of a non-circulating geometrically controlled phase gate can be written as

[0097]

[0098] Clearly, the dynamic phase β + and β - Because the opposite signs cancel each other out, and the geometric phase δ + and δ - When the symbols are the same and superimposed, the phase obtained by the final qubit is a complete geometric phase.

[0099] The magnitude of the obtained phase depends on the range of phase modulation. By adjusting the phase modulation range, the qubit can be rotated at any angle.

[0100] However, adiabatic manipulation takes a long time. For qubits, excessive manipulation time can lead to severe decoherence effects, thus affecting gate fidelity. Therefore, to accelerate the adiabatic process, this invention incorporates a quantum adiabatic shortcut by adding an auxiliary Hamiltonian. This eliminates errors caused by non-adiabatic processes during rapid evolution, while incorporating non-circuitous operations to reduce gate operation time. For a non-circuitous geometrically controlled phase gate, the phase expression can be written as...

[0101]

[0102] Where 'a' is an arbitrary constant used to control the phase modulation range, T is the total gate duration, and τ = T / 2. For the Cz gate, the manipulation waveform is as follows: Figure 2B As shown, the parameters are set as follows: Ω = 2π × 4MHz, a = 1, T = 500ns. Under these parameters, the auxiliary Hamiltonian can be written as...

[0103]

[0104] This Hamiltonian can be realized through detuning modulation. Under the condition of incorporating quantum adiabatic shortcuts, the evolution trajectories of the |11> state, |10> state, and |01> state are as follows: Figure 2B As shown in Figures C and C, it is clear that the population of these states eventually returns to the initial state and acquires a phase of magnitude π. Now, let's return to the evolution operator of the basis vectors {|00>, |01>, |10>, |11>}. This evolution operator can obviously be written as...

[0105]

[0106] When we set a = 1, Satisfying Cz gate Requirements.

[0107] In practical experiments, qubits are affected by system bias or noise. Figures D and E compare the effects of three schemes—the non-circuitous geometry scheme, Sun Yuan's non-resonant modulation driving scheme, and Evered's time-optimal pulse scheme—on Rabi frequency and detuning bias to improve fidelity. Fidelity in the figures is defined as... Where U is the time evolution operator for each scheme, and V is the time evolution operator under ideal conditions.

[0108] In Figure D, the magnitude of the Rabi frequency after adding the bias is Ω'(t) = Ω(t) + k Ω Ω max Ω max The maximum value of the Rabi frequency waveform is shown in the figure. It can be seen that the Rabi frequency bias has no effect on the non-circuitous geometry scheme because, in this invention, the Rabi frequency only affects the magnitude of the dynamic phase, which has already been eliminated during evolution. The remaining geometric phase is unaffected by the Rabi frequency. Therefore, the non-circuitous geometry scheme has a significant advantage in terms of Rabi frequency bias. In the detuning bias, the magnitude of the detuning after adding the bias is Δ'(t) = Δ(t) + k. Δ Ω maxAs shown in Figure E, the robustness of this invention to mistuned bias is significantly superior to the other two schemes. This is because the overall phase in the other two schemes includes both dynamic and geometric phases, and mistuned bias affects both dynamic and geometric phases simultaneously. Since this invention eliminates the dynamic phase, i.e., eliminates a portion of the error source, it exhibits better performance against mistuned bias.

[0109] Figure F shows the fidelity of the present invention after being affected by Rabi frequency and detuned random noise, where Ω'(t) = Ω + γ(t)Ω, Δ'(t) = Δ(t) + η(t)Ω. γ(t)∈[-k Ω k Ω ],η(t)∈[-k Δ k Δ [ ] represents a time-varying random number used to simulate random noise. It is easy to see from Figure F that the non-circuitous geometry scheme exhibits high robustness to random noise. Even when both the Rabi frequency and detuning noise reach 0.1Ω, the fidelity remains above 0.9999. This is because the dynamic phase is more affected by noise, while the geometric phase depends on the solid angle, which is less affected by noise. Therefore, this invention eliminates the dynamic phase, resulting in better robustness to random noise.

[0110] To test the performance of this invention more closely to actual experiments, we tested its performance under the influence of decoherence. First, we present the simulated Hamiltonian, H = H 11 +H 10 +H 01 ,in

[0111]

[0112] H 11 The effect of finite Rydberg interactions is considered, where B = 2π × 500 MHz is the Rydberg interaction strength. 10 Can be written

[0113]

[0114] H 01 With H 01 Similarly, we use the master equation to describe the decoherence process, which can be written as...

[0115]

[0116] Where ρ is the density operator of the states, For spontaneous emission from the Rydberg state to the ground state, For spontaneous emission from the Rydberg state to the outer energy level of the system, This represents decoherence between the Rydberg state and the ground state. For the Rydberg state |r>=|79D 5 / 2 We can set Γ1 = 1kHz, Γ2 = 4kHz, and Γ3 = 30kHz. Then... Figure G shows the relationship between gate fidelity and total gate duration in this invention. Except for the total gate duration T, all other parameters are related to... Figure 2B , Figure 2C The waveform parameters used in the evolution are consistent, and the fidelity is defined as follows: ρ ideal This represents the density matrix under ideal conditions. It is clear from the figure that the shorter the gate operation time, the less affected by decoherence, and the higher the gate fidelity. To achieve a quantum error correction threshold above 0.99, the total gate duration must be below 560 ns; to improve the fidelity above 0.999, the total gate duration needs to be below 80 ns. In summary, the total operation time of this invention is adjustable, meeting the requirements for a fast and robust quantum gate.

[0117] At the heart of Shor's algorithm, namely the quantum Fourier transform, two types of gates are required: a single-bit Hadamard gate and a gate with a rotation angle of... A two-qubit controlled phase gate. For non-circuitous geometry schemes incorporating quantum adiabatic shortcuts, the gate operation speed is primarily limited by energy consumption; here we define the power consumption as... exist Figure 2G In this paper, we compare the time required to complete the quantum Fourier transform with Evered's scheme. In Evered's scheme, Ω = 2π × 4.6 MHz and Δ = 0. Therefore, we limit the maximum power of this invention to Evered's power P = 2π × 4.6 MHz. In this invention, the Rabi frequency is still set to Ω = 2π × 4 MHz, thus limiting the maximum detuning value and consequently the total gate operation time. However, the detuning magnitude is not only negatively correlated with the total gate operation time but also positively correlated with the phase modulation range, i.e., the rotation angle. In the quantum Fourier transform, many controlled phase gates with small-angle rotations are required. This invention achieves a faster speed for small-angle rotations, further reducing the total time required to complete the quantum Fourier transform. The relationship between the total time required to complete the quantum Fourier transform and the number of atoms is as follows: Figure 2F As shown, single-bit gates in quantum Fourier transform all use π / 2 pulses. Obviously, the scheme of this invention has a great advantage as a two-bit gate. Based on this invention, the time spent on small-angle rotation is much less than that of the comparative scheme. As the number of atoms increases, the advantage of this invention in small-angle rotation becomes more and more obvious.

[0118] In summary, the non-circuitous geometric two-qubit gate of this invention combines non-circuitous manipulation, geometric manipulation, and quantum adiabatic shortcut techniques. Utilizing Rydberg interactions, it enables a two-qubit controlled phase gate. In this invention, the qubits acquire a geometric phase, resulting in stronger robustness to system bias and noise. Furthermore, the gate operation speed is significantly improved by applying quantum adiabatic shortcuts and non-circuitous operations. Simultaneously, this invention allows control of the qubit rotation angle by adjusting the phase modulation range, which is more convenient than gradient descent algorithms in finding waveforms at different rotation angles, especially at small angles, and achieves faster speeds for small-angle rotations. Therefore, this invention represents a novel, fast, and robust two-qubit gate solution.

[0119] The method of this application has been described above; the apparatus of this application will be described below.

[0120] See Figure 3 , Figure 3 This is a schematic diagram of the structure of a quantum computing device based on Rydberg atoms provided in an embodiment of this application. Figure 3 As shown, this Rydberg atom-based quantum computing device includes:

[0121] Evolution unit 301 is used to evolve Rydberg atom qubits under preset conditions through adiabatic geometric manipulation to accumulate the first phase;

[0122] Acquisition unit 302 is used to acquire the phase of the first control field corresponding to the adiabatic geometry manipulation under preset conditions;

[0123] Operation unit 303 is used to perform a non-circuit operation on the first control field phase to obtain the second control field phase;

[0124] The evolution unit 301 is further configured to evolve the Rydberg atom qubit under the condition of the second control field phase through the adiabatic geometric manipulation, and accumulate to obtain the second phase;

[0125] The determining unit 304 is used to obtain the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate based on the first phase and the second phase.

[0126] In the aforementioned scheme implemented using Rydberg atoms in quantum computing methods, devices, equipment, and storage media, firstly, under preset conditions, the Rydberg atom qubits are evolved through adiabatic geometric manipulation to accumulate a first phase. Secondly, a first control field phase corresponding to the adiabatic geometric manipulation under the preset conditions is obtained. Then, a non-circuit operation is performed on the first control field phase to obtain a second control field phase. Under the conditions of the second control field phase, the Rydberg atom qubits are evolved through the adiabatic geometric manipulation to accumulate a second phase. Finally, based on the first and second phases, the target phase of the Rydberg atom qubits conforming to a two-qubit controlled phase gate is obtained. This method, by using Rydberg atoms as qubits, enables efficient quantum state control. Furthermore, through the combined effects of non-circuit processing and adiabatic geometric manipulation, a fast, more robust, and arbitrarily phase-angle-controlled two-qubit phase gate is achieved.

[0127] In one embodiment, in the process of performing adiabatic geometric manipulation on the qubit in the Rydberg state to obtain a first control field phase, the evolution unit 301 is further configured to: accelerate the adiabatic geometric manipulation through a quantum adiabatic shortcut under preset conditions to obtain an adiabatic geometric manipulation in an accelerated state; and evolve the Rydberg atom qubit through the adiabatic geometric manipulation in the accelerated state to accumulate and obtain a first phase.

[0128] In one embodiment, before the evolution of the Rydberg atom qubits under preset conditions through adiabatic geometric manipulation to accumulate a first phase, the evolution unit 301 is further configured to: acquire an initial control field phase; and perform an adiabatic operation on the initial control field phase to obtain a first control field phase that satisfies the adiabatic geometric manipulation conditions.

[0129] In one embodiment, the first phase includes a first dynamic phase and a first geometric phase, and the second phase includes a second dynamic phase and a second geometric phase; in obtaining the target phase of the Rydberg atom qubit conforming to a two-bit gate controlled phase gate based on the first phase and the second phase, the determining unit 304 is further configured to: superimpose the first dynamic phase and the second dynamic phase to obtain a third dynamic phase, wherein the third dynamic phase is 0; superimpose the first geometric phase and the second geometric phase to obtain a third geometric phase; and obtain the target phase of the Rydberg atom qubit conforming to a two-bit gate controlled phase gate based on the third dynamic phase and the third geometric phase.

[0130] In one embodiment, the non-circuit operation is to perform a π flip.

[0131] In one embodiment, under the condition of the second control field phase, the evolution unit 301 is further configured to: accelerate the adiabatic geometric manipulation through a quantum adiabatic shortcut under the condition of the second control field phase to obtain an accelerated adiabatic geometric manipulation; and control the Rydberg atom qubit to evolve through the accelerated adiabatic geometric manipulation to obtain a second phase.

[0132] In one embodiment, the quantum adiabatic shortcut is obtained by reverse engineering the Hamiltonian to obtain the form of an auxiliary Hamiltonian, and an auxiliary Hamiltonian is added during the evolution process to perform the quantum adiabatic shortcut operation.

[0133] See Figure 4 , Figure 4 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Figure 4 As shown, the computer device 40 includes a processor 401 and a memory 402. The memory 402 is connected to the processor 401, for example, via a bus.

[0134] Processor 401 is configured to support the computer device 40 in performing the corresponding functions in the methods described in the above method embodiments. Processor 401 may be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The aforementioned PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0135] Specifically, the processor 401 may include a transmitting card, a receiving card, and a driver chip.

[0136] Memory 402 is used to store program code, etc. Memory 402 may include volatile memory (VM), such as random access memory (RAM); memory 402 may also include non-volatile memory (NVM), such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); memory 402 may also include combinations of the above types of memory.

[0137] Processor 401 can call the program code to perform the following operations:

[0138] Under preset conditions, the Rydberg atomic qubits are evolved through adiabatic geometric manipulation to accumulate the first phase;

[0139] Obtain the first control field phase corresponding to the adiabatic geometric manipulation under preset conditions;

[0140] A non-circuit operation is performed on the first control field phase to obtain the second control field phase;

[0141] Under the conditions of the second control field phase, the Rydberg atom qubit is evolved through the adiabatic geometric manipulation to accumulate and obtain the second phase;

[0142] Based on the first phase and the second phase, the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate is obtained.

[0143] This application also provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a computer, cause the computer to perform the method described in the foregoing embodiments.

[0144] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0145] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A quantum computing method based on Rydberg atoms, characterized in that, include: Under preset conditions, the Rydberg atomic qubits are evolved through adiabatic geometric manipulation to accumulate the first phase; Obtain the first control field phase corresponding to the adiabatic geometric manipulation under preset conditions; A non-circuit operation is performed on the first control field phase to obtain the second control field phase; the non-circuit operation is to perform a π flip on the control field. Under the conditions of the second control field phase, the Rydberg atomic qubits are evolved through the adiabatic geometric manipulation to accumulate a second phase; the process of controlling the Rydberg atomic qubits to evolve through the adiabatic geometric manipulation to accumulate a second phase under the conditions of the second control field phase includes: Under the condition of the second control field phase, the adiabatic geometry is accelerated through the quantum adiabatic shortcut to obtain the adiabatic geometry in the accelerated state. The Rydberg atom qubits are evolved by controlling the adiabatic geometry of the accelerated state to accumulate a second phase; Based on the first phase and the second phase, the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate is obtained; The first phase includes a first dynamic phase and a first geometric phase, and the second phase includes a second dynamic phase and a second geometric phase; The step of obtaining the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate based on the first phase and the second phase includes: By superimposing the first dynamic phase and the second dynamic phase, a third dynamic phase is obtained, and the third dynamic phase is 0. The first geometric phase and the second geometric phase are superimposed to obtain the third geometric phase; Based on the third dynamic phase and the third geometric phase, the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate is obtained.

2. The method according to claim 1, characterized in that, The process of controlling the evolution of Rydberg atomic qubits under preset conditions through adiabatic geometric manipulation to accumulate the first phase includes: Under preset conditions, thermal geometry manipulation is accelerated through quantum thermal shortcuts to obtain thermal geometry manipulation in an accelerated state. The Rydberg atomic qubits are evolved through adiabatic geometric manipulation in an accelerated state, and the first phase is accumulated.

3. The method according to claim 1 or 2, characterized in that, Before the first phase is accumulated by controlling the evolution of Rydberg atomic qubits through adiabatic geometric manipulation under preset conditions, the method includes: Obtain the initial control field phase; The initial control field phase is subjected to adiabatic operation to obtain a first control field phase that satisfies the adiabatic geometric manipulation conditions.

4. The method according to claim 3, characterized in that, The quantum adiabatic shortcut is obtained by reverse engineering the Hamiltonian to obtain the form of the auxiliary Hamiltonian, and the auxiliary Hamiltonian is added during the evolution process to perform the quantum adiabatic shortcut operation.

5. A quantum computing device based on Rydberg atoms, characterized in that, include: The evolution unit is used to evolve the Rydberg atom qubit under preset conditions through adiabatic geometric manipulation, and accumulate to obtain the first phase; The acquisition unit is used to acquire the phase of the first control field corresponding to the adiabatic geometric manipulation under preset conditions; An operation unit is used to perform a non-circular operation on the first control field phase to obtain a second control field phase; the non-circular operation is to perform a π flip on the control field. The evolution unit is further configured to evolve the Rydberg atomic qubits under the conditions of the second control field phase through the adiabatic geometric manipulation, accumulating to obtain a second phase; the step of controlling the Rydberg atomic qubits to evolve under the conditions of the second control field phase through the adiabatic geometric manipulation, accumulating to obtain a second phase, includes: Under the condition of the second control field phase, the adiabatic geometry is accelerated through the quantum adiabatic shortcut to obtain the adiabatic geometry in the accelerated state. The Rydberg atom qubits are evolved by controlling the adiabatic geometry of the accelerated state to accumulate a second phase; A determining unit is configured to obtain a target phase of the Rydberg atom qubit that conforms to a two-bit gate controlled phase gate based on the first phase and the second phase; the first phase includes a first dynamic phase and a first geometric phase, and the second phase includes a second dynamic phase and a second geometric phase; The step of obtaining the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate based on the first phase and the second phase includes: By superimposing the first dynamic phase and the second dynamic phase, a third dynamic phase is obtained, and the third dynamic phase is 0. The first geometric phase and the second geometric phase are superimposed to obtain the third geometric phase; Based on the third dynamic phase and the third geometric phase, the target phase of the Rydberg atom qubit that conforms to the two-bit gate controlled phase gate is obtained.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions that, when executed by a processor, cause the processor to perform the quantum computing method based on Rydberg atoms as described in any one of claims 1-4.

7. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the quantum computing method based on Rydberg atoms as described in any one of claims 1 to 4.

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