22 results about "Quantum system" patented technology

The invention relates to a quantum system (1) for stabilizing a cat qubit comprising: - a command circuit (5) including a microwave source (11) and a DC voltage source (13), and - a non-linear superconducting quantum circuit (3) including a non-linear element (7) comprising a Josephson junction, a first and a second resonant portions respectively having a first mode with a first resonant frequency fa and a second mode with a second resonant frequency fb. The non-linear superconducting quantum circuit (3) stabilizes a two-dimensional manifold hosting the cat qubit when: • the microwave source (11) delivers microwave radiation at a frequency equal to fb to the second resonant portion to drive the second mode, and • the DC voltage source (13) delivers DC voltage to bias the non-linear element (7), with the delivered DC voltage having a value inducing a microwave oscillation having a frequency equal to |2fa - fb|.

Provided are quantum control methods and systems. The method includes generating a control pulse in a quantum system, determining a measurement of a state of the quantum system in response to the control pulse, determining a control pulse correction based on the control pulse, the measurement of the state of the quantum system, and a model reference state, modifying the control pulse based on the control pulse correction, resulting in a modified control pulse, and generating the modified control pulse in the quantum system.

A method (100) for determining a ground state (1000) of a quantum system is disclosed, comprising the following steps: 6) determining (102) the thermal state (1020) of the quantum system at a temperature value (1001', 1001) by optimizing the free energy (3020) of the thermal state (1020) at the temperature value (1001', 1001) by iteratively adjusting gate parameters (1022', 1022) by means of a variational quantum thermalizer (1010) until a first termination criterion is met; 7) checking (1025) whether the previously found thermal state meets a second termination criterion; 8) if the second termination criterion is not met (10250): decreasing (1026) the temperature value (1001', 1001); initializing (301) the quantum circuit (1011) of the variational quantum thermalizer using the gate parameters (1022', 1022) from the last iteration of step 2); repeating steps 2) and 3); 9) if the second termination criterion is met (10251): providing (103) an energy spectrum (1030) of the quantum system using the gate parameters (1022) of the last iteration of step 2) before the second termination criterion (10251) is met; determining (104) the ground state (1000) of the quantum system by selecting the state of the energy spectrum that is assigned the lowest energy.

The invention discloses a quantum information feature extraction method, computer equipment and a computer readable storage medium. The method comprises the steps of obtaining quantum observation data of a quantum system; performing frequency domain conversion processing on the quantum observation data, and determining frequency domain characteristic data corresponding to the quantum observation data; according to the frequency domain feature data, target feature parameters are determined, and the target feature parameters are used for regulating and controlling the quantum system. Therefore, the frequency domain feature data can be obtained by performing frequency domain conversion processing on the quantum observation data, so that the target feature parameters are accurately obtained according to the frequency domain feature data, high-precision extraction of the target feature parameters is ensured, support is provided for accurate calibration of a quantum system, and automatic extraction of the quantum information feature data is realized. In addition, compared with a mode of judging the regulation and control parameter value of the quantum system only depending on experience, the implementation mode of the invention can eliminate subjective errors and improve the calibration precision of the quantum system.

This invention relates to the field of traffic safety technology, specifically to an efficient simulation method for quantum systems based on parallel order reduction. The method includes the following steps: receiving the physical parameters of the quantum system and simulation requirements, whereby the physical parameters include electron mass, potential well size, and initial wave packet parameters; and the simulation requirements include simulation physical time and accuracy requirements. Based on the physical parameters, a time-dependent Schrödinger equation describing the dynamic behavior of the quantum system is established, and the Schrödinger equation is rearranged into matrix form using the Kronecker product. This invention utilizes Arnoldi to reduce the order of the matrix-form Schrödinger equation. By reducing the order, the large matrix in the original space is projected into a relatively small subspace, improving the efficiency of the simulation solution. The reduced-order Schrödinger equation is solved using a time-parallel algorithm. This approach overcomes the time step limitation imposed by the CFL condition, ensuring that a stable solution can be obtained with fewer time steps.

Systems, methods, and quantum circuits for estimating an expectation value of an observable of a physical quantum system. A plurality of qubits is received, including inner and outer register qubits and state simulation qubits prepared in a reference eigenstate of a Hermitian operator having a reference eigenvalue. A first unitary operation is performed that receives the inner register and state simulation qubits as input and outputs phase information. The phase information is related to the reference eigenvalue and a plurality of eigenvalues of a first operator corresponding to the observable. The outer phase register qubits are measured to obtain classical measurement results that are used to determine an expectation value of the observable for the reference state.

The invention relates to a method for determining a resonance frequency (4) of a quantum system (6) in a frequency range (8), wherein in a first method step (34) the frequency range (8) is divided into a number of frequency bins (36, 36a... 36h), wherein in a second method step (42) for each frequency bin (36, 36a...36h): a measurement frequency (14) is generated, the measurement frequency (14) is expanded by signal processing to a frequency group (18) covering the frequency bin (36, 36a...36h), the quantum system (6) of the frequency group (18) is manipulated, and a resulting measurement signal (26) is acquired, and the measurement signal (26) is compared with a stored threshold value, wherein in a third method step (52) a resonance frequency (4) is determined on the basis of those measurement signals (26) which have reached or exceeded the threshold value.

A method of using a quantum-based system for outputting a variable for use with a first problem. A set of parameters is determined, for a second problem, for running the quantum-based system. The set of parameters are associated with at least one or more variables of the version of the second problem and enable the quantum-based system to output a plurality of solutions to the second problem. Each of the plurality of solutions is associated with a common set of quantum states of the quantum-based system and a different value of at least one of the said the variables of the second problem. The quantum-based system is run using at least the determined set of parameters to identify a set of one or more of the qubits corresponding to at least one of the solutions to the second problem. At least one solution to the second problem is determined to be a new variable for the first problem. The new variable is output for use with the version of the first problem.

An apparatus comprising a crystal; at least three first wires arranged substantially parallel to each other; at least two second wires arranged substantially parallel to each other, each second wire arranged non-parallel to each first wire, such that each second wire crosses each first wire, forming at least six cross points; and at least six colour centres, each colour centre located within the crystal adjacent a different one of the at least six cross points.

Non-linear superconducting circuit for stabilizing at least one cat qubit, the non-linear superconducting circuit comprising: a four-wave mixing non-linear element (7); a first resonant portion (29); and a second resonant portion (31) which is coupled to the first resonant portion via the four-wave mixing non-linear element; wherein the first resonant portion, the second resonant portion, and the four-wave mixing non-linear element are configured together to provide a first physical oscillatory mode (a) with a first resonant frequency for hosting a cat qubit and a second physical oscillatory mode (b) with a second resonant frequency which is more dissipative than the first physical oscillatory mode (a); and wherein at least one of the first and second resonant portions comprises a tunable inductor (8) and a capacitor (43,39) such that at least one of the first and second resonant frequencies are tunable with the inductance of the tunable inductor.

This application provides a method, system, device, and storage medium for measuring the external field parameters of a superconducting quantum system, relating to the technical field of quantum information computing. The method for measuring the external field parameters of a superconducting quantum system includes: performing quantum evolution at multiple preset evolution times on multiple first preset external field parameters based on a target Hamiltonian and an initial state to determine first quantum state data; determining a target probability set based on the first quantum state data; performing quantum evolution at multiple preset evolution times on second preset external field parameters based on the target Hamiltonian and the initial state to determine second quantum state data; performing joint time-domain Bayesian estimation based on the target probability set, the second quantum state data, and a Bayesian estimation framework to determine the target posterior probability distribution corresponding to the second preset external field parameters; and determining the target external field parameters based on the target posterior probability distribution and the second preset external field parameters. This application can achieve stable and high-precision measurement of unknown external field parameters.

This invention belongs to the field of information security and random number generation technology, and relates to a method and apparatus for enhancing the security of random number generation based on degenerate state mapping. The method includes: establishing the parameter space and energy level boundaries of a virtual quantum system in a classical computer, and initializing a basic pseudo-random number generator (PRNG); compressing and mapping the integer output of the PRNG to virtual quantum state indices; calculating feedback perturbations using the output values ​​of the previous round, correcting the indices, and dividing the energy levels and degenerate indices to obtain virtual quantum state labels; obtaining new random numbers from the PRNG, generating different degenerate indices within the same energy level, and constructing new virtual quantum states; calculating observable eigenvalues ​​in conjunction with measurement perturbations, processing them according to the measurement mode, and outputting the random numbers for the current round; iterating until the quantity requirement is met. It can sever linear relationships and has advantages such as time-varying mapping, removal of deterministic correlations, irreversible enhancement, configurable parameters, low hardware dependence, and compatibility with existing PRNGs.

This application proposes a quantum state tomography method, apparatus, and storage medium. The quantum state tomography method includes: receiving quantum system specifications and measurement constraints; preparing multiple quantum state replicas based on the quantum system specifications and measurement constraints; analyzing the multiple quantum state replicas based on Hamiltonian evolution to obtain a manifold of a predetermined quantum state; selecting an optimal measurement basis according to the manifold of the predetermined quantum state; acquiring measurement data of the multiple quantum state replicas under the optimal measurement basis to form a compressed measurement set; and generating a compressed measurement protocol based on the compressed measurement set, including: selecting a preset reconstruction algorithm and reconstructing the quantum state density matrix based on the compressed measurement set and the preset reconstruction algorithm. Based on this, this application can exponentially reduce the amount of measurement data, achieve complete state reconstruction of large-scale quantum systems, and ensure reconstruction fidelity.

The application discloses a multi-physical field coupling and impedance spectrum analysis flame detector nondestructive testing method and system, and relates to the technical field of helicopter flame detector nondestructive testing.The temperature field and the electromagnetic field are coupled to replace light, so that a simulation environment of fire radiation effect is provided for the flame detector, and the photochemical reaction of the photoelectric material caused by light is avoided; the error is eliminated through wide frequency scanning and the four-electrode method, the impedance spectrum is obtained through inversion calculation, and the physical parameters are obtained through deconstruction, so that the problem that the continuous relaxation process information contained in the wide frequency data is lost in traditional impedance analysis is avoided; the classical physical parameters of the sensor fault are mapped into the Hamiltonian of the quantum system, the fault is sensed by solving the ground state, and the defects that the classical machine learning is easy to fall into local optimization when processing high-dimensional, nonlinear and strongly correlated fault features, and the model is poor in interpretability.

This invention discloses a method for generating entanglement in a hybrid quantum system based on geometric phase. The method first constructs a hybrid quantum system containing superconducting transporter qubits, semiconductor spin qubits, and a surface acoustic wave resonator. Virtual phonons within the resonator serve as quantum transducers, and the system is placed in a dispersive region to achieve effective coupling between two qubits. Then, based on non-adiabatic geometric phase manipulation, a three-segment driving pulse sequence is designed to form an entanglement gate. Finally, the amplitude and phase of the driving field are controlled to accumulate the geometric phase and generate a high-fidelity entangled state. This invention achieves compact on-chip integration of the hybrid system, forming an entanglement gate with a fidelity ≥0.96 within 100 nanoseconds, achieving a quantum state transfer fidelity of over 0.966. It exhibits excellent robustness to parameter fluctuations and environmental dissipation. The scheme is easy to implement and scalable to similar hybrid quantum systems, providing technical support for scalable quantum information processing.

Methods and apparatus for measuring quantum systems involve: applying first optical pulses to the quantum system and monitoring for a first resulting photon after each first optical pulse; in response to detecting one or more first resulting photons, performing a π operation on the quantum system; and, after performing the π operation, applying second optical pulses to the quantum system and monitoring for a second resulting photon after each second optical pulse. The first and second optical pulses comprise a wavelength corresponding to a transition from a first basis state of the quantum system to an excited state. A measurement result is determined based on results of the monitoring.

This invention discloses a hardware-aware intelligent scheduling system for quantum tasks, relating to the field of quantum technology. The system includes a hardware monitoring module, a feature extraction module, a matching prediction module, and a scheduling optimization module. The hardware monitoring module collects physical parameters and constructs an instantaneous state matrix. The feature extraction module extracts resource and noise features. The matching optimization module maximizes the global expected success rate of the target quantum system. The scheduling optimization module updates the global expected success rate and the optimal task queue based on the changed instantaneous state matrix. This invention periodically collects and records key physical parameters of physical qubits and dynamically adjusts the task queue and optimizes the expected success rate in real time, enabling the quantum system to adjust according to the real-time state of the hardware. This ensures improved task success rate and overall system stability even with increased task load and resource requirements.

A method for optimizing a set of control parameter of a quantum system comprises obtaining a set of control parameter values and executing at least one measurement process. The at least one measurement process comprises acting with a sequence of operations of a sequence length on the quantum system to measure a sequence fidelity; updating the set of control parameter values by using an optimization routine based on a cost function obtained from the measured sequence fidelity and repeating the aforementioned steps, wherein the sequence length is determined according to an optimal sensitivity criterion.

There is provided a method for resetting an arbitrary state, hosted in a quantum system, to the vacuum Fock state or a coherent state, wherein the quantum system comprises: (I) at least one resonant portion configured to have a first mode having a first resonant frequency and wherein the arbitrary state is hosted in the first mode, (II) a non-linear element coupled to the at least one resonant portion so as to non-linearly couple to the first mode, and (III) one or more signal generator(s) coupled to the at least one resonant portion and / or to the non-linear element and configured to input control signals to physically stabilize a cat qubit subspace in the first mode having a cat phase angle. The method comprises: (i) physically stabilizing for a first period of time, with the one or more signal generator(s), a first cat qubit subspace having a first cat phase angle and first cat size ΙαΙ2, wherein α is a first amplitude which is the amplitude of the superposed coherent states Ι ± α > defining the first cat qubit subspace (702); (ii) after the first period of time, physically performing for a second period of time, with the one or more signal generator(s), a first parallel displacement drive by inputting electromagnetic radiation having a first phase substantially equal with the first cat phase angle, a frequency substantially equal to the first resonant frequency, and a first displacement amplitude greater than or equal to the first amplitude (704); (iii) after the second period of time, physically stabilizing for a third period of time, with the one or more signal generator(s), a second cat qubit subspace having a second cat phase angle which is substantially equal to the first cat phase angle and second cat size ΙβΙ2, wherein β is a second amplitude which is the amplitude of the superposed coherent states Ι ± β > defining the first cat qubit subspace, such that a coherent state Ιβ> with the second amplitude β is stabilized in the first mode (706). There is also provided a corresponding quantum processor, a computer program product, and a computer-readable medium.

A method, apparatus, device, and storage medium for determining the topological type of a quantum system are provided. The proposed method includes: using a neural network for the quantum system, determining multiple quantum states of the quantum system by inserting magnetic flux into the quantum system, wherein the neural network represents the wave function of the quantum system, and the multiple quantum states correspond to the inserted multiple magnetic fluxes; determining the corresponding polarization states of the quantum system under the multiple quantum states based on the neural network; and determining the topological type of the quantum system based on the corresponding polarization states under the multiple quantum states. In this manner, by inserting magnetic flux into the quantum system and utilizing a neural network, the topological type of the system can be determined, thereby facilitating the acquisition of more properties of the system.