81 results about "Ground state" patented technology

The invention relates to the technical field of quantum computing, and provides a polariton quantum computing simulation method and related device.The method comprises the steps that parameterized quantum circuits are generated based on micromodels used for describing polaritons for all to-be-computed excitation states respectively, and the parameterized quantum circuits are generated based on initial Hamiltonian of polaritons in a ground state; the target Hamiltonian amount of the polariton in the current excitation state is obtained, then the value of each parameter is adjusted at least once, and the target energy of the corresponding excitation state is obtained. In the primary adjustment process, parameter updating is carried out on the quantum circuit, a reference quantum state of the corresponding excitation state is obtained by utilizing the updated quantum circuit, reference energy of the corresponding excitation state is obtained based on the reference quantum state and in combination with the target Hamiltonian, and then when a set convergence condition is met, the target Hamiltonian is obtained. And taking the reference energy as target energy of the corresponding excited state. The polaritons are simulated through the quantum computer, and the simulation efficiency is improved.

Aspects of the present disclosure may include a method and / or a system for identifying an ion chain having a plurality of trapped ions, selecting at least two non-consecutive trapped ions in the ion chain for implementing a qubit, applying at least a first Raman beam to shuttle at least one neighbor ion of the at least two non-consecutive trapped ions from a ground state to a metastable state, and applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold.

The invention relates to the field of electric field quantum measurement, in particular to a low-frequency electric field measurement method and a three-photon Rydberg system. The low-frequency electric field measurement method comprises the following steps: moving an atom gas chamber containing cesium atoms to a low-frequency electric field to be measured; cesium atoms are driven by probe light to transition from a ground state 6S1 / 2 to an excited state 6P1 / 2; driving cesium atoms to jump from an excited state 6P1 / 2 to an excited state 9S1 / 2 through decoration light; driving the cesium atoms to transition from an excited state 9S1 / 2 to a higher Rydberg state nP3 / 2 through coupled light to obtain Rydberg atoms; a photoelectric detector is adopted to detect the absorption condition of the detection light; based on the absorption condition, an oscilloscope is adopted to observe EIT spectrum change; based on the EIT spectrum change, obtaining a spectrum frequency shift amount; and the electric field intensity of the low-frequency electric field to be measured is calculated through the spectral frequency shift amount and the polarizability of the Rydberg atoms, so that the shielding problem of the atomic air chamber to the low-frequency electric field can be reduced, the spectral line width is narrower, and the electric field measurement resolution is greatly improved.

Techniques are provided for performing an optically heralded entanglement process to entangle states of a first data quantum bit and a second data quantum bit into an entangled state of computational basis states comprising a ground state and a first excited state. An optically heralded entanglement process comprises performing a first optically heralded entanglement process to determine whether the entangled state of the first data quantum bit and the second data quantum bit excludes a state in which both the first data quantum bit and the second data quantum bit can be in the ground state, and performing a second optically heralded entanglement process to determine whether the entangled state of the first data quantum bit and the second data quantum bit excludes a state in which both the first data quantum bit and the second data quantum bit can be in the first excited state.

Technologies and techniques for estimating the ground state energy of a quantum chemical system. The method includes classically computing states close to the ground state of the quantum chemical system, assessing the quality of the classically computed states based on their energy distribution, selecting a state based on the assessment result, implementing the selected state on a quantum computer, and estimating the ground state energy of the quantum chemical system on the quantum computer based on the implemented state. The disclosure also encompasses various technologies and techniques for preparing a quantum state for quantum energy estimation on a quantum chemical system and a system for performing these methods.

The disclosure is directed to a quantum processor system. The system includes a transmission line, a resonator, a qubit coupled to the resonator, and a switching device that couples and decouples the resonator to the transmission line. The resonator stores a range of energies based on a frequency that characterizes the resonator. When a quantum state of the qubit is equivalent to an excited state and the qubit is tuned in accordance with the frequency, energy is transferred from the qubit to the resonator, which stores the energy. The quantum state of the qubit is transitioned to a ground state. When the switching device is closed, the resonator is coupled to the transmission line such that the energy is transferred to the transmission line. When the switching device is opened, the resonator is decoupled from the transmission line.

The invention discloses a quantum phase-locked detection method based on entanglement enhancement, and the method comprises the steps: encoding quantum bits in a ground state and an excited state, and preparing the quantum bits into an initialized quantum state; loading a periodic multi-pulse sequence to act on the quantum bits; and loading a carrier pulse resonating with the ground state and the excited state, detecting the final quantum state of the quantum bit, and comparing curves of each component of the measurement density matrix and the theoretical density matrix changing along with the pulse time interval of the periodic multi-pulse sequence to obtain the half cycle and the amplitude of the sine wave to be measured. According to the method, measurement noise under the condition that the rotation angle and the detuning error exist can be effectively restrained, high measurement precision is kept under the condition that the rotation angle and the detuning error exist, and the robustness enables the method to be more reliable in practical application.

Aspects of the present disclosure may include methods and systems for applying a first light to transition at least one trapped ion of a first quantum processing unit from a ground state to an intermediate state via a narrow quadrupole transition, applying a second light to transition the at least one trapped ion from the intermediate state to an excited state, and directing at least one photon, emitted from the trapped ion relaxing from the excited state back to the ground state, toward a second quantum processing unit to entangle the first quantum processing unit and the second quantum processing unit.

The invention provides a measurement-based quantum calculation method for a physical driving variable component sub-character solicitation solver, and the method comprises the steps: S1, constructing a variational structure according to a Hamiltonian expression of a to-be-solved quantum multi-body system; s2, converting the variational structure into a graph state and a measurement mode corresponding to a measurement type quantum calculation scheme; s3, initializing an input state; s4, according to the designed measurement sequence, performing a series of single particle measurement on the graph state from the input state to obtain the output state of the variable component sub-line; and S5, continuously iteratively optimizing the variational parameters until the ground state energy of the target Hamiltonian is solved. According to the method, a variational structure is constructed from Hamiltonian of a problem to be solved, the advantages of single-particle measurement operation in measurement type quantum calculation are utilized, implementation of a multi-quantum-bit revolving door is simplified by introducing a small number of auxiliary quantum bits, and therefore quantum resource overhead of a quantum circuit is greatly reduced.

A method of performing improved Kohn-Sham Density Functional Theory, DFT, calculations, for simulation of a material, chemical, or biological system includes: (i) constructing a model Hamiltonian of the system to be simulated; (ii) inputting an electron density of the system to be simulated; (iii) constructing a Kohn-Sham potential and (iv) executing a quantum Kohn-Sham DFT algorithm iteration using the electron density from (ii) and the Kohn-Sham potential from (iii) to compute an updated electron density and an updated total energy of the system to be simulated. The Kohn-Sham potential is constructed by: (1) providing a second Hamiltonian based on the model Hamiltonian; (2) calculating a ground state energy of the second Hamiltonian, as a function of electron density, using a quantum algorithm executed by a noisy intermediate-scale quantum, NISQ, processor; (3) computing a quantum-obtained exchange correlation energy functional, as a function of electron density, from the NISQ processor-obtained ground state energy of step (2); (4) obtaining a quantum-obtained exchange correlation potential functional by differentiation of the quantum-obtained exchange correlation energy functional from step (3); and (5) using the quantum-obtained exchange correlation potential functional from (4) to construct the Kohn-Sham potential.

The invention relates to a method for estimating a ground state energy (10) of a quantum chemical system, the method comprising: classically computing states (4) close to the ground state of the quantum chemical system, assessing the quality of the classically computed states (4) based on the energy distribution of each state (4), selecting a state (4) based on the assessment result, implementing the selected state (5) on a quantum computer (3), and estimating the ground state energy (10) of the quantum chemical system on the quantum computer based on the implemented state (5). Further, the invention relates various methods for preparing a quantum state (4,5) for quantum energy estimation on a quantum chemical system and to a system (1).

The application discloses a kind of based on ensemble rare earth ions double quantum bit controlled gate construction method, it is related to quantum control technical field, it includes to double quantum bit frequency site selection, and respectively as control bit, target bit;Utilize the blocking effect generated by the dipole-dipole interaction between double quantum bits to construct controlled gate, including: to control bit apply light pulse driving control bit is from ground state transition to excited state;To target bit apply single quantum gate to drive its evolution, and apply compensation pulse;To control bit apply light pulse driving control bit from excited state de-excitation to ground state.The application utilizes the interaction of the light pulse and quantum system medium that can be optimized to produce arbitrary geometric quantum logic gate on target quantum bit, and simultaneously by using the blocking effect caused by dipole-dipole interaction, the evolution of target bit quantum bit can be constrained by control bit.

An information processing apparatus creates qubit pairs, each being formed by combining first and second qubits. A first qubit corresponds to a first orbital on which an electron is present in an initial arrangement. A second qubit corresponds to a second orbital on which no electron is present in the initial arrangement. The apparatus generates a quantum circuit that applies two-qubit gates to at least some of the qubit pairs. Each two-qubit gate generates, based on the value of a parameter, a superposition state of a first state in which the states of the first and second qubits are not switched and a second state in which these states are switched. The apparatus acquires an energy expectation value in the ground state of the molecule by causing a quantum computer to iteratively execute the quantum circuit.

The invention discloses a method and device for calculating energy of a target system and a medium, and the method comprises the steps: firstly, determining a Fermi-form Hartree Fock state of the target system, then constructing a quantum phase estimation line, generating a control pulse of a quantum logic gate in the quantum phase estimation line, and calculating the energy of the target system according to the control pulse. The method comprises the following steps of: constructing a quantum phase estimation circuit capable of being used for current quantum computing hardware equipment, enabling a control pulse to act on a quantum bit in the quantum phase estimation circuit to evolve the specified quantum bit from a Hartree Fock state to a target quantum state, and finally calculating ground state energy of a target system according to the Hartree Fock state and the target quantum state, so that the ground state energy of the target system is calculated by constructing the quantum phase estimation circuit capable of being used for the current quantum computing hardware equipment. The method provides support for realizing quantum chemistry simulation calculation of target system energy, improves calculation speed and calculation precision, and promotes simulation calculation of target system ground state energy.

The application discloses a quantum phase-locked detection method based on entanglement enhancement, encodes quantum bits in a ground state and an excited state, and prepares the quantum bits as initial quantum states; a periodic multi-pulse sequence is loaded on the quantum bits; a carrier wave pulse resonating with the ground state and the excited state is loaded; a final quantum state of the quantum bits is detected; curves of each component of a measured density matrix and a theoretical density matrix changing with a pulse time interval of the periodic multi-pulse sequence are compared; and a half period and an amplitude of a to-be-measured sinusoidal wave are obtained. The application can effectively suppress measurement noise under the condition of existing rotation angles and detuning errors, and can maintain high measurement precision under the condition of existing rotation angles and detuning errors. The robustness makes the application more reliable in practical application.

This invention provides a method and apparatus for determining the ground state energy of a target molecular system. The method includes: determining a first Hamiltonian of the target molecular system using the Born-Oppenheimer approximation; determining a first correction term using a preset perturbation expansion based on a preset mass ratio parameter of electrons to atomic nuclei in the target molecular system and the first Hamiltonian; applying the first correction term to the first Hamiltonian to obtain a second Hamiltonian; and determining the ground state energy corresponding to the second Hamiltonian based on the second Hamiltonian and a preset variable quantum circuit.

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 various embodiments pertain to extracting one or more noiseless configurations from a collection of noisy configurations generated by a quantum processor. A configuration can be represented as a series of bits, 1's and 0's, whereby 1 indicates a spin orbital is occupied and 0 indicates spin orbital is empty. Noise in the quantum system can cause a respective bit to be flipped from a 0 to a 1, and vice-versa. During removal of the noise effect(s), bits can be flipped from their current value to an alternate value (e.g., 0 → 1, 1 → 0). After bit flipping, a Hamiltonian diagonalization process can be applied to the noiseless configuration to generate an eigenstate from which a ground state of the system represented by the noisy configuration can be determined. The system can be an atom or molecule, with the bits relating to a spin orbital of an electron.

Systems and methods are disclosed for determining interaction parameters for multiple particles, each particle having a ground state, an excited state, and one or more intermediate states The multiple particles are configured to interact with a plurality of electromagnetic fields associated with a (different) transition between two states. The method comprises performing a spectroscopy measurement, measuring an effective Rabi frequency Ωeff, measuring a single-photon Ramsey frequency ΩR i , and determining the interaction parameters based on the measured effective detuning δ eff, the measured effective Rabi frequency Ωeff, and the measured single-photon Ramsey frequencies ΩR i . The interaction parameters may be determined for each of the multiple particles. The interaction parameters may comprise a single-photon Rabi frequency Ω i for each electromagnetic field, which may be used to align the electromagnetic fields with respect to the particles.

The embodiment of the invention provides a method for determining a ground state energy value of a target quantum system and a related device. The method comprises the following steps: acquiring a plurality of parameter value sets corresponding to a specified parameter set; taking minimization of the energy value of the quantum state as a target, adjusting at least part of parameter values in the parameter value set until a specified convergence condition is achieved, and obtaining a ground state energy value of the target quantum system; adjusting at least a part of parameter values in the parameter value set: when the gradient information is used for updating the parameter value set until the energy value corresponding to the quantum state meets a preset local convergence condition, using the global optimal position information of the plurality of parameter value sets for updating; or, when global optimal position information of the multiple parameter value sets is used for updating the parameter value sets until the distance between the position of the parameter value sets in the search space and the global optimal position is smaller than a preset distance threshold value, gradient information is used for updating. The accuracy of the determined ground state energy value can be improved to a certain extent.

The invention relates to the cross technical field of quantum calculation and quantum chemistry, and particularly discloses a variable component subscript solicitation method and device based on physical symmetry, a medium and equipment, the method comprises the following steps: obtaining target system information, the target system information comprises Hamiltonian, electron number, orbit energy distribution and symmetry of a target system; reducing the Hamiltonian based on the electron number and the orbit energy distribution, and converting the reduced Hamiltonian from a Fermi operator form to a Fouli operator form to obtain a Fouli Hamiltonian; determining a variable component sub-line based on the symmetry; and solving the Follicle Hamiltonian quantity based on the variable component sub-line to obtain the ground state energy of the target system. The method solves the problem that the current quantum calculation bit number is difficult to adapt to a large chemical system.

System and method for simulated quantum annealing to solve optimization problems. The method comprises performing simulated quantum annealing by: generating quantum annealing simulations of an objective function that represents an optimization problem by initializing a guiding wave function with a variational ansatz, wherein the guiding wave function represents a ground state wave function of a quantum optimization Hamiltonian that the objective function represented as a classical Hamiltonian and a non-commutating driving term causing quantum fluctuations; stochastically evolving the quantum annealing simulations under a time-dependent driving schedule according to an imaginary-time Schrödinger equation supplemented by the guiding wave function until a predetermined condition is met; and outputting a plurality of output states responsive to the predetermined condition being met, each output state representing a solution to the optimization problem of the application-specific parameters within the application-specific constraints.

A method for measuring a preferably static magnetic field is claimed, comprising the following steps in this order: i) Excitation of a valence electron of one or more alkali atoms (2) from a ground state to an initiation state in a manifold with principal quantum number n; ii) Application of a ½ control pulse to generate a superposition, preferably a uniformly distributed superposition, between the initiation state and a control state; iii) Application of a sequence of circulation pulses and one or more control pulses, preferably with specific time intervals, to shift the valence electron within the manifold of the initiation state; iv) Application of a further ½ control pulse for coherent mixing of the populations in the initiation state and control state; v) Measurement of the state of the valence electron, and preferably calculation of the magnetic field;

This invention discloses a molecular dynamics calculation method and system based on quantum simulation. The method first applies a discrete quantum Fourier transform to the atomic coordinates of the molecular system, mapping the original plane wave basis to a system containing only O(N) atoms. 2 The invention constructs a plane-wave bibasic quantum mechanics equation; then, it constructs and solves the electronic structure Hamiltonian on a quantum computer to obtain the ground state energy. This quantum energy is combined with the classical empirical potential energy according to predetermined weighting coefficients to calculate the total synthesized energy, from which the atomic forces are determined. The integration time step is then adaptively adjusted based on a comparison of the quantum energy change between consecutive time steps with a preset threshold. This adaptive mechanism shortens the time step to ensure accuracy when quantum effects are significant, and lengthens the step to improve efficiency when changes are gradual. This invention significantly reduces Hamiltonian complexity, balancing quantum accuracy and classical efficiency, and is applicable to various fields such as drug screening, materials design, and catalytic reaction simulation.

The invention provides a multi-component magnetic alloy Curie temperature calculation method and device, a medium and equipment, and the method comprises the steps: defining to-be-calculated alloy components, and generating an input file needed by an EMTO calculation program based on preset calculation parameters; traversing each alloy component, and generating corresponding KGRN and KFCD input files in combination with preset crystal structure types and magnetic configuration configurations; an EMTO calculation program is called, calculation tasks are executed in batches based on the input file, and the calculation tasks comprise KGRN and KFCD tasks which are executed in sequence; automatically extracting state equation data based on an output result of the calculation task; batch fitting is carried out based on the extracted state equation data so as to predict ferromagnetic state ground state total energy and paramagnetic state ground state total energy; and based on the total energy of the ferromagnetic ground state and the total energy of the paramagnetic ground state, which are obtained by fitting, calculating the Curie temperature by adopting an average field theoretical formula. The method greatly reduces the time components of experiment trial and error and saves the capital cost.

The present invention provides a method and device for range ambiguity suppression with multi-physics parameter coupling constraints, belonging to the field of radar technology. The method comprises: establishing a range ambiguity suppression model with multi-physics parameter coupling constraints, constructing an optimization model for solving the optimal weighting factor; using a ground near-field scanning antenna system ground state error acquisition method to obtain the ground state amplitude and phase errors of each radiating element; using a ground-based high-precision measurement method based on a calibration network to obtain the delay error; using an on-orbit calibration single TR traversal test method to obtain the on-orbit amplitude and phase error; and proposing a high-precision error compensation method based on the comprehensive ground state amplitude and phase error, delay error, and on-orbit amplitude and phase error to obtain an accurate on-orbit antenna pattern, thereby suppressing range ambiguity. The present invention can improve the control accuracy of the antenna pattern.

The application discloses a kind of method, device and medium for calculating the energy of target system, method includes: first determine the Hartree Fock state of fermion form of target system, then construct quantum phase estimation circuit, generate the control pulse of quantum logic gate in quantum phase estimation circuit, and the control pulse is acted on quantum bit in quantum phase estimation circuit, so that specified quantum bit is evolved from Hartree Fock state to target quantum state, finally, according to Hartree Fock state and target quantum state, the ground state energy of the target system is calculated, it is constructed by quantum phase estimation circuit that can be used for current quantum computing hardware equipment, for the realization of quantum chemistry simulation calculation target system energy provides support, improve computing speed and calculation accuracy, promote the simulation calculation of target system ground state energy.

The invention discloses a double-quantum-bit controlled gate construction method based on ensemble rare earth ions, and relates to the technical field of quantum control, and the method comprises the steps: carrying out the site selection of double-quantum-bit frequency, and taking the double-quantum-bit frequency as a control bit and a target bit; a controlled gate is constructed by using a blocking effect generated by dipole-dipole interaction between double quantum bits. The method comprises the following steps: applying an optical pulse to a control bit to drive the control bit to transition from a ground state to an excited state; applying a single quantum gate to the target bit to drive the target bit to evolve, and applying a compensation pulse; and applying an optical pulse to the control bit to drive the control bit to be de-excited from the excited state to the ground state. According to the invention, any geometric quantum logic gate is generated on a target quantum bit by utilizing the interaction of optimizable light pulses and a quantum system medium, and meanwhile, the evolution of the target bit quantum bit can be restrained by a control bit by utilizing a blocking effect caused by dipole-dipole interaction.

The application provides a Curie temperature calculation method, device, medium and equipment of a multi-component magnetic alloy, which comprises the following steps: defining alloy components to be calculated, and generating input files required by an EMTO calculation program based on preset calculation parameters; traversing each alloy component, and generating corresponding KGRN and KFCD input files in combination with preset crystal structure types and magnetic configuration configurations; calling the EMTO calculation program, performing a calculation task in batches based on the input files, including sequentially performing KGRN and KFCD tasks; automatically extracting state equation data based on the output results of the calculation task; performing batch fitting based on the extracted state equation data to predict ferromagnetic state ground state total energy and paramagnetic state ground state total energy; and calculating the Curie temperature by using an average field theory formula based on the ferromagnetic state ground state total energy and the paramagnetic state ground state total energy obtained by fitting. The method greatly reduces the time component of experimental trial and error and saves the cost.

A technique is provided for cooling generic many-body quantum systems of unknown Hamiltonians to their ground states with a very high fidelity. The technique works by switching on a strong field and applying a sequence of projective measurements and RF pulses to polarize the system along the direction of the external field before we adiabatically switch the field off. The evolution of the system towards its ground state is governed by the quantum adiabatic theorem. We numerically simulate the proposed technique for quantum spin chains with long and short range interactions.