Method and device for obtaining eigenstate of quantum system, equipment, medium and product

Abstract

The invention discloses a method and device for obtaining eigenstate of a quantum system, equipment, a medium and a product, and relates to the technical field of quantum. The method comprises the steps of obtaining a circuit generation state of a target quantum system in an evolution process of the target quantum system; updating hamiltonian operator parameters in quantum dynamics expression by taking the minimum eigenstate as a target, wherein the quantum dynamics expression is dynamics expression based on quantum virtual time, and Hamiltonian operators are controlled; and circularly updating the Hamiltonian operator parameter and the circuit parameter until the minimum eigenstate is obtained. Quantum virtual time evolution and quantum real time control theories are combined, and the two mechanisms are analyzed, so that a set of control method which can be implemented on virtual time evolution is provided, the requirements on an initial state and a system are reduced, the requirement on control capability is also reduced, elastic selection is achieved, and meanwhile, a strategy of large-amplitude acceleration can be provided, and the convergence process is accelerated as much as possible or the requirement on the initial state is reduced in the controllable state.

Description

technical field [0001] The embodiments of the present application relate to the field of quantum technology, and in particular to a method, device, equipment, medium and product for obtaining eigenstates of a quantum system. Background technique [0002] With the rapid development of quantum computing, quantum algorithms have important applications in many fields, among which, solving the eigenstates and eigenenergy of quantum systems is a very critical issue. [0003] In related technologies, a method for obtaining the lowest eigenstate by imaginary time evolution is provided. After expressing the wave function in the imaginary time Schrödinger equation as an eigenvector expansion, the minimum eigenvalue is determined. Since the minimum eigenvalue is smaller than any eigenvalue Eigenvalue, when the time approaches infinity, other eigenvalues ​​will disappear at an exponential rate, so given any wave function with a non-zero overlap with the lowest eigenvalue, the initial lo...

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Problems solved by technology

[0004] However, in the above method, it is necessary to ensure the relationship between the initial state and the lowest eigenstate, and the difference between other eigenstates and the lowest eigenstate. The relationship between them will greatly affect the convergence rate of the program.

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