公开(公告)号：US20240346360A1

公开(公告)日：2024-10-17

申请号：US18510020

申请日：2023-11-15

Applicant: Google LLC

Inventor： Ryan Babbush ,  Joonho Lee ,  William Huggins

IPC: G06N10/80

CPC classification number: G06N10/80

Abstract: Methods, systems, and apparatus for simulating a quantum system. In one aspect, a method includes performing a first quantized quantum algorithm on an initial quantum state to simulate time evolution of a fermionic system and generate a time evolved quantum state; and measuring, by the quantum computer, the time evolved quantum state to obtain one or more reduced density matrices in first quantization, the measuring including performing a classical shadows method that applies separate random Clifford channels to each qubit register of multiple qubit registers that represent respective occupied orbitals in the fermionic system.

公开(公告)号：US20240296362A1

公开(公告)日：2024-09-05

申请号：US18574922

申请日：2022-06-28

Applicant: Google LLC

Inventor： William Huggins ,  Joonho Lee ,  Ryan Babbush

IPC: G06N10/20

CPC classification number: G06N10/20

Abstract: Methods, systems, and apparatus for hybrid quantum-classical quantum Monte Carlo. In one aspect, a method includes receiving, by a classical computer, data generated by a quantum computer, the data representing results of measurements of a trial wavefunction, wherein the trial wavefunction approximates the target wavefunction and is prepared by the quantum computer, computing, by the classical computer, a classical shadow of the trial wavefunction using the data representing the results of the measurements of the trial wavefunction, and performing, by the classical computer, imaginary time propagation for a sequence of imaginary time steps of an initial wavefunction using a Hamiltonian that characterizes the fermionic quantum system, wherein: the imaginary time propagation is performed until predetermined convergence criteria are met; and performing each imaginary time step of the imaginary time propagation comprises updating the wavefunction for the previous imaginary time step using the classical shadow of the trial wavefunction to obtain a wavefunction for the current imaginary time step.