Cost function deformation in quantum approximate optimization

    公开(公告)号:GB2582515A

    公开(公告)日:2020-09-23

    申请号:GB202008794

    申请日:2018-11-26

    Applicant: IBM

    Abstract: Techniques for performing cost function deformation in quantum approximate optimization are provided. The techniques include mapping a cost function associated with a combinatorial optimization problem to an optimization problem over allowed quantum states. A quantum Hamiltonian is constructed for the cost function, and a set of trial states are generated by a physical time evolution of the quantum hardware interspersed with control pulses. Aspects include measuring a quantum cost function for the trial states, determining a trial state resulting in optimal values, and deforming a Hamiltonian to find an optimal state and using the optimal state as a next starting state for a next optimization on a deformed Hamiltonian until an optimizer is determined with respect to a desired Hamiltonian.

    Short depth circuits as quantum classifiers

    公开(公告)号:GB2581942A

    公开(公告)日:2020-09-02

    申请号:GB202009136

    申请日:2017-12-21

    Applicant: IBM

    Abstract: A system comprises quantum hardware, a memory that stores computer-executable components and a processor that executes computer-executable components stored in the memory. The computer-executable components comprise a calibration component that calibrates quantum hardware to generate a short depth quantum circuit. The computer-executable components further comprise a cost function component that determines a cost function for the short depth quantum circuit based on an initial value for a parameter of a machine-learning classifier. The computer-executable components further comprise a training component that modifies the initial value for the parameter during training to a second value for the parameter based on the cost function for the short depth quantum circuit.

    Efficient reduction of resources for the simulation of fermionic hamiltonians on quantum hardware

    公开(公告)号:GB2566885A

    公开(公告)日:2019-03-27

    申请号:GB201901049

    申请日:2017-08-03

    Applicant: IBM

    Abstract: A technique relates to reducing qubits required on a quantum computer. A Fermionic system is characterized in terms of a Hamiltonian. The Fermionic system includes Fermions and Fermionic modes with a total number of 2M Fermionic modes. The Hamiltonian has a parity symmetry encoded by spin up and spin down parity operators (1005). Fermionic modes are sorted such that the first half to 2M modes corresponds to spin up and the second half of 2M modes corresponds to spin down (1010). The Hamiltonian and the parity operators are transformed utilizing a Fermion to qubit mapping that transforms parity operators to a first single qubit Pauli operator on a qubit M and a second single qubit Pauli operator on a qubit 2M (1015). The qubit M having been operated on by the first single qubit Pauli operator and the qubit 2M having been operated on by the second single qubit Pauli operator are removed (1020).

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