Fermionic simulation gates
AssigneeGoogle Inc.
InventorRyan Babbush
Life of this patent
Estimating the term…
Abstract
Methods, systems, and apparatus for simulating a physical system. A Hamiltonian describing the physical system is transformed into a qubit Hamiltonian describing a corresponding system of qubits, the qubit Hamiltonian comprising a transformed kinetic energy operator. The evolution of the system of qubits under the qubit Hamiltonian is simulated, including simulating the evolution of the system of qubits under the transformed kinetic energy operator by applying a fermionic swap network to the system of qubits. The simulated evolution of the system of qubits under the qubit Hamiltonian is used to determine properties of the physical system.
Claims17
A method performed by a quantum computer comprising a system of qubits with linear nearest neighbor connectivity, the method comprising:
- implementing a Trotter step of evolution of the system of qubits under a qubit Hamiltonian by applying a fermionic swap network to the system of qubits, wherein applying the fermionic swap network comprises:
- applying a plurality of layers of fermionic simulation gates to the system of qubits to simulate a kinetic energy operator included in the qubit Hamiltonian, wherein each fermionic simulation gate is a quantum logic gate that operates on two qubits and is configured to perform, within a single gate operation, (i) a fermionic mode exchange between the two qubits and (ii) time evolution of the kinetic energy operator acting between the two qubits,
- applying multiple single qubit gates to the system of qubits to simulate single qubit terms in an external potential term and single qubit terms arising from an interaction term included in the qubit Hamiltonian, wherein the single qubit gates are interleaved between successive layers of the fermionic simulation gates;
- and
- measuring the system of qubits to determine an output of the Trotter step of evolution.
An apparatus comprising:
- quantum hardware, comprising:
- a system of qubits with linear nearest neighbor connectivity,
- a plurality of single qubit gates,
- a plurality of two qubit gates;
- one or more classical processors;
- wherein the apparatus is configured to perform operations comprising:
- implementing a Trotter step of evolution of the system of qubits under a qubit Hamiltonian by applying a fermionic swap network to the system of qubits, wherein applying the fermionic swap network comprises:
- applying a plurality of layers of fermionic simulation gates to the system of qubits to simulate a kinetic energy operator included in the qubit Hamiltonian, wherein each fermionic simulation gate is a quantum logic gate that operates on two qubits and is configured to perform, within a single gate operation, (i) a fermionic mode exchange between the two qubits and (ii) time evolution of the kinetic energy operator acting between the two qubits,
- applying multiple single qubit gates to the system of qubits to simulate single qubit terms in an external potential term and single qubit terms arising from an interaction term included in the qubit Hamiltonian, wherein the single qubit gates are interleaved between successive layers of the fermionic simulation gates;
- and
- measuring the system of qubits to determine an output of the Trotter step of evolution.
Dependencies are inferred from the claim text.