Holographic quantum dynamics simulation

Patent metadata

Field	Value
Publication number	US-11442891-B2
Application number	US-201916705727-A
Country	US
Kind code	B2
Filing date	Dec 6, 2019
Priority date	Dec 6, 2019
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

A quantum computer controller receives a quantum circuit comprising circuit slices. The first slice comprises a past causal cone of a first system qubit wire at a fully evolved level of the circuit. An i-th slice contains all gates that are within a past causal cone of a system qubit wire that reaches the fully evolved level in slice i that are not in the past causal cone of a system qubit wire that reaches the fully evolved level in slice i−j. The controller causes execution of the i-th slice using the physical qubits; causes a physical qubit that was evolved along a system qubit wire to the fully evolved level via execution of the i-th slice to be reinitialized and reintroduced onto a system qubit wire at a base level of the i+m-th slice; and causes the quantum computer to use the physical qubit to execute the i+m-th slice.

First claim

The invention claimed is:

1. A method comprising:
receiving, by a controller of a quantum computer comprising qubit management systems and a plurality of physical qubits, a quantum circuit comprising a plurality of circuit slices, wherein a first slice of the plurality of circuit slices comprises a past causal cone of a first system qubit wire at a fully evolved level of the quantum circuit, and an i-th slice of the plurality of circuit slices is defined to contain all gates that are not within a past causal cone of any system qubit wire of the quantum circuit that reaches the fully evolved level of the quantum circuit in slice i−j, where 0≤j<i is an integer, but that can now be executed by initiating one or more physical qubits that have reached the fully evolved level during execution of slice i−1, have optionally been measured, and reset onto the system qubit wires in a base level of slice i;
causing, by the controller, execution of the i-th slice of the quantum circuit using the physical qubits of the quantum computer;
causing, by the controller, a physical qubit that was evolved as the system qubit fully evolved via execution of the i-th slice to be optionally measured, and reinitialized and reintroduced onto a system qubit wire at a base level of the i+m-th slice, m a positive integer; and
causing, by the controller, the quantum computer to use the physical qubit to execute the i+m-th slice of the quantum circuit.

2. The method of claim 1 , wherein executing the i-th slice of the quantum circuit comprises executing all gates for which incoming and outgoing wires lie within the i-th slice in order to propagate the system qubits forward in time.

3. The method of claim 2 , wherein the quantum circuit comprises at least one ancilla wire and executing the i-th slice of the quantum circuit comprises interacting one or more system qubits at a bottom of the i-th slice with at least one ancilla qubit via unitary gates in order to introduce initial correlations between the one or more system qubits at the bottom of the i-th slice and system qubits at the bottom of one or more other slices.

4. The method of claim 1 , wherein the quantum circuit encodes interactions governed by a Hamiltonian characterized by local interactions.

5. The method of claim 1 , wherein each system qubit wire corresponds to a degree of freedom associated with a section of a physical domain being simulated.

6. The method of claim 5 , wherein executing the i-th slice of the quantum circuit comprises evolving the degree of freedom in accordance with an operator.

7. The method of claim 6 , wherein the operator is a Hamiltonian.

8. The method of claim 5 , wherein the physical domain is one of a one dimensional, two dimensional, or three dimensional physical domain.

9. The method of claim 5 , wherein the quantum circuit simulates the dynamics of the evolution of quantum states defined on a lattice representing the physical domain.

10. The method of claim 1 , further comprising performing one or more measurements of at least one physical qubit of the plurality of qubits to determine a value corresponding to at least one degree of freedom within the physical domain.

11. The method of claim 1 , wherein at least one system qubit wire of the quantum circuit extends through multiple slices of quantum circuit.

12. A computing entity in communication with a controller of a quantum computer comprising qubit management systems and a plurality of physical qubits, the computing entity configured to cause the controller to control elements of the quantum computer to:
receive, by the controller, a quantum circuit comprising a plurality of circuit slices, wherein a first slice of the plurality of circuit slices comprises a past causal cone of a first system qubit wire at a fully evolved level of the quantum circuit, and an i-th slice of the plurality of circuit slices is defined to contain all gates that are not within a past causal cone of any system qubit wires of the quantum circuit that reach the fully evolved level of the quantum circuit in slice i−j, where 0≤j<i is an integer, but that can now be executed by initiating one or more physical qubits that have reached the fully evolved level during execution of slice i−1, have optionally been measured, and reset onto the system qubit wires in a base level of slice i;
cause the quantum computer to execute of the i-th slice of the quantum circuit using the physical qubits;
cause the quantum computer to initialize a physical qubit, which was evolved along at least one system qubit wire to be fully evolved via execution of the i-th slice, onto a system qubit wire at a base level of the i+m-th slice of the quantum circuit, m a positive integer; and
cause the quantum computer to use the physical qubit to execute the i+m-th slice of the quantum circuit.

13. The computing entity of claim 12 , wherein executing the i-th slice of the quantum circuit comprises executing all gates for which incoming and outgoing wires lie within the i-th slice in order to propagate the system qubits forward in time.

14. The computing entity of claim 13 , wherein the quantum circuit comprises at least one ancilla wire and executing the i-th slice of the quantum circuit comprises interacting one or more system qubits at a bottom of the i-th slice with at least one ancilla qubit via unitary gates in order to introduce initial correlations between the one or more system qubits at the bottom of the i-th slice and system qubits at the bottom of one or more other slices.

15. The computing entity of claim 12 , wherein (a) the quantum circuit encodes interactions governed by a Hamiltonian characterized by local interactions and (b) each system qubit wire corresponds to a degree of freedom associated with a section of a physical domain being simulated.

16. The computing entity of claim 15 , wherein the quantum circuit simulates the dynamics of the evolution of quantum states defined on a lattice representing the physical domain.

17. The computing entity of claim 15 , wherein executing the i-th slice of the quantum circuit comprises evolving the degree of freedom in accordance with the Hamiltonian.

18. The computing entity of claim 15 , wherein the physical domain is one of a one dimensional, two dimensional, or three dimensional physical domain.

19. The computing entity of claim 12 , wherein the computing entity is further configured to cause the controller to control elements of the quantum computer to perform one or more measurements of at least one physical qubit of the plurality of qubits to determine a value of at least one degree of freedom within the physical domain.

20. The computing entity of claim 12 , wherein at least one system qubit wire of the quantum circuit extends through multiple slices of quantum circuit.

Assignees

• Quantinuum Llc

Inventors

• Feig Michael
• Potter Andrew C

Classifications

• B82Y10/00

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title

• G06N10/60

  Quantum algorithms, e.g. based on quantum optimisation, quantum Fourier or Hadamard transforms · CPC title

• G06F30/20

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• G06N10/00

  Quantum computing, i.e. information processing based on quantum-mechanical phenomena · CPC title

• G06F15/82 Primary

  data or demand driven · CPC title