Optical control of atomic quantum bits for phase control of operation

Patent metadata

Field	Value
Publication number	US-11710061-B2
Application number	US-202117313450-A
Country	US
Kind code	B2
Filing date	May 6, 2021
Priority date	Jan 4, 2018
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

The disclosure describes various aspects of optical control of atomic quantum bits (qubits) for phase control operations. More specifically, the disclosure describes methods for coherently controlling quantum phases on atomic qubits mediated by optical control fields, applying to quantum logic gates, and generalized interactions between qubits. Various attributes and settings of optical/qubit interactions (e.g., atomic energy structure, laser beam geometry, polarization, spectrum, phase, background magnetic field) are identified for imprinting and storing phase in qubits. The disclosure further describes how these control attributes are best matched in order to control and stabilize qubit interactions and allow extended phase-stable quantum gate sequences.

First claim

What is claimed is:

1. A method for optical control of atomic quantum bits (qubits), comprising:
identifying a qubit operation from multiple qubit operations in an extended quantum computation; and
applying optical beams to at least one of the atomic qubits for phase control of the qubit operation as co-propagating optical beams or as counter-propagating optical beams based on whether the qubit operation is identified as a single qubit operation or as a multi-qubit operation.

2. The method of claim 1 , wherein applying the optical beams to at least one of the atomic qubits for phase control of the qubit operation as co-propagating optical beams or as counter-propagating optical beams is further based on whether the qubit operation is to be motion sensitive or motion insensitive.

3. The method of claim 1 , further comprising applying the optical beams as co-propagating optical beams in response to the qubit operation being identified as a single qubit operation and the qubit operation being motion insensitive.

4. The method of claim 1 , further comprising applying the optical beams as counter-propagating optical beams in response to the qubit operation being identified as a single qubit operation and the qubit operation being motion sensitive.

5. The method of claim 1 , wherein the atomic qubits correspond to atomic ions in a crystal formed by an ion trap.

6. The method of claim 5 , further comprising:
applying the optical beams as counter-propagating optical beams in response to the qubit operation being identified as a multi-qubit operation;
configuring the optical beams in a phase insensitive configuration; and
applying the optical beams by applying up to N individually addressing Raman beams for N atomic ions in the crystal with multiple optical frequencies on each of the individually addressing Raman beams, and a single global counter-propagating Raman beam against the up to N individually addressing Raman beams.

7. The method of claim 1 , wherein applying the optical beams includes controlling a polarization of the optical beams to compensate for an AC Stark shift of a qubit level in the at least one of the atomic qubits.

8. The method of claim 7 , further comprising configuring the polarization of the optical beams to compensate for the AC Stark shift in order to balance the AC Stark shift and enable different types of qubit gates associated with performing the quantum operation.

9. The method of claim 7 , wherein the polarization of the optical beams is a dynamic polarization, a static polarization, or a combination thereof.

10. The method of claim 1 , wherein applying the optical beams includes controlling one or more of a geometry, a spectrum, or a polarization of the optical beams.

11. A quantum information processing (QIP) system for optical control of atomic quantum bits (qubits), comprising:
one or more optical sources that generate optical beams; and
an optical controller configured to:
identify a qubit operation from multiple qubit operations in an extended quantum computation; and
apply the optical beams to at least one of the atomic qubits for phase control of the qubit operation as co-propagating optical beams or as counter-propagating optical beams based on whether the qubit operation is identified as a single qubit operation or as a multi-qubit operation.

12. The QIP system of claim 11 , wherein the optical controller is further configured to apply the optical beams to at least one of the atomic qubits for phase control of the qubit operation as co-propagating optical beams or as counter-propagating optical beams further based on whether the qubit operation is to be motion sensitive or motion insensitive.

13. The QIP system of claim 11 , wherein the optical controller is further configured to apply the optical beams as co-propagating optical beams in response to the qubit operation being identified as a single qubit operation and the qubit operation being motion insensitive.

14. The QIP system of claim 11 , wherein the optical controller is further configured to apply the optical beams as counter-propagating optical beams in response to the qubit operation being identified as a single qubit operation and the qubit operation being motion sensitive.

15. The QIP system of claim 11 , further comprising an ion trap, wherein the atomic qubits correspond to atomic ions in a crystal formed by the ion trap.

16. The QIP system of claim 15 , wherein:
the optical beams are applied as counter-propagating optical beams in response to the qubit operation being identified as a multi-qubit operation,
the optical beams are configured in a phase insensitive configuration, and
the optical controller is further configured to apply the optical beams as up to N individually addressing Raman beams for N atomic ions in the crystal with multiple optical frequencies on each of the individually addressing Raman beams, and a single global counter-propagating Raman beam against the up to N individually addressing Raman beams.

17. The QIP system of claim 11 , wherein the optical controller is further configured to apply the optical beams to at least one of the atomic qubits for phase control of the qubit operation is further configured to control a polarization of the optical beams to compensate for an AC Stark shift of a qubit level in the at least one of the atomic qubits.

18. The QIP system of claim 17 , wherein the polarization of the optical beams to compensate for the AC Stark shift is configured to balance the AC Stark shift and enable different types of qubit gates associated with performing the quantum operation.

19. The QIP system of claim 17 , wherein the polarization of the optical beams is a dynamic polarization, a static polarization, or a combination thereof.

20. The QIP system of claim 11 , wherein the optical controller is further configured to apply the optical beams to the at least one of the atomic qubits for phase control of the qubit operation by being configured to control one or more of a geometry, a spectrum, or a polarization of the optical beams.

Assignees

• Univ Maryland

Inventors

• Monroe Christopher
• Cetina Marko
• Linke Norbert
• Debnath Shantanu

Classifications

• G06N10/40 Primary

  Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control · CPC title

• G06N10/00 Primary

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

• G06E1/00

  Devices for processing exclusively digital data · CPC title

• B82Y10/00

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