Optimal control in large open quantum systems: the case of transmon readout and reset

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Gautier, Ronan, Genois, Élie, Blais, Alexandre
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866915161964544000
author Gautier, Ronan
Genois, Élie
Blais, Alexandre
author_facet Gautier, Ronan
Genois, Élie
Blais, Alexandre
contents We present a framework that combines the adjoint-state method together with reverse-time backpropagation to solve prohibitively large open-system quantum control problems. Our approach enables the optimization of arbitrary cost functions with fully general controls applied on large open quantum systems described by a Lindblad master equation. It is scalable, computationally efficient, and has a low-memory footprint. We apply this framework to optimize two inherently dissipative operations in superconducting qubits which lag behind in terms of fidelity and duration compared to other unitary operations: the dispersive readout and all-microwave reset of a transmon qubit. Our results show that while standard pulses for dispersive readout are nearly optimal, adding a transmon drive during the protocol can yield 2x improvements in fidelity and duration. We further demonstrate a 2x improvement in reset fidelity and duration through pulse shaping, indicating significant potential for enhancement in reset protocols. Our approach can readily be applied to optimize quantum controls in a vast range of applications such as reservoir engineering, autonomous quantum error correction, and leakage-reduction units.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14765
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimal control in large open quantum systems: the case of transmon readout and reset
Gautier, Ronan
Genois, Élie
Blais, Alexandre
Quantum Physics
We present a framework that combines the adjoint-state method together with reverse-time backpropagation to solve prohibitively large open-system quantum control problems. Our approach enables the optimization of arbitrary cost functions with fully general controls applied on large open quantum systems described by a Lindblad master equation. It is scalable, computationally efficient, and has a low-memory footprint. We apply this framework to optimize two inherently dissipative operations in superconducting qubits which lag behind in terms of fidelity and duration compared to other unitary operations: the dispersive readout and all-microwave reset of a transmon qubit. Our results show that while standard pulses for dispersive readout are nearly optimal, adding a transmon drive during the protocol can yield 2x improvements in fidelity and duration. We further demonstrate a 2x improvement in reset fidelity and duration through pulse shaping, indicating significant potential for enhancement in reset protocols. Our approach can readily be applied to optimize quantum controls in a vast range of applications such as reservoir engineering, autonomous quantum error correction, and leakage-reduction units.
title Optimal control in large open quantum systems: the case of transmon readout and reset
topic Quantum Physics
url https://arxiv.org/abs/2403.14765