Sub-microsecond high-fidelity dispersive readout of a spin qubit with squeezed photons

Fuente: arXiv
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Main Authors: Kam, Chon-Fai, Hu, Xuedong
Format: Preprint
Published: 2023
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author Kam, Chon-Fai
Hu, Xuedong
author_facet Kam, Chon-Fai
Hu, Xuedong
contents Fast and high-fidelity qubit measurement is essential for realizing quantum error correction, which is in turn a key ingredient to universal quantum computing. For electron spin qubits, fast readout is one of the significant road blocks toward error correction. Here we examine the dispersive readout of a single spin in a semiconductor double quantum dot coupled to a microwave resonator. We show that using displaced squeezed vacuum states for the probing photons can improve the qubit readout fidelity and speed. Under condition of proper phase matching, we find that a moderate, and only moderate, squeezing can enhance both the signal-to-noise ratio and the fidelity of the qubit-state readout, and the optimal readout time can be shortened to the sub-microsecond range with above $99\%$ fidelity. These enhancements are achieved at low probing microwave intensity, ensuring non-demolition qubit measurement.
format Preprint
id arxiv_https___arxiv_org_abs_2312_10820
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Sub-microsecond high-fidelity dispersive readout of a spin qubit with squeezed photons
Kam, Chon-Fai
Hu, Xuedong
Quantum Physics
Mesoscale and Nanoscale Physics
Fast and high-fidelity qubit measurement is essential for realizing quantum error correction, which is in turn a key ingredient to universal quantum computing. For electron spin qubits, fast readout is one of the significant road blocks toward error correction. Here we examine the dispersive readout of a single spin in a semiconductor double quantum dot coupled to a microwave resonator. We show that using displaced squeezed vacuum states for the probing photons can improve the qubit readout fidelity and speed. Under condition of proper phase matching, we find that a moderate, and only moderate, squeezing can enhance both the signal-to-noise ratio and the fidelity of the qubit-state readout, and the optimal readout time can be shortened to the sub-microsecond range with above $99\%$ fidelity. These enhancements are achieved at low probing microwave intensity, ensuring non-demolition qubit measurement.
title Sub-microsecond high-fidelity dispersive readout of a spin qubit with squeezed photons
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2312.10820