Noise-resistant quantum memory enabled by Hamiltonian engineering

TL;DR

This paper presents a Hamiltonian engineering protocol that significantly enhances the fidelity of quantum memory in quantum dots by suppressing nuclear spin noise, even at low nuclear polarization levels.

Contribution

It introduces a noise-resistant method for quantum memory in quantum dots that achieves high fidelity with lower nuclear polarization requirements.

Findings

Achieves over 80% fidelity at 30% nuclear polarization.

Suppresses nuclear spin noise through Hamiltonian engineering.

Enables practical quantum memory implementation in quantum dots.

Abstract

Nuclear spins in quantum dots are promising candidates for fast and scalable quantum memory. By utilizing the hyperfine interaction between the central electron and its surrounding nuclei, quantum information can be transferred to the collective state of the nuclei and be stored for a long time. However, nuclear spin fluctuations in a partially polarized nuclear bath deteriorate the quantum memory fidelity. Here we introduce a noise-resistant protocol to realize fast and high-fidelity quantum memory through Hamiltonian engineering. With analytics and numerics, we show that high-fidelity quantum state transfer between the electron and the nuclear spins is achievable at relatively low nuclear polarizations, due to the strong suppression of nuclear spin noises. For a realistic quantum dot with $10^4$ nuclear spins, a fidelity surpassing 80% is possible at a polarization as low as 30%. Our approach reduces the demand for high nuclear polarization, making experimentally realizing quantum memory in quantum dots more feasible.