2020/04/01 by Alexander McDonald, Aashish A. Clerk · 3 citations
Physics and Astronomy · #quant-ph #cond-mat.mes-hall
paper · pdf · doi:10.1038/s41467-020-19090-4
published as Nature Communications 11, 5382 (2020) · 17 pages (including appendices), 4 figures
arxiv created 2020/04/01 · arxiv updated 2020/10/26
We study how unique features of non-Hermitian lattice systems can be harnessed to improve Hamiltonian parameter estimation in a fully quantum setting. While the so-called non-Hermitian skin effect does not provide any distinct advantage, alternate effects yield dramatic enhancements. We show that certain asymmetric non-Hermitian tight-binding models with a ℤ2 symmetry yield a pronounced sensing advantage: the quantum Fisher information per photon increases exponentially with system size. We find that these advantages persist in regimes where non-Markovian and non-perturbative effects become important. Our setup is directly compatible with a variety of quantum optical and superconducting circuit platforms, and already yields strong enhancements with as few as three lattice sites.