McDonald Alexander, Clerk Aashish A
Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA.
Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
Nat Commun. 2020 Oct 23;11(1):5382. doi: 10.1038/s41467-020-19090-4.
Non-Hermitian systems exhibit markedly different phenomena than their conventional Hermitian counterparts. Several such features, such as the non-Hermitian skin effect, are only present in spatially extended systems. Potential applications of these effects in many-mode systems however remains largely unexplored. Here, 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 quintessential 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 [Formula: see text] 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.
非厄米系统表现出与传统厄米系统截然不同的现象。若干此类特征，比如非厄米趋肤效应，仅出现在空间扩展系统中。然而，这些效应在多模系统中的潜在应用在很大程度上仍未得到探索。在此，我们研究如何利用非厄米晶格系统的独特特征，在全量子环境中改进哈密顿量参数估计。虽然典型的非厄米趋肤效应并未提供任何明显优势，但其他效应却能带来显著增强。我们表明，某些具有[公式：见正文]对称性的非对称非厄米紧束缚模型具有明显的传感优势：每个光子的量子费舍尔信息随系统规模呈指数增长。我们发现，这些优势在非马尔可夫和非微扰效应变得重要的情况下依然存在。我们的设置与多种量子光学和超导电路平台直接兼容，并且仅需三个晶格位点就能产生强大的增强效果。
