Santos Raul A, Iemini Fernando, Kamenev Alex, Gefen Yuval
T.C.M. Group, Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, UK.
Instituto de Física, Universidade Federal Fluminense, Niterói, 24210-346, Brazil.
Nat Commun. 2020 Nov 19;11(1):5899. doi: 10.1038/s41467-020-19646-4.
Quantum systems are always subject to interactions with an environment, typically resulting in decoherence and distortion of quantum correlations. It has been recently shown that a controlled interaction with the environment may actually help to create a state, dubbed as "dark", which is immune to decoherence. To encode quantum information in the dark states, they need to span a space with a dimensionality larger than one, so different orthogonal states act as a computational basis. Here, we devise a symmetry-based conceptual framework to engineer such degenerate dark spaces (DDS), protected from decoherence by the environment. We illustrate this construction with a model protocol, inspired by the fractional quantum Hall effect, where the DDS basis is isomorphic to a set of degenerate Laughlin states. The long-time steady state of our driven-dissipative model exhibits thus all the characteristics of degenerate vacua of a unitary topological system.
量子系统总是会与环境发生相互作用，通常会导致量子相关性的退相干和失真。最近有研究表明，与环境的可控相互作用实际上可能有助于创建一种被称为“暗态”的状态，这种状态对退相干具有免疫能力。为了在暗态中编码量子信息，它们需要跨越一个维度大于一的空间，这样不同的正交态就可以作为计算基。在这里，我们设计了一个基于对称性的概念框架来构建这样的简并暗空间（DDS），使其免受环境引起的退相干影响。我们用一个受分数量子霍尔效应启发的模型协议来说明这种构建方式，其中DDS基与一组简并的劳克林态同构。我们的驱动耗散模型的长时间稳态因此展现出了酉拓扑系统简并真空的所有特征。
