Chen Weijian, Abbasi Maryam, Ha Byung, Erdamar Serra, Joglekar Yogesh N, Murch Kater W
Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
Center for Quantum Sensors, Washington University, St. Louis, Missouri 63130, USA.
Phys Rev Lett. 2022 Mar 18;128(11):110402. doi: 10.1103/PhysRevLett.128.110402.
Open quantum systems interacting with an environment exhibit dynamics described by the combination of dissipation and coherent Hamiltonian evolution. Taken together, these effects are captured by a Liouvillian superoperator. The degeneracies of the (generically non-Hermitian) Liouvillian are exceptional points, which are associated with critical dynamics as the system approaches steady state. We use a superconducting transmon circuit coupled to an engineered environment to observe two different types of Liouvillian exceptional points that arise either from the interplay of energy loss and decoherence or purely due to decoherence. By dynamically tuning the Liouvillian superoperators in real time we observe a non-Hermiticity-induced chiral state transfer. Our study motivates a new look at open quantum system dynamics from the vantage of Liouvillian exceptional points, enabling applications of non-Hermitian dynamics in the understanding and control of open quantum systems.
与环境相互作用的开放量子系统表现出由耗散和相干哈密顿演化相结合所描述的动力学。综合起来，这些效应由一个刘维尔超算符来描述。（一般非厄米的）刘维尔算符的简并点是例外点，当系统接近稳态时，这些点与临界动力学相关。我们使用一个耦合到工程环境的超导transmon电路来观测两种不同类型的刘维尔例外点，它们要么源于能量损失和退相干的相互作用，要么纯粹是由于退相干产生的。通过实时动态调整刘维尔超算符，我们观测到了一种非厄米性诱导的手性态转移。我们的研究促使从刘维尔例外点的角度重新审视开放量子系统动力学，从而使非厄米动力学在开放量子系统的理解和控制中得到应用。
