Optimal control of open quantum systems: cooperative effects of driving and dissipation

缓慢驱动量子系统中的量子几何与耗散界

Quantum geometry and bounds on dissipation in slowly driven quantum systems

本研究揭示低温慢驱动马尔可夫量子系统的能量耗散与驱动协议几何通过量子度量关联，建立双频协议耗散率下界，该下界在适当极限下仅由拓扑和有效品质因数决定，搭建了拓扑几何现象与开放量子系统耗散的桥梁并提供驱动设计原则。

Cooperative effects driving the multi-periodic dynamics of cyclically sheared amorphous solids

Plasticity in amorphous materials, such as glasses, colloids, or granular materials, is mediated by local rearrangements called "soft spots". Experiments and simulations have shown that soft spots are two-state entities interacting via quadrupolar displacement fields generated when they switch states. When the system is subjected to cyclic strain driving, the soft spots can return to their original state after one or more forcing cycles. In this case, the system has periodic dynamics and will always repeat the same microscopic states. Here we focus on multi-periodic dynamics, i.e. dynamics tha…

Switching mechanism in periodically driven quantum systems with dissipation

We introduce a switching mechanism in the asymptotic occupations of quantum states induced by the combined effects of a periodic driving and a weak coupling to a heat bath. It exploits one of the ubiquitous avoided crossings in driven systems and works even if both involved Floquet states have small occupations. It is independent of the initial state and the duration of the driving. As a specific example of this general switching mechanism we show how an asymmetric double well potential can be switched between the lower and the upper well by a periodic driving that is much weaker than the asym…

Energy dissipation and information flow in coupled Markovian systems

A stochastic system under the influence of a stochastic environment is correlated with both present and future states of the environment. Such a system can be seen as implicitly implementing a predictive model of future environmental states. The non-predictive model complexity has been shown to lower-bound the thermodynamic dissipation. Here we explore these statistical and physical quantities at steady state in simple models. We show that under quasi-static driving this model complexity saturates the dissipation. Beyond the quasi-static limit, we demonstrate a lower bound on the ratio of this…

A real-space description of the glass transition based on heterogeneities and entropy barriers

An alternative scenario for the glass transition based on the cooperative nature of nucleation processes and the role of entropic effects is presented. The new ingredient is to relate the dissipation during the relaxation process to the release of strain energy driven by the nucleation of progressively larger cooperative spatial regions. Using an equiprobability hypothesis for the transition between different metastable configurations, we obtain a relation between the free energy dissipation rate and the size of the largest cooperative regions. Th is leads to a new phenomenological relation be…

驱动与耗散下无序多体量子系统的时间弛豫

Temporal relaxation of disordered many-body quantum systems under driving and dissipation

本文研究无序量子自旋链在驱动与耗散下的非平衡弛豫，提出用光驱动区分不同局域化区域，并证明结合动力学量子典型性与随机 unraveling 可高效模拟开放系统动力学。