摘要

Almost all the quantum systems are inevitably coupled with their surroundings, which brings two-fold effect: dissipations and fluctuations. Understanding the open quantum many-body system is a topic of fundamental interest in various fields of physics and challenging both the theorists and experimentalists. Even though dissipation and noise-induced decoherence are detrimental for almost all the quantum-based experimental devices and techniques, from the theoretic point of view, the open quantum many-body system itself is fundamentally different from the traditional Hamiltonian systems, and provides a new perspective to the quantum many-body physics. In the first part, I will give an example of a natural generalization of the spin-boson model to the many-spin case, where I will show that dissipation can qualitatively change the properties of the quantum many-body systems, and give rise to novel quantum phases and phase transitions. In the second part, we will show that the conspiracy of interaction and noise can give rise to universal long-time dynamics: an algebraic decoherence behavior with infinite-long decoherence time, fundamentally different from the exponential decoherence behavior in single particle scenario.

报告人简介

蔡子博士，奥地利量子信息与量子光学组博士后。 2010年中科院物理所获得博士学位。先后在美国加州大学圣迭戈分校，德国慕尼黑大学，奥地利科学院量子光学与量子信息研究所从事博士后研究。主要研究方向为量子多体物理中的理论和数值计算。研究领域包括凝聚态物理，冷原子系统，以及量子开放系统中涌现的的量子多体尤其是强关联物理。