Long-time dynamics and control of one-dimensional quantum-many-body systems
Speaker: Prof. Lea Santos, Yeshiva University
Series: Topical Seminars
Location: Bowen Hall Auditorium
Date/Time: Monday, November 8, 2010, 12:30 p.m. - 1:30 p.m.
One of the main applications of quantum computers will be the simulation of quantum many-body systems; but at the same time, implementations of quantum computers are themselves many-body systems. A clear understanding of the dynamics of quantum many-body systems and how to control their evolution is therefore crucial to the future development of quantum computers.
In this talk we will discuss the long-time dynamics of one-dimensional quantum many-body systems. We will first introduce the conditions under which they may thermalize. Thermalization occurs when the eigenstates of the systems become chaotic. Chaotic eigenstates may appear in the middle of the spectrum of systems with few-body interactions, but not at the edges, and they are observed even when the systems become gapped and/or different symmetry sectors are mixed. Second, we will show how dynamical decoupling methods may be used to manipulate the time evolution of such many-body systems. These methods consist of sequences of external control operations designed to induce a desired dynamics. We will show, for instance, that an appropriate control sequence may lead a chaotic chain to evolve as an integrable chain and a system in the gapless phase to behave as a system in the gapped phase.