Personal tools
You are here: Home Administration Physics Department Events 2020 February Physics Colloquium: Zala Lenarčič, Ph.D., Pumping (realistic) approximately integrable and many-body localized systems.

Physics Colloquium: Zala Lenarčič, Ph.D., Pumping (realistic) approximately integrable and many-body localized systems.

Physics Colloquium: Zala Lenarčič, Ph.D., Pumping (realistic) approximately integrable and many-body localized systems.
When Feb 18, 2020
from 04:00 PM to 05:00 PM
Where MR418N
Contact Name
Contact Phone 212-650-5625
Add event to calendar vCal
iCal

Zala Lenarčič, Ph.D.
Postdoctoral Researcher
Department of Physics
University of California, Berkeley

Pumping (realistic) approximately integrable and many-body localized systems

When an approximate conservation law protects a degree of freedom, even weak perturbations can cause a strong response in that quantity and can drive the system far from its equilibrium steady state. A simple classical example is a well-insulated greenhouse, which can be heated up significantly even by weak sunlight, due to the approximate conservation of the energy within the greenhouse.

Quantum platforms with macroscopically many conserved quantities are integrable and many-body localized (MBL) systems. When perfectly closed, these systems exhibit exceptional properties, such as ballistic transport in integrable systems and a complete absence of transport in MBL systems. Both properties are a direct consequence of the nature of corresponding conservation laws. However, in realistic setups conservation laws are weakly broken, for example, due to coupling to phonons. Such coupling to a thermal bath causes decay of local conservation laws towards a thermal value, therefore all special properties are gone.

I will show that the decay can be compensated by weak driving which pumps into the conservation laws and stabilizes exceptional non-thermal steady states. This allows us to study the MBL transition in open driven setups, which circumvent numerical limitations posed by the complete isolation. For nearly integrable systems, driving stabilizes steady states with huge heat and spin currents, which paves the way for a new type of heat and spin pumps. On the more fundamental side, I will show that steady states of weakly driven nearly integrable systems can be efficiently parametrize in terms of generalized Gibbs ensembles, despite the fact that the system is only approximately integrable. This is of relevance for statistical physics and non-equilibrium thermodynamics and should apply more generally to classical systems as well.

-----------------

Bio

Currently I am a postdoctoral employee in the group of Prof. Ehud Altman at the Department of physics, UC Berkeley. Before that I worked as a postdoc with Prof. Achim Rosch and did my PhD with prof. Peter Prelovšek.