CANES SEMINAR-- Effective temperatures in isolated quantum systems

Dr Laura Foini 

Department of Physics, ENS, Paris

Wednesday 14 February 2018
Time: 4 pm
Venue: King's College London, Strand Campus, Strand building, Room S-2.08
Contact: CANES Centre Manager
Tel: 02074847951

Recent experimental progress in the field of cold atomic systems have triggered a renewal of interest in questions related to the equilibration and the thermalization properties of isolated quantum systems.

In Gibbs equilibrium, fluctuation-dissipation relations can be generically used to probe the thermal behavior of the system and measure its temperature.

However, when the system under study is integrable the dynamics fails to approach such a Gibbs state, reaching instead a generalized ensemble with a macroscopic number of temperature-like parameters which enforce the value of the underlying conserved quantities.

In this setting we show that generalized fluctuation-dissipation relations for appropriately chosen -- yet very physical -- observables, can be used to infer such temperatures allowing us to reconstruct the non-thermal state.

These results can be applied to a large variety of models including the one dimensional Bose gas where the relevant correlation function is provided by the structure factor, a quantity that can be experimentally accessed.


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