ELFT HÍRADÓ

[Janos Asboth <janos.asboth AT gmail.com>]

Meghívó

BME Elméleti Fizika Szeminárium,

február 28. péntek 10h15,

1111 Budapest, Budafoki út 8., BME F III. magasföldszint 01.,
Elméleti Fizika Tanszék szemináriumi szoba

 Hódsági Kristóf (BME, Elméleti Fizika Tanszék):

A field theoretical approach to non-equilibrium many-body dynamics:
perturbative calulation of post-quench overlaps

The history of realizing non-equilibrium quantum many-body dynamics in
experiments spans almost two decades by now. The aim to understand these
revolutionary experiments called for a renewed and fruitful effort on the
theoretical side in setting up and solving models of quantum systems far
from equilibrium. A particularly successful paradigm of this field is the
quantum quench that describes a setup where the initial state is not an
eigenstate of the Hamiltonian generating the time evolution. This setup can
be studied in several ways, in a recent work [1] we took a field
theoretical approach to obtain perturbatively the post-quench overlaps that
are necessary ingredients to characterize the time evolution after a
quantum quench. After briefly introducing the broader context of quantum
quenches, I am going to present the results of this work in the seminar
talk. In the paper we derive an expression for the overlaps assuming that
either the model before or after the quench is integrable. Our calculations
distinguish between the two approaches, showing serious constraints in the
former case, while the latter calculation yields precise results. We
illustrate this in a specific integrable model: the Ising Field Theory in a
magnetic field where we contrast the perturbative expressions against
numerical data using obtained using the Truncated Conformal Space Approach.

[1] K. Hódsági, M. Kormos, G. Takács: Perturbative post-quench overlaps in
Quantum Field Theory, J. High Energ. Phys. (2019) 2019:47 [1905.05623]


Minden érdeklődőt szeretettel várunk.

Asbóth János
szemináriumi koordinátor