Séminaire du LPTMS: Jean-Marie Stephan

Quand

02/02/2016    
11:00 - 12:15

LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay
15 Rue Georges Clemenceau, Orsay, 91405

Type d’évènement

Chargement de la carte…

Filling fraction quantum quenches and the arctic circle

Jean-Marie Stephan (PKS-MPG Dresden)

I consider a simple non-equilibrium problem, where a critical one-dimensional system is prepared in a state with two different densities on the left and on the right, and let evolve with a Hamiltonian that conserves the number of particles. A typical example would be a fermionic system prepared with different left/right chemical potentials. For free systems a lot can, and has been understood by making use of a semiclassical picture, in which particles carrying a momentum k propagate ballistically with velocity v(k). Generalization to interacting systems is very much an open problem. I will discuss attempts at understanding such dynamics using field theory. A possible strategy is to study the behavior in imaginary time, the real time dynamics being recovered by performing the Wick rotation. I will show that all degrees of freedom outside a certain region may freeze in imaginary time, contrary to naive expectations. This behavior is analogous to the celebrated « arctic circle » phenomenon found in the study of two-dimensional classical dimer or vertex models. I will also show that the fluctuating region is described by a massless field theory with a position-dependent metric, a field theory in curved space. Such imaginary time pictures can be used to make predictions about the behavior of correlation functions, entanglement entropies, or return probabilities after the quench.

Retour en haut