Momentum-space entanglement and Loschmidt echo in Luttinger liquids

Rövid cím: 
Momentum-space entanglement and Loschmidt echo
Időpont: 
2017. 09. 08. 10:15
Hely: 
BME Fizikai Intézet, Elméleti Fizika Tanszék, Budafoki út 8. F-épület, III lépcsőház, szemináriumi szoba
Előadó: 
Dóra Balázs (Dept. Theor. Phys.)

Luttinger liquids arise by coupling left- and right-moving particles through interactions in one dimension. This most natural partitioning of Luttinger liquids is investigated by the momentum-space entanglement after a quantum quench using analytical and numerical methods. We show that the momentum-space entanglement spectrum of a LL possesses many universal features both in equilibrium and after a quantum quench. The largest entanglement eigenvalue is identical to the Loschmidt echo, i.e. the overlap of the disentangled and final wavefunctions of the system. The entanglement gap is universal both in equilibrium and after a quantum quench. The momentum-space entanglement entropy is always extensive and saturates fast to a time independent value after the quench, in sharp contrast to a spatial bipartitioning.