We theoretically study the dynamics of a transverse-field Ising chain with power-law decaying interactions characterized by an exponent α, which can be experimentally realized in ion traps. We focus on two classes of emergent dynamical critical phenomena following a quantum quench from a ferromagnetic initial state: The first one manifests in the time-averaged order parameter, which vanishes at a critical transverse field. We argue that such a transition occurs only for long-range interactions α≤2. The second class corresponds to the emergence of time-periodic singularities in the return probability to the ground-state manifold which is obtained for all values of α and agrees with the order parameter transition for α≤2. We characterize how the two classes of nonequilibrium criticality correspond to each other and give a physical interpretation based on the symmetry of the time-evolved quantum states.
|Titolo:||Dynamical Quantum Phase Transitions in Spin Chains with Long-Range Interactions: Merging Different Concepts of Nonequilibrium Criticality|
|Autori:||Žunkovič, Bojan; Heyl, Markus; Knap, Michael; Silva, Alessandro|
|Data di pubblicazione:||2018|
|Numero di Articolo:||130601|
|Digital Object Identifier (DOI):||10.1103/PhysRevLett.120.130601|
|Appare nelle tipologie:||1.1 Journal article|