Excited-state quantum phase transitions and periodic dynamics
Georg Engelhardt, V. M. Bastidas, Wassilij Kopylov, Tobias Brandes · Physical Review A · 2015
We investigate signatures of the excited-state quantum phase transition in the periodic dynamics of the Lipkin-Meshkov-Glick model and the Tavis-Cummings model. In the thermodynamic limit, expectation values of observables in eigenstates of the system can be calculated using classical trajectories. Motivated by this, we suggest a method based on the time evolution of the finite-size system to find singularities in observables, which arise due to the excited-state quantum phase transition.