Time Evolution of Entanglement entropy for Thermofield Double States

• Mostafa Ghasemi (IPM)

We review the time evolution of the entanglement entropy of the thermofield double (TFD) states for scalar quantum field theory on a circle‎. ‎It is observed that the entanglement entropy growth linearly in early times and saturates after a time of the order of the length of subregion‎, ‎similar to the time evolution of the entanglement entropy in non-equilibrium quantum systems following quench‎. The ‎zero ‎mode‎ effect has also been shown to manifest itself as logarithmic growth‎‎‎, ‎which is derived analytically for a subsystem consisting of a single degrees of freedom on each side of the TFD at the massless limit‎.