Aspects of Pseudo Entropy in Field Theories

Understand

In this article, we explore properties of pseudo entropy [1] in quantum field theories and spin systems from several approaches.

• Pseudo entropy is a generalization of entanglement entropy such that it depends on both an initial and final state and has a clear gravity dual via the AdS/CFT.
• We numerically analyze a class of free scalar field theories and the XY spin model.
• This reveals the basic properties of pseudo entropy in many-body systems, namely, the area law behavior, the saturation behavior, and the non-positivity of difference between the pseudo entropy and averaged entanglement entropy in the same quantum phase.