Date: 2018.1.3 (Wedenseday) 15:00

Place: Rm 323, Physics Building, Sichuan University

Speaker: Dr. Yang Run Qiu (杨润秋)

Title: Title: Complexity in quantum field theory and its application in thermofield double states

Abstract:

In this talk, I will talk about a recent work on how to define the complexity in quantum field theory.  It introduces a Finsler structure based on created and annihilated operators to define the complexity of operators and between states.  Two simple models will be shown as examples to clarify the differences between complexity and other conceptions such as complexity of formation and entanglement entropy.  When it is applied into thermofield double states, results show the complexity between them and corresponding vacuum state is finite and proportional to T^{d-1} in d-dimensional conformal field theory.  Especially, a proof will be given to show the fidelity susceptibility of a TFD state is equivalent to the complexity between it and corresponding vacuum state, which gives an explanation why they may share the same object in holographic duality.  The enlightenment to holographic conjectures of complexity will also be discussed.