Title : 
Probing quantum phase transition with spread complexity 

Speaker  :  Kunal Pal , Indian Institute of Technology, Kanpur 
Date  :  December 13, 2022 
Time  :  2:30 PM 
Venue  :  seminar room 3307 
Abstract  : 
The notion of Krylov complexity is an effective measure of operator growth, that quantifies the evolution of a simple operator under a given Hamiltonian. In this talk, I will discuss how the Krylov basis construction generated by the Hamiltonian can be used to describe the spread complexity of preparing a target state starting from a given reference state. Then I will discuss the geometric approach of extracting the Lanczos coefficients under a quantum quench, which are essential for calculating the complexity. Finally, I will explain our recent work on using the spread complexity as an efficient marker of ground state quantum phase transition. 