Title: [NCTS-NTU String Theory Seminar] Digital quantum simulation of higher-charge Schwinger model with topological term
Speaker: Dr. Masazumi Honda (YITP)
Time: Apr. 29, 2022 (Fri) 14:30-15:30
Venue: Online & Rm. 803, Dept. of Physics, NTU (Hybrid)
Meeting Link:
https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=m259033b9610429f763f79fba1cf67d5a

Abstract:
I am going to talk about application of quantum computation to numerical simulation of quantum field theory. Specifically we implement  a digital quantum simulation of a gauge theory with a topological term in Minkowski spacetime, which is practically inaccessible by standard lattice Monte Carlo simulations.
We focus on 1+1 dimensional quantum electrodynamics with a topological term and a charge-q Dirac fermion known as the Schwinger model.
We construct the true vacuum state of a lattice Schwinger model using adiabatic state preparation which, in turn, allows us to compute an expectation value of the fermion mass operator with respect to the vacuum.
Upon taking a continuum limit we find that our result in massless case agrees with the known exact result.
In massive case, we find an agreement with mass perturbation theory in small mass regime and deviations in large mass regime.
We also study a potential between heavy charged particles and see that the potential changes its qualitative behavior as changing parameters:
it shows confinement, screening and an exotic behavior called negative tension behavior in which particles with opposite charges repel with each other.

Refs:
[1]  B.Chakraborty, M. Honda, T. Izubuchi, Y. Kikuchi and A. Tomiya, arXiv:2001.00485
[2]  M. Honda, E. Itou, Y. Kikuchi, L. Nagano and T. Okuda, arXiv:2105.03276
[3]  M. Honda, E. Itou, Y. Kikuchi and Y. Tanizaki arXiv:2110.14105