Grega Saksida

Correlation functions of the quantum XY model

The quantum XY model describes the behaviour of spin particles on a
lattice. We study the spin-1/2 system, where at each site the spin
measured along any axis can be in two states: "up" or "down". The model
is quantum, meaning the spin at each site is a complex linear
combination of the two possible "measured" states. The spins at
adjacent sites interact in a way that favours alignment. A natural
question is whether this alignment persists across the entire system.
This motivates the study of so-called correlation functions.

In this talk, I will define the quantum XY model, and present some new
results on the correlation functions. I will explain how we derived
these results by representing the quantum XY model as an Ising model
with some additional interactions. This is an ongoing joint work with
Vedran Sohinger and Daniel Ueltschi.