Two-dimensional antiferromagnetic Ising model as a toy model for usual $\theta$ physics
The severe sign problem (SSP) is a longstanding challenge for high energy and solid-state theorists. In order to test new proposals to simulate physical systems with SSP it would be very useful to dispose of systems with SSP, and non trivial phase structure, the dynamics of which is well known. We study here the two-dimensional antiferromagnetic Ising model within an imaginary magnetic field, which may be seen as a toy model for usual $\theta$ physics. By means of a cumulant expansion of the effective Hamiltonian, and with the help of standard multiprecision algorithms, we compute several observables of the model.
Preferred track (if multiple tracks have been selected)