Lee-Yang theory of the two-dimensional quantum Ising model

Determining the phase diagram of interacting quantum many-body systems is an important task for a wide range problems such as understanding and design materials. For classical equilibrium systems, Lee-Yang formalism provides rigorous foundation transitions, these ideas have also been extended to realm. Here, we develop theory transitions that can include thermal fluctuations caused by finite temperature, it thereby link between recent theories at zero temperature. Our methodology exploits analytic properties moment generating function order parameter in size, be implemented combination with tensor-network calculations. Specifically, onset symmetry-broken signaled zeros approaching origin complex plane counting field couples parameter. Moreover, obtained measuring or calculating high cumulants We determine two-dimensional Ising model demonstrate potential our method predict critical behavior temperatures.