Finite-temperature properties of one-dimensional chiral XY model under an external field and a uniaxial potential

We investigate finite-temperature properties of chiral XY model on a one-dimensional lattice with an external magnetic field and a uniaxial potential by solving numerically the integral equation. We calculate the internal energy, the free energy, the winding number, the magnetization, the susceptibility and so on in order to discuss the stability of the ground state due to the temperature effect. We calculate the specific heat and find at least four peaks in the specific heat as a function of temperature. By using low-temperature expansions, we discuss two different origins of double peak in the specific heat around the phase boundaries in the ground-state phase diagram.