Ground state of one-dimensional chiral XY model under external magnetic field and uniaxial potential

We investigate the ground-state property of a chiral XY model on a one-dimensional lattice with an external magnetic field and a uniaxial potential by numerical calculations. The competition among the magnetic field, the uniaxial potential and a natural cantedness leads to some qualitatively different behavior from that obtained by the competition between two of them. We find in the ground-state phase diagram where there are two different phases with a same rotation number. We find a strong evidence for existence of φ points.