Quantum phase transitions of a quasiperiodic anisotropic XY chain in a transverse magnetic field -: art. no. 064421

The zero-temperature phase diagram of a quasiperiodic anisotropic XY quantum spin chain in a transverse magnetic field is studied. In the isotropic limit, the system exhibits an infinite number of quantum phase transitions with a devils-staircase-like magnetization curve. Anisotropy decreases the number of transitions. A mechanism is proposed for the successive transitions based on the ordering of finite clusters of spins along the chain.