Simulation of Jahn-Teller-Dicke Magnetic Structural Phase Transition   with Trapped Ions
  We study theoretically the collective E$\otimes$e Jahn-Teller-Dicke distortion in a system of trapped ions. We focus in the limit of infinite range interactions in which an ensemble of effective spins interacts with two collective vibrational modes with U(1) symmetric couplings. Our model is exactly solvable in the thermodynamical limit and it is amenable to be solved by exact numerical diagonalization for a moderate number of ions. We show that trapped ions are ideally suited to study the emergence of spontaneous symmetry breaking of a continuous symmetry and magnetic structural phase transition in a mesoscopic system. 
Peter A. Ivanov, Diego Porras, Svetoslav S. Ivanov, Ferdinand   Schmidt-Kaler
quant-ph