1208.2042 (A. V. Zampetaki et al.)

Crossover from a crystalline to a cluster phase for a confined finite
chain of ions    [PDF]

A. V. Zampetaki, F. K. Diakonos, P. Schmelcher

Employing Monte-Carlo simulation techniques we investigate the statistical properties of equally charged particles confined in an one-dimensional box trap. We detect a crossover from a crystalline to a cluster phase with increasing temperature. The corresponding transition temperature depends separately on the number of particles N and the box size L, implying non-extensivity due to the long-range character of the interactions. The probability density of the spacing between the particles exhibits at low temperatures an accumulation of discrete peaks with an overall asymmetric shape. Around the transition temperature it is of a Gaussian form whereas in the high temperature regime it obeys an exponential decay. The high temperature behaviour shows a cluster phase with a mean cluster size that first increases with the temperature but finally saturates.The crossover is clearly identifiable also in the non-linear behaviour of the heat capacity with varying the temperature. Possible experimental realizations are briefly addressed.

View original: http://arxiv.org/abs/1208.2042