Hannover 2013 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 29: Poster: Ultra-cold atoms, ions and BEC (with Q)
A 29.18: Poster
Mittwoch, 20. März 2013, 16:00–18:30, Empore Lichthof
Crossover from a crystalline to a cluster phase for a confined finite chain of ions — •Alexandra Zampetaki1, Fotios Diakonos2, and Peter Schmelcher1 — 1Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 2Department of Physics, University of Athens, GR-15874, Athens, Greece
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.