Darmstadt 2008 – scientific programme
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A: Fachverband Atomphysik
A 28: Transport in ultracold gases and plasmas (jointly with Q)
A 28.3: Talk
Friday, March 14, 2008, 11:45–12:00, 3C
Structural phase transitions in low-dimensional ion crystals — •Gabriele De Chiara1, Shmuel Fishman2, Tommaso Calarco3, and Giovanna Morigi1 — 1Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain — 2Physics Department, Technion, 32000 Haifa, Israel — 3Institut für Quanteninformationsverarbeitung, Universität Ulm, D89069 Ulm, Germany
A chain of singly-charged particles, confined by a harmonic potential, exhibits a sudden transition to a zigzag configuration when the radial potential reaches a critical value, depending on the particle number. This structural change is a phase transition of second order, whose order parameter is the crystal displacement from the chain axis. We study analytically the transition using Landau theory and find full agreement with numerical predictions by J. Schiffer [Phys. Rev. Lett. 70, 818 (1993)] and Piacente et al. [Phys. Rev. B 69, 045324 (2004)]. Our theory allows us to determine analytically the system's behaviour at the transition point.