Volume 84, Number 6, December 2008
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||12 January 2009|
Dynamical non-ergodic scaling in continuous finite-order quantum phase transitions
Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory - Hanover, NH 03755, USA
2 Department of Physics, Indiana University - Bloomington, IN 47405, USA
Corresponding author: Lorenza.Viola@Dartmouth.EDU
Accepted: 13 November 2008
We investigate the emergence of universal dynamical scaling in quantum critical spin systems adiabatically driven out of equilibrium, with emphasis on quench dynamics which involves non-isolated critical points (i.e., critical regions) and cannot be a priori described through standard scaling arguments nor time-dependent perturbative approaches. Comparing to the case of an isolated quantum critical point, we find that non-equilibrium scaling behavior of a large class of physical observables may still be explained in terms of equilibrium critical exponents. However, the latter are in general non-trivially path-dependent, and detailed knowledge about the time-dependent excitation process becomes essential. In particular, we show how multiple level crossings within a gapless phase may completely suppress excitation depending on the control path. Our results typify non-ergodic scaling in continuous finite-order quantum phase transitions.
PACS: 73.43.Nq – Quantum phase transitions / 05.70.Jk – Critical point phenomena / 75.10.Jm – Quantized spin models
© EPLA, 2008
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