Defect Production in Nonlinear Quench across a Quantum Critical Point

Sen, Diptiman and Sengupta, K and Mondal, Shreyoshi (2008) Defect Production in Nonlinear Quench across a Quantum Critical Point. In: Physical Review Letters, 101 (1). 016806-1.

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Abstract

We show that the defect density n, for a slow nonlinear power-law quench with a rate $\tau^{-1}$ and an exponent \alpha > 0, which takes the system through a critical point characterized by correlation length and dynamical critical exponents \nu and z, scales as $n\sim \tau ^{-\alpha \nu d}^/^{(\alpha z \nu + 1)}$ $[n \sim ( \alpha g^{ ( \alpha -1)/ \alpha} / \tau )^ { \nu d /z \nu + 1)}$ if the quench takes the system across the critical point at time t = 0 $[t = t_0 \neq 0]$, where g is a nonuniversal constant and d is the system dimension. These scaling laws constitute the first theoretical results for defect production in nonlinear quenches across quantum critical points and reproduce their well-known counterpart for a linear quench ( \alpha = 1) as a special case. We supplement our results with numerical studies of well-known models and suggest experiments to test our theory.

Item Type:	Journal Article
Publication:	Physical Review Letters
Publisher:	American Physical Society
Additional Information:	Copyright of this article belongs to American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	29 Jul 2008
Last Modified:	19 Sep 2010 04:48
URI:	http://eprints.iisc.ac.in/id/eprint/15336

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