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arXiv · 1506.00416

Numerical evidence of the double-Griffiths phase of the random quantum Ashkin-Teller chain

Christophe Chatelain·Dimitrios Voliotis
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Abstract

The random quantum Ashkin-Teller chain is studied numerically by means of time-dependent Density-Matrix Renormalization Group. The critical lines are estimated as the location of the peaks of the integrated autocorrelation times, computed from spin-spin and polarization-polarization autocorrelation functions. Disorder fluctuations of magnetization and polarization are observed to be maximum on these critical lines. Entanglement entropy leads to the same phase diagram, though with larger Finite-Size effects. The decay of spin-spin and polarization-polarization autocorrelation functions provides numerical evidence of the existence of a double Griffiths phase when taking into account finite-size effects. The two associated dynamical exponents z increase rapidly as the critical lines are approached, in agreement with the recent conjecture of a divergence at the two transitions in the thermodynamic limit.

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Christophe Chatelain, Dimitrios Voliotis. 2015-06-01. Numerical evidence of the double-Griffiths phase of the random quantum Ashkin-Teller chain. https://doi.org/10.1140/epjb%2Fe2015-60593-3

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