Griffiths-McCoy singularities in the random transverse-field Ising spin chain
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منابع مشابه
Griffiths-McCoy singularities in the random transverse-field Ising spin chain
We consider the paramagnetic phase of the random transverse-field Ising spin chain and study the dynamical properties by numerical methods and scaling considerations. We extend our previous work @Phys. Rev. B 57, 11 404 ~1998!# to new quantities, such as the nonlinear susceptibility, higher excitations, and the energydensity autocorrelation function. We show that in the Griffiths phase all the ...
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We report a Monte Carlo study of the effects of fluctuations in the bond distribution of Ising spin glasses in a transverse magnetic field, in the paramagnetic phase in the T → 0 limit. Rare, strong fluctuations give rise to Griffiths singularities, which can dominate the zero-temperature behavior of these quantum systems, as originally demonstrated by McCoy for one-dimensional (d = 1) systems....
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We consider random quantum (tight-binding, XX and Ising) spin chains in the off-critical region and study their Griffiths-McCoy singularities. These are obtained from the density of states of the low-energy excitations, which is calculated exactly by the Dyson-Schmidt method. In large finite systems the low-energy excitations are shown to follow the statistics of extremes and their distribution...
متن کاملNumerical study of the random transverse-field Ising spin chain.
We study numerically the critical region and the disordered phase of the random transverse-field Ising chain. By using a mapping of Lieb, Schultz, and Mattis to noninteracting fermions, we can obtain a numerically exact solution for rather large system sizes, L<128. Our results confirm the striking predictions of earlier analytical work and, in addition, give results for some probability distri...
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We study the quantum phase transition in the two-dimensional random Ising model in a transverse field by Monte Carlo simulations. We find results similar to those known analytically in one dimension. At the critical point the dynamical exponent is infinite and the typical correlation function decays with a stretched exponential dependence on distance. Away from the critical point there are Grif...
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ژورنال
عنوان ژورنال: Physical Review B
سال: 1999
ISSN: 0163-1829,1095-3795
DOI: 10.1103/physrevb.59.11308