Exact ground states of one-dimensional long-range random-field Ising magnets

Article

关键词: 1ST-ORDER PHASE-TRANSITIONS;    CRITICAL-BEHAVIOR;    SCALING THEORY;    MODEL;    FERROMAGNET;    SYSTEMS;    EXISTENCE;   

DOI  :  10.1103/PhysRevB.90.014207

来源: SCIE

【 摘 要 】

We investigate the one-dimensional long-range random-field Ising magnet with Gaussian distribution of the random fields. In this model, a ferromagnetic bond between two spins is placed with a probability p similar to r (1 sigma), where r is the distance between these spins and sigma is a parameter to control the effective dimension of the model. Exact ground states at zero temperature are calculated for system sizes up to L = 2(19) via graph theoretical algorithms for four different values of sigma is an element of{0.25,0.4,0.5,1.0} while varying the strength h of the random fields. For each of these values several independent physical observables are calculated, i.e., magnetization, Binder parameter, susceptibility, and a specific-heat-like quantity. The ferromagnet-paramagnet transitions at critical values h(c) (sigma) as well as the corresponding critical exponents are obtained. The results agree well with theory, and interestingly we find for sigma = 1/2 the data is compatible with a critical random-field strength h(c) > 0.

【 授权许可】

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