Chaotic temperature dependence in a model of spin glasses
نویسندگان
چکیده
We address the problem of chaotic temperature dependence in disordered glassy systems at equilibrium by following states of a random-energy random-entropy model in temperature; of particular interest are the crossings of the free-energies of these states. We find that this model exhibits strong, weak or no temperature chaos depending on the value of an exponent. This allows us to write a general criterion for temperature chaos in disordered systems, predicting the presence of temperature chaos in the Sherrington-Kirkpatrick and Edwards-Anderson spin glass models, albeit when the number of spins is large enough. The absence of chaos for smaller systems may justify why it is difficult to observe chaos with current simulations. We also illustrate our findings by studying temperature chaos in the näıve mean field equations for the Edwards-Anderson spin glass. PACS. 75.50.Lk Spin glasses and other random magnets – 05.70.Fh Phase transitions: general studies – 64.70.Pf Glass transitions
منابع مشابه
Short-Range Spin Glasses: Results and Speculations
This paper is divided into two parts. The first part concerns several standard scenarios for how short-range spin glasses might behave at low temperature. Earlier theorems of the authors are reviewed, and some new results presented, including a proof that, in a thermodynamic system exhibiting infinitely many pure states and with the property (such as in replica-symmetrybreaking scenarios) that ...
متن کاملTemperature and disorder chaos in three-dimensional Ising spin glasses.
We study the effects of small temperature as well as disorder perturbations on the equilibrium state of three-dimensional Ising spin glasses via an alternate scaling ansatz. By using Monte Carlo simulations, we show that temperature and disorder perturbations yield chaotic changes in the equilibrium state and that temperature chaos is considerably harder to observe than disorder chaos.
متن کاملDisorder Chaos and Multiple Valleys in Spin Glasses
We prove that the Sherrington-Kirkpatrick model of spin glasses is chaotic under small perturbations of the couplings at any temperature in the absence of an external field. The result is proved for two kinds of perturbations: (a) distorting the couplings via OrnsteinUhlenbeck flows, and (b) replacing a small fraction of the couplings by independent copies. We further prove that the S-K model e...
متن کاملSpin States and Entropy of Ising Spin Glasses
The relative volume of spin states in the phase space is introduced for the ±J model of spin glasses. Analysis of its temperature dependence shows that the Nishimori line separates the pure ferromagnetic-like region in the high-temperature side of the ferromagnetic phase from the randomness-dominated region in the low-temperature side. The peak value of the relative volume of the perfect ferrom...
متن کاملChaotic, memory, and cooling rate effects in spin glasses: Evaluation of the Edwards-Anderson model
We investigate chaotic, memory, and cooling rate effects in the three-dimensional Edwards-Anderson model by doing thermoremanent ~TRM! and ac susceptibility numerical experiments and making a detailed comparison with laboratory experiments on spin glasses. In contrast to the experiments, the Edwards-Anderson model does not show any trace of reinitialization processes in temperature change exper...
متن کامل