Portal de Periódicos da CAPES

The de Ahneida-Thouless line in the four dimensional Ising spin glass

1993; EDP Sciences; Volume: 3; Issue: 11 Linguagem: Inglês

10.1051/jp1

1286-4862

J. C. Ciria, Giorgio Parisi, F. Pdtort, J. J. Ruiz-Lorenzo,

Random Matrices and Applications

We confirm recent results obtained in a previous work by studying the Ising spin glass at finite magnetic field in four dimensions.Different JOURNAL DE PHYSIQUE I N°11 Huse [7, 8] in a series of papers.Nevertheless, some predictions of these phenomenological models are substantially different from thosefound in short-ranged systems if a mean-field picture were valid in this case.From the experimental point of view recent cycling temperature experiments have been interpreted within the mean-field picture [9,10].It has also been claimed that they are incon- sistent with predictions of the droplet model even though there is not general agreement on this point.One of the most striking differences among droplet models and mean-field theory is the response of the system to an applied magnetic field.If the droplet theory predicts that a magnetic field should destroy the spin glass phase, the mean-field picture suggests that, even though some pure states are suppressed by the magnetic field, an infinite number of them will survive to the perturbation.In this case a transition line in finite magnetic field (de Almeida-Thouless -AT-line ill] is expected.Recently this issues has been adressed in a previous work in the four dimensional Ising spin glass [12].The advantages of studying the Ising spin glass in four dimensions are mainly numerical and we believe it captures the main features of spin glasses below the upper critical dimension and (we hope) those at three dimensions.In that work II 2], it was found evidence of a phase transition at finite field using standard finite-size scaling methods.A different approach was used in [13].Also numerical work in zero magnetic field [14,15] has shown that the spin glass phase seems to consist of an infinite number of pure states