Anderson Model

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Felix Ritort - One of the best experts on this subject based on the ideXlab platform.

  • Chaotic, memory, and cooling rate effects in spin glasses: Evaluation of the Edwards-Anderson Model
    Physical Review B, 2001
    Co-Authors: Marco Picco, Federico Ricci-tersenghi, Felix Ritort
    Abstract:

    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 experiments ~TRM or ac! .A detailed comparison with ac relaxation experiments in the presence of dc magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson Model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson Model to reproduce the experimental results.

  • Chaotic, memory and cooling rate effects in spin glasses: Is the Edwards-Anderson Model a good spin glass?
    Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2001
    Co-Authors: Marco Picco, Federico Ricci-tersenghi, Felix Ritort
    Abstract:

    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 re-initialization processes in temperature change experiments (TRM or AC). A detailed comparison with AC relaxation experiments in the presence of DC magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson Model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson Model to reproduce the experimental results.

Marco Picco - One of the best experts on this subject based on the ideXlab platform.

  • Chaotic, memory, and cooling rate effects in spin glasses: Evaluation of the Edwards-Anderson Model
    Physical Review B, 2001
    Co-Authors: Marco Picco, Federico Ricci-tersenghi, Felix Ritort
    Abstract:

    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 experiments ~TRM or ac! .A detailed comparison with ac relaxation experiments in the presence of dc magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson Model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson Model to reproduce the experimental results.

  • Chaotic, memory and cooling rate effects in spin glasses: Is the Edwards-Anderson Model a good spin glass?
    Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2001
    Co-Authors: Marco Picco, Federico Ricci-tersenghi, Felix Ritort
    Abstract:

    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 re-initialization processes in temperature change experiments (TRM or AC). A detailed comparison with AC relaxation experiments in the presence of DC magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson Model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson Model to reproduce the experimental results.

NED SCOTT WINGREEN - One of the best experts on this subject based on the ideXlab platform.

  • low temperature transport through a quantum dot the Anderson Model out of equilibrium
    Physical Review Letters, 1993
    Co-Authors: Yigal Meir, NED SCOTT WINGREEN
    Abstract:

    Abstract : The infinite-U Anderson Model is applied to non-equilibrium transport through a quantum dot containing two spin levels weakly coupled to two leads. At low temperatures, the Kondo peak in the equilibrium density of states is split upon the application of a voltage bias. The split peaks, one at the chemical potential of each lead, are suppressed by non-equilibrium dissipation. In a magnetic field, the Kondo peaks shift away from the chemical potentials by the Zeeman energy, leading to an observable peak in the differential conductance when the non-equilibrium bias equals the Zeeman energy. Infinite-U Anderson Model, Kondo peak, Zeeman energy, Low-temperature transport through a quantum dot, Kondo effect.

Wolfgang Nolting - One of the best experts on this subject based on the ideXlab platform.

  • Kondo screening and exhaustion in the periodic Anderson Model
    Physical Review B, 2000
    Co-Authors: D. Meyer, Wolfgang Nolting
    Abstract:

    We investigate the paramagnetic periodic Anderson Model using the dynamical mean-field theory in combination with the modified perturbation theory that interpolates between the weak and strong coupling limits. For the symmetric periodic Anderson Model, the ground state is always a singlet state. However, as function of the hybridization strength, a crossover from collective to local Kondo screening is found. Reducing the number of conduction electrons, the local Kondo singlets remain stable. The unpaired $f$ electrons dominate the physics of the system. For very low conduction electron densities, a large increase of the effective mass of the quasiparticles is visible, which is interpreted as the approach of the Mott-Hubbard transition.

  • Periodic Anderson Model: magnetic properties
    Physica B-condensed Matter, 2000
    Co-Authors: D. Meyer, Wolfgang Nolting
    Abstract:

    Abstract We investigate the periodic Anderson Model using dynamical mean-field theory. The effective impurity problem is solved by means of the modified perturbation theory. Our focus is on the possibility of ferromagnetic order, and on the properties of the ferromagnetic phase. Within the ferromagnetic phase, the coupling between f- and s-electrons changes from anti- to ferromagnetic depending on the total number of electrons.

Federico Ricci-tersenghi - One of the best experts on this subject based on the ideXlab platform.

  • Chaotic, memory, and cooling rate effects in spin glasses: Evaluation of the Edwards-Anderson Model
    Physical Review B, 2001
    Co-Authors: Marco Picco, Federico Ricci-tersenghi, Felix Ritort
    Abstract:

    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 experiments ~TRM or ac! .A detailed comparison with ac relaxation experiments in the presence of dc magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson Model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson Model to reproduce the experimental results.

  • Chaotic, memory and cooling rate effects in spin glasses: Is the Edwards-Anderson Model a good spin glass?
    Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2001
    Co-Authors: Marco Picco, Federico Ricci-tersenghi, Felix Ritort
    Abstract:

    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 re-initialization processes in temperature change experiments (TRM or AC). A detailed comparison with AC relaxation experiments in the presence of DC magnetic field or coupling distribution perturbations reveals that the absence of chaotic effects in the Edwards-Anderson Model is a consequence of the presence of strong cooling rate effects. We discuss possible solutions to this discrepancy, in particular the smallness of the time scales reached in numerical experiments, but we also question the validity of the Edwards-Anderson Model to reproduce the experimental results.