The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform

J.j. Mason - One of the best experts on this subject based on the ideXlab platform.

Francesca Vidotto - One of the best experts on this subject based on the ideXlab platform.

  • many node many link spinfoam the homogeneous and Isotropic Case
    Classical and Quantum Gravity, 2011
    Co-Authors: Francesca Vidotto
    Abstract:

    I compute the Lorentzian EPRL/FK/KKL spinfoam vertex amplitude at the first order for regular graphs, with an arbitrary number of links and nodes, and coherent states peaked on a homogeneous and Isotropic geometry. This form of the amplitude can be applied for example to a dipole with an arbitrary number of links or to the 4-simplex given by the complete graph on five nodes. All the resulting amplitudes have the same support, independently of the graph used, in the large-j (large-volume) limit. This implies that they all yield the Friedmann equation: I show this in the presence of the cosmological constant. This result indicates that in the semiclassical limit, quantum corrections in spinfoam cosmology do not come from just refining the graph, but rather from relaxing the large-j limit.

  • Many-node/many-link spinfoam: the homogeneous and Isotropic Case
    Classical and Quantum Gravity, 2011
    Co-Authors: Francesca Vidotto
    Abstract:

    I compute the Lorentzian EPRL/FK/KKL spinfoam vertex amplitude at the first order for regular graphs, with an arbitrary number of links and nodes, and coherent states peaked on a homogeneous and Isotropic geometry. This form of the amplitude can be applied for example to a dipole with an arbitrary number of links or to the 4-simplex given by the complete graph on five nodes. All the resulting amplitudes have the same support, independently of the graph used, in the large-j (large-volume) limit. This implies that they all yield the Friedmann equation: I show this in the presence of the cosmological constant. This result indicates that in the semiclassical limit, quantum corrections in spinfoam cosmology do not come from just refining the graph, but rather from relaxing the large-j limit.

C. Rubio-gonzalez - One of the best experts on this subject based on the ideXlab platform.

P Simonetti - One of the best experts on this subject based on the ideXlab platform.

  • tunneling in quantum wires exact solution of the spin Isotropic Case
    Physical Review B, 1997
    Co-Authors: F Lesage, H Saleur, P Simonetti
    Abstract:

    We show that the problem of impurity tunneling in a Luttinger liquid of electrons with spin is solvable in the spin Isotropic Case (g{sub {sigma}}=2, g{sub {rho}} arbitrary). The resulting integrable model is similar to a two-channel anIsotropic Kondo model, but with the impurity spin in a {open_quotes}cyclic representation{close_quotes} of the quantum algebra su(2){sub q} associated with the anisotropy. Using exact, nonperturbative techniques we study the renormalization-group flow, and compute the dc conductance. As expected from the analysis of Kane and Fisher we find that the IR fixed point corresponds to two separate leads. We also prove an exact duality between the UV and IR expansions of the current at vanishing temperature. {copyright} {ital 1997} {ital The American Physical Society}

P Jouve - One of the best experts on this subject based on the ideXlab platform.

  • behavior of unbound granular materials part i Isotropic Case
    Computers and Geotechnics, 2003
    Co-Authors: Rabah Bouzidi, L Coulibaly, P Jouve
    Abstract:

    Abstract The paper discusses the modeling of the behavior of unbound granular materials. A representative approach that highlights some salient features of the behavior is proposed. This approach is essentially based on experimental results and the study is extended to the construction of the elastic potential from test results. to complete the analysis, two no-linear elastic models involving 3 parameters are proposed. In the construction of these models, two important aspects—the accuracy and the numerical stability—are analyzed.

  • Behavior of unbound granular materials—part I: Isotropic Case
    Computers and Geotechnics, 2003
    Co-Authors: Rabah Bouzidi, L Coulibaly, P Jouve
    Abstract:

    Abstract The paper discusses the modeling of the behavior of unbound granular materials. A representative approach that highlights some salient features of the behavior is proposed. This approach is essentially based on experimental results and the study is extended to the construction of the elastic potential from test results. to complete the analysis, two no-linear elastic models involving 3 parameters are proposed. In the construction of these models, two important aspects—the accuracy and the numerical stability—are analyzed.