Monte Carlo test of the Goldstone mode singularity in 3D XY model

Monte Carlo simulations of magnetization and susceptibility in the 3D XY model are performed for system sizes up to L=384 (significantly exceeding the largest size L=160 considered in work published previously), and fields h ≥ 0.0003125 at two different coupling constants β=0.5, and β=0.55 in the ordered phase. We examine the prediction of the standard theory that the longitudinal susceptibility χ∥ has a Goldstone mode singularity such that χ∥ ∝h-1/2 holds when h↦0. Most of our results, however, support another theoretical prediction that the singularity is of a more general form χ∥ ∝hρ-1, where 1/2<ρ<1 is a universal exponent related to the ∼hρ variation of the magnetization

Monte Carlo test of the Goldstone mode singularity in 3D XY model

Monte Carlo simulations of magnetization and susceptibility in the 3D XY model are performed for system sizes up to L=384 (significantly exceeding the largest size L=160 considered in work published previously), and fields h ≥ 0.0003125 at two different coupling constants β=0.5, and β=0.55 in the ordered phase. We examine the prediction of the standard theory that the longitudinal susceptibility χ ∥ has a Goldstone mode singularity such that χ ∥ ∝h -1/2 holds when h↦0. Most of our results, however, support another theoretical prediction that the singularity is of a more general form χ ∥ ∝h ρ-1 , where 1/2>ρ>1 is a universal exponent related to the ∼h ρ variation of the magnetization. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200705.10.Ln Monte Carlo methods, 75.10.Hk Classical spin models, 05.50.+q Lattice theory and statistics (Ising, Potts, etc.),

Experimental Study of the Radiative Scattering PI-P-]PI-P-gamma at 43 GEV

The pion radiative scattering (x-p + x-py) has been studied at 43 GeV in the interval 0.2 lt, l 0.4 (GeV/c)2 of the momentum transfer squared to the proton and in the range of photon energy 2 &lt; w &lt; 40 GeV. Calculations based on Low theorem agree well with measured w, t, and m, (final xy-invariant mass) differential cross-sections. The results obtained extend the validity of Low approach to the radiative scattering at high energies