6,746 research outputs found
Dynamical correlations in the spin-half two-channel Kondo model
Dynamical correlations of various local operators are studied in the
spin-half two-channel Kondo (2CK) model in the presence of channel anisotropy
or external magnetic field. A conformal field theory-based scaling approach is
used to predict the analytic properties of various spectral functions in the
vicinity of the two-channel Kondo fixed point. These analytical results compare
well with highly accurate density matrix numerical renormalization group
results. The universal cross-over functions interpolating between
channel-anisotropy or magnetic field-induced Fermi liquid regimes and the
two-channel Kondo, non-Fermi liquid regimes are determined numerically. The
boundaries of the real 2CK scaling regime are found to be rather restricted,
and to depend both on the type of the perturbation and on the specific operator
whose correlation function is studied. In a small magnetic field, a universal
resonance is observed in the local fermion's spectral function. The dominant
superconducting instability appears in the composite superconducting channel.Comment: 20 pages, 24 figures, PRB forma
Lattice QCD at non-vanishing density: phase diagram, equation of state
We propose a method to study lattice QCD at non-vanishing temperature (T) and
chemical potential (\mu). We use n_f=2+1 dynamical staggered quarks with
semi-realistic masses on L_t=4 lattices. The critical endpoint (E) of QCD on
the Re(\mu)-T plane is located. We calculate the pressure (p), the energy
density (\epsilon) and the baryon density (n_B) of QCD at non-vanishing T and
\mu.Comment: Contributed to Workshop on Strong and Electroweak Matter (SEWM 2002),
Heidelberg, Germany, 2-5 Oct 200
The QCD equation of state at finite T/\mu on the lattice
We present N_t=4 lattice results for the equation of state of 2+1 flavour
staggered, dynamical QCD at finite temperature and chemical potential. We use
the overlap improving multi-parameter reweighting technique to extend the
equation of state for non-vanishing chemical potentials. The results are
obtained along the line of constant physics. Our physical parameters extend in
temperature and baryon chemical potential upto \approx 500-600 MeV.Comment: 13 pages 9 figures, talk given at Finite Density QCD at Nara, Nara,
Japan, 10-12 July 200
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