arXiv subjects

Gábor Papp

Publications and source records attributed to Gábor Papp.

21 records · Page 2Linked to original sources

arXiv1997

Macroscopic Universality : Why QCD in Matter is Subtle?

We use a chiral random matrix model with 2N_f flavors to mock up the QCD Dirac spectrum at finite chemical potential. We show that the 1/N approximation breaks down in the quenched state with spontaneously broken chiral symmetry. The breakdown condition is set by the divergence of a two-point function, that is shown to follow the general lore of macroscopic universality. In this state, the fermionic fluctuations are not suppressed in the large N limit.

hep-ph↗

arXiv1996

QCD-Inspired Spectra from Blue's Functions

We use the law of addition in random matrix theory to analyze the spectral distributions of a variety of chiral random matrix models as inspired from QCD whether through symmetries or models. In terms of the Blue's functions recently discussed by Zee, we show that most of the spectral distributions in the macroscopic limit and the quenched approximation, follow algebraically from the discontinuity of a pertinent solution to a cubic (Cardano) or a quartic (Ferrari) equation. We use the end-point equation of the energy spectra in chiral random matrix models to argue for novel phase structures, in which the Dirac density of states plays the role of an order parameter.

hep-ph↗

arXiv1996

Lattice QCD Spectra at Finite Temperature: a Random Matrix Approach

We suggest that the lattice Dirac spectra in QCD at finite temperature may be understood using a gaussian unitary ensemble for Wilson fermions, and a chiral gaussian unitary ensemble for Kogut-Susskind fermions. For Kogut-Susskind fermions, the lattice results by the Columbia group are in good agreement with the spectral distribution following from a cubic equation, both for the valence quark distribution and the anomalous symmetry breaking. We explicitly construct a number of Dirac spectra for Wilson fermions at finite temperature, and use the end-point singularities to derive analytically the pertinent critical lines. For the physical current masses, the matrix model shows a transition from a delocalized phase at low temperature, to a localized phase at high temperature. The localization is over the thermal wavelength of the quark modes. For heavier masses, the spectral distribution reflects on localized states with competitive effects between the quark Compton wavelength and the thermal wavelength. Some further suggestions for lattice simulations are made.

hep-ph↗