Massimo D'Elia

Phase diagram of the lattice SU(2) Higgs model

Abstract We perform a detailed study of the phase diagram of the lattice Higgs SU ( 2 ) model with fixed Higgs field length. Consistently with previsions based on the Fradkin–Shenker theorem we find a first order transition line with an endpoint whose position we determined. The diagram also shows cross-over lines: the cross-over corresponding to the pure SU ( 2 ) bulk is also present at nonzero coupling with the Higgs field and merges with the one that continues the line of first order transition beyond the critical endpoint. At high temperature the first order line becomes a crossover, whose position moves by varying the temperature.

The critical line of two-flavor QCD at finite isospin or baryon densities from imaginary chemical potentials

We determine the (pseudo)critical lines of QCD with two degenerate staggered nfermions at nonzero temperature and quark or isospin density, in the region of nimaginary chemical potentials; analytic continuation is then used to prolongate nto the region of real chemical potentials. We obtain an accurate determination nof the curvatures at zero chemical potential, quantifying the deviation between nthe case of finite quark and of finite isospin chemical potential. Deviations nfrom a quadratic dependence of the pseudocritical lines on the chemical npotential are clearly seen in both cases: we try different extrapolations and, nfor the case of nonzero isospin chemical potential, confront them with the nresults of direct Monte Carlo simulations. Finally we find that, as for the nfinite quark density case, an imaginary isospin chemical potential can nstrengthen the transition till turning it into strong first order.

A test of first order scaling in Nf =2 QCD: a progress report

SUMMARY We present the status of our analysis on the order of the finite temperature ntransition in QCD with two flavors of degenerate fermions. Our new simulations non large lattices support the hypothesis of the first order nature of the ntransition, showing a preliminary two state signal. We will discuss the nimplications and the next steps in our analysis.

On the phase diagram of the Higgs SU(2) model

SUMMARY The Higgs SU(2) model with fixed Higgs length is usually believed to have two ndifferent phases at high gauge coupling (beta), separated by a line of first norder transitions but not distinuguished by any typical symmetry associated nwith a local order parameter, as first proved by Fradkin and Shenker. We show nthat in regions of the parameter space where it is usually supposed to be a nfirst order phase transition only a smooth crossover is in fact present.

Analytical continuation from imaginary to real chemical potential in two-color QCD under scrutiny

The method of analytical continuation from imaginary to real chemical npotential is tested in 2-color QCD. In comparison to previous studies in the nsame theory, an exact updating algorithm is used and simulations are performed ncloser to the thermodynamic limit. It is shown that the method considerably nimproves if suitable functions are used to interpolate data with imaginary nchemical potential.

Deconfining transition in two-flavor QCD

SUMMARY The order and the nature of the finite-temperature phase transition of QCD nwith two flavors of dynamical quarks is investigated. An analysis of the ncritical exponent of the specific heat is performed through finite-size and nfinite-mass scaling of various susceptibilities. Dual superconductivity of QCD nvacuum is investigated using a disorder parameter, namely the v.e.v. of a nmonopole creation operator. Hybrid R simulations were run at lattice spatial nsizes of

Gauge-invariant field strength correlators in full QCD

12^3

Staggered fermions simulations on GPUs

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Study of the systematic errors in the calculation of renormalization constants of the topological susceptibility on the lattice

16^3

Investigations on the deconfining phase transition in QCD

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