1,408 research outputs found
Instanton-dyon ensembles reproduce deconfinement and chiral restoration phase transitions
Paradigm shift in gauge topology at finite temperatures, from the instantons
to their constituents -- instanton-dyons -- has recently lead to studies of
their ensembles and very significant advances. Like instantons, they have
fermionic zero modes, and their collectivization at sufficiently high density
explains the {\em chiral symmetry breaking transition}. Unlike instantons,
these objects have electric and magnetic charges. Simulations of the
instanton-dyon ensembles have demonstrated that their back reaction on the
Polyakov line modifies its potential and generates the {\em deconfinement phase
transition}. For the gauge theory the transition is second order, for
QCD-like theory with
and two light quark flavors both transitions are weak
crossovers at happening at about the same condition. Introduction of
quark-flavor-dependent periodicity phases (imaginary chemical potentials) leads
to drastic changes in both transitions. In particulaly, in the so called
model the deconfinement transforms to strong first order
transition, while the chiral condensate does not disappear at all. The talk
will also cover more detailed studies of correlations between the dyons,
effective eta' mass and other screening masses.Comment: this is a short version of a talk at Lattice 2017, written for
proceedings. arXiv admin note: text overlap with arXiv:1610.0878
The sounds of the Little and Big Bangs
Studies of heavy ion collisions have discovered that tiny fireballs of new
phase of matter -- quark gluon plasma (QGP) -- undergoes explosion, called the
Little Bang. In spite of its small size, it is not only well described by
hydrodynamics, but even small perturbations on top of the explosion turned to
be well described by hydrodynamical sound modes. The cosmological Big Bang also
went through phase transitions, the QCD and electroweak ones, which are
expected to produce sounds as well. We discuss their subsequent evolution and
hypothetical inverse acoustic cascade, amplifying the amplitude. Ultimately,
collision of two sound waves leads to formation of gravity waves, with the
smallest wavelength. We briefly discuss how those can be detected.Comment: This paper is a short semi-popular review describing some recent
developments in two very different fields, united by some common physics. It
was written for the Universe journa
The Instanton Density at Finite Temperatures
For {\it low} T new strict results for the instanton density n(T) are
reported. Using the PCAC methods, we express n(T) in terms of {\it vacuum}
average values of certain operators, times their {\it calculated} T-dependence.
At high T, we discuss the {\it applicability} limits of the perturbative
results. We further speculate about possible behaviour of n(T) at
Finite Temperature Phase Diagrams of Gauge Theories
We discuss finite temperature phase diagrams of SU(N) gauge theory with
massless fermions as a function of the number of fermion flavors. Inside the
conformal window we find a phase boundary separating two different conformal
phases. Below the conformal window we find different phase structures depending
on if the beta function of the theory has a first or higher order zero at the
lower boundary of the conformal window. We also outline how the associated
behaviors will help in distinguishing different types of theories using lattice
simulations.Comment: 5 pages, 5 figure
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