22 research outputs found
Vacuum creation of quarks at the time scale of QGP thermalization and strangeness enhancement in heavy-ion collisions
The vacuum parton creation in quickly varying external fields is studied at
the time scale of order 1 fm/ typical for the quark-gluon plasma formation
and thermalization. To describe the pre-equilibrium evolution of the system the
transport kinetic equation is employed. It is shown that the dynamics of
production process at times comparable with particle inverse masses can deviate
considerably from that based on classical Schwinger-like estimates for
homogeneous and constant fields. One of the effects caused by non-stationary
chromoelectric fields is the enhancement of the yield of quark
pairs. Dependence of this effect on the shape and duration of the field pulse
is studied together with the influence of string fusion and reduction of quark
masses.Comment: REVTEX, 11pp. incl. 4 figures, to be published in Phys. Lett.
Gas-liquid transition in the model of particles interacting at high energy
An application of the ideas of the inertial confinement fusion process in the
case of particles interacting at high energy is investigated. A possibility of
the gas-liquid transition in the gas is considered using different approaches.
In particular, a shock wave description of interactions between particles is
studied and a self-similar solution of Euler's equation is discussed.
Additionally, Boltzmann equation is solved for self-consistent field (Vlasov's
equation) in linear approximation for the case of a gas under external pressure
and the corresponding change of Knudsen number of the system is calculated.Comment: 24 pages, 2 figur
Lattice QCD Constraints on the Nuclear Equation of State
Based on the quasi-particle description of the QCD medium at finite
temperature and density we formulate the phenomenological model for the
equation of state that exhibits crossover or the first order deconfinement
phase transition. The models are constructed in such a way to be
thermodynamically consistent and to satisfy the properties of the ground state
nuclear matter comply with constraints from intermediate heavy--ion collision
data. Our equations of states show quite reasonable agreement with the recent
lattice findings on temperature and baryon chemical potential dependence of
relevant thermodynamical quantities in the parameter range covering both the
hadronic and quark--gluon sectors. The model predictions on the isentropic
trajectories in the phase diagram are shown to be consistent with the recent
lattice results. Our nuclear equations of states are to be considered as an
input to the dynamical models describing the production and the time evolution
of a thermalized medium created in heavy ion collisions in a broad energy range
from SIS up to LHC.Comment: 13 pages, 11 figure
Electromagnetic superconductivity of vacuum induced by strong magnetic field
The quantum vacuum may become an electromagnetic superconductor in the
presence of a strong external magnetic field of the order of 10^{16} Tesla. The
magnetic field of the required strength (and even stronger) is expected to be
generated for a short time in ultraperipheral collisions of heavy ions at the
Large Hadron Collider. The superconducting properties of the new phase appear
as a result of a magnetic-field-assisted condensation of quark-antiquark pairs
with quantum numbers of electrically charged rho mesons. We discuss
similarities and differences between the suggested superconducting state of the
quantum vacuum, a conventional superconductivity and the Schwinger pair
creation. We argue qualitatively and quantitatively why the superconducting
state should be a natural ground state of the vacuum at the sufficiently strong
magnetic field. We demonstrate the existence of the superconducting phase using
both the Nambu-Jona-Lasinio model and an effective bosonic model based on the
vector meson dominance (the rho-meson electrodynamics). We discuss various
properties of the new phase such as absence of the Meissner effect, anisotropy
of superconductivity, spatial inhomogeneity of ground state, emergence of a
neutral superfluid component in the ground state and presence of new
topological vortices in the quark-antiquark condensates.Comment: 37 pages, 14 figures, to appear in Lect. Notes Phys. "Strongly
interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K.
Landsteiner, A. Schmitt, H.-U. Ye
Lattice QCD Simulations in External Background Fields
We discuss recent results and future prospects regarding the investigation,
by lattice simulations, of the non-perturbative properties of QCD and of its
phase diagram in presence of magnetic or chromomagnetic background fields.
After a brief introduction to the formulation of lattice QCD in presence of
external fields, we focus on studies regarding the effects of external fields
on chiral symmetry breaking, on its restoration at finite temperature and on
deconfinement. We conclude with a few comments regarding the effects of
electromagnetic background fields on gluodynamics.Comment: 31 pages, 10 figures, minor changes and references added. To appear
in Lect. Notes Phys. "Strongly interacting matter in magnetic fields"
(Springer), edited by D. Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Ye
The Chiral Magnetic Effect and Axial Anomalies
We give an elementary derivation of the chiral magnetic effect based on a
strong magnetic field lowest-Landau-level projection in conjunction with the
well-known axial anomalies in two- and four-dimensional space-time. The
argument is general, based on a Schur decomposition of the Dirac operator. In
the dimensionally reduced theory, the chiral magnetic effect is directly
related to the relativistic form of the Peierls instability, leading to a
spiral form of the condensate, the chiral magnetic spiral. We then discuss the
competition between spin projection, due to a strong magnetic field, and
chirality projection, due to an instanton, for light fermions in QCD and QED.
The resulting asymmetric distortion of the zero modes and near-zero modes is
another aspect of the chiral magnetic effect.Comment: 33 pages, 5 figures, to appear in Lect. Notes Phys. "Strongly
interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K.
Landsteiner, A. Schmitt, H.-U. Ye