118677030
Finite temperature Mott transition in a nonlocal PNJL model
We provide a novel calculation of the Mott effect in non-local PNJL models. We find that the "deconfinement" transition temperature in these models is lower than the Mott temperature. Furthermore, the mass and the width of the $\sigma$ and the $\pi$ meson modes is calculated with the result that the width in nonlocal models is in general reduced as compared to local models. Difficulties encountered while attempting to "Wick rotate" covariant models are carefully discussed.
19005376
Bound States and Superconductivity in Dense Fermi Systems
A quantum field theoretical approach to the thermodynamics of dense Fermi systems is developed for the description of the formation and dissolution of quantum condensates and bound states in dependence of temperature and density. As a model system, we study the chiral and superconducting phase transitions in two-flavor quark matter within the NJL model and their interrelation with the formation of quark-antiquark and diquark bound states. The phase diagram of quark matter is evaluated as a function of the diquark coupling strength and a coexistence region of chiral symmetry breaking, and color superconductivity is obtained at very strong coupling. The crossover between Bose-Einstein condensation (BEC) of diquark bound states and condensation of diquark resonances (Cooper pairs) in the continuum (BCS) is discussed as a Mott effect. This effect consists in the transition of bound states into the continuum of scattering states under the influence of compression and heating. We explain the physics of the Mott transition with special emphasis on the role of the Pauli principle for the case of the pion in quark matter.
16235650
Pulsations of the electron-positron plasma in the field of optical lasers
The possibility to observe vacuum electron-positron pair creation due to a powerful optical laser pulse is discussed. We employ a quantum kinetic formulation of the problem with a source term describing the vacuum pair production in a homogeneous electric field with arbitrary time dependence (dynamical Schwinger mechanism). For a periodic field weak in comparison with the critical value E_{cr}=m^2/|e|, the electron-positron plasma density changes approximately periodically with twice the field frequency. Under these conditions, the mean value $ $ for the density per period in the volume lambda^3 is a more appropriate characteristic quantity than the residual density n_r which is taken over an integer number of field periods and calculated using the imaginary time method. The value is proportional to the squared field intensity and does not depend on the frequency. We show that in terms of the parameter an optical laser can be more effective than a X-ray one. We expect that it is possible to observe the vacuum creation effect not only by means of the planned X-ray free electron lasers but already at present-day optical lasers.
119222844
Kinetics of Photon Radiation off an e–e+-Plasma Created from the Vacuum in a Strong Laser Field
We consider the one-photon annihilation mechanism in a electron - positron quasiparticle plasma (EPP) created from the vacuum in a strong subcritical laser field due to the dynamical Schwinger mechanism. On the basis of a kinetic theory approach we show that the secondary photons have a radiation spectrum proportional to 1/k (flicker noise). This effect is very small for EPP excitations in the optical spectrum but can reach quite observable values in the γ -ray region (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
119278144
An effective model of QCD thermodynamics
A combined effective model reproducing the equation of state of hadronic matter as obtained in recent lattice QCD simulations is presented. The model reproduces basic physical characteristics encountered in dense hadronic matter in the quark-gluon plasma (QGP) phase and the lower temperature hadron resonance gas phase. The hadronic phase is described by means of an extended Mott-Hagedorn resonance gas while the QGP phase is described by the extended PNJL model. The dissociation of hadrons is obtained by including the state dependent hadron resonance width.
15235622
Asymmetric neutrino propagation in newly born magnetized strange stars; GRB and kicks
AbstractWe consider the early cooling evolution of strongly magnetized strange stars in a color–ﬂavor-lockedphase with high gap 100 MeV. We demonstrate how this model may explain the main features ofthe gamma-ray burst phenomena and also yield a strong star kick. The mechanism is based on beaming ofneutrino emission along the magnetic vortex lines. We show that for sufﬁciently high initial temperaturesT 0 ∼ 30–60 MeV and surface magnetic ﬁelds B s ∼ 10 15 –10 17 G, the energy release within the narrowbeam is up to 10 52 erg with a magnetic ﬁeld dependent timescale between 10 −2 s (for a smaller magneticﬁe ld)and 10 s. The above mechanism together with the parity violation of the neutrino-producing weakinteraction processes in a magnetic ﬁeld allow for the strange star kick. The higher the magnetic ﬁeld thelarger the star kick velocity. These velocities may cover the same range as observed pulsar kick velocities. c 2006 Elsevier B.V. All rights reserved. Keywords: Gamma-ray bursts; Strange stars; Color superconductivity; Pulsar kicks
5623998
Wong's Equations and Charged Relativistic Particles in Non-Commutative Space
In analogy to Wong's equations describing the motion of a charged relativistic point particle in the presence of an external Yang{Mills field, we discuss the motion of such a particle in non-commutative space subject to an external U?(1) gauge field. We conclude that the latter equations are only consistent in the case of a constant field strength. This formulation, which is based on an action written in Moyal space, provides a coarser level of description than full QED on non-commutative space. The results are compared with those obtained from the different Hamiltonian approaches. Furthermore, a continuum version for Wong's equations and for the motion of a particle in non-commutative space is derived.
119232022
Compactified rotating branes in the matrix model, and excitation spectrum towards one loop
We study compactified brane solutions of type $\mathbb{R}^{4} \times K$ in the IIB matrix model, and obtain explicitly the bosonic and fermionic fluctuation spectrum required to compute the one-loop effective action. We verify that the one-loop contributions are UV finite for $\mathbb{R}^{4} \times T^{2}$, and supersymmetric for $\mathbb{R}^{3} \times S^{1}$. The higher Kaluza–Klein modes are shown to have a gap in the presence of flux on T2, and potential problems concerning stability are discussed.
14134311
Improved localization of a renormalizable non-commutative translation invariant U(1) gauge model
Motivated by the recent work of Vilar et al. (arXiv:0902.2956) we enhance our non-commutative translation invariant gauge model (Blaschke D. N. et al., arXiv:0901.1681) by introducing auxiliary fields and ghosts forming a BRST doublet structure. In this way localization of the problematic term can be achieved without the necessity for any additional degrees of freedom. The resulting theory is suspected to be renormalizable. A rigorous proof, however, has not been accomplished up to now.
59471827
Special Geometries Emerging from Yang-Mills Type Matrix Models
I review some recent results which demonstrate how various geometries, such as Schwarzschild and Reissner-Nordstrom, can emerge from Yang-Mills type matrix models with branes. Furthermore, explicit embeddings of these branes as well as appropriate Poisson structures and starproducts which determine the non-commutativity of space-time are provided. These structures are motivated by higher order terms in the effective matrix model action which semi-classically lead to an Einstein-Hilbert type action.
18811875
Quantum Corrections for Translation-Invariant Renormalizable Non-Commutative Phi**4 Theory
In this paper we elaborate on the translation-invariant renormalizable 4 theory in 4-dimensional non-commu\-ta\-tive space which was recently introduced by the Orsay group. By explicitly performing Feynman graph calculations at one loop and higher orders we illustrate the mechanism which overcomes the UV/IR mixing problem and ultimately leads to a renormalizable model. The obtained results show that the IR divergences are also suppressed in the massless case, which is of importance for the gauge field theoretic generalization of the scalar field model.