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)
15681349
Unmasking neutron star interiors using cooling simulations
We introduce a new tool for 'unmasking' the composition of neutron star (NS) interiors which is based on the fact that the state of matter at high densities determines the statistics of both NS observables, the temperature-age (TA) data as well as the mass distribution. We use modern cooling simulations to extract distributions of NS masses required to reproduce those of the yet sparse data in the TA plane. By comparing the results with a mass distribution for young, nearby NSs from population synthesis we can sharpen two NS cooling problems. The direct Urca (DU) problem consists in a narrowing of the NS population at the mass value for which the DU process as the most effective cooling mechanism in the hadronic layer of the star can occur. The Vela mass problem is a broadening of the population beyond the range of the typical mass window of 1.1 - 1.5 M_sun. Applying this tool to modern EoS we discuss examples for pure hadronic stars which are in conflict with these constraints while hybrid stars with a color superconducting quark matter core can predict a satisfactory mass distribution, provided the smallest diquark pairing gap has a properly defined density dependence.
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.
204938505
Charmonium and bottomonium production in heavy-ion collisions
We review the present status in the theoretical and phenomenological understanding of charmonium and bottomonium production in heavy-ion collisions. We start by recapitulating the basic notion of"anomalous quarkonium suppression"in heavy-ion collisions and its recent amendments involving regeneration reactions. We then survey in some detail concepts and ingredients needed for a comprehensive approach to utilize heavy quarkonia as a probe of hot and dense matter. The theoretical discussion encompasses recent lattice QCD computations of quarkonium properties in the Quark-Gluon Plasma, their interpretations using effective potential models, inelastic rate calculations and insights from analyses of electromagnetic plasmas. We illustrate the powerful techniques of thermodynamic Green functions (T-matrices) to provide a general framework for implementing microscopic properties of heavy quarkonia into a kinetic theory of suppression and regeneration reactions. The theoretical concepts are tested in applications to heavy-ion reactions at SPS, RHIC and LHC. We outline perspectives for future experiments on charmonium and bottomonium production in heavy-ion collisions over a large range in energy (FAIR, RHIC-II and LHC). These are expected to provide key insights into hadronic matter under extreme conditions using quarkonium observables.
119418108
Cooling of Neutron Stars with Color Superconducting Quark Cores
We show that within a recently developed nonlocal chiral quark model the critical density for a phase transition to color superconducting quark matter under neutron star conditions can be low enough for these phases to occur in compact star configurations with masses below 1.3 M_sun. We study the cooling of these objects in isolation for different values of the gravitational mass and argue that, if the quark matter phase would allow unpaired quarks, the corresponding hybrid stars would cool too fast. The comparison with observational data puts tight constraints on possible color superconducting quark matter phases. Possible candidates with diquark gaps of the order of 10 keV - 1 MeV such as the"2SC+X"and the color spin locking (CSL) phase are presented.
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
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.
119090950
A new approach to non-commutative U (N) gauge fields
Based on the model recently introduced by the present author et al. (arXiv:0912.2634) for non-commutative U(1) gauge fields, a generalized version of that action for U(N) gauge fields is put forward. In this approach to non-commutative gauge field theories, UV/IR mixing effects are circumvented by introducing additional "soft breaking" terms in the action which implement an IR damping mechanism. The techniques used are similar to those of the well-known Gribov-Zwanziger approach to QCD.
118497059
Gauge fields on non‐commutative spaces and renormalization
Constructing renormalizable models on non-commutative spaces constitutes a big challenge. Only few examples of renormalizable theories are known, such as the scalar Grosse-Wulkenhaar model. Gauge fields are even more difficult, since new renormalization techniques are required which are compatible with the inherently non-local setting on the one hand, and also allow to properly treat the gauge symmetry on the other hand. In this proceeding (which is based on my talk given at the “Workshop on Noncommutative Field Theory and Gravity” in Corfu/Greece, September 8–15, 2013), I focus on this last point and present new extensions to existing renormalization schemes (which are known to work for gauge field theories in commutative space) adapted to non-commutative Moyal space.
15916075
One-loop calculations for a translation invariant non-commutative gauge model
In this paper we discuss one-loop results for the translation invariant non-commutative gauge field model we introduced recently. This model relies on the addition of some carefully chosen extra terms in the action which mix long and short scales in order to circumvent the infamous UV/IR mixing, and which were motivated by the renormalizable non-commutative scalar model of Gurau et al. [arXiv:0802.0791].
16216330
A vector supersymmetry in noncommutative U(1) gauge theory with the Slavnov term
We consider noncommutative U(1) gauge theory with the additional term, involving a scalar field λ, introduced by Slavnov in order to cure the infrared problem. We show that this theory, with an appropriate space-like axial gauge-fixing, exhibits a linear vector supersymmetry similar to the one present in the 2-dimensional BF model. This vector supersymmetry implies that all loop corrections are independent of the λAA-vertex and thereby explains why Slavnov found a finite model for the same gauge-fixing.