Implementing the LPM effect in a parton cascade model

Parton Cascade Models (PCM), which describe the full time-evolution of a system of quarks and gluons using pQCD interactions are ideally suited for the description of jet production, including the emission, evolution and energy-loss of the full parton shower in a hot and dense QCD medium. The Landau-Pomeranchuk-Migdal (LPM) effect, the quantum interference of parton wave functions due to repeated scatterings against the background medium, is likely the dominant in-medium effect affecting jet suppression. We have implemented a probabilistic implementation of the LPM effect within the PCM which can be validated against previously derived analytical calculations by Baier et al (BDMPS-Z). Presented at the 6th International Conference on Physics and Astrophysics of Quark Gluon Plasma (ICPAQGP 2010).Comment: 4 pages, 1 figure. A proceeding of ICPAGQP 201

Correlations in the Parton Recombination Model

We describe how parton recombination can address the recent measurement of dynamical jet-like two particle correlations. In addition we discuss the possible effect realistic light-cone wave-functions including higher Fock-states may have on the well-known elliptic flow valence-quark number scaling law.Comment: 4 pages, two figures, proceedings of the 18th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2005 (QM 2005), Budapest, Hungary, 4-9 Aug 200

Stationary solutions of the one-dimensional nonlinear Schroedinger equation: I. Case of repulsive nonlinearity

All stationary solutions to the one-dimensional nonlinear Schroedinger equation under box and periodic boundary conditions are presented in analytic form. We consider the case of repulsive nonlinearity; in a companion paper we treat the attractive case. Our solutions take the form of stationary trains of dark or grey density-notch solitons. Real stationary states are in one-to-one correspondence with those of the linear Schr\"odinger equation. Complex stationary states are uniquely nonlinear, nodeless, and symmetry-breaking. Our solutions apply to many physical contexts, including the Bose-Einstein condensate and optical pulses in fibers.Comment: 11 pages, 7 figures -- revised versio

On an asymptotic estimate of the nn-loop correction in perturbative QCD

A recently proposed method of estimating the asymptotic behaviour of QCD perturbation theory coefficients is critically reviewed and shown to contain numerous invalid mathematical operations and unsubstantiated assumptions. We discuss in detail why this procedure, based solely on renormalization group (RG) considerations and analyticity constraints, cannot lead to such estimates. We stress the importance of correct renormalization scheme (RS) dependence of any meaningful asymptotic estimate and argue that the unambiguous summation of QCD perturbation expansions for physical quantities requires information from outside of perturbation theory itself.Comment: PRA-HEP-92/17, Latex, 20 pages of text plus 5 figures contained in 5 separate PS files. Four of them (corresponding to Figs.1,2,3,5) are appended at the end of this file, the (somewhat larger one) corresponding to Fig.4 can be obtained from any of the mentioned E-mail addresses upon request. E-mail connections: J. Chyla - [email protected]) or h1kchy@dhhdesy3 P. Kolar - [email protected]

Magnetotransport in two-dimensional electron gas at large filling factors

We derive the quantum Boltzmann equation for the two-dimensional electron gas in a magnetic field such that the filling factor $\nu \gg 1$. This equation describes all of the effects of the external fields on the impurity collision integral including Shubnikov-de Haas oscillations, smooth part of the magnetoresistance, and non-linear transport. Furthemore, we obtain quantitative results for the effect of the external microwave radiation on the linear and non-linear $dc$ transport in the system. Our findings are relevant for the description of the oscillating resistivity discovered by Zudov {\em et al.}, zero-resistance state discovered by Mani {\em et al.} and Zudov {\em et al.}, and for the microscopic justification of the model of Andreev {\em et al.}. We also present semiclassical picture for the qualitative consideration of the effects of the applied field on the collision integral.Comment: 28 pages, 19 figures; The discussion of the role of the effect of the microwave field on the distribution function is revised (see also cond-mat/0310668). Accepted in Phys. Rev.

Inclusive Heavy-Flavor Production from Nuclei

We describe a light-cone wave function formulation for hadroproduction of heavy-flavors at high energies. At moderate values of $x_F$ heavy-flavor production can be viewed as a diffractive excitation of heavy quark-antiquark Fock states, present in the interacting gluon from the projectile. The approach developed here is well suited to address coherence effects in heavy-quark production from nuclei at small values of x_{t} \lsim 0.1\cdot A^{-1/3}.Comment: 14 pages with 3 figures. To appear in Z. Phys.

Classical/quantum integrability in non-compact sector of AdS/CFT

We discuss non-compact SL(2,R) sectors in N=4 SYM and in AdS string theory and compare their integrable structures. We formulate and solve the Riemann-Hilbert problem for the finite gap solutions of the classical sigma model and show that at one loop it is identical to the classical limit of Bethe equations of the spin (-1/2) chain for the dilatation operator of SYM.Comment: 27 pages, 1 figure; v2: unphysical windings around the time direction eliminated; v3: dicsussion of finite-size corrections remove

Electromagnetic probes

We introduce the seminal developments in the theory and experiments of electromagnetic probes for the study of the dynamics of relativistic heavy ion collisions and quark gluon plasma.Comment: 47 pages, 33 Figures; Lectures delivered by Dinesh K. Srivastava at QGP Winter School (QGPWS08) at Jaipur, India, February 1-3, 200

Schottky barrier heights at polar metal/semiconductor interfaces

Using a first-principle pseudopotential approach, we have investigated the Schottky barrier heights of abrupt Al/Ge, Al/GaAs, Al/AlAs, and Al/ZnSe (100) junctions, and their dependence on the semiconductor chemical composition and surface termination. A model based on linear-response theory is developed, which provides a simple, yet accurate description of the barrier-height variations with the chemical composition of the semiconductor. The larger barrier values found for the anion- than for the cation-terminated surfaces are explained in terms of the screened charge of the polar semiconductor surface and its image charge at the metal surface. Atomic scale computations show how the classical image charge concept, valid for charges placed at large distances from the metal, extends to distances shorter than the decay length of the metal-induced-gap states.Comment: REVTeX 4, 11 pages, 6 EPS figure