Quantum theory of electron tunneling into intersubband cavity polariton states

Through a non-perturbative quantum theory, we investigate how the quasi-electron excitations of a two-dimensional electron gas are modified by strong coupling to the vacuum field of a microcavity. We show that the electronic dressed states originate from a Fano-like coupling between the bare electron states and the continuum of intersubband cavity polariton excitations. In particular, we calculate the electron spectral function modified by light-matter interactions and its impact on the electronic injection of intersubband cavity polaritons. The domain of validity of the present theoretical results is critically discussed. We show that resonant electron tunneling from a narrow-band injector can selectively excite superradiant states and produce efficient intersubband polariton electroluminescence

Charmless B Decays to Final States with Radially Excited Vector Mesons

We consider the weak decays of a B meson to final states that contain a S-wave radially excited vector meson. We consider vector-pseudoscalar final states and calculate ratios of the type $B \to \rho^{\prime} \pi/B \to \rho \pi$, $B \to \omega^{\prime} \pi/B \to \omega \pi$ and $B \to \phi^{\prime} \pi/B \to \phi \pi$ where $\rho^{\prime}$, $\omega^{\prime}$ and $\phi^{\prime}$ are higher $\rho$, $\omega$ and $\phi$ S-wave radial excitations. We find such decays to have larger or similar branching ratios compared to decays where the final state $\rho$, $\omega$ and $\phi$ are in the ground state. We also study the effect of radial mixing in the vector system generated from hyperfine interaction and the annihilation term.Comment: Latex, 12 pages, one figur

Energy resolved STM mapping of C60_{60} on metal surfaces: A theoretical study

We present a detailed theoretical study of scanning tunneling imaging and spectroscopy of \Csixty on silver and gold surfaces, motivated by the recent experiments and discussion by X. Lu et al. [PRL \textbf{90}, 096802 (2003) and PRB \textbf{70}, 115418 (2004)]. The surface/sample/tip system is described within a self--consistent DFT based tight--binding model. The topographic and conductance images are computed at constant current from a full self--consistent transport theory based on nonequilibrium Green's functions and compared with those simulated from the local density of states. The molecular orbitals of \Csixty are clearly identified in the energy resolved maps, in close correspondence with the experimental results. We show how the tip structure and orientation can affect the images. In particular, we consider the effects of truncated tips on the energy resolved maps.Comment: 9 pages, 8 figure

Vortex free energies in SO(3) and SU(2) lattice gauge theory

Lattice gauge theories with gauge groups SO(3) and SU(2) are compared. The free energy of electric twist, an order parameter for the confinement-deconfinement transition which does not rely on centre-symmetry breaking, is measured in both theories. The results are used to calibrate the scale in SO(3).Comment: 3 pages, 2 figures, talk presented at Lattice2002(topology

Contrasting Supersymmetry and Universal Extra Dimensions at Colliders

We contrast the experimental signatures of low energy supersymmetry and the model of Universal Extra Dimensions and discuss various methods for their discrimination at hadron and lepton colliders. We study the discovery reach of hadron colliders for level 2 Kaluza-Klein modes, which would indicate the presence of extra dimensions. We also investigate the possibility to differentiate the spins of the superpartners and KK modes by means of the asymmetry method of Barr. We then review the methods for discriminating between the two scenarios at a high energy linear collider such as CLIC. We consider the processes of Kaluza-Klein muon pair production in universal extra dimensions in parallel to smuon pair production in supersymmetry. We find that the angular distributions of the final state muons, the energy spectrum of the radiative return photon and the total cross-section measurement are powerful discriminators between the two models.Comment: 6 pages, 8 figures, to appear in the proceedings of the 2005 International Linear Collider Workshop, Stanford, US

Strong coupling series for QCD at finite temperature and density

We discuss the use of strong coupling expansions for Yang-Mills theory and QCD at finite temperature and density. In particular we consider the onset of temperature effects for the free energy and screening masses, derive the hadron resonance gas model from first principles and compute the weakening of the deconfinement transition with chemical potential.Comment: 4 pages; invited talk presented at 'New Frontiers in QCD 2010' at the Yukawa Institute for Theoretical Physics, Kyoto, Japan, March 1-1

Parallel Jacket Transformation in Multi-Mesh Network

In this paper a parallel algorithm for Jacket transform is proposed in multi mesh architecture having n4 processing elements. Multi mesh architecture is formed by collection of meshes having n × n structure. These meshes are arranged in n rows and n columns. In this paper, in place generation of the Jacket matrix elements in multi mesh of size n4 processors has been presented, which is then followed by an algorithm for the Jacket transformation. This parallel algorithm for Jacket transformation of vector of length N has been proposed with O (log ?N)) addition time and O (?N) data movement time

Quarkonium at finite temperature

Lattice QCD studies on charmonium at finite temperature are presented After a discussion about problems for the Maximum Entropy Method applied to finite temperature lattice QCD, I show several results on charmonium spectral functions. The ``wave function'' of charmonium is also discussed to study the spatial correlation between quark and anti-quark in deconfinement phase.Comment: 8pages, 4figures, talk presented at Hard Probes 200