Supercooling and final-state effects on dilepton spectra.
We consider two problems associated with the production of dileptons during collisions between heavy nuclei at the Brookhaven Relativistic Heavy Ion Collider energy. One is the difference in dilepton yield between an idealized Maxwell construction of phase coexistence and a dynamical phase transition with finite nucleation and phase conversion rates. The other is the contribution from dilepton-producing reactions involving free-streaming hadrons in the final state. We find that the mass spectrum in the range 2${\mathit{m}}_{\mathrm{\ensuremath{\pi}}}$M2 GeV is dominated by the mixed phase and the final hadron phase, is somewhat sensitive to the degree of supercooling, but is remarkably insensitive to the ``freeze-out'' temperature which delineates the passage from local thermal equilibrium to free streaming.

title: Photon interferometry of Au+Au collisions at the BNL Relativistic Heavy-Ion Collider.
abstract: We calculate the two-body correlation function of direct photons produced in central Au+Au collisions at the Relativistic Heavy-Ion Collider. Our calculation includes contributions from the early preequilibrium phase in which photons are produced via hard parton scatterings as well as radiation of photons from a thermalized quark-gluon plasma and the subsequent expanding hadron gas. We find that high energy photon interferometry provides a faithful probe of the details of the space-time evolution and of the early reaction stages of the system.

title: Photons and Dileptons at LHC
abstract: We discuss real and virtual photon sources in heavy ion collisions and present results for dilepton yields in Pb+Pb collisions at the LHC at intermediate and large transverse momentum p_T.

title: High-energy photons from passage of jets through Quark-Gluon plasma.
abstract: We calculate the production of high-energy photons from Compton scattering and annihilation of a quark jet passing through a quark gluon plasma produced in a relativistic heavy ion collision. The contributions are large and reflect the momentum distribution of the jets and the initial conditions of the plasma.

title: How relativistic heavy ion collisions can help us understand the universe
abstract: We discuss the anthropic principle and its implications for our existence and the physical laws which govern the universe. Several amazing coincidences which provide conditions necessary for creation of life suggest that the "laws of nature" are not uniquely determined. The idea that our universe is only one among a multitude of universes with different physical laws, as predicted by the theory of chaotic cosmic inflation, provides a logically simple, but speculative resolution of the anthropic principle. An important insight of modern quantum field theory is that the physical laws are not only determined by symmetry principles, but also by the nature of the vacuum state. Experiments involving collisions of relativistic heavy ions provide the clearest tests of the hypothesis that properties of particles and forces can be modified by a change in the vacuum state. We outline the goals of these experiments and briefly review their current status.

title: Single photons, dileptons and hadrons from relativistic heavy ion collisions and quark-hadron phase transition
abstract: The production of single photons in Pb+Pb collisions at the CERN SPS as measured by the WA98 experiment is analysed. A quark gluon plasma is assumed to be formed initially, which expands, cools, hadronizes, and undergoes freeze-out. A rich hadronic equation of state is used and the transverse expansion of the interacting system is taken into account. The recent estimates of photon production in quark-matter (at two loop level) along with the dominant reactions in the hadronic matter leading to photons are used. About half of the radiated photons are seen to have a thermal origin. The same treatment and the initial conditions provide a very good description to hadronic spectra measured by several groups and the intermediate mass dileptons measured by the NA50 experiment, lending a strong support to the conclusion that quark gluon plasma has been formed in these collisions. Predictions for RHIC and LHC energies are also given.

title: Implications of the chiral anomaly for quantum Hall-effect devices.
abstract: The anomaly equation ${\ensuremath{\partial}}_{\ensuremath{\mu}}$${J}_{5}$${}^{\ensuremath{\mu}}$=-(${e}^{2}$/8${\ensuremath{\pi}}^{2}$ ${\ensuremath{\Elzxh}}^{2}$c) (${F}_{\ensuremath{\lambda}\ensuremath{\sigma}}^{\mathrm{*}}$${F}^{\ensuremath{\lambda}\ensuremath{\sigma}}$) is used to derive a relationship between the filling factor (\ensuremath{\nu}) and the Hall conductance on the gate capacitor of a field-effect-transistor device. In addition, the chiral phase (\ensuremath{\theta}) states are shown to be related to those of the filling factor by \ensuremath{\Vert}\ensuremath{\theta}〉=\ensuremath{\Vert}2\ensuremath{\pi}\ensuremath{\nu}〉.