Transverse energy density fluctuations in the Color Glass Condensate Model

We calculate the transverse correlation of fluctuations of the deposited energy density in nuclear collisions in the framework of the Gaussian color glass condensate model.Comment: Corrections of some typographical and numerical error

Hot Spaghetti: Viscous Gravitational Collapse

We explore the fate of matter falling into a macroscopic Schwarzschild black hole for the simplified case of a radially collapsing thin spherical shell for which the back reaction of the geometry can be neglected. We treat the internal dynamics of the infalling matter in the framework of viscous relativistic hydrodynamics and calculate how the internal temperature of the collapsing matter evolves as it falls toward the Schwarzschild singularity. We find that viscous hydrodynamics fails when either, the dissipative radial pressure exceeds the thermal pressure and the total radial pressure becomes negative, or the time scale of variation of the tidal forces acting on the collapsing matter becomes shorter than the characteristic hydrodynamic response time.Comment: Invited talk presented at the FIAS International Symposion on Discoveries at the Frontiers of Science - Dedicated to the memory of Walter Greine

The Decoherence Time in High Energy Heavy Ion Collisions

We calculate the decoherence time of the ground state wave function of a nucleus in a high energy heavy ion collision. We define this time as the decay time of the ratio Tr D^2 / (Tr D)^2 of traces of the density matrix D. We find that this time is smaller or equal to 1/Q_s, where the saturation scale Q_s is defined within the color glass condensate model of parton saturation. Our result supports the notion that the extremely rapid entropy production deduced for the early stage of heavy ion collisions at collider energies is to a large extent caused by the decoherence of the initial-state wave functions.Comment: Final, slightly modified version as it will be published in Phys. Rev.

New scheme for spontaneous symmetry breaking of color SU(3)

A new spontaneous-symmetry-breaking mechanism is formulated for SU(3), which is used to describe the formation of bags around quarks. The Higgs field is replaced by the scalar product of two colored fermion fields. This model gives mass only to one gluon (equivalent to Aμ8) when spontaneously broken. The consequences of this scheme are discussed, and it is argued that it can explain several puzzling high-energy heavy-ion experiments

Stress Tensor and Bulk Viscosity in Relativistic Nuclear Collisions

We discuss the influence of different initial conditions for the stress tensor and the effect of bulk viscosity on the expansion and cooling of the fireball created in relativistic heavy-ion collisions. In particular, we explore the evolution of longitudinal and transverse components of the pressure and the extent of dissipative entropy production in the one-dimensional, boost-invariant hydrodynamic model. We find that a bulk viscosity consistent with recent estimates from lattice QCD further slows the equilibration of the system, however it does not significantly increase the entropy produced

Towards a Theory of Entropy Production in the Little and Big Bang

We propose a broadly applicable formalism for the description of coarse grained entropy production in quantum mechanical processes. Our formalism is based on the Husimi transform of the quantum state, which encodes the notion that information about any quantum state is limited by the experimental resolution. We show in two analytically tractable cases (the decay of an unstable vacuum state and reheating after cosmic inflation) that the growth rate of the Wehrl entropy associated with the Husimi function approaches the classical Kolmogorov-Sinai entropy. We also discuss various possible applications of our formalism, including the production of entropy in the early stages of a relativistic heavy ion collision.Comment: 21 pages, 6 figures. One section is added in v

Phenomenological consequences of a hypothetical light neutral particle in heavy ion collisions

We discuss the possibility that the line structure observed in the spectrum of the positrons produced in heavy ion collisions is due to the decay of a new neutral elementary particle. We argue that this can be ruled out unless one is willing to accept fine tuning of parameters, or to assume the dominance of nonlinear effects