Role of quantum fluctuations in a system with strong fields

In this work we study how quantum fluctuations modify the quantum evolution of an initially classical field theory. We consider a scalar $\phi^4$ theory coupled to an external source as a toy model for the Color Glass Condensate description of the early time dynamics of heavy-ion collisions. We demonstrate that quantum fluctuations considerably modify the time evolution driving the system to evolve in accordance with ideal hydrodynamics. We attempt to understand the mechanism behind this relaxation to ideal hydrodynamics by using modified initial spectra and studying the particle content of the theory.Comment: Prepared for the New Journal of Physics Focus Issue "Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to QCD Plasmas

Evidence for BFKL and saturation dynamics from di-hadron spectra at the LHC

We demonstrate that rapidity separated di-hadron spectra in high multiplicity proton-proton collisions at the LHC can be quantitatively described by a combination of BFKL and saturation dynamics. Based on these results, we predict the systematics of di-hadron spectra in proton-nucleus collisions at the LHC.Comment: 9 pages, 5 figures. v3 corrects for a numerical error in the BFKL cross-section for asymmetric collisions, modifying fig. 5. Figs. 2-4 containing the main results of the paper remain unchange

Thermal photons from heavy ion collisions: A spectral function approach

We analyze the photon rates from a hadronic gas in equilibrium using chiral reduction formulas and a density expansion. The chiral reduction is carried to second order in the pion density which in principal includes all kinetic processes of the type $X\to \pi\gamma$ and $X\to \pi\pi\gamma$. The resulting rates are encoded in the form of vacuum correlation functions which are amenable to experiment. The hadronic rates computed in this work along with the known perturbative QGP rates are integrated over the space-time evolution of a hydrodynamic model tuned to hadronic observables. The resulting yields are compared to the recent photon and low mass dilepton measurements at the SPS and RHIC. Predictions for the LHC are made