Early Time Evolution of High Energy Heavy Ion Collisions

We solve the Yang-Mills equations in the framework of the McLerran-Venugopalan model for small times tau after a collision of two nuclei. An analytic expansion around tau=0 leads to explicit results for the field strength and the energy momentum tensor of the gluon field at early times. We then discuss constraints for the energy density, pressure and flow of the plasma phase that emerges after thermalization of the gluon field.Comment: 4 pages, 1 figure; contribution to Quark Matter 2006; submitted to J. Phys.

Early Time Dynamics of Gluon Fields in High Energy Nuclear Collisions

Nuclei colliding at very high energy create a strong, quasi-classical gluon field during the initial phase of their interaction. We present an analytic calculation of the initial space-time evolution of this field in the limit of very high energies using a formal recursive solution of the Yang-Mills equations. We provide analytic expressions for the initial chromo-electric and chromo-magnetic fields and for their energy-momentum tensor. In particular, we discuss event-averaged results for energy density and energy flow as well as for longitudinal and transverse pressure of this system. For example, we find that the ratio of longitudinal to transverse pressure very early in the system behaves as $p_L/p_T = -[1-\frac{3}{2a}(Q\tau)^2]/[1-\frac{1}{a}(Q\tau)^2]+\mathcal{O}(Q\tau)^4$ where $\tau$ is the longitudinal proper time, $Q$ is related to the saturation scales $Q_s$ of the two nuclei, and $a = \ln (Q^2/\hat{m}^2)$ with $\hat m$ a scale to be defined later. Our results are generally applicable if $\tau \lesssim 1/Q$. As already discussed in a previous paper, the transverse energy flow $S^i$ of the gluon field exhibits hydrodynamic-like contributions that follow transverse gradients of the energy density $\nabla^i \varepsilon$. In addition, a rapidity-odd energy flow also emerges from the non-abelian analog of Gauss' Law and generates non-vanishing angular momentum of the field. We will discuss the space-time picture that emerges from our analysis and its implications for observables in heavy ion collisions.Comment: 26 pages, 9 figure

European vs. American Engineering: Pierre Charles L\u27Enfant and the Water Power System of Paterson, NJ

No abstract is available at this time

Entanglement and relative entropy of a chiral fermion on the torus

We derive the entanglement entropy of chiral fermions on the circle at arbitrary temperature. The spin-sector contribution depends only on the total length of the entangling region, regardless of the configuration of the intervals. Thus mutual information is independent of the spin boundary conditions, a property that does not hold for higher R\'enyi mutual information. Together with the modular Hamiltonian, this provides a systematic way of obtaining relative entropy on the torus

From Color Fields to Quark Gluon Plasma

We discuss a model for the energy distribution and the early space-time evolution of a heavy ion collision. We estimate the gluon field generated in the wake of hard processes and through primordial fluctuations of the color charges in the nuclei. Without specifying the dynamical mechanism of thermalization we calculate the energy momentum tensor of the following plasma phase. The results of this model can be used as initial conditions for a further hydrodynamic evolution.Comment: Contribution to Quark Matter 2005; 4 pages, 4 figure

Chemical composition of the decaying glasma

The the initial stage of a relativistic heavy ion collision can be described by a classical color field configuration known as the Glasma. The production of quark pairs from this background field is then computed nonperturbatively by numerically solving the Dirac equation in the classical background. The result seems to point towards an early chemical equilibration of the plasma.Comment: 8 pages, 5 figures, invited talk at Stangeness in Quark Matter 2006 (SQM06), UCLA, March 200

Characteristics of a New Carbonaceous Chondrite, Metal-Rich-Lithology Found in the Carbonaceous Chondrite Breccia Aguas Zarcas

The Aguas Zarcas meteorite fell in Costa Rica on 23 April 2019 at 21:07 local time, with a total mass of about 27 kg. Hundreds of fusion-crusted stones ranging from 0.1 to 1868 g were recovered (The Meteoritical Bulletin). The meteorite was classified as a CM chondrite, but some lithlogies show a different texture to that of CM. In this study, we investigated the petrography, mineral-ogy, chemistry, and isotopic composition of an unusual Metal-rich-lithology from this fresh fall