What is the temperature in heavy ion collisions?

We consider the Tsallis distribution as the source of the apparent slope of one-particle spectra in heavy-ion collisions and investigate the equation of state of this special quark matter in the framework of non-extensive thermodynamics.Comment: Talk given by T.S.Biro at RHIC School 2003, Dec.8-11, 2003, Budapest, Hungar

SO(3) Yang-Mills theory on the lattice

We numerically investigate the phase structure of pure SO(3) LGT at zero and non-zero temperature in the presence of a Z2 blind monopole chemical potential. The physical meaning of the different phases, a possible symmetry breaking mechanism as well as the existence of an order parameter for the finite temperature phase transition are discussed.Comment: 3 pages, 2 figures LaTeX file. Uses espcrc2 style and amssymb package. Talk given at Lattice2002(nonzerot), Boston. Corrected version with one added referenc

SO(3) vs. SU(2) Yang-Mills theory on the lattice: an investigation at non-zero temperature

The adjoint SU(2) lattice gauge theory in 3+1 dimensions with the Wilson plaquette action modified by a Z(2) monopole suppression term is reinvestigated with special emphasis on the existence of a finite-temperature phase transition decoupling from the well-known bulk transitions.Comment: 13 pages, 9 figures. Based on contributions to CONFINEMENT 2003 and Lattice2003(topology). To be published in Proceedings of CONFINEMENT 2003, Tokyo, Japa

SAFT-γ Force Field for the Simulation of Molecular Fluids 6. Binary and ternary mixtures comprising water, carbon dioxide, and n-alkanes

AbstractThe SAFT-γ coarse graining methodology (Avendaño et al., 2011) is used to develop force fields for the fluid-phase behaviour of binary and ternary mixtures comprising water, carbon dioxide, and n-alkanes. The effective intermolecular interactions between the coarse grained (CG) segments are directly related to macroscopic thermodynamic properties by means of the SAFT-γ equation of state for molecular segments represented with the Mie (generalised Lennard–Jones) intermolecular potential (Papaioannou et al., 2014). The unlike attractive interactions between the components of the mixtures are represented with a single adjustable parameter, which is shown to be transferable over a wide range of conditions. The SAFT-γ Mie CG force fields are used in molecular-dynamics simulations to predict the challenging (vapour+liquid) and (liquid+liquid) fluid-phase equilibria characterising these mixtures, and to study phenomena that are not accessible directly from the equation of state, such as the interfacial properties. The description of the fluid-phase equilibria and interfacial properties predicted with the SAFT-γ Mie force fields is in excellent agreement with the corresponding experimental data, and of comparable if not superior quality to that reported for the more sophisticated atomistic and united-atom models

Buried heterostructure vertical-cavity surface-emitting laser with semiconductor mirrors

We report a buried heterostructure vertical-cavity surface-emitting laser fabricated by epitaxial regrowth over an InGaAs quantum well gain medium. The regrowth technique enables microscale lateral confinement that preserves a high cavity quality factor (loaded $Q\approx$ 4000) and eliminates parasitic charging effects found in existing approaches. Under optimal spectral overlap between gain medium and cavity mode (achieved here at $T$ = 40 K) lasing was obtained with an incident optical power as low as $P_{\rm th}$ = 10 mW ($\lambda_{\rm p}$ = 808 nm). The laser linewidth was found to be $\approx$3 GHz at $P_{\rm p}\approx$ 5 $P_{\rm th}$

Regularized adaptive long autoregressive spectral analysis

This paper is devoted to adaptive long autoregressive spectral analysis when (i) very few data are available, (ii) information does exist beforehand concerning the spectral smoothness and time continuity of the analyzed signals. The contribution is founded on two papers by Kitagawa and Gersch. The first one deals with spectral smoothness, in the regularization framework, while the second one is devoted to time continuity, in the Kalman formalism. The present paper proposes an original synthesis of the two contributions: a new regularized criterion is introduced that takes both information into account. The criterion is efficiently optimized by a Kalman smoother. One of the major features of the method is that it is entirely unsupervised: the problem of automatically adjusting the hyperparameters that balance data-based versus prior-based information is solved by maximum likelihood. The improvement is quantified in the field of meteorological radar