Related papers: Speed of Sound in String Gas Cosmology
We systematically investigate the speed of sound in QCD matter under different conditions in the grand canonical ensemble within the Polyakov loop improved Nambu--Jona-Lasinio (PNJL) model. The numerical results indicate that the dependence…
The main goal of this paper is to reach an explicit formulation and possible interpretation of thermodynamic length in a thermodynamic state space with two degrees of freedom. Using the energy and entropy metric in a general form, we get…
We study string propagation in an anisotropic, cosmological background. We solve the equations of motion and the constraints by performing a perturbative expansion of the string coordinates in powers of c^2, the world-sheet speed of light.…
We investigate $(n+1)$-dimensional string-dilaton cosmology with effective dilaton potential in presence of perfect-fluid matter.We get exact solutions parametrized by the constant $\gam$ of the state equation $p=(\gam-1)\rho$, the spatial…
We analyse the properties of a fluid generating a spinning cosmic string spacetime with flat limiting cases corresponding to a constant angular momentum in the infinite past and static configuration in the infinite future. The spontaneous…
We study the classical cosmic string solution in a theory with dynamical $U(1)$ symmetry breaking. We calculate the energy per unit length of the string and compare it to that obtained in a model with a fundamental Higgs. We find that the…
We consider cosmological solutions to general relativity with a single barotropic fluid, where the pressure is a general function of the density, $p = f(\rho)$. We derive conditions for static and oscillating solutions and provide examples,…
Cosmic strings in realistic particle physics models have fermion zero modes in the string core. Such zero modes change the underlying cosmology; for example, the string can carry a current. We consider the stability of fermion zero modes to…
We examine variations in the equation of state of the cosmic string portion of the cosmological fluid which lead to perturbations of the background matter density. These fluctuations in the equation of state are due to variations in the…
Groups of aircraft have the potential to save significant amounts of energy by flying in formations; all but the leading aircraft can benefit from the upwash of the wakes of preceding aircraft. A potential obstacle as the number of aircraft…
In this Note we study supersymmetry breaking via gaugino condensation in string gas cosmology. We show that the same gaugino condensate which is introduced to stabilize the dilaton breaks supersymmetry. We study the constraints on the scale…
We show that cosmological observables can constrain the topology of the compact additional dimensions predicted by string theory. To do this, we develop a general strategy for relating cosmological observables to the microscopic parameters…
Cosmic strings provide a radically different paradigm for the formation of structure to the prevailing inflationary one. They afford some extra technical complications: for example, the calculation of the power spectrum of matter and…
We compute the running of the spectrum of cosmological perturbations in String Gas Cosmology, making use of a smooth parametrization of the transition between the early Hagedorn phase and the later radiation phase. We find that the running…
We present an inexpensive apparatus for measuring the speed of sound, with a time of flight method, using a computer with a stereo sound board. Students measure the speed of sound by timing the delay between the arrivals of a pulse to two…
String Theory is a hot topic of physics and mathematics. For the former, it stands as a huge sandbox where the formulation of difficult problems can be simplified and their hard computations carried out. For the latter, it stands as a…
We investigate the stability of supercurrents in a Bose-Einstein condensate with one-dimensional spin-orbit and Raman couplings. The consequence of the lack of Galilean invariance is explicitly discussed. We show that in the plane-wave…
In this talk we describe recent progress in construction of inflationary models in the context of string theory with flux compactification and moduli stabilization. We also discuss a possibility to test string theory by cosmological…
We study cosmic strings in the complex symmetron model, a scalar-tensor theory with a spontaneously broken local $U(1)$ symmetry in low matter density regions. Using numerical simulations, we show that these strings preferentially attach to…
We investigate sound wave propagation in a monatomic gas using a volume-based hydrodynamic model. In Physica A vol 387(24) (2008) pp6079-6094, a microscopic volume-based kinetic approach was proposed by analyzing molecular spatial…