Related papers: The viscosity bound in string theory
In this paper we examine the methodology for extracting the Knudsen number (K) and the ratio of shear viscosity to entropy density (eta/s) developed by Drescher et al. The final result for eta/s turns out to be quite sensitive to Glauber…
The notion of stringy naturalness-- that an observable O_2 is more natural than O_1 if more (phenomenologically acceptable) vacua solutions lead to O_2 rather than O_1-- is examined within the context of the Standard Model (SM) and various…
The shear ($\eta$) and bulk ($\zeta$) viscosities are calculated in a quasiparticle relaxation time approximation for a hadron matter described within the relativistic mean-field based model with scaled hadron masses and couplings.…
We study the temperature dependence of the ratio of the shear viscosity to entropy density for the LQCD-contrasted hadron resonance gas of different finite system-sizes, which may represent the final state hadronic matter, formed in systems…
We analyze systems where an effective large-N expansion arises naturally in gauge theories without a large number of colors: a sufficiently large charge density alone can produce a perturbative string ('tHooft) expansion. One example is…
We consider the holographic principle, in its lightsheet formulation, in the semiclassical context of statistical-mechanical systems in classical Einstein spacetimes. A local condition, in terms of entropy and energy local densities of the…
We consider strongly coupled gauge theory plasma with conserved global charges that allow for a dual gravitational description. We study the shear viscosity of the gauge theory plasma in the presence of chemical potentials for these…
We explore the extent to which string theories with higher-level gauge symmetries and non-standard hypercharge normalizations can reconcile the discrepancy between the string unification scale and the GUT scale extrapolated from the Minimal…
We revisit the membrane paradigm calculations of the holographic shear viscosity tensor of strongly coupled isotropic plasmas with Einstein gravity dual by emphasizing the fact which was overlooked in the previous literatures that the shear…
Using $\varepsilon$-expansion technique we compute $\eta/s$, where $\eta$ is the shear viscosity, $s$ is the entropy density, of the normal phase of unitary Fermi gas in $d=4-\varepsilon$ dimensions to LO in $\varepsilon$. We use kinetic…
We perform a lattice Monte-Carlo calculation of the two-point functions of the energy-momentum tensor at finite temperature in the SU(3) gauge theory. Unprecedented precision is obtained thanks to a multi-level algorithm. The lattice…
Zero-point fluctuations in the background of a cosmic string provide an opportunity to study the effects of topology in quantum field theory. We use a scattering theory approach to compute quantum corrections to the energy density of a…
One of the most striking results from the Relativistic Heavy Ion Collider is the strong elliptic flow. This review summarizes what is observed and how these results are combined with reasonable theoretical assumptions to estimate the shear…
The ratio of shear viscosity ($\eta$) to entropy density ($s$) for an equilibrated system is investigated in intermediate energy heavy ion collisions below 100$A$ MeV within the framework of the Boltzmann-Uehling-Uhlenbeck (BUU) model .…
In 4D general relativity, the angular momentum of a black hole is limited by the Kerr bound. We suggest that in string theory, this bound can be breached and compact black-hole-like objects can spin faster. Near such "superspinars," the…
We study string propagation on $AdS_3$ times a compact space from an ``old fashioned'' worldsheet point of view of perturbative string theory. We derive the spacetime CFT and its Virasoro and current algebras, thus establishing the…
We study the ratio of the entropy to the total energy in conformal field theories at finite temperature. For the free field realizations of N=4 super Yang-Mills theory in D=4 and the (2,0) tensor multiplet in D=6, the ratio is bounded from…
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…
In this paper, we study the entanglement entropy in string theory in the simplest setup of dividing the nine dimensional space into two halves. This corresponds to the leading quantum correction to the horizon entropy in string theory on…
We study entropy production in the early stage of high-energy heavy-ion collisions due to shear viscosity. We employ the second-order theory of Israel-Stewart with two different stress relaxation times, as appropriate for strong coupling or…