94 research outputs found
Holography and the speed of sound
No full textStephanov, M.. (2009). Holography and the speed of sound. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/53229
Bulk properties of strongly interacting matter
No full textLeupold S, Redlich K, Stephanov M, et al. Bulk properties of strongly interacting matter. In: Friman B, Höhne C, Knoll J, et al., eds. The CBM Physics Book. Compressed Baryonic Matter in Laboratory Experiments. Lecture Notes in Physics. Vol 814. Berlin ; Heidelberg: Springer; 2011: 39-334
On spinodal points and Lee-Yang edge singularities
No full textWe address a number of outstanding questions associated with the analytic properties of the universal equation of state of the φ4 theory, which describes the critical behavior of the Ising model and ubiquitous critical points of the liquid–gas type. We focus on the relation between spinodal points that limit the domain of metastability for temperatures below the critical temperature, i.e. T Tc. The extended analyticity conjecture (due to Fonseca and Zamolodchikov) posits that, for T < Tc, the Lee- Yang edge singularities are the closest singularities to the real H axis. This has interesting implications, in particular, that the spinodal singularities must lie o the real H axis for d < 4, in contrast to the commonly known result of the mean-field approximation. We find that the parametric representation of the Ising equation of state obtained in the ε = 4 − d expansion, as well as the equation of state of the O(N)-symmetric φ4 theory at large N, are both nontrivially consistent with the conjecture. We analyze the reason for the difficulty of addressing this issue using the ε expansion. It is related to the long-standing paradox associated with the fact that the vicinity of the Lee-Yang edge singularity is described by Fisher’s φ3 theory, which remains nonperturbative even for d → 4, where the equation of state of the φ4 theory is expected to approach the mean-field result. We resolve this paradox by deriving the Ginzburg criterion that determines the size of the region around the Lee-Yang edge singularity where mean-field theory no longer applies
Functional renormalization group approach to the Yang-Lee edge singularity
No full textWe determine the scaling properties of the Yang-Lee edge singularity as described by a one-component scalar field theory with imaginary cubic coupling, using the nonperturbative functional renormalization group in 3 ≤ d ≤ 6 Euclidean dimensions. We find very good agreement with high-temperature series data in d = 3 dimensions and compare our results to recent estimates of critical exponents obtained with the four-loop ⋲ = 6 - d expansion and the conformal bootstrap. The relevance of operator insertions at the corresponding fixed point of the RG ß functions is discussed and we estimate the error associated with O(Ә⁴) truncations of the scale-dependent e ective action
Of Death and Dominion: Queen Victoria and the cult of colonial loyalty
No full textThis is the author accepted manuscript. The final version is available from Routledge via the DOI in this recordThe image of Queen Victoria, painted and sculpted, still dominates public spaces scattered throughout every continent. More than any other historic individual, places, institutions and squares still bear her name. As the overarching symbol that sought to meld together the disparate parts of the British Empire, Victoria is a pioneering modern example of the global creation of a ruler personality cult. My essay seeks to demonstrate the specific discourses and practices through affection and loyalty to her were promoted by the colonial elite, and the consequent way it was remediated and challenged by, indigenous and settler communities. Victoria’s charismatic figure is most evident in the versions exported across the British Empire. The colonial representation of Victoria was an intensification of the existing familial discourse around her. From Kolkata to Cape Town, her motherly concern for all of her subjects, was used to emphasize the existence of an imperial family and to soften the imposition of British rule
Sign of Kurtosis near the QCD Critical Point
No full textWe point out that the quartic cumulant (and kurtosis) of the order parameter fluctuations is universally negative when the critical point is approached on the crossover side of the phase separation line. As a consequence, the kurtosis of a fluctuating observable, such as, e.g., proton multiplicity, may become smaller than the value given by independent Poisson statistics. We discuss implications for the beam energy scan program at RHIC at BNL
Hydrodynamics with parametric slowing down and fluctuations near the critical point
No full textThe search for the QCD critical point in heavy-ion collision experiments requires dynamical simulations of the bulk evolution of QCD matter as well as of fluctuations. We consider two essential ingredients of such a simulation: a generic extension of hydrodynamics by a parametrically slow mode or modes (“Hydro+”) and a description of fluctuations out of equilibrium. By combining the two ingredients, we are able to describe the bulk evolution and the fluctuations within the same framework. Critical slowing-down means that equilibration of fluctuations could be as slow as hydrodynamic evolution, and thus fluctuations could significantly deviate from equilibrium near the critical point. We generalize hydrodynamics to partial-equilibrium conditions where the state of the system is characterized by the off-equilibrium magnitude of fluctuations in addition to the usual hydrodynamic variables—conserved densities. We find that the key element of the new formalism—the extended entropy taking into account the off-equilibrium fluctuations—is remarkably similar to the 2PI action in the quantum field theory. We show how the new Hydro+ formalism reproduces two major effects of critical fluctuations on the bulk evolution: the strong frequency dependence of the anomalously large bulk viscosity as well as the stiffening of the equation of state with an increasing frequency or wave number. While the agreement with known results confirms its validity, the fact that Hydro+ achieves this within a local and deterministic framework gives it significant advantages for dynamical simulations.United States. Department of Energy (Grant DE-SC0011090
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