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Register a new userQuasi-Local Conserved Charges in Covariant Theory of Gravity
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In any generally covariant theory of gravity, we show the relationship between the linearized asymptotically conserved current and its non-linear completion through the identically conserved current. Our formulation for conserved charges is based on the Lagrangian description, and so completely covariant. By using this result, we give a prescription to define quasi-local conserved charges in any higher derivative gravity. As applications of our approach, we demonstrate the angular momentum invariance along the radial direction of black holes and reproduce more efficiently the linearized potential on the asymptotic AdS space.
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We study non-Einstein Bach-flat gravitational instanton solutions that can be regarded as the generalization of the Taub-NUT/Bolt and Eguchi-Hanson solutions of Einstein gravity to conformal gravity. These solutions include non-Einstein spaces which are either asymptotically locally flat spacetimes (ALF) or asymptotically locally Anti-de Sitter (AlAdS). Nevertheless, solutions with different asymptotic conditions exist: we find geometries that present a weakened AlAdS asymptotia, exhibiting the typical low decaying mode of conformal gravity. This permits to identify the simple Neumann boundary condition that, as it happens in the asymptotically AdS sector, selects the Einstein solution out of the solutions of conformal gravity. All the geometries present non-vanishing Hirzebruch signature and Euler characteristic, being single-centered instantons. We compute the topological charges as well as the Noether charges of the Taub-NUT/Bolt and Eguchi-Hanson spacetimes, which happen to be finite. This enables us to study the thermodynamic properties of these geometries.
In this report we present the first quantitative determination of the correlations between baryons and anti-baryons induced by local baryon number conservation. This is important in view of the many experimental studies aiming at probing the phase structure of strongly interacting matter. We confront our results with the recent measurements of net-proton fluctuations reported by the CERN ALICE experiment. The role of local baryon number conservation is found to be small on the level of second cumulants.
We consider the timelike version of Warped Anti-de Sitter space (WAdS), which corresponds to the three-dimensional section of the G{o}del solution of four-dimensional cosmological Einstein equations. This geometry presents closed timelike curves (CTCs), which are inherited from its four-dimensional embedding. In three dimensions, this type of solutions can be supported without matter provided the graviton acquires mass. Here, among the different ways to consistenly give mass to the graviton in three dimensions, we consider the parity-even model known as New Massive Gravity (NMG). In the bulk of timelike WAdS$_{3}$ space, we introduce defects that, from the three-dimensional point of view, represent spinning massive particle-like objects. For this type of sources, we investigate the definition of quasi-local gravitational energy as seen from infinity, far beyond the region where the CTCs appear. We also consider the covariant formalism applied to NMG to compute the mass and the angular momentum of spinning particle-like defects, and compare the result with the one obtained by means of the quasi-local stress-tensor. We apply these methods to special limits in which the WAdS$_3$ solutions coincide with locally AdS$_3$ and locally AdS$_{2}times mathbb{R}$ spaces. Finally, we make some comments about the asymptotic symmetry algebra of asymptotically WAdS$_3$ spaces in NMG.
Torsion gravity is a natural extension to Einstein gravity in the presence of the fermion matter sources. In this paper we adopt Walds covariant method of Noether charge to construct the quasi-local energy of the Einstein-Cartan-fermion system, and find that its explicit expression is formally independent of the coupling constant between torsion and axial current. This seemingly topological nature is unexpected and is reminiscent of similar nature of quantum Hall effect and topological insulator. However, the coupling dependence does enter when evaluating it on-shell, and thus the topological nature is pseudo. Based on the expression of the quasi-local energy, we evaluate it for a particular solution on the entanglement wedge and find the agreement with the holographic relative entropy obtained before. This shows that the equivalence of these two quantities in the Einstein-Cartan-fermion system. Moreover, the quasi-local energy in this case is not always positive definite so that it provides an example of swampland in torsion gravity. Based on the covariant Noether charge, we also derive the nonzero fermion effect on Komar angular momentum. The implication of our results to the tests of torsion gravity in the future gravitational wave astronomy is also discussed.
We present cross-correlators of QCD conserved charges at $mu_B=0$ from lattice simulations and perform a Hadron Resonance Gas (HRG) model analysis to break down the hadronic contributions to these correlators. We construct a suitable hadronic proxy for the ratio $-chi_{11}^{BS}/chi_2^S$ and discuss the dependence on the chemical potential and experimental cuts. We then perform a comparison to preliminary STAR results and comment on a possible direct comparison of lattice and experiment.
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