Quantum Anomalies (in) Matter

Over the last decade it has bee realized that triangle anomalies give rise to dissipationless transport phenomena in hot and dense relativistic matter. I will review anomalous transport theory and then discuss its applications to the quark gluon plasma and the electronics of Weyl semimetals. Finally I briefly discuss the absence of genuine chiral torsional transport.

Charged gravastars in modified Gauss–Bonnet gravity

This work probes the influence of charge field on the unique stellar structure, regarded as gravastar, under the corrections of [Formula: see text] theory, i.e. [Formula: see text] theory, where [Formula: see text] is named as Gauss–Bonnet invariant. The gravastar has also been recognized as an alternate candidate of black hole structure and is illustrated by three distinct regions termed as (1) the exterior (2) the intermediate thin shell (3) the interior domain. We discussed the mathematical solutions for each of three regions separately with the assistance of different equation-of-states (EoS). The exterior charged vacuum domain is expressed by the Reissner–Nordström solution. The central region is illustrated by the EoS, i.e. a positive pressure of ultra-relativistic matter is equal to the energy density. Whereas, the interior domain reflects that the negative pressure is equal to energy density and manifests a non-attractive force over the central spherical shell. We deduce that in the context of [Formula: see text] theory, the nonsingular charged model with distinct physical features, such as energy, length, entropy, is physically viable and consistent.

Non-Extensive Thermodynamics Effects in the Cosmology of f(T) Gravity

Using f(T) gravitational theory, we construct modified cosmological models via the first law of thermodynamics by using the non-extensive thermodynamics framework, the effects of which are captured by the parameter δ. The resulting cosmological equations are modified compared to the standard Einstein-Hilbert ones, with the modifications coming from the f(T) gravitational theory and from the non-extensive parameter which quantifies the non-extensive thermodynamics effects quantified by the parameter δ, which when is set equal to unity, one recovers the field equations of f(T) gravity. We study in detail the cosmological evolution of the model in the presence of collisionless non-relativistic matter case, and we derive the exact forms of the dark energy density parameter and of the dark energy equation of state parameter, from which we impose constraints on the non-extensive thermodynamics parameter, δ, by using the Planck 2018 data on cosmological parameters. Accordingly, we repeat our calculations after including the relativistic matter along with the non-relativistic one, and we derive the new forms of the dark energy density parameter and of the dark energy equation of state parameter. Our study shows that the inclusion of non-extensive thermodynamic effects, quantified by the parameter δ, for a flat Friedmann-Robertson-Walker Universe, has measurable differences compared with the normal thermodynamics case. We confront our results with Type Ia supernovae observations for z≥0.4 and we obtain reasonably agreement with the observational data.

Experimental hint for gravitational CP violation

An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Gravity dependence on rotation or spin direction is experimentally constrained for non-relativistic matter. Here, a method based on high-energy Compton scattering is developed to measure the gravitational interaction of accelerated charged particles. Within that formalism, the Compton spectra measured at HERA rule out the speculated anti-gravity possibility for antimatter at a confidence level close to 100%. The same data, however, imply a gravitational CP violation around 13 GeV energies, by a maximal amount of [Formula: see text] for the charge and [Formula: see text] for the space parity. The detected asymmetry hints for a stronger gravitational coupling to left helicity electrons relative to right helicity positrons.