The Raychaudhuri equations for the expansion, shear, and vorticity are generalized in a spacetime with torsion for timelike as well as null congruences. These equations are purely geometrical like the original Raychaudhuri equations and could be reduced to them when there is no torsion. Using the Einstein-Cartan-Sciama-Kibble field equations, the effective stress-energy tensor is derived. We also consider

We discuss helicity polarization, which can be locally induced from both vorticity and helicity charge in noncentral heavy ion collisions. Helicity charge redistribution can be generated in viscous fluid, and contributes to azimuthal asymmetry of the polarization along global angular momentum or beam momentum. We also discuss detecting the initial net helicity charge from topological charge fluctuation

The exact one-loop beta functions for the four-derivative terms (Weyl tensor squared, Ricci scalar squared, and the Gauss-Bonnet) are derived for the minimal six-derivative quantum gravity (QG) theory in four spacetime dimensions. The calculation is performed by means of the Barvinsky and Vilkovisky generalized Schwinger-DeWitt technique. With this result we gain, for the first time, the full set of

We perform canonical quantization of gravity in the background of a Schwarzschild black hole in the generalized Regge-Wheeler gauge proposed in Kallosh and Rahman [Quantization of gravity in the black hole background, Phys. Rev. D 104, 086008 (2021)]. We find that the Hamiltonian at the quadratic level is unitary and ghost-free. Two canonical degrees of freedom are associated with Zerilli-Moncrief

The goal of this short note is to provide a simpler derivation of the effective potential surrounding a Schwarzschild black hole for spherically symmetric perturbations in the framework of torsion bigravity than the one presented in [V. Nikiforova, Spherically symmetric perturbations of a Schwarzschild black hole in torsion bigravity, Phys. Rev. D 104, 024032 (2021).]. We also discuss the unicity of

Symmetry in neutrino oscillation serves for a better understanding of the physical properties of the phenomenon. We present a systematic way of finding symmetry in neutrino oscillation, which we call symmetry finder (SF). By extending the known framework in vacuum into a matter environment, we derive the SF equation, a powerful machinery for identifying symmetry in the system. After learning lessons

A systematic approach is developed in order to obtain spherically symmetric midisuperspace models that accept holonomy modifications in the presence of matter fields with local degrees of freedom. In particular, starting from the most general Hamiltonian quadratic in radial derivatives of the variables, we obtain a family of effective modified constraints that satisfy Dirac’s deformation algebra, which

Symmetry is among the most fundamental and powerful concepts in nature, whose existence is usually taken as given, without explanation. We explore whether symmetry can be derived from more fundamental principles from the perspective of quantum information. Starting with a two-qubit system, we show there are only two minimally entangling logic gates: the identity and the SWAP, which interchanges the