Modern Physics Letters A

The 1.5 formalism played a key role in the discovery of supergravity and it has been used to prove the invariance of essentially all supergravity theories under local supersymmetry. It emerged from the gauging of the super Poincaré group to find supergravity. We review both of these developments as well as the auxiliary fields for simple supergravity and its most general coupling to matter using the tensor calculus.

In this work, we calculate the expression for the potential due to neutrino–(anti)neutrino forward scattering at low energies $(E\ll m_{Z^0})$ for ultra-relativistic massive neutrinos $(E\gg m_{\nu })$, a representative regime within astrophysical scenarios. There is a broadly used expression for this potential in the literature, which, however, lacks an explicit derivation from basic principles of quantum field theory. Therefore, this paper has an intention to guide the reader through the steps and concepts to derive this potential, trying to be clear and pedagogical. Moreover, we used a rigorous approach concerning the massive nature of the neutrinos, using massive quantized neutrino fields throughout the entire process, while the usual approach is to consider massless neutrino fields at the interaction. In this context, we explicitly show the validity of the massless neutrino fields approximation at the ultra-relativistic regime, as expected. As the last step, we connect the potential expression to the density matrix formalism, which is a usual framework for works considering neutrino–neutrino interactions. We also discuss some theoretical details through the paper such as the normal ordering of quantum operators and the implications of massive fields in the neutrino state at its production.

In this paper, we discuss the dynamics of the anisotropic Bianchi I Universe filled with perfect fluid in teleparallel $f(T)$-gravity. Using both analytical and numerical approaches, we confirm the main results of the previous authors such as the presence of a future isotropic attractor, and find a number of new ones such as the existence of an essential number of bounce solutions and the possibility to construct late-time acceleration without any specific matter.

In this paper, we explore thermodynamics, thermal stability, effects of logarithmic corrections on thermodynamic quantities and phase transitions of spherically symmetric regular black hole with the de Sitter core. We first calculate the expressions for Hawking temperature as well as heat capacity and investigate its thermal stability. We also discuss the effects of logarithmic corrections on thermodynamical quantities such as pressure, Gibbs–Helmholtz free energy, internal energy and enthalpy of the system. Finally, we analyze the behavior of Hawking temperature as well as specific heat capacity of the regular black hole versus entropy for different values of the de Sitter parameter $(b)$. It is found that Hawking temperature changes its phase from positive to negative and heat capacity changes its phase from negative to positive for large values of $b$.

In the framework of massive gravity theory which is coupled to the Maxwell and Born–Infeld electrodynamics, we review derivation of the exact four-dimensional black hole solutions by use of a static and spherically symmetric geometry. The exact solutions are asymptotically AdS and show two-horizon, one-horizon, extreme and black holes without horizon. The Maxwell and Born–Infeld black hole solutions are compatible in the limit of large nonlinearity parameter and, both reduce to the Reissner–Nordström black hole in the absence of massive gravitons. By reviewing thermodynamic and conserved quantities, and making use of a Smarr-type mass formula, we check validity of the thermodynamical first law for both of Maxwell and Born–infeld black holes. We investigate thermal stability of the black holes by use of the canonical ensemble and geometrical approaches, separately. By calculating the specific heats and Ricci scalars of alternative thermodynamic metrics, we compare the results of geometrothermodynamics with those of canonical ensemble method. Also, we perform a global stability analysis by use of the grand canonical ensemble and noting the Gibbs free energy of the Maxwell and Born–Infeld black holes.

Conventional relativistic electrodynamics is set on flat Minkowski spacetime, where all computable quantities are calculated from the flat metric ${\eta }_{\mu \nu }$. We can redefine the metric of spacetime from the Dirac algebra. In this paper, we study how an electrodynamic interaction can alter the normal gamma matrix to an effective one and result in a shift in the metric perturbatively. The curvature properties inferred from the curved metric are also investigated. We also study how the spin operator is changed under the interaction that contributes to an effective spin operator and how the spin of an electron will be slightly deviated from $1/2$. Then we perform canonical quantization of the effective Dirac algebra. Finally, we apply our results to the relativistic hydrogen case and demonstrate how such system curves the spacetime metric.

In this paper, we introduce a protocol for mutual sharing of known quantum information between different parties. We show that it is possible to exchange known non-maximally entangled Bell states between three parties through a protocol by use of a multipartite entangled state. The scheme is overseen by a controller.