We study the Euclidean action and Brown–York quasilocal mass of the Melvin and Schwarzschild–
Melvin geometries in four-dimensional Einstein–Maxwell theory. Since these spacetimes do not
exhibit the usual spherically asymptotically flat behavior, we introduce a cylindrical regularization
scheme adapted to the magnetic axis. The boundary is placed at a fixed cylindrical radius, while
the...
Non-unitary evolution described by the Lindblad formalism offers a powerful pathway to search for physics beyond the Standard Model in neutrino propagation. This contribution explores energy-dependent quantum decoherence in the $\nu_\mu \rightarrow \nu_\mu$ disappearance channel, using public reconstructed spectra from the NO$\nu$A experiment at an 810 km baseline. We investigate how...
