Published in Journal of High Energy Physics
We compute the Kaluza-Klein spectrum of the non-supersymmetric SO(3) × SO(3)-invariant AdS4 vacuum of 11-dimensional supergravity, whose lowest-lying Kaluza-Klein modes belong to a consistent truncation to 4-dimensional N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{am...
We study the Jeans instability of an infinite homogeneous dissipative self-gravitating Bose–Einstein condensate described by generalized Gross–Pitaevskii–Poisson equations [Chavanis, P.H. Eur. Phys. J. Plus 2017, 132, 248]. This problem has applications in relation to the formation of dark matter halos in cosmology. We consider the case of a static...
"Brane supersymmetry breaking" is a peculiar phenomenon that can occur in perturbative orientifold vacua. It results from the simultaneous presence, in the vacuum, of non-mutually BPS sets of BPS branes and orientifolds, which leave behind a net tension and thus a runaway potential, but no tachyons. In the simplest ten-dimensional realization, the ...
When supersymmetry is spontaneously broken at tree level, the spectrum of the heterotic string compactified on orbifolds of tori contains an infinite number of potentially tachyonic modes. We show that this implies instabilities of Minkowski spacetime, when the scale of supersymmetry breaking is of the order of the string scale. We derive the phase...
Published in Journal of High Energy Physics
We consider phase transitions occurring in four-dimensional heterotic orbifold models, when the scale of spontaneous breaking of N\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{d...
Published in Journal of High Energy Physics
We consider a realisation of composite Higgs models in the context of SU(6)/SO(6) symmetry, which features a custodial bi-triplet, two Higgs doublets and dark matter candidates. This model can arise from an underlying gauge-fermion theory. The general vacuum structure is explored using the top partial compositeness to generate a special vacuum char...
Heavy scalar fields can undergo an instability during inflation as a result of their kinetic couplings with the inflaton. This is known as the geometrical destabilization of inflation, as it relies on the effect of the negative curvature of the field-space manifold overcoming the stabilizing force of the potential. This instability can drive the sy...
We consider a class of heterotic N=2→0 super no-scale Z2 -orbifold models. An appropriate stringy Scherk–Schwarz supersymmetry breaking induces tree level masses to all massless bosons of the twisted hypermultiplets and therefore stabilizes all twisted moduli. At high supersymmetry breaking scale, the tachyons that occur in the N=4→0 parent theorie...
Published in Open Physics
We review the tachyon model derived from the dynamics of a 3-brane moving in the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model extended to include the radion. The effective tachyon Lagrangian is modified due to the back-reaction of the brane on the bulk geometry.
Published in Theoretical and Mathematical Physics
We discuss mathematical aspects of the nonexistence of continuous (nontrivial) solutions of boundary value problems for equations of p-adic closed and open strings in the one-dimensional case. We find that the number of sign changes of the solution ψ(t) is not equal to the order of zeros of the function ψn(t) and that nonnegative (nonpositive) solu...
