Related papers: Density Induced Vacuum Instability
The extreme temperatures and densities of many astrophysical environments tends to destabilize nuclear isomers by inducing transitions to higher energy states. Those states may then cascade to ground. However, not all environments…
We identify a new dust instability that occurs in warped discs. The instability is caused by the oscillatory gas motions induced by the warp in the bending wave regime. We first demonstrate the instability using a local 1D (vertical) toy…
We examine the steady state of turbulent flows in thin layers using direct numerical simulations. It is shown that when the layer thickness is smaller than a critical height, an inverse cascade arises which leads to the formation of a…
Prolongating our previous paper on the Einstein relation, we study the motion of a particle diffusing in a random reversible environment when subject to a small external forcing. In order to describe the long time behavior of the particle,…
Dark energy is the candidate that can produce effective negative pressure and make the galaxies and galaxy clusters move away from each other in an accelerated way. The structures of the Universe have evolved from some initial primordial…
We study the linear properties, nonlinear saturation and a steady, strongly nonlinear state of the Parker instability in galaxies. We consider magnetic buoyancy and its consequences with and without cosmic rays. Cosmic rays are described…
A number of properties of dense matter can be understood semiquantitatively in terms of simple physical arguments. We begin with the outer parts of neutron stars, and consider the density at which pressure ionization occurs, the density at…
We consider a phase transition induced by the growth of Q-balls in a false vacuum. Such a transition could occur in the early universe in the case of broken supersymmetry with a metastable false vacuum. Small Q-balls with a negative…
We show that the optically-thick dusty envelopes surrounding young high-mass stars are subject to the photon bubble instability. The infrared radiation passing through the envelope amplifies magnetosonic disturbances, with growth rates in…
We study the formation of voids in a modified gravity model in which gravity is generically stronger or weaker on large scales. We show that void abundances provide complementary information to halo abundances: if normalized to the CMB,…
This paper studies interacting massive particles on the de Sitter background. It is found that the vacuum acts as an inversely populated medium which is able to generate stimulated radiation. Without back reaction (not considered in this…
Multistability cannot be derived from any theoretical model that is based on a monostable master equation. On the other hand, multistability is experimentally-observed in a variety of quantum systems. A master equation having a nonlinear…
We calculate the extent to which collisionless dark matter impacts the stability of supermassive stars $(M\gtrsim10^4\,M_\odot)$. We find that, depending on the star's mass, a dark matter content in excess of ${\sim}1\%$ by mass throughout…
Instabilities of fluid flows often generate turbulence. Using extensive direct numerical simulations, we study two-dimensional turbulence driven by a wavenumber-localised instability superposed on stochastic forcing, in contrast to previous…
Under certain conditions, the propagation of a beam of oscillating neutrinos in a variable-density medium takes the form of an almost complete transformation of the initial type of neutrino into another type. The depth of oscillations is…
We argue a scenario motivated by the context of string landscape, where our universe is produced by a new vacuum bubble embedded in an old bubble and these bubble universes have not only different cosmological constants, but also their own…
Colloidal particles are often seen as big atoms that can be directly observed in real space. They are therefore playing an increasingly important role as model systems to study processes of interest in condensed matter physics such as…
I discuss the possibility of using a massive vector field to generate the density perturbation in the Universe. I find that a scale-invariant superhorizon spectrum of vector field perturbations is possible to generate during inflation. The…
We study the effect of strong magnetic fields, of the order of $10^{18}$-$10^{19}$ G, on the instability region of nuclear matter at subsaturation densities. Relativistic nuclear models both with constant couplings and with density…
In this work, we explore the link between star formation, turbulence and the thermal state of the multi-phase ISM. We analyse a suite of stratified box simulations modelling a realistic ISM that aims to probe environments similar to those…