Stability of cosmological detonation fronts

Abstract

The steady state propagation of a phase transition front is classified, according to hydrodynamics, as a deflagration or a detonation, depending on its velocity with respect to the fluid. These propagation modes are further divided into three types, namely, weak, Jouguet, and strong solutions, according to their disturbance of the fluid. However, some of these hydrodynamic modes will not be realized in a phase transition. One particular cause is the presence of instabilities. In this work we study the linear stability of weak detonations, which are generally believed to be stable. After discussing in detail the weak detonation solution, we consider small perturbations of the interface and the fluid configuration. When the balance between the driving and friction forces is taken into account, it turns out that there are actually two different kinds of weak detonations, which behave very differently as functions of the parameters. We show that the branch of stronger weak detonations are unstable, except very close to the Jouguet point, where our approach breaks down.Comment: 34 pages, 11 figures. v2: typos corrected and minor change

Science with the space-based interferometer eLISA. II: gravitational waves from cosmological phase transitions

“…(13) differs by a factor β/H * with respect to the envelope result in Eq. (7). The enhancement of the spectral amplitude by a factor β/H * for long-lasting sources w.r.t to short lasting ones has been predicted on the basis of analytical arguments in Ref.…”

“…Isolated spherical bubbles do not source GWs. It is therefore processes arising during the collision of bubbles that are relevant for GW physics (we ignore possible instabilities [7,8]). Depending on the details of the model, the bubble walls can move with velocities up to the speed of light.…”

“…6 Here, φ should be thought of as a vector in field space for scenarios in which more than one field changes its VEV during the transition. 7 The Higgs and Goldstone contributions are typically numerically negligible. 8 Note that the expression above differs from that in Ref.…”

“…7 The Higgs and Goldstone contributions are typically numerically negligible. 8 Note that the expression above differs from that in Ref. [9]; we believe this discrepancy is due to an algebraic error in the latter.…”

Bubble expansion and the viability of singlet-driven electroweak baryogenesis

“…5 Recent years have seen progress in matching models onto these existing results [54,[80][81][82] and in the hydrodynamic considerations associated with bubble wall expansion (see e.g. [83][84][85][86][87][88][89]). …”