Cosmic bubble and domain wall instabilities III: the role of oscillons in three-dimensional bubble collisions

We introduce a new picture of vacuum decay which, in contrast to existing semiclassical techniques, provides a real-time description and does not rely on classically-forbidden tunneling paths. Using lattice simulations, we observe vacuum decay via bubble formation by generating realizations of vacuum fluctuations and evolving with the classical equations of motion. The decay rate obtained from an ensemble of simulations is in excellent agreement with existing techniques. Future applications include bubble correlation functions, fast decay rates, and decay of non-vacuum states.

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“…(obtained using the method of Ref. [31]). We also include the leading order prediction to compare to an exponential falloff at large φ 0 .…”

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confidence: 99%

New Semiclassical Picture of Vacuum Decay

et al. 2019

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“…Oscillons can be produced during preheating after different models of inflation [7][8][9][10][11], as well as in various types of field theories [12][13][14][15][16][17][18][19]. In [20], it has been shown that they form when a scalar field oscillates in a potential that opens up away from the minimum, i.e.…”

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confidence: 99%

Gravitational Waves from Oscillons after Inflation

2017

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We investigate the production of gravitational waves during preheating after inflation in the common case of field potentials that are asymmetric around the minimum. In particular, we study the impact of oscillons, comparatively long lived and spatially localized regions where a scalar field (e.g. the inflaton) oscillates with large amplitude. Contrary to a previous study, which considered a symmetric potential, we find that oscillons in asymmetric potentials associated with a phase transition can generate a pronounced peak in the spectrum of gravitational waves, that largely exceeds the linear preheating spectrum. We discuss the possible implications of this enhanced amplitude of gravitational waves. For instance, for low scale inflation models, the contribution from the oscillons can strongly enhance the observation prospects at current and future gravitational wave detectors.Introduction: Inflation is a very successful paradigm for early universe cosmology. The accelerated expansion can solve the horizon and flatness problems, while the quantum fluctuations of the inflaton field provide the seed for structure in the universe. After inflation, the potential energy of the inflaton is transferred to a thermal bath of the matter species present in the universe today in a process called reheating. The early stage of reheating, referred to as preheating, is often governed by non-linear dynamics of the inflaton field and other fields coupled to it, typically resulting in inhomogeneous field configurations. A generic consequence of preheating is the production of a stochastic background of gravitational waves (GW) [1, 2].

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“…[30][31][32] and the references therein), these studies have not included the effect of inhomogeneities, which would be interesting to explore. See [33][34][35] for related work suggesting that domain walls (neglecting self-gravity) are unstable to perturbations. extent, and not properties of the nonlinear interaction in gravitational wave scattering.…”

Section: Collision Of Point Particlesmentioning

confidence: 99%

Black hole formation from the collision of plane-fronted gravitational waves

Pretorius

East

2018

Phys. Rev. D

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This paper introduces a new effort to study the collision of plane-fronted gravitational waves in four dimensional, asymptotically flat spacetime, using numerical solutions of the Einstein equations. The pure vacuum problem requires singular, Aichelburg-Sexl-type sources to achieve finite energy solutions, which are problematic to treat both mathematically and numerically. Instead then, we use null (massless) particles to source nontrivial geometry within the initial wave fronts. The main purposes of this paper are to (a) motivate the problem, (b) introduce methods for numerically solving the Einstein equations coupled to distributions of collisionless massless or massive particles, and (c) present a first result on the formation of black holes in the head-on collision of axisymmetric distributions of null particles. Regarding the last-named, initial conditions are chosen so that a black hole forms promptly, with essentially no matter escaping the collision. This can be interpreted as approaching the ultrarelativistic collision problem from within an infinite boost limit, but where the matter distribution is spread out, and thus nonsingular. We find results that are consistent with earlier perturbative calculations of the collision of Aichelburg-Sexl singularities, as well as numerical studies of the high-speed collision of boson stars, black holes, and fluid stars: a black hole is formed containing most of the energy of the spacetime, with the remaining 15 ± 1% of the initial energy radiated away as gravitational waves. The methods developed here could be relevant for other problems in strong-field gravity and cosmology that involve particle distributions of matter.

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Cosmic bubble and domain wall instabilities III: the role of oscillons in three-dimensional bubble collisions

Cited by 45 publications

References 109 publications

New Semiclassical Picture of Vacuum Decay

New Semiclassical Picture of Vacuum Decay

Gravitational Waves from Oscillons after Inflation

Black hole formation from the collision of plane-fronted gravitational waves

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