We study the vacuum Cauchy problem for K-essence, i.e. cosmologically relevant scalar-tensor theories that involve first-order derivative self-interactions, and which pass all existing gravitational wave bounds. We restrict to spherical symmetry and show that there exists a large class of theories for which no breakdown of the Cauchy problem occurs outside apparent black hole horizons, even in the presence of scalar shocks/caustics, except for a small set of initial data sufficiently close to critical black hole collapse. We characterise these problematic initial data, and show that they lead to large or even diverging (coordinate) speeds for the characteristic curves. We discuss the physical relevance of this problem and propose ways to overcome it. © 2021 IOP Publishing Ltd and Sissa Medialab.

K-dynamics: well-posed 1+1 evolutions in K-essence / Miguel, Bezares; Crisostomi, Marco; Palenzuela, Carlos; Barausse, Enrico. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - 2021:3(2021), pp. 1-20.

K-dynamics: well-posed 1+1 evolutions in K-essence

Miguel Bezares;Marco Crisostomi;Enrico Barausse
2021

Abstract

We study the vacuum Cauchy problem for K-essence, i.e. cosmologically relevant scalar-tensor theories that involve first-order derivative self-interactions, and which pass all existing gravitational wave bounds. We restrict to spherical symmetry and show that there exists a large class of theories for which no breakdown of the Cauchy problem occurs outside apparent black hole horizons, even in the presence of scalar shocks/caustics, except for a small set of initial data sufficiently close to critical black hole collapse. We characterise these problematic initial data, and show that they lead to large or even diverging (coordinate) speeds for the characteristic curves. We discuss the physical relevance of this problem and propose ways to overcome it. © 2021 IOP Publishing Ltd and Sissa Medialab.
2021
3
1
20
072
10.1088/1475-7516/2021/03/072
https://iopscience.iop.org/article/10.1088/1475-7516/2021/03/072
https://arxiv.org/abs/2008.07546
Miguel, Bezares; Crisostomi, Marco; Palenzuela, Carlos; Barausse, Enrico
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/119149
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