Zobrazeno 1 - 10
of 631
pro vyhledávání: '"Vilenkin, Alexander"'
We study the formation of gravitating global strings through quantum mechanical tunneling. The instantons that describe the nucleation process are characterized by two parameters: the string core thickness and its gravitational backreaction controlle
Externí odkaz:
http://arxiv.org/abs/2410.24149
We study the dynamics of a cosmic string loop captured by a rotating black hole, ignoring string reconnections. A loop is numerically evolved in Kerr spacetime, with the result that it turns into one or more growing or contracting double-lines rotati
Externí odkaz:
http://arxiv.org/abs/2303.02726
Autor:
Chen, Yilin, Vilenkin, Alexander
We revisit the question addressed in recent papers by Garriga et al: What determines the rest frame of pair nucleation in a constant electric field? The conclusion reached in these papers is that pairs are observed to nucleate at rest in the rest fra
Externí odkaz:
http://arxiv.org/abs/2302.11501
Autor:
Fanaras, Georgios, Vilenkin, Alexander
In light of the recent swampland conjectures, we explore quantum cosmology and eternal inflation beyond the slow roll regime. We consider a model of a closed universe with a scalar field $\phi$ in the framework of tunneling approach to quantum cosmol
Externí odkaz:
http://arxiv.org/abs/2302.04962
Autor:
Fanaras, Georgios, Vilenkin, Alexander
We use a path-integral approach to study the tunneling wave function in quantum cosmology with spatial topology $S^{1}\times S^{2}$ and positive cosmological constant (the Kantowski-Sachs model). If the initial scale factors of both $S^1$ and $S^2$ a
Externí odkaz:
http://arxiv.org/abs/2206.05839
Autor:
Fanaras, Georgios, Vilenkin, Alexander
We study quantum cosmology of the $2D$ Jackiw-Teitelboim (JT) gravity with $\Lambda>0$ and calculate the Hartle-Hawking (HH) wave function for this model in the minisuperspace framework. Our approach is guided by the observation that the JT dynamics
Externí odkaz:
http://arxiv.org/abs/2112.00919
Publikováno v:
Phys. Rev. D 104, 023528 (2021)
Eternally inflating universes lead to an infinite number of Boltzmann brains but also an infinite number of ordinary observers. If we use the scale factor measure to regularize these infinities, the ordinary observers dominate the Boltzmann brains if
Externí odkaz:
http://arxiv.org/abs/2105.00457
Publikováno v:
Phys. Rev. D 103, 103528 (2021)
We estimate the chirality of the cosmological medium due to parity violating decays of standard model particles, focusing on the example of tau leptons. The non-trivial chirality is however too small to make a significant contribution to the cosmolog
Externí odkaz:
http://arxiv.org/abs/2101.06344
Recent work by Jenkins and Sakellariadou claims that cusps on cosmic strings lead to black hole production. To derive this conclusion they use the hoop conjecture in the rest frame of the string loop, rather than in the rest frame of the proposed bla
Externí odkaz:
http://arxiv.org/abs/2101.05040