Personne

Sergey Sibiryakov

Cette personne n’est plus à l’EPFL

Publications associées (40)

Time-sliced perturbation theory II: baryon acoustic oscillations and infrared resummation

Sergey Sibiryakov, Diego Blas Temino, Mikhail Ivanov

We use time-sliced perturbation theory (TSPT) to give an accurate description of the infrared non-linear effects affecting the baryonic acoustic oscillations (BAO) present in the distribution of matter at very large scales. In TSPT this can be done via a s ...

Iop Publishing Ltd2016

Supergravity with broken Lorentz invariance

Sergey Sibiryakov

The supersymmetric extension of the Lorentz violating Einstein-aether theory of gravity is considered. The most general Lagrangian of the linearized Einstein-aether supergravity is constructed using the superfield formalism. The constraints imposed by supe ...

EDP Sciences2016

On holography for (pseudo-)conformal cosmology

Sergey Sibiryakov

We propose a holographic dual for (pseudo-)conformal cosmological scenario, with a scalar field that forms a moving domain wall in adS(5). The domain wall separates two vacua with unequal energy densities. Unlike in the existing construction, the 5d soluti ...

Elsevier2015

Experimental assessment of the speed of light perturbation in free-fall absolute gravimeters

Sergey Sibiryakov, Diego Blas Temino

Precision absolute gravity measurements are growing in importance, especially in the context of the new definition of the kilogram. For the case of free fall absolute gravimeters with a Michelson-type interferometer tracking the position of a free falling ...

Iop Publishing Ltd2015

On stability of electroweak vacuum during inflation

Sergey Sibiryakov, Andrey Shkerin

We study Coleman-De Luccia tunneling of the Standard Model Higgs field during inflation in the case when the electroweak vacuum is metastable. We verify that the tunneling rate is exponentially suppressed. The main contribution to the suppression is the sa ...

Elsevier2015

Cosmological constraints on deviations from Lorentz invariance in gravity and dark matter

Sergey Sibiryakov, Julien Lesgourgues, Diego Blas Temino, Benjamin Audren, Mikhail Ivanov

We consider a scenario where local Lorentz invariance is violated by the existence of a preferred time direction at every space-time point. This scenario can arise in the context of quantum gravity and its description at low energies contains a unit time-l ...

Iop Publishing Ltd2015

Semiclassical S-matrix for black holes

Sergey Sibiryakov

We propose a semiclassical method to calculate S-matrix elements for two-stage gravitational transitions involving matter collapse into a black hole and evaporation of the latter. The method consistently incorporates back-reaction of the collapsing and emi ...

Springer Nature2015

Completing Lorentz violating massive gravity at high energies

Sergey Sibiryakov, Diego Blas Temino

Theories with massive gravitons are interesting for a variety of physical applications, ranging from cosmological phenomena to holographic modeling of condensed matter systems. To date, they have been formulated as effective field theories with a cutoff pr ...

Springer Verlag2015

UV-extending ghost inflation

Sergey Sibiryakov, Mikhail Ivanov

We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether t ...

Iop Publishing Ltd2014

From Scale Invariance to Lorentz Symmetry

Sergey Sibiryakov

It is shown that a unitary translationally invariant field theory in 1 + 1 dimensions, satisfying isotropic scale invariance, standard assumptions about the spectrum of states and operators, and the requirement that signals propagate with finite velocity, ...

Amer Physical Soc2014

Prospective constraints on Lorentz violation from ultrahigh-energy photon detection

Sergey Sibiryakov

We point out that violation of Lorentz invariance affects the interaction of high-energy photons with the Earth's atmosphere and magnetic field. In a certain parameter region this interaction becomes suppressed and the photons escape observation, passing t ...

American Physical Society2014

Cosmological constraints on Lorentz violating dark energy

Sergey Sibiryakov, Julien Lesgourgues, Diego Blas Temino, Benjamin Audren

The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the c ...

Iop Publishing Ltd2013

Higgs inflation: consistency and generalisations

Mikhail Chapochnikov, Amaury Magnin, Sergey Sibiryakov

We analyse the self-consistency of inflation in the Standard Model, where the Higgs field has a large non-minimal coupling to gravity. We determine the domain of energies in which this model represents a valid effective field theory as a function of the ba ...

Springer Nature2011

Models of non-relativistic quantum gravity: the good, the bad and the healthy

Sergey Sibiryakov, Diego Blas Temino

Horava's proposal for non-relativistic quantum gravity introduces a preferred time foliation of space-time which violates the local Lorentz invariance. The foliation is encoded in a dynamical scalar field which we call 'khronon'. The dynamics of the khrono ...

Springer Nature2011

Horava gravity versus thermodynamics: The black hole case

Sergey Sibiryakov, Diego Blas Temino

Under broad assumptions, breaking of Lorentz invariance in gravitational theories leads to tension with unitarity because it allows for processes that apparently violate the second law of thermodynamics. The crucial ingredient of this argument is the exist ...

American Physical Society2011

Technically natural dark energy from Lorentz breaking

Sergey Sibiryakov, Diego Blas Temino

We construct a model of dark energy with a technically natural small contribution to cosmic acceleration, i.e. this contribution does not receive corrections from other scales in the theory. The proposed acceleration mechanism appears generically in the lo ...

2011

Comment on "Strong coupling in extended Horava-Lifshitz gravity" [Phys. Lett. B 685 (2010) 197]

Sergey Sibiryakov, Diego Blas Temino

We show that, contrary to the claim made in arXiv:0911.1299, the extended Horava gravity model proposed in arXiv:0909.3525 does not suffer from a strong coupling problem. By studying the observational constraints on the model we determine the bounds on the ...

2010

Consistent Extension of Horava Gravity

Sergey Sibiryakov, Diego Blas Temino

We propose a natural extension of Horava's model for quantum gravity, which is free from the notorious pathologies of the original proposal. The new model endows the scalar graviton mode with a regular quadratic action and remains power-counting renormaliz ...

2010

Signatures of unstable semiclassical trajectories in tunneling

Sergey Sibiryakov

It was found recently that processes of multidimensional tunneling are generally described at high energies by unstable semiclassical trajectories. We study two observational signatures related to the instability of trajectories. First, we find an addition ...

2009

Gravity Cutoff in Theories with Large Discrete Symmetries

Michele Redi, Sergey Sibiryakov

We set an upper bound on the gravitational cutoff in theories with exact quantum numbers of large N periodicity, such as Z(N) discrete symmetries. The bound stems from black hole physics. It is similar to the bound appearing in theories with N particle spe ...

2008