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Title:

Price for environmental neutrino-superluminality

Description:

We ask whether the recent OPERA results on neutrino superluminality could be an environmental effect characteristic of the local neighborhood of our planet, without the need of violation of the Poincaré-invariance at a fundamental level. We show, that model-indepenently, such a possibility implies the existence of new gravitational degrees of fr...

We ask whether the recent OPERA results on neutrino superluminality could be an environmental effect characteristic of the local neighborhood of our planet, without the need of violation of the Poincaré-invariance at a fundamental level. We show, that model-indepenently, such a possibility implies the existence of new gravitational degrees of freedom. Namely, this explanation requires the existence of a new spin-2 field of a planetary Compton wave-length that is coupled to neutrinos and the rest of the matter asymmetrically, both in the magnitude and in the sign. Sourced by the earth this field creates an effective metric on which neutrinos propagate superluminally, whereas other species are much less sensitive to the background. Such a setup, at an effective field theory level, passes all immediate phenomenological tests, but at the expense of sacrificing calculability for some of the phenomena that are under perturbative control in ordinary gravity. The natural prediction is an inevitable appearance of a testable long-range gravity-type fifth force. Despite phenomenological viability, the sign asymmetry of the coupling we identify as the main potential obstacle for a consistent UV-completion. We also discuss the possible identification of this field with a Kaluza-Klein state of an extra dimension in which neutrino can propagate. Minimize

Publisher:

Springer-Verlag

Year of Publication:

2012-02-01

Source:

Journal of High Energy Physics, 2012-02-01, Volume 2012, pp 1-9

Journal of High Energy Physics, 2012-02-01, Volume 2012, pp 1-9 Minimize

Language:

En

Subjects:

Beyond Standard Model ; Neutrino Physics ; Space-Time Symmetries

Beyond Standard Model ; Neutrino Physics ; Space-Time Symmetries Minimize

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Title:

aus Kiev

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Description:

geometry

geometry Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2012-06-21

Source:

http://edoc.ub.uni-muenchen.de/7761/1/Vikman_Alexander.pdf

http://edoc.ub.uni-muenchen.de/7761/1/Vikman_Alexander.pdf Minimize

Document Type:

text

Language:

en

Rights:

Metadata may be used without restrictions as long as the oai identifier remains attached to it.

Metadata may be used without restrictions as long as the oai identifier remains attached to it. Minimize

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Title:

The imperfect fluid behind kinetic gravity braiding

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We present a standard hydrodynamical description for non-canonical scalar field theories with kinetic gravity braiding. In particular, this picture applies to the simplest galileons and k-essence. The fluid variables not only have a clear physical meaning but also drastically simplify the analysis of the system. The fluid carries charges corresp...

We present a standard hydrodynamical description for non-canonical scalar field theories with kinetic gravity braiding. In particular, this picture applies to the simplest galileons and k-essence. The fluid variables not only have a clear physical meaning but also drastically simplify the analysis of the system. The fluid carries charges corresponding to shifts in field space. This shift-charge current contains a spatial part responsible for diffusion of the charges. Moreover, in the incompressible limit, the equation of motion becomes the standard diffusion equation. The fluid is indeed imperfect because the energy flows neither along the field gradient nor along the shift current. The fluid has zero vorticity and is not dissipative: there is no entropy production, the energy-momentum is exactly conserved, the temperature vanishes and there is no shear viscosity. Still, in an expansion around a perfect fluid one can identify terms which correct the pressure in the manner of bulk viscosity. We close by formulating the non-trivial conditions for the thermodynamic equilibrium of this imperfect fluid. Minimize

Publisher:

Springer-Verlag

Year of Publication:

2011-11-01

Source:

Journal of High Energy Physics, 2011-11-01, Volume 2011, pp 1-33

Journal of High Energy Physics, 2011-11-01, Volume 2011, pp 1-33 Minimize

Language:

En

Subjects:

Cosmology of Theories beyond the SM ; Classical Theories of Gravity ; Global Symmetries ; Nonperturbative Effects

Cosmology of Theories beyond the SM ; Classical Theories of Gravity ; Global Symmetries ; Nonperturbative Effects Minimize

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Title:

LOOKING BEYOND THE HORIZON

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In our previous work1 we have shown that it is principally possible to send information from the interior of a black hole (BH) without modifying Hilbert-Einstein action a. This may happen provided a special type of scalar field theory with noncanonical kinetic term is realized in nature. In our approach we have considered the accretion of a part...

In our previous work1 we have shown that it is principally possible to send information from the interior of a black hole (BH) without modifying Hilbert-Einstein action a. This may happen provided a special type of scalar field theory with noncanonical kinetic term is realized in nature. In our approach we have considered the accretion of a particular noncanonical field φ onto a black hole b. The scalar field flow forms an acoustic black hole similar to the well known ”dumb hole”. 12 This background dynamically breaks Lorentz invariance and serves as a ”new ether”. Due to the nonlinearity of the equation of motion, the ”new ether ” allows a superluminal propagation of small perturbations δφ of the field φ c. The field theories with nonstandard kinetic terms have been subjects of investigation since a long time ago. 4 In cosmology they were first introduced in the context of k-inflation and k-essence models. 5 The letter seems to require a superluminal sound speed during a period of cosmic evolution. 7 The models with superluminal sound speed may have other interesting applications in cosmology. 8,9 In this short talk we review our results from the paper1 with the main stress on the issues of causality and acoustic metric in Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2013-08-04

Source:

http://arxiv.org/pdf/0704.3301v1.pdf

http://arxiv.org/pdf/0704.3301v1.pdf Minimize

Document Type:

text

Language:

en

DDC:

539 Modern physics *(computed)*

Rights:

Metadata may be used without restrictions as long as the oai identifier remains attached to it.

Metadata may be used without restrictions as long as the oai identifier remains attached to it. Minimize

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Preprint typeset in JHEP style- HYPER VERSION LMU-ASC 54/07

Preprint typeset in JHEP style- HYPER VERSION LMU-ASC 54/07 Minimize

Contributors:

The Pennsylvania State University CiteSeerX Archives

Year of Publication:

2012-11-26

Source:

http://arxiv.org/pdf/0708.0561v1.pdf

http://arxiv.org/pdf/0708.0561v1.pdf Minimize

Document Type:

text

Language:

en

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Metadata may be used without restrictions as long as the oai identifier remains attached to it.

Metadata may be used without restrictions as long as the oai identifier remains attached to it. Minimize

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Title:

Suppressing Quantum Fluctuations in Classicalization

Description:

We study vacuum quantum fluctuations of simple Nambu-Goldstone bosons - derivatively coupled single scalar-field theories possessing shift-symmetry in field space. We argue that quantum fluctuations of the interacting field can be drastically suppressed with respect to the free-field case. Moreover, the power-spectrum of these fluctuations can s...

We study vacuum quantum fluctuations of simple Nambu-Goldstone bosons - derivatively coupled single scalar-field theories possessing shift-symmetry in field space. We argue that quantum fluctuations of the interacting field can be drastically suppressed with respect to the free-field case. Moreover, the power-spectrum of these fluctuations can soften to become red for sufficiently small scales. In quasiclassical approximation, we demonstrate that this suppression can only occur for those theories that admit such classical static backgrounds around which small perturbations propagate faster than light. Thus, a quasiclassical softening of quantum fluctuations is only possible for theories which classicalize instead of having a usual Lorentz invariant and local Wilsonian UV- completion. We illustrate our analysis by estimating the quantum fluctuations for the DBI-like theories. ; Comment: 6 pages, no figures, published version, more general discussion of uncertainty relation in QFT, improved and more general derivation of the main result Minimize

Year of Publication:

2012-08-17

Document Type:

text

Subjects:

High Energy Physics - Theory ; Astrophysics - Cosmology and Extragalactic Astrophysics ; General Relativity and Quantum Cosmology ; High Energy Physics - Phenomenology

High Energy Physics - Theory ; Astrophysics - Cosmology and Extragalactic Astrophysics ; General Relativity and Quantum Cosmology ; High Energy Physics - Phenomenology Minimize

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Title:

Inflation with large gravitational waves

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It is well known that in manifestly Lorentz invariant theories with nontrivial kinetic terms, perturbations around some classical backgrounds can travel faster than light. These exotic "supersonic" models may have interesting consequences for cosmology and astrophysics. In particular, one can show that in such theories the contribution of the gr...

It is well known that in manifestly Lorentz invariant theories with nontrivial kinetic terms, perturbations around some classical backgrounds can travel faster than light. These exotic "supersonic" models may have interesting consequences for cosmology and astrophysics. In particular, one can show that in such theories the contribution of the gravitational waves to the CMB fluctuations can be significantly larger than that in standard inflationary models. This increase of the tensor-to-scalar perturbation ratio leads to a larger B-component of the CMB polarization, thus making the prospects for future detection much more promising. Interestingly, the spectral index of scalar perturbations and mass of the scalar field considered in the model are practically indistinguishable from the standard case. Whereas the energy scale of inflation and hence the reheating temperature can be much higher compared to a simple chaotic inflation. ; Comment: Contributed to XLIst Rencontres de Moriond Workshop on Contents and Structures of the Universe, La Thuile, Italy, March 18-25, 2006 Minimize

Year of Publication:

2006-06-01

Document Type:

text

Subjects:

Astrophysics

Astrophysics Minimize

DDC:

539 Modern physics *(computed)*

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Title:

Can dark energy evolve to the Phantom?

Description:

Dark energy rapidly evolving from the dustlike state in the close past to the phantomlike state at present has been recently proposed as the best fit for the supernovae Ia data. Assuming that a dark energy component with an arbitrary scalar-field Lagrangian, which has a general dependence on the field itself and its first derivatives, dominates ...

Dark energy rapidly evolving from the dustlike state in the close past to the phantomlike state at present has been recently proposed as the best fit for the supernovae Ia data. Assuming that a dark energy component with an arbitrary scalar-field Lagrangian, which has a general dependence on the field itself and its first derivatives, dominates in the flat Friedmann universe, we analyze the possibility of a dynamical transition from the states with w>-1 to those with w<-1 or vice versa. We have found that generally such transitions are physically implausible because they are either realized by a discrete set of trajectories in the phase space or are unstable with respect to the cosmological perturbations. This conclusion is confirmed by a comparison of the analytic results with numerical solutions obtained for simple models. Without the assumption of the dark energy domination, this result still holds for a certain class of dark energy Lagrangians, in particular, for Lagrangians quadratic in field's first derivatives. The result is insensitive to topology of the Friedmann universe as well. ; Comment: 15 pages, 9 figures, corrected typos, exposition is improved;published version Minimize

Year of Publication:

2004-07-06

Document Type:

text

Subjects:

Astrophysics ; General Relativity and Quantum Cosmology ; High Energy Physics - Theory

Astrophysics ; General Relativity and Quantum Cosmology ; High Energy Physics - Theory Minimize

DDC:

539 Modern physics *(computed)*

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Title:

K-essence: cosmology

Description:

In this work we consider different aspects of k-essence theories, which are scalar field theories described by the generally covariant and Lorentz invariant action with non-canonical kinetic terms. It is shown that, because of the intrinsic nonlinearity, these theories can have rather unexpected and unusual physical properties. As in the usual r...

In this work we consider different aspects of k-essence theories, which are scalar field theories described by the generally covariant and Lorentz invariant action with non-canonical kinetic terms. It is shown that, because of the intrinsic nonlinearity, these theories can have rather unexpected and unusual physical properties. As in the usual relativistic field theories, any nontrivial dynamical solution of the k-essence equation of motion spontaneously breaks the Lorentz invariance. Thus the perturbations around such solutions propagate in a "new aether". In contrast to the usual relativistic field theories, these perturbations propagate in an "effective" metric which is different from the usual gravitational metric. This effective metric can be interpreted as the so-called "emergent spacetime". In this thesis we show that the dynamics of the perturbations can be described by the action which is generally covariant with respect to the reparameterization of this "emergent spacetime". The most interesting manifestation of this "emergent spacetime" is that perturbations can propagate faster than light. We show that despite the superluminal propagation the causal paradoxes do not arise in these theories, and in this respect these theories are not less safe than General Relativity. This superluminal propagation of perturbations has interesting consequences for cosmology and black hole physics. In particular, it is possible to construct models of inflation with an enhanced production of gravitational waves. This in turn can be verified in the nearest future by the observations of the B-mode polarization of the Cosmic Microwave Background Radiation (CMBR). Moreover, we have shown that there exist k-essence models which in principle allow to obtain information from the region beyond the black hole horizon. This information is encoded in the perturbations around the solution describing the stationary accretion of the k-essence onto the black hole. In addition, we discuss the possible dynamical violation of the Null Energy Condition (NEC) in the k-essence models. The violation of NEC by the dynamical Dark Energy (DE) is not excluded and even slightly preferred by observations Moreover, the violation of NEC plays a crucial role in the pre-Big-Bang scenarios. We have shown that in the framework of general k-essence the dynamical violation of NEC is physically implausible. Minimize

Publisher:

Ludwig-Maximilians-Universität München

Year of Publication:

2007-11-30

Document Type:

Dissertation ; NonPeerReviewed

Subjects:

Fakultät für Physik

Fakultät für Physik Minimize

DDC:

539 Modern physics *(computed)*

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Title:

Suppressing Quantum Fluctuations

Description:

We study vacuum quantum fluctuations of simple Nambu-Goldstone bosons - derivatively coupled single scalar-field theories possessing shift-symmetry in field space. We argue that quantum fluctuations of the interacting field can be drastically suppressed with respect to the free-field case. Moreover, the power-spectrum of these fluctuations can s...

We study vacuum quantum fluctuations of simple Nambu-Goldstone bosons - derivatively coupled single scalar-field theories possessing shift-symmetry in field space. We argue that quantum fluctuations of the interacting field can be drastically suppressed with respect to the free-field case. Moreover, the power-spectrum of these fluctuations can soften to become red for sufficiently small scales. In quasiclassical approximation, we demonstrate that this suppression can only occur for those theories that admit such classical static backgrounds around which small perturbations propagate faster than light. Thus a quasiclassical softening of quantum fluctuations is only possible for theories which classicalize instead of having a usual Lorentz invariant and local Wilsonian UV- completion. We illustrate our analysis by estimating the quantum fluctuations for the DBI-like theories. Minimize

Year of Publication:

2012-08-20

Language:

eng

Subjects:

Particle Physics - Theory

Particle Physics - Theory Minimize

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