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Concept

Tachyon

Related publications (12)

Preheating in Palatini Higgs inflation on the lattice

Inar Timiryasov, Andrey Shkerin, Juraj Klaric, Adrien Florio

We study preheating following Higgs inflation in the Palatini formulation of gravity. We numerically evolve perturbations of the radial mode of the Higgs field and that of three scalars modeling the gauge bosons. We compare the two non-perturbative mechani ...

IOP Publishing Ltd2022

On constraining the speed of gravitational waves following GW150914

Sergey Sibiryakov, Diego Blas Temino, Mikhail Ivanov

We point out that the observed time delay between the detection of the signal at the Hanford and Livingston LIGO sites from the gravitational wave event GW150914 places an upper bound on the speed of propagation of gravitational waves, c (gw) ae(2) 1.7 in ...

Springer Verlag2016

Advances in the physics basis for the European DEMO design

Ambrogio Fasoli, Javier García Hernández, Marco Wischmeier, Emiliano Fable

In the European fusion roadmap, ITER is followed by a demonstration fusion power reactor (DEMO), for which a conceptual design is under development. This paper reports the first results of a coherent effort to develop the relevant physics knowledge for tha ...

IOP Publishing Ltd2015

Definition of the radiation fields for the JET gamma-ray spectrometer diagnostics

Patrick Blanchard

The JET gamma-ray diagnostics system provides information on the behaviour of fast particles within the tokamak plasma. Information on the spatial distribution of the interacting fast particles is obtained from the gamma-ray cameras, while energy distribut ...

Elsevier Science Sa2013

Axial phase measurements of light interacting with microstructures

Hans Peter Herzig, Toralf Scharf, Myun Sik Kim

We present an experimental method to study field structures of highly confined light after interaction with microstructures. A high-resolution interference microscope (HRIM) allows us to measure the three-dimensional (3D) amplitude and phase distributions ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2012

Drift stabilization of ballooning modes in an inward-Shifted LHD configuration

Jonathan Graves, Wilfred Anthony Cooper

A drift-magnetohydrodynamic theory is applied to a background anisotropic pressure equilibrium state to generate a drift corrected ballooning mode equation. The ratio of the mode frequency to the hot particle drift frequency constitutes the critical expans ...

Wiley-VCH2010

Energy's and amplitudes' positivity

Riccardo Rattazzi

In QFT, the null energy condition (NEC) for a classical field configuration is usually associated with that configuration's stability against small perturbations, and with the sub-luminality of these. Here, we exhibit an effective field theory that allows ...

Springer Nature2010

Galileon as a local modification of gravity

Riccardo Rattazzi

In the Dvali-Gabadadze-Porrati (DGP) model, the "self-accelerating" solution is plagued by a ghost instability, which makes the solution untenable. This fact, as well as all interesting departures from general relativity (GR), are fully captured by a four- ...

American Physical Society2009

De Sitter vacua in no-scale supergravities and Calabi-Yau string models

Claudio Scrucca

We perform a general analysis on the possibility of obtaining metastable vacua with spontaneously broken N = 1 supersymmetry and non-negative cosmological constant in the moduli sector of string models. More specifically, we study the condition under which ...

Springer Nature2008

Simple scheme for realizing fast light with low distortion in optical fibers

Luc Thévenaz, Sang Hoon Chin

In a previous paper (Song et al., 2005) we reported the first experimental demonstration of pulse advancement with gain in optical fibers using stimulated Brillouin scattering (SBS). We tested the two methods described above to achieve gain-assisted fast l ...

IEEE2007

Light controlling light in an optical fibre: from very slow to faster-than-light speed

Luc Thévenaz, Kwang-Yong Song

We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fibre. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scatteri ...

Faculté Polytechnique de Mons2005

Slow, superluminal and negative group velocity in optical fibres using stimulated Brillouin scattering

Luc Thévenaz

Active control of the group velocity in optical fibres is demonstrated, allowing long delays, faster-than-light propagation and even negative velocity, for which the peak of a pulse exits the fibre before entering the input end ...

IET2005