The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Marieke Postma - One of the best experts on this subject based on the ideXlab platform.
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quantum corrections in higgs inflation the real Scalar Case
Journal of Cosmology and Astroparticle Physics, 2014Co-Authors: Damien P George, Sander Mooij, Marieke PostmaAbstract:We present a critical discussion of quantum corrections, renormalisation, and the computation of the beta functions and the effective potential in Higgs inflation. In contrast with claims in the literature, we find no evidence for a disagreement between the Jordan and Einstein frames, even at the quantum level. For clarity of discussion we concentrate on the Case of a real Scalar Higgs. We first review the classical calculation and then discuss the back reaction of gravity. We compute the beta functions for the Higgs quartic coupling and non-minimal coupling constant. Here, the mid-field regime is non-renormalisable, but we are able to give an upper bound on the 1-loop corrections to the effective potential. We show that, in computing the effective potential, the Jordan and Einstein frames are compatible if all mass scales are transformed between the two frames. As such, it is consistent to take a constant cutoff in either the Jordan or Einstein frame, and both prescriptions yield the same result for the effective potential. Our results are extended to the Case of a complex Scalar Higgs.
Chao Tian - One of the best experts on this subject based on the ideXlab platform.
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broadcast correlated gaussians the vector Scalar Case
International Symposium on Information Theory, 2012Co-Authors: Lin Song, Jun Chen, Chao TianAbstract:The problem of sending a set of correlated Gaussian sources over a bandwidth-matched two-user Scalar Gaussian broadcast channel is studied in this work, where the strong receiver wishes to reconstruct several source components (i.e., a vector source) under a distortion covariance matrix constraint and the weak receiver wishes to reconstruct a single source component (i.e., a Scalar source) under the mean squared error distortion constraint. We provide a complete characterization of the optimal tradeoff between the transmit power and the achievable reconstruction distortion pair for this problem. The converse part is based on a new bounding technique which involves the introduction of an appropriate remote source. The forward part is based on a hybrid scheme where the digital portion uses dirty paper channel code and Wyner-Ziv source code. This scheme is different from the optimal scheme proposed by Tian et al. in a recent work for the Scalar-Scalar Case, which implies that the optimal scheme for the Scalar-Scalar Case is in fact not unique.
Hoaiminh Nguyen - One of the best experts on this subject based on the ideXlab platform.
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superlensing using hyperbolic metamaterials the Scalar Case
Journal de l’École polytechnique — Mathématiques, 2017Co-Authors: Eric Bonnetier, Hoaiminh NguyenAbstract:Reference EPFL-ARTICLE-228492doi:10.5802/jep.61 URL: https://arxiv.org/abs/1606.05516 Record created on 2017-05-30, modified on 2017-10-18
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superlensing using hyperbolic metamaterials the Scalar Case
arXiv: Analysis of PDEs, 2016Co-Authors: Eric Bonnetier, Hoaiminh NguyenAbstract:This paper is devoted to superlensing using hyperbolic metamaterials: the possibility to image an arbitrary object using hyperbolic metamaterials without imposing any conditions on size of the object and the wave length. To this end, two types of schemes are suggested and their analysis are given. The superlensing devices proposed are independent of the object. It is worth noting that the study of hyperbolic metamaterials is challenging due to the change type of modelling equations, elliptic in some regions, hyperbolic in some others.
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generalized impedance boundary conditions for scattering by strongly absorbing obstacles the Scalar Case
Mathematical Models and Methods in Applied Sciences, 2005Co-Authors: Houssem Haddar, Patrick Joly, Hoaiminh NguyenAbstract:We derive different classes of generalized impedance boundary conditions for the scattering problem from strongly absorbing obstacles. Compared to existing works, our construction is based on an asymptotic development of the solution with respect to the medium absorption. Error estimates are derived to validate the accuracy of each condition.
Damien P George - One of the best experts on this subject based on the ideXlab platform.
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quantum corrections in higgs inflation the real Scalar Case
Journal of Cosmology and Astroparticle Physics, 2014Co-Authors: Damien P George, Sander Mooij, Marieke PostmaAbstract:We present a critical discussion of quantum corrections, renormalisation, and the computation of the beta functions and the effective potential in Higgs inflation. In contrast with claims in the literature, we find no evidence for a disagreement between the Jordan and Einstein frames, even at the quantum level. For clarity of discussion we concentrate on the Case of a real Scalar Higgs. We first review the classical calculation and then discuss the back reaction of gravity. We compute the beta functions for the Higgs quartic coupling and non-minimal coupling constant. Here, the mid-field regime is non-renormalisable, but we are able to give an upper bound on the 1-loop corrections to the effective potential. We show that, in computing the effective potential, the Jordan and Einstein frames are compatible if all mass scales are transformed between the two frames. As such, it is consistent to take a constant cutoff in either the Jordan or Einstein frame, and both prescriptions yield the same result for the effective potential. Our results are extended to the Case of a complex Scalar Higgs.
Wolfgang Kreitmeier - One of the best experts on this subject based on the ideXlab platform.
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Asymptotic Optimality of Scalar Gersho Quantizers
Constructive Approximation, 2013Co-Authors: Wolfgang KreitmeierAbstract:In his famous paper (Gersho, IEEE Trans. Inf. Theory 25(4):373–380, 1979 ), Gersho stressed that the codecells of optimal quantizers asymptotically make an equal contribution to the distortion of the quantizer. Motivated by this fact, we investigate in this paper quantizers in the Scalar Case, where each codecell contributes with exactly the same portion to the quantization error. We show that such quantizers of Gersho type—or Gersho quantizers for short—exist for nonatomic Scalar distributions. As a main result, we prove that Gersho quantizers are asymptotically optimal.
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asymptotic optimality of Scalar gersho quantizers
arXiv: Functional Analysis, 2012Co-Authors: Wolfgang KreitmeierAbstract:In his famous paper [7] Gersho stressed that the codecells of optimal quantizers asymptotically make an equal contribution to the distortion of the quantizer. Motivated by this fact, we investigate in this paper quantizers in the Scalar Case, where each codecell contributes with exactly the same portion to the quantization error. We will show that such quantizers of Gersho type - or Gersho quantizers for short - exist for non-atomic Scalar distributions. As a main result we will prove that Gersho quantizers are asymptotically optimal.
