The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
Igor O Cherednikov - One of the best experts on this subject based on the ideXlab platform.
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on casimir energy contribution to Observable Value of the cosmological constant
AcPPB, 2002Co-Authors: Igor O CherednikovAbstract:AbstractThe contribution of the ground state energy of quantum fields to the cosmological constant is esti-mated from the point of view of the standard Casimir energy calculation scheme. It is shown thatthe requirement of the renormalization group invariance leads to the Value of the effective Λ-termwhich is of 11 orders higher than the result extracted from the experimental data. 1 Introduction One of the most intriguing and challenging problems of the modern physics is the enormously largedifference between the experimentally extracted cosmological constant and it’s Value estimated withinthe convenient quantum field theory [1]. This is so-called old cosmological constant problem, while thenew one is why it is comparable to the present mass density [2, 3]. Here we will study only the oldone. This problem attracts a great interest of the physical community (just mention that the SPIRES-SLAC database gives more than 800 references for “cosmological constant”), and a lot of sophisticatedapproaches have been proposed to it’s solution [1, 4]. However, the present situation seems to be far fromsatisfactory.The Einstein’s equationR
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on casimir energy contribution to Observable Value of the cosmological constant
arXiv: Astrophysics, 2001Co-Authors: Igor O CherednikovAbstract:The contribution of the ground state energy of quantum fields to the cosmological constant is estimated from the point of view of the standard Casimir energy calculation scheme. It is shown that the requirement of the renormalization group invariance leads to the Value of the effective $\L$-term which is of 11 orders higher than the result extracted from the experimental data.
Ilya L Shapiro - One of the best experts on this subject based on the ideXlab platform.
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scaling behavior of the cosmological constant and the possible existence of new forces and new light degrees of freedom
Physics Letters B, 2000Co-Authors: Ilya L Shapiro, Joan SolaAbstract:Abstract A large Value of the cosmological constant (CC) is induced in the Standard Model (SM) of Elementary Particle Physics because of Spontaneous Symmetry Breaking. To provide a small Value of the Observable CC one has to introduce the vacuum term which cancels the induced one at some point in the very far infrared cosmic scale. Starting from this point we investigate whether the cancellation is preserved at different energy scales. We find that the running of the Higgs mass, couplings and the vacuum term inevitably result in a scaling dependence of the Observable Value. As a consequence one meets a nonzero CC at an energy scale comparable to the typical electron neutrino mass suggested by some experiments, and the order of magnitude of this constant is roughly the one derived from recent supernovae observations. However the sign of it is negative – opposite to what is suggested by these observations. This discrepancy may be a hint of the existence of an extra very light scalar, perhaps a Cosmon-like dilaton, which should essentially decouple from the SM Lagrangian, but that it nevertheless could mediate new macroscopic forces in the submillimeter range.
Joan Sola - One of the best experts on this subject based on the ideXlab platform.
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scaling behavior of the cosmological constant and the possible existence of new forces and new light degrees of freedom
Physics Letters B, 2000Co-Authors: Ilya L Shapiro, Joan SolaAbstract:Abstract A large Value of the cosmological constant (CC) is induced in the Standard Model (SM) of Elementary Particle Physics because of Spontaneous Symmetry Breaking. To provide a small Value of the Observable CC one has to introduce the vacuum term which cancels the induced one at some point in the very far infrared cosmic scale. Starting from this point we investigate whether the cancellation is preserved at different energy scales. We find that the running of the Higgs mass, couplings and the vacuum term inevitably result in a scaling dependence of the Observable Value. As a consequence one meets a nonzero CC at an energy scale comparable to the typical electron neutrino mass suggested by some experiments, and the order of magnitude of this constant is roughly the one derived from recent supernovae observations. However the sign of it is negative – opposite to what is suggested by these observations. This discrepancy may be a hint of the existence of an extra very light scalar, perhaps a Cosmon-like dilaton, which should essentially decouple from the SM Lagrangian, but that it nevertheless could mediate new macroscopic forces in the submillimeter range.
Bradley Efron - One of the best experts on this subject based on the ideXlab platform.
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empirical bayes deconvolution estimates
Biometrika, 2016Co-Authors: Bradley EfronAbstract:An unknown prior density $g(\theta )$ has yielded realizations $\Theta _1,\ldots ,\Theta _N$. They are unObservable, but each $\Theta _i$ produces an Observable Value $X_i$ according to a known probability mechanism, such as $X_i\sim {\rm Po}(\Theta _i)$. We wish to estimate $g(\theta )$ from the observed sample $X_1,\ldots ,X_N$. Traditional asymptotic calculations are discouraging, indicating very slow nonparametric rates of convergence. In this article we show that parametric exponential family modelling of $g(\theta )$ can give useful estimates in moderate-sized samples. We illustrate the approach with a variety of real and artificial examples. Covariate information can be incorporated into the deconvolution process, leading to a more detailed theory of generalized linear mixed models.
Pieter Koopman - One of the best experts on this subject based on the ideXlab platform.
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task oriented programming in a pure functional language
Principles and Practice of Declarative Programming, 2012Co-Authors: Rinus Plasmeijer, Bas Lijnse, Steffen Michels, Peter Achten, Pieter KoopmanAbstract:Task-Oriented Programming (TOP) is a novel programming paradigm for the construction of distributed systems where users work together on the internet. When multiple users collaborate, they need to interact with each other frequently. TOP supports the definition of tasks that react to the progress made by others. With TOP, complex multi-user interactions can be programmed in a declarative style just by defining the tasks that have to be accomplished, thus eliminating the need to worry about the implementation detail that commonly frustrates the development of applications for this domain. TOP builds on four core concepts: tasks that represent computations or work to do which have an Observable Value that may change over time, data sharing enabling tasks to observe each other while the work is in progress, generic type driven generation of user interaction, and special combinators for sequential and parallel task composition. The semantics of these core concepts is defined in this paper. As an example we present the iTask3 framework, which embeds TOP in the functional programming language Clean.
