Results 11 to 20 of about 199,809 (94)

Spectral asymptotics for sub-Riemannian Laplacians. I: quantum ergodicity and quantum limits in the 3D contact case [PDF]

, 2017
This is the first paper of a series in which we plan to study spectral asymptotics for sub-Riemannian Laplacians and to extend results that are classical in the Riemannian case concerning Weyl measures, quantum limits, quantum ergodicity, quasi-modes ...
de Verdière, Yves Colin, Hillairet, Luc, Trélat, Emmanuel   +2 more
core   +3 more sources

Commutators of Littlewood-Paley gκ∗$g_{\kappa}^{*} $-functions on non-homogeneous metric measure spaces

Open Mathematics, 2017
The main purpose of this paper is to prove that the boundedness of the commutator Mκ,b∗$\mathcal{M}_{\kappa,b}^{*} $ generated by the Littlewood-Paley operator Mκ∗$\mathcal{M}_{\kappa}^{*} $ and RBMO (μ) function on non-homogeneous metric measure ...
Lu Guanghui, Tao Shuangping
doaj   +1 more source

A unified mode decomposition method for physical fields in homogeneous cosmology [PDF]

, 2013
The methods of mode decomposition and Fourier analysis of classical and quantum fields on curved spacetimes previously available mainly for the scalar field on Friedman- Robertson-Walker (FRW) spacetimes are extended to arbitrary vector bundle fields on ...
Avetisyan, Zhirayr G.
core   +2 more sources

Renormalization group properties in the conformal sector: towards perturbatively renormalizable quantum gravity

Journal of High Energy Physics, 2018
The Wilsonian renormalization group (RG) requires Euclidean signature. The conformal factor of the metric then has a wrong-sign kinetic term, which has a profound effect on its RG properties.
Tim R. Morris
doaj   +1 more source

Initial Conditions in String Cosmology [PDF]

, 1998
We take a critical look at a recent conjecture concerning the past attractor in the pre-big-bang scenario. We argue that the Milne universe is unlikely to be a general past attractor for such models and support this with a number of examples.Comment: 10 ...
A. Buonanno, A. G. Doroshkevich, A. G. Doroshkevich, C. B. Collins, C. G. Hewitt, C. G. Hewitt, Ch. Charach, D. Clancy, Dominic Clancy, E. Kasner, G. F. R. Ellis, G. Veneziano, G. Veneziano, J. D. Barrow, J. D. Barrow, J. D. Barrow, J. Maharana, J. Wainwright, James E. Lidsey, K. C. Jacobs, L. D. Landau, M. B. Green, M. Carmeli, M. Gasperini, M. Gasperini, M. Gasperini, M. P. Ryan, M. S. Turner, R. Brustein, Reza Tavakol, S. T. C. Siklos, V. N. Lukash   +31 more
core   +2 more sources

The $L^p$-diameter of the group of area-preserving diffeomorphisms of $S^2$

, 2016
We show that for each $p \geq 1,$ the $L^p$-metric on the group of area-preserving diffeomorphisms of the two-sphere has infinite diameter. This solves the last open case of a conjecture of Shnirelman from 1985.
Brandenbursky, Michael, Shelukhin, Egor
core   +1 more source

A two measure model of dark energy and dark matter

, 2012
In this work we construct a unified model of dark energy and dark matter. This is done with the following three elements: a gravitating scalar field, phi with a non-conventional kinetic term, as in the string theory tachyon; an arbitrary potential, V(phi)
Douglas Singleton, E. Bergshoeff, E. Guendelman, E. Guendelman, E.A. Lim, Eduardo Guendelman, N Yongram, S. Ansoldi, S. del Campo, Supernova Cosmology Project collaboration, Supernova Search Team collaboration, U. Alam, V. Sahni   +12 more
core   +1 more source

Isodiametric inequality in Carnot groups

, 2010
The classical isodiametric inequality in the Euclidean space says that balls maximize the volume among all sets with a given diameter. We consider in this paper the case of Carnot groups.
Rigot, Severine
core   +4 more sources

Global, Local and Vector-Valued Tb Theorems on Non-Homogeneous Metric Spaces [PDF]

, 2011
Various Tb theorems play a key role in the modern harmonic analysis. They provide characterizations for the boundedness of Calderón-Zygmund type singular integral operators.
Martikainen, Henri
core  

Homogeneous Modes of Cosmological Instantons

, 2000
We discuss the O(4) invariant perturbation modes of cosmological instantons. These modes are spatially homogeneous in Lorentzian spacetime and thus not relevant to density perturbations.
A. Khvedelidze, C.G. Callan, Jr., G. Lavrelashvili, G.V. Lavrelashvili, G.W. Gibbons, J. Garriga, J.B. Hartle, K. Kirklin, L.G. Jensen, Neil Turok, P.A.M. Dirac, S. Coleman, S. Coleman, S. Coleman, S. Gratton, S. Gratton, S.W. Hawking, S.W. Hawking, Steven Gratton, T. Tanaka, T. Tanaka, V.A. Rubakov   +21 more
core   +1 more source