/ 01 12 32 3 v 2 1 4 Ja n 20 02 Do the fundamental constants vary in the course of the cosmological evolution ?

2 00 1 Do the fundamental constants vary in the course of the cosmological evolution ?

Do the fundamental constants vary in the course of the cosmological evolution ? Abstract – We estimate the cosmological variation of the proton-to-electron mass ratio µ = m p /m e by measuring the wavelengths of molecular hydrogen transitions in the early universe. The analysis is performed using high spectral resolution observations (F W HM ≈ 7 km/s) of two damped Lyman-α systems at z abs = 2....

Preconditioning Legendre Spectral Collocation Approximations to Elliptic Problems

This work deals with the H1 condition numbers and the distribution of the ~ N;Msingular values of the preconditioned operators f~ 1 N;M WN;M ÂN;Mg. ÂN;M is the matrix representation of the Legendre Spectral Collocation discretization of the elliptic operator A de ned by Au := u + a1ux + a2uy + a0u in (the unit square) with boundary conditions: u = 0 on 0; @u @ A = u on 1. ~ N;M is the sti ness ...

ar X iv : h ep - t h / 01 12 11 4 v 2 2 1 Ja n 20 02 CCNY - HEP - 01 / 10 Gravitational fields on a noncommutative space

Noncommutative three-dimensional gravity can be described in terms of a noncommuta-tive Chern-Simons theory. We extend this structure and also propose an action for gravi-tational fields on an even dimensional noncommutative space. The action is worked out in some detail for fields on a noncommutative CP 2 and on S 4 .

/ 02 01 28 9 v 1 3 0 Ja n 20 02 The η ′ → ηππ decay in U ( 3 ) chiral perturbation theory 1

ar X iv : h ep - p h / 02 10 05 7 v 1 3 O ct 2 00 2 Varying Constants in Brane World Scenarios

Higher–dimensional theories imply that some constants, such as the gravitational constant and the strength of the gauge–couplings, are not fundamental constants. Instead they are related to the sizes of the extra–dimensional space, which are moduli fields in the four– dimensional effective theory. We study the cosmological evolution of the moduli fields appearing in brane world scenarios and di...