Two-point function for the Maxwell field in flat Robertson-Walker spacetimes

We obtain an explicit two-point function for the Maxwell field in flat Roberson-Walker spaces, thanks to a new gauge condition which takes the scale factor into account and assume a simple form. The two-point function is found to have the short distance Hadamard behavior.Comment: 4 pages, Revte

Massive scalar field on (A)dS space from a massless conformal field in R6\mathbb{R}^6

We show how the equations for the scalar field (including the massive, massless, minimally and conformally coupled cases) on de Sitter and Anti-de Sitter spaces can be obtained from both the SO$(2,4)$-invariant equation $\square \phi = 0$ in $\mathbb{R}^6$ and two geometrical constraints defining the (A)dS space. Apart from the equation in $\mathbb{R}^6$, the results only follow from the geometry.Comment: Revtex 4.1, 6 pages. In v3: New material added (references, relation with mass ladder operator), accepted in JM

A toy model of a fake inflation

Discontinuities in non linear field theories propagate through null geodesics in an effective metric that depends on its dynamics and on the background geometry. Once information of the geometry of the universe comes mostly from photons, one should carefully analyze the effects of possible nonlinearities on Electrodynamics in the cosmic geometry. Such phenomenon of induced metric is rather general and may occurs for any nonlinear theory independently of its spin properties. We limit our analysis here to the simplest case of non linear scalar field. We show that a class of theories that have been analyzed in the literature, having regular configuration in the Minkowski space-time background is such that the field propagates like free waves in an effective deSitter geometry. The observation of these waves would led us to infer, erroneously, that we live in a deSitter universe

Conformally covariant quantization of Maxwell field in de Sitter space

In this article, we quantize the Maxwell ("massless spin one") de Sitter field in a conformally invariant gauge. This quantization is invariant under the SO$_0(2,4)$ group and consequently under the de Sitter group. We obtain a new de Sitter invariant two-points function which is very simple. Our method relies on the one hand on a geometrical point of view which uses the realization of Minkowski, de Sitter and anti-de Sitter spaces as intersections of the null cone in \setR^6 and a moving plane, and on the other hand on a canonical quantization scheme of the Gupta-Bleuler type.Comment: v2 is is the definitive (improved compare to v1) versio

Examples of Berezin-Toeplitz Quantization: Finite sets and Unit Interval

We present a quantization scheme of an arbitrary measure space based on overcomplete families of states and generalizing the Klauder and the Berezin-Toeplitz approaches. This scheme could reveal itself as an efficient tool for quantizing physical systems for which more traditional methods like geometric quantization are uneasy to implement. The procedure is illustrated by (mostly two-dimensional) elementary examples in which the measure space is a $N$-element set and the unit interval. Spaces of states for the $N$-element set and the unit interval are the 2-dimensional euclidean $\R^2$ and hermitian \C^2 planes

Monitoring of Cd, Cr, Cu, Fe, Mn, Pb, and Zn in fine uruguayan wines by atomic absorption spectroscopy

Seven elements were determined in 14 white and 33 red wines from nine Uruguayan wineries. Flame atomic absorption spectrometry (FAAS) was used for the determination of Cu, Fe, Mn and Zn by preparation of a calibration curve in a wine matrix simulator and graphite furnace-atomic absorption spectrometry (GF-AAS) for Cd, Cr and Pb by diluting the wine samples with. 1 % HNO3. For the determinations a Perkin Elmer Model 5000 atomic absorption spectrometer was used. The following concentration ranges (mg/l) were obtained for Cd (0.002-0.003), Cr (0.004-0.052), Pb (0.006-0.057), Cu (0.034-0.65), Fe (0.73-4.6), Mn (0.74-2.2) and Zn (0.49-2.2). So far the concentrations are typical for wines from around the world. None of them is above the limits established by the O.I.V. [17124] (H. Eschnauer, Ingelheim

Wick ordering for coherent state quantization in 1+1 de Sitter space

We show that the coherent state quantization of massive particles in 1+1 de Sitter space exhibits an ordering property: There exist some classical observables $A$ and $A^*$ such that $O_{A^{*p}}O_{A^q}=O_{A^{*p} A^q}$ $p, q \in \Z$, where $O_A$ is the quantum observable corresponding to the classical observable $A$.Comment: Accepted in Phys. Lett.