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

Are 21st-century citizens grieving for their loss of privacy?

Although much research exists that examines cognitive events leading up to information disclosure, such as risk-benefit analysis and state-based and trait-based attributes, minimal research exists that examines user responses after a direct or indirect breach of privacy. The present study examines 1,004 consumer responses to two different high-profile privacy breaches using sentiment analysis. Our findings indicate that individuals who experience an actual or surrogate privacy breach exhibit similar emotional responses, and that the pattern of responses resembles well-known reactions to other losses. Specifically, we present evidence that users contemplating evidence of a privacy invasion experience and communicate very similar responses as individuals who have lost loved ones, gone through a divorce or who face impending death because of a terminal illness. These responses parallel behavior associated with the Kübler-Ross’s five stages of grief

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

Maximizing the Strength of Fused-Deposition ABS Plastic Parts

Fused-Deposition (FD) creates parts using robotic extrusion of set.D.i-liquid .polymer fiber, which molecularly bonds with neighboring fibers via thermal-dlffuslo.n bonding. T~e strength ofthe. part depends on the bulk polymer strength, themesostructure ~flber layout, vOid geom~try, extent of fiber bonding), and thefiber-t~-fiber ~ond strength. The ~nfluence of these factors on the mechanical strength of FD-ABS.plasttc parts IS reported.along with the.FD process variable settingsfor maximum strength. Substantial increases in transverse strength are achieved at the optirnal settings and additional increases can be achieved by post..fabrication annealing. Keywords: Stratasys, fused-deposition, ABSplastic, functional parts, strength, mesostructure, polymer diffusion.Mechanical Engineerin