Lorentz-Violating Vector Fields Slow the Universe Down

We consider the gravitational effects of a single, fixed-norm, Lorentz-violating timelike vector field. In a cosmological background, such a vector field acts to rescale the effective value of Newton's constant. The energy density of this vector field precisely tracks the energy density of the rest of the universe, but with the opposite sign, so that the universe experiences a slower rate of expansion for a given matter content. This vector field similarly rescales Newton's constant in the Newtonian limit, although by a different factor. We put constraints on the parameters of the theory using the predictions of primordial nucleosynthesis, demonstrating that the norm of the vector field should be less than the Planck scale by an order of magnitude or more.Comment: 15 pages, Revtex4, updated version. Added References. Minor Typos corrected. Older version published in PR

Kinetics and moving species during Co2Si formation by rapid thermal annealing

We have investigated the growth kinetics and identified the moving species during Co2Si formation by rapid thermal annealing (RTA). For the kinetics study, samples which consisted of a thin Co film on an evaporated Si substrate were used. To study which species moves, samples imbedded with two very thin Ta markers were employed. Upon RTA, only one silicide phase, Co2Si, was observed to grow before all Co was consumed. The square root of time dependence and the activation energy of about 2.1±0.2 eV were observed during the Co2Si formation up to 680 °C. The marker study indicated that Co is the dominant mobile species during Co2Si formation by RTA. We conclude that Co2Si grows by the same mechanisms during RTA and conventional thermal annealing

Silicon resistor to measure temperature during rapid thermal annealing

A resistor composed of a piece of Si wafer and two thin silver wires attached to it, can reliably sense the temperature during rapid thermal annealing (RTA). As constant electric current passes through the Si piece, the resistivity change of Si with temperature produces a voltage signal that can be readily calibrated and converted to an actual temperature of the samples. An accuracy better than ±10 °C is achieved between 300° and 600 °C

Properties of kinematic singularities

The locally rotationally symmetric tilted perfect fluid Bianchi type V cosmological model provides examples of future geodesically complete spacetimes that admit a `kinematic singularity' at which the fluid congruence is inextendible but all frame components of the Weyl and Ricci tensors remain bounded. We show that for any positive integer n there are examples of Bianchi type V spacetimes admitting a kinematic singularity such that the covariant derivatives of the Weyl and Ricci tensors up to the n-th order also stay bounded. We briefly discuss singularities in classical spacetimes.Comment: 13 pages. Published version. One sentence from version 2 correcte

The ethics of the living wage: a review and research agenda

To date, business ethicists, corporate social responsibility scholars as well as management theorists have been slow to provide a comprehensive and critical scrutiny of the Living Wage concept. The aim of this article, therefore, is to conceptualize the living wage (LW) in its philosophical as well as practical dimensions in order to open up the ethical implications of its introduction and implementation by companies. We set out the legal, socio-institutional and economic contexts for the debates around the LW and review arguments for, and against, it. Key philosophical arguments from the perspectives of sustainability, capability and externality are invoked and discussed in order to demonstrate the issues and challenges involved for companies, state and civil society actors. Relevant examples from the private sector are examined to demonstrate some of the practical issues involved when the LW is introduced by employers. The article also recommends avenues for a research agenda into the LW for business ethicists, CSR and management researchers in contexts such as the UK, where a voluntary, rather than mandatory, approach to the implementation of the LW is adopted

A new living contract: cases in the implementation of the Living Wage by British SME retailers

Purpose of this paper: This paper aims to provide evidence for the motivations of SMEs for introducing the Living Wage, focusing on retail as one specific sector. It develops understanding of the strategic benefits and challenges these employers face in balancing financial, ethical and social considerations in small businesses. Design/methodology/approach: The study employed mixed methods: a survey and semi-structured interviews. The interviews are presented as part of three case studies. Findings: Findings indicate that employers were, for the most part, motivated by personal ethics and beliefs about fair wages and social justice. They suggest that SME accrue benefits from Living Wage accreditation such as reputational benefits and higher employee morale, but that there are also potential pitfalls of Living Wage adoption related to pay structure and incentives. The sustainability of the Living Wage emerged as an issue in terms of the long-term strategy and brand positioning of the companies involved. Research limitations/implications: The nature of the research was exploratory and thus the study only allows for limited generalisation. Recommended avenues for further research include gathering data from different levels of organisations and from different stakeholders. What is original/value of paper: This is the first paper to investigate the drivers for, and implementation of, the Living Wage in SMEs. The specific characteristics of SMEs – their ethos, low visibility, reliance on trusting relationships and limited resources, among others – make the study of why and how they choose to implement the LW very interesting. This study is the first to gather and analyse data from SME retailers and wholesalers that have implemented the Living Wage

Multi-photon entanglement from distant single photon sources on demand

We describe a scheme that allows for the generation of any desired N-photon state on demand. Under ideal conditions, this requires only N single photon sources, laser pulses and linear optics elements. First, the sources should be initialised with the help of single-qubit rotations and repeat-until-success two-qubit quantum gates [Lim et al., Phys. Rev. Lett. 95, 030305 (2005)]. Afterwards, the state of the sources can be mapped onto the state of N newly generated photons whenever needed.Comment: 9 pages, 3 figure

Quantum Communication in Spin Systems With Long-Range Interactions

We calculate the fidelity of transmission of a single qubit between distant sites on semi-infinite and finite chains of spins coupled via the magnetic dipole interaction. We show that such systems often perform better than their Heisenberg nearest-neighbour coupled counterparts, and that fidelities closely approaching unity can be attained between the ends of finite chains without any special engineering of the system, although state transfer becomes slow in long chains. We discuss possible optimization methods, and find that, for any length, the best compromise between the quality and the speed of the communication is obtained in a nearly uniform chain of 4 spins.Comment: 15 pages, 8 eps figures, updated references, corrected text and corrected figs. 1, 4 and