Energy-Momentum Problem of Bell-Szekeres Metric in General Relativity and Teleparallel Gravity

This paper is devoted to the investigation of the energy-momentum problem in two theories, i.e., General Relativity and teleparallel gravity. We use Einstein, Landau-Lifshitz, Bergmann-Thomson and M\"{o}ller's prescriptions to evaluate energy-momentum distribution of Bell-Szekeres metric in both the theories. It is shown that these prescriptions give the same energy-momentum density components in both General Relativity and teleparallel theory. M\"{o}ller's prescription yields constant energy in both the theories.Comment: 21 pages, accepted for publication in Braz. J. Phy

Optical network technologies for future digital cinema

Digital technology has transformed the information flow and support infrastructure for numerous application domains, such as cellular communications. Cinematography, traditionally, a film based medium, has embraced digital technology leading to innovative transformations in its work flow. Digital cinema supports transmission of high resolution content enabled by the latest advancements in optical communications and video compression. In this paper we provide a survey of the optical network technologies for supporting this bandwidth intensive traffic class. We also highlight the significance and benefits of the state of the art in optical technologies that support the digital cinema work flow

Trust in Transformational Leadership: Do Followers’ Perceptions of Leader Femininity, Masculinity, and Androgyny Matter?

This paper takes an authenticity perspective to examine whether followers’ perceptions of a leader’s feminine, masculine, or androgynous characteristics influence the relationship between transformational leadership and followers’ perceived trust in the leader. The research was quantitative in approach. A cross-sectional survey design was used to collect data from employees from different public and private sector organizations in Pakistan. The findings show that the relationship between transformational leadership and trust is weaker when followers perceive leaders to be high on masculine and androgynous attributes. Leaders’ femininity was found to have a positive effect in the relationship of transformational leadership with trust in the leader. The paper suggests practical implications and directions for future research

A master equation for strongly interacting dipoles

We consider a pair of dipoles for which direct electrostatic dipole-dipole interactions may be significantly larger than the coupling to transverse radiation. We derive a master equation using the Coulomb gauge, which naturally enables us to include the inter-dipole Coulomb energy within the system Hamiltonian rather than the interaction. In contrast, the standard master equation for a two- dipole system, which depends entirely on well-known gauge-invariant S-matrix elements, is usually derived using the multipolar gauge, wherein there is no explicit inter-dipole Coulomb interaction. We show using a generalised arbitrary-gauge light-matter Hamiltonian that this master equation is obtained in other gauges only if the inter-dipole Coulomb interaction is kept within the interaction Hamiltonian rather than the unperturbed part as in our derivation. Thus, our master equation, while still gauge-invariant, depends on different S-matrix elements, which give separation-dependent corrections to the standard matrix elements describing resonant energy transfer and collective decay. The two master equations coincide in the large separation limit where static couplings are negligible. We provide an application of our master equation by finding separation-dependent corrections to the natural emission spectrum of the two-dipole system.Comment: 18 pages including appendix, 8 figure