Quantum noise in gravitational-wave interferometers: Overview and recent developments

We present an overview of quantum noise in gravitational wave interferometers. Gravitational wave detectors are extensively modified variants of a Michelson interferometer and the quantum noise couplings are strongly influenced by the interferometer configuration. We describe recent developments in the treatment of quantum noise in the complex interferometer configurations of present-day and future gravitational-wave detectors. In addition, we explore prospects for the use of squeezed light in future interferometers, including consideration of the effects of losses, and the choice of optimal readout schemes.Comment: 13 pages, 5 figure

Mathematical framework for simulation of quantum fields in complex interferometers using the two-photon formalism

We present a mathematical framework for simulation of optical fields in complex gravitational-wave interferometers. The simulation framework uses the two-photon formalism for optical fields and includes radiation pressure effects, an important addition required for simulating signal and noise fields in next-generation interferometers with high circulating power. We present a comparison of results from the simulation with analytical calculation and show that accurate agreement is achieved

Quantum noise reduction using a cavity with a Bose Einstein condensate

We study an optomechanical system in which the collective density excitations (Bogoliubov modes) of a Bose Einstein condensate (BEC) is coupled to a cavity field. We show that the optical force changes the frequency and the damping constant of the collective density excitations of the BEC. We further analyze the occurrence of normal mode splitting (NMS) due to mixing of the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction. The NMS is found to vanish for small values of the two-body interaction. We further show that the density excitations of the condensate can be used to squeeze the output quantum fluctuations of the light beam. This system may serve as an optomechanical control of quantum fluctuations using a Bose Einstein condensate.Comment: 8 figure

ICT for eco-sustainability: an assessment of the capability of the Australian ICT sector

Executive summary As eco-sustainability issues become increasingly important to most, if not all, Australian organisations, the Information and Communication Technology (ICT) industry is expected to provide solutions that reduce material consumption (dematerialise), emissions (decarbonise), and energy use and waste production (demobilise) in both the ICT infrastructure and the business processes and practices of industries. The term \u27Green ICT\u27 represents this eco- sustainability enabling role of the ICT industry. The School of Business Information Technology and Logistics, RMIT University in collaboration with the Australian Information Industries Association (AIIA) surveyed all members and affiliates of the AIIA at the beginning of 2010 to understand Australian ICT firms\u27 capability to enhance the eco-sustainability of other industries. Based on data collected from 133 ICT firms, this report constitutes the first comprehensive study that exclusively focuses on the Australian ICT industry

A Stable Optical Trap from a Single Optical Field Utilizing Birefringence

We report a stable double optical spring effect in an optical cavity pumped with a single optical field that arises as a result of birefringence. One end of the cavity is formed by a multilayer Al$_{0.92}$Ga$_{0.08}$As/GaAs stack supported by a microfabricated cantilever, with a natural mode frequency of $274$ Hz. The optical spring shifts the resonance to $21$ kHz, corresponding to a suppression of low frequency vibrations by a factor of more than $10^{4}$. The stable nature of the optical trap allows the cavity to be operated without any external feedback and with only a single optical field incident

The Gut Microbiota and the Liver: Collaborators in Host Immunity and Metabolism

The gut microbiota consists of over one hundred trillion commensal bacteria required for proper gut immunity development. Commensals also augment the host’s ability to extract energy from the diet. Although restricted to the gut lumen by intestinal barrier epithelia, commensals shed microbial associated molecule patterns (MAMPs) into the circulation where they augment aspects of systemic immunity. Commensals also release fermentation byproducts into the portal blood stream. Since the liver receives 80% of its blood via the portal vein and contains a unique repertoire of immune cells particularly enriched in Kupffer Cells (KC) and Natural Killer T cells, we proposed that gut-derived MAMPs contribute to the development of residential hepatic leukocyte subsets. Because of the contributions of gut bacteria to digestion, we suspected that gut bacteria add an additional level of regulation to host metabolism and would generate a specific hepatic metabolic gene profile. Results showed that a cocktail of MAMPs translocate into the portal circulation of normal conventional (CL) mice stimulating KC expansion. ICAM1 expression, thought to be constitutive on sinusoidal endothelium, was significantly reduced without gut bacteria and was required for KC accumulation. The finding that constitutive ICAM1 expression by LSEC was dependent on gut bacteria lead us to investigate if the frequency of intra-hepatic lymphocytes known to bind ICAM1 were affected by gut bacteria. Results showed that intra-hepatic T lymphocyte populations including NKT (TCRβ+NK1.1+) cells and T helper (CD4+TCRβ+) cells were significantly reduced in GF mice and AVMN mice. In addition to the significant cellular composition changes of the liver related to gut bacteria density, notable changes in murine weight and metabolic gene profiles were observed. The average body mass of CL, GF, and AVMN mice was 37.8g, 33.4g, and 34.1g respectively. Our whole-liver gene array analysis included 217 probe sets mapped to 163 differentially expressed genes between groups, of which forty-eight have roles in lipid metabolism. In conclusion, gut bacteria affect both the hepatic metabolic gene profile and the inflammatory potential of the liver. These finding have implications for many hepatic pathologies including obesity, NAFLD, and autoimmune disease like PBC and AIH mediated by liver leukocytes

Perspectives on IT Outsourcing Success: Covariance Structure Modelling of a Survey of Outsourcing in Australia

Australia has been at the forefront of the adoption of outsourcing as a means for delivering IT services, but the success of IT outsourcing in Australia has been mixed. With two hundred and forty one responses from the top 1000 IT users in the country, the survey reported in this paper is one of the largest and most representative IT outsourcing studies in the world. Covariance structure modelling and confirmatory factor analysis has shed new light on the concept of outsourcing success, highlighting its complex, multidimensional nature. It has also confirmed many insights gained to date from qualitative research. Analysis also emphasises the importance to the outsourcing relationship of the management processes adopted by the client organization. L'Australie a été un pionnier dans l'adoption de l'impartition pour les services informatiques. Toutefois, les résultats ont été mitigés. Avec plus de deux cent répondants, provenant des 1000 plus grandes entreprises australiennes, cette étude et une des plus larges et représentatives faites jusqu'à0501ntenant. Une analyse des structure de co-variance, de même qu'une anlayse factorielle confirmatoire jettent un regard neuf sur la notion de succès de l'impartition. L'étude met en lumière le caractère complexe et multi-dimensionel de ce succès.Outsourcing, Australia, survey research, success, information systems, Impartition, Australie, enquête, succès, services informatiques

Antibacterial activity of conjugated electrolytes

A series of water soluble, cationic, anionic and zwitterionic conjugated polyelectrolytes (CPEs) with main chains based on an arylene ethynylene repeat unit structure with tetraalkylammonium and/or alkylsulfonate side groups were found to exhibit significant antibacterial activity. A number of these complexes also showed pronounced light-induced modulation of their effectiveness, with either biocidal enhancement or suppression, depending on such properties as singlet oxygen sensitization potential and lipophilicity. These collected studies examine the biocidal activity of the CPEs, as determined by Confocal Laser Scanning Microscopy (CLSM) and Flow Cytometry, correlating this activity with the photophysical properties of the polymers. We demonstrate biocidal activity, both in solution and immobilized, of similar ionic conjugated polyelectrolytes. These polymers were tested and shown to be effective in solution, physisorbed or surface grafted on non-porous borosilicate microspheres and grafted on fabrics. Also, studies with templated hollow spheres formed from polymer multilayers show considerable bacterial sequestration and significant biocidal activity, especially upon light exposure. The effective killing of Cobetia marina, Pseudomonas aeruginosa and Bacillus atrophaeus in these systems is also correlated with a requirement for oxygen suggesting that interfacial generation of singlet oxygen is the crucial step in the light-induced biocidal activity. This document begins with an introduction to the problem, including a review of literature. This is followed by an experimental section describing in detail the selection, growth and harvesting parameters for the bacteria and a summary of substrate preparation protocols. A number of biocidal experiments using a variety of compounds and substrates and evaluated with confocal microscopy and flow cytometry are then covered, followed by conclusions and future directions