Two-mode state reconstruction using photon chopping

Abstract

The reconstruction of the complete quantum state of a pure-state two-mode field is shown to be possible by the photon-chopping method, that is, by spreading the signal with balanced multiports over an array of detectors and by measuring coincidences. In particular, correlations between the two modes can be detected with high efficiency.     

Investigating public health impacts of deer in a protected drinking water supply watershed

The World Health Organisation's (WHO) Water Safety Plans highlight the need for preventative risk management when managing water contamination risks. As part of this approach, a management framework incorporating multiple barriers is necessary and there is a need to validate those barriers through scientific evidence. This paper reports on a study undertaken to validate the effectiveness, in terms of pathogen numbers, of having protected watersheds. The study aimed to determine if the deer population in a protected watershed carried Cryptosporidium and whether or not it was human infectious. Deer faecal samples were collected from the protected watersheds over a 12 month period and analysed using a new method, developed as part of this project, for genotyping Cryptosporidium. Early results showed the presence of Cryptosporidium, but following a refinement in the method no human infectious Cryptosporidium was detected. The results give some confidence that having protected watersheds is an effective barrier against pathogen contamination. They do not, however, imply that continued monitoring and management of the deer should cease. To maintain compliance with the Water Safety Plans, continual validation of barrier effectiveness is required.     

Emission Spectra of a Two-level Atom in a Kerr-like Medium

Abstract

We have investigated the spectrum of light emitted by a single atom interacting with a single mode of the radiation field in an ideal cavity filled with a Kerr-like medium. It is shown that owing to the Kerr-like nonlinearity in the system the spectrum of the emitted light exhibits a single-peaked structure for sufficiently high intensities of the initial coherent field instead of the triplet structure in the case of the standard Jaynes-Cummings model.     

Interference of composite bosons

We investigate multi-boson interference. A Hamiltonian is presented that treats pairs of bosons as a single composite boson. This Hamiltonian allows two pairs of bosons to interact as if they were two single composite bosons. We show that this leads to the composite bosons exhibiting novel interference effects, such as Hong–Ou–Mandel interference. We then investigate generalisations of the formalism to the case of interference between two general composite bosons. Finally, we show how one can realise interference between composite bosons in the two-atom Dicke model.     

Work-home boundary management using communication and information technology.

Contemporary workers heavily use communication/information technologies (CIT; e.g., e-mails, mobile phones) at work and home. However, little research has investigated the effects of CIT use on work-family interference. Based on boundary theory, the present study focuses on employees' boundary creation around CIT use as a potential means to reduce psychological work-family interference. Hierarchical regression analyses based on the data from 281 office workers supported the mediation models where boundary creation around CIT use mediated the relationships between individual factors and psychological work-family interference. The findings suggested that maintaining impermeable work and home domains by creating more boundaries around CIT use for cross-role enactment can be beneficial for employees' psychological work-family interference. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The impact of self-efficacy on stressor–strain relations: Coping style as an explanatory mechanism.

The present study was designed to examine whether coping style influences the impact of self-efficacy on stressor–strain relations. It was hypothesized that high self-efficacy would weaken stressor–strain relations when accompanied by frequent use of active coping and infrequent use of avoidance coping. Data collected from 2,293 members of the U.S. Army revealed 3-way interactions among self-efficacy, role clarity, and active coping and among self-efficacy, work overload, and avoidance coping. As predicted, self-efficacy mitigated the effects of low role clarity on strain only when active coping was high. Also as expected, strain levels were lower for participants with high self-efficacy than for participants with lower self-efficacy when work overload was low but avoidance coping was high. Implications of these findings for occupational stress research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of unitary transforms using Franson interferometry

Unknown unitary transforms may be compared to each other in a way which makes it possible to obtain an unambiguous answer, indicating that the transforms are different, already after a single application of each transform. Quantum comparison strategies may be useful for example if we want to test the performance of individual gates in a quantum information or quantum computing network. It is then possible to check for errors by comparing the elements to a master copy of the gate, instead of performing a complete tomography of the gate. In this paper we propose a versatile linear optical implementation based on the Franson interferometer with short and long arms. A click in the wrong output port unambiguously determines that the tested gate is faulty. This set-up can also be used for a variety of other tasks, such as confirming that the two transforms do not commute or do not anticommute.