A note on the measurement of phase space observables with an eight-port homodyne detector

It is well known that the Husimi Q-function of the signal field can actually be measured by the eight-port homodyne detection technique, provided that the reference beam (used for homodyne detection) is a very strong coherent field so that it can be treated classically. Using recent rigorous results on the quantum theory of homodyne detection observables, we show that any phase space observable, and not only the Q-function, can be obtained as a high amplitude limit of the signal observable actually measured by an eight-port homodyne detector. The proof of this fact does not involve any classicality assumption.Comment: 8 pages, 1 figur

On the notion of coexistence in quantum mechanics

The notion of coexistence of quantum observables was introduced to describe the possibility of measuring two or more observables together. Here we survey the various different formalisations of this notion and their connections. We review examples illustrating the necessary degrees of unsharpness for two noncommuting observables to be jointly measurable (in one sense of the phrase). We demonstrate the possibility of measuring together (in another sense of the phrase) noncoexistent observables. This leads us to a reconsideration of the connection between joint measurability and noncommutativity of observables and of the statistical and individual aspects of quantum measurements

Making Accessibility Services Accessible Through Implementation of Information and Communication Technology

Post-secondary institutions are facing increased pressure by accessibility legislation, such as the Accessibility for Ontarians with Disabilities Act (AODA), to ensure students with disabilities have equitable access to the academic environment (Flaherty & Roussy, 2014). This Organizational Improvement Plan (OIP) examines the situation regarding the Student Accessibility Office (SAO) in a large Ontario university. Traditionally, student service-based offices like the SAO require an in-person visit to access tools, services and resources. The growth of information and communication technology (ICT) into post- secondary education is increasing accessibility of academic programs (Yamamoto & Yamaguchi, 2019), but not student services. The research Problem of Practice (PoP) for this OIP determines how post-secondary institutions can make student service-based departments more accessible through the implementation of ICT. Using transformational (Bass 1996; Burns, 1978) and distributed leadership (Spillane, 2004) models while viewing the PoP through the social model of disability lens (Oliver, 2013) informs the leadership approach to change. An integrated change model (Cawsey et al., 2016; Beckhard & Harris, 1987) leads the change process. The zone of proximal agency determines that developing an online course for the SAO is the best solution to increase the accessibility of tools, services and resources. The course will be developed in consultation with university stakeholders and adhere to the AODA’s accessibility standards (Flaherty & Roussy, 2014). Future considerations of this OIP are to develop a framework to support the implementation of ICT university wide. Keywords: accessibility, information and communication technology, distance education, AODA, social model of disabilit

On the structure of covariant phase observables

We study the mathematical structure of covariant phase observables. Such an observable can alternatively be expressed as a phase matrix, as a sequence of unit vectors, as a sequence of phase states, or as an equivalent class of covariant trace-preserving operations. Covariant generalized operator measures are defined by structure matrices which form a W*-algebra with phase matrices as its subset. The properties of the Radon-Nikodym derivatives of phase probability measures are studied.Comment: 11 page