Cram\'er-Rao bound for time-continuous measurements in linear Gaussian quantum systems

We describe a compact and reliable method to calculate the Fisher information for the estimation of a dynamical parameter in a continuously measured linear Gaussian quantum system. Unlike previous methods in the literature, which involve the numerical integration of a stochastic master equation for the corresponding density operator in a Hilbert space of infinite dimension, the formulas here derived depends only on the evolution of first and second moments of the quantum states, and thus can be easily evaluated without the need of any approximation. We also present some basic but physically meaningful examples where this result is exploited, calculating analytical and numerical bounds on the estimation of the squeezing parameter for a quantum parametric amplifier, and of a constant force acting on a mechanical oscillator in a standard optomechanical scenario.Comment: 9 pages, 2 figure

Continuous-variable entanglement distillation and non-commutative central limit theorems

Entanglement distillation transforms weakly entangled noisy states into highly entangled states, a primitive to be used in quantum repeater schemes and other protocols designed for quantum communication and key distribution. In this work, we present a comprehensive framework for continuous-variable entanglement distillation schemes that convert noisy non-Gaussian states into Gaussian ones in many iterations of the protocol. Instances of these protocols include (a) the recursive-Gaussifier protocol, (b) the temporally-reordered recursive-Gaussifier protocol, and (c) the pumping-Gaussifier protocol. The flexibility of these protocols give rise to several beneficial trade-offs related to success probabilities or memory requirements, which that can be adjusted to reflect experimental demands. Despite these protocols involving measurements, we relate the convergence in this protocols to new instances of non-commutative central limit theorems, in a formalism that we lay out in great detail. Implications of the findings for quantum repeater schemes are discussed.Comment: published versio

The global reception of post-national literary fiction: the case of Gerald Murnane

This paper considers the situation of the changing global market for Australian literary fiction. In particular it uses the case of Gerld Murnane to examine ways in which these changes might be beneficial to at least some authors as we enter an era of 'post-national' literary fiction.The paper traces the international reception of Murnane's fiction and the subsequently the development of his global reputation. It incorporates Murnane's own observations (drawn from personal correspondence with the author) and suggests that although it has been argued that the impacts of globalisation will be detrimental for Australian literary fiction, there may also be some reasons for optimism

Juliana de Nooy. What’s France Got to Do with It?: Contemporary Memoirs of Australians in France.

Revie

Libraries, the Long Tail and the Future of Legacy Print Collections

Chris Anderson's concept of the 'long tail has evoked considerable interest and discussion from librarians. To date these discussions have largely accepted without question the veracity of Anderson's model and its applicability to library collections. The purpose of this article is to examine some elements of the model in order to firstly, determine if it can indeed be simply adopted for use when describing the library collecting environment; and secondly, if there is some divergence, what does this tell us about the future management of print collections