Spatial entanglement patterns and Einstein-Podolsky-Rosen steering in a Bose-Einstein condensate

Many-particle entanglement is a fundamental concept of quantum physics that still presents conceptual challenges. While spin-squeezed and other nonclassical states of atomic ensembles were used to enhance measurement precision in quantum metrology, the notion of entanglement in these systems remained controversial because the correlations between the indistinguishable atoms were witnessed by collective measurements only. Here we use highresolution imaging to directly measure the spin correlations between spatially separated parts of a spin-squeezed Bose-Einstein condensate. We observe entanglement that is strong enough for Einstein-Podolsky-Rosen steering: we can predict measurement outcomes for non-commuting observables in one spatial region based on a corresponding measurement in another region with an inferred uncertainty product below the Heisenberg relation. This could be exploited for entanglement-enhanced imaging of electromagnetic field distributions and quantum information tasks beyond metrology

Gaussian Boson Sampling using threshold detectors

We study what is arguably the most experimentally appealing Boson Sampling architecture: Gaussian states sampled with threshold detectors. We show that in this setting, the probability of observing a given outcome is related to a matrix function that we name the Torontonian, which plays an analogous role to the permanent or the Hafnian in other models. We also prove that, provided that the probability of observing two or more photons in a single output mode is sufficiently small, our model remains intractable to simulate classically under standard complexity-theoretic conjectures. Finally, we leverage the mathematical simplicity of the model to introduce a physically motivated, exact sampling algorithm for all Boson Sampling models that employ Gaussian states and threshold detectors.Comment: 5+5 pages, 2 figures. Closer to published versio

Sex, Soap and Silk: Japanese Businesswomen in North Queensland, 1887–1941

Few historians have considered Japanese women in northern Australia beyond their role as impoverished sex workers, overlooking their entrepreneurial activities in the sex industry as well as in laundries and shops. This article adds to research by Su-Jane Hunt (1977) and Yuriko Nagata (2004) about Japanese women who were entrepreneurs and community members in Western Australia and the Torres Strait, incorporating more detail about their business activities throughout north Queensland, both within the sex industry and outside it. A mosaic of newly accessible documentary sources—including newspaper, immigration and internment records—provides the foundation for a more complex history of Japanese women and their roles in the economic life of north Queensland between 1887 and 1941. This material reveals that Japanese women worked in partnership with their husbands, or sometimes as sole operators, to manage and run businesses such as brothels, laundries, stores and even cafes. Not all Japanese women were in business, but discussing those who undertook business activities invites us to cast aside the ‘moral suspicion’ that has loomed over these women’s stories. The reality of their lives was far more interesting

Visible participation: Japanese migrants in north Queensland, 1880–1941

Between 1880 and 1941, many Japanese migrants arrived in north Queensland and became active participants in their communities. Despite arriving during an era where a White Australia was broadly envisioned, these migrants formed lasting connections within the unique geographical and cultural climate of north Queensland. Government records and newspapers archives reveal these individuals’ positive contributions to the region through business, civic engagement, and social events. This article focuses on Japanese migrant families’ economic, civic, and social contributions to north Queensland communities to highlight the longevity and depth of their connections within the history of northern Australia

Open for Climate Justice

This is the winning entry in James Cook University's 2022 HDR Open Access Advocate Competition. The competition was open to all JCU Higher Degree by Research (HDR) candidates, with a prize awarded for the best short communication that answered the question: How does Open Access help the cause of climate justice