Measurement back-action on the quantum spin-mixing dynamics of a spin-1 Bose-Einstein condensate

We consider a small F=1 spinor condensate inside an optical cavity driven by an optical probe field, and subject the output of the probe to a homodyne detection, with the goal of investigating the effect of measurement back-action on the spin dynamics of the condensate. Using the stochastic master equation approach, we show that the effect of back-action is sensitive to not only the measurement strength but also the quantum fluctuation of the spinor condensate. The same method is also used to estimate the atom numbers below which the effect of back-action becomes so prominent that extracting spin dynamics from this cavity-based detection scheme is no longer practical

Light scattering detection of quantum phases of ultracold atoms in optical lattices

Ultracold atoms loaded on optical lattices can provide unprecedented experimental systems for the quantum simulations and manipulations of many quantum phases. However, so far, how to detect these quantum phases effectively remains an outstanding challenge. Here, we show that the optical Bragg scattering of cold atoms loaded on optical lattices can be used to detect many quantum phases which include not only the conventional superfluid and Mott insulating phases, but also other important phases such as various kinds of density waves (CDW), valence bond solids (VBS), CDW supersolids and VBS supersolids.Comment: 4 pages, 3 colour figures, to appear in Phys. Rev. A, Rapid Communicatio

Compactness of the space of causal curves

We prove that the space of causal curves between compact subsets of a separable globally hyperbolic poset is itself compact in the Vietoris topology. Although this result implies the usual result in general relativity, its proof does not require the use of geometry or differentiable structure.Comment: 15 page

Choroidal ischemia as one cardinal sign in giant cell arteritis

Purpose: To describe chorioretinal signs in a case series of Giant Cell Arteritis (GCA). Methods: This is a multicenter retrospective observational case series with GCA that presented with a headache and an abrupt, unilateral loss in vision. Workup included temporal artery biopsies, intravenous fluorescein angiography, optical coherence tomography (OCT), optical coherence tomography angiography (OCTA), blood levels of erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Results: There are a total of 8 GCA instances presented. Average age was 74.5. (Range 68–83 years). The patients reported that one eye's visual loss had suddenly started, along with a fresh headache and other systemic symptoms. Eight patients exhibited choroidal ischemia, five paracentral acute middle maculopathy (PAMM) lesions, five cotton wool spots, four anterior ischemic optic neuropathy, and one central retinal arterial occlusion at the time of presentation. The average ESR at presentation was 68 mm/hr (range 4–110), and 4/6 individuals had a significant increase. The mean CRP level was 6.2 mg/dL (range 2.0–15.4), and the level was always over the normal range. All patients' temporal artery biopsies were positive. Conclusion: Alongside PAMM lesions, cotton wool spots, anterior ischemic optic neuropathy, and central retinal artery occlusion, choroidal ischemia is a key angiographic indicator in the diagnosis of GCA. It may be crucial to recognize these typical ischemic chorioretinal signs while diagnosing GCA. © 2022, The Author(s)

10232 Report -- The Semantics of Information

The Dagstuhl Seminar 10232, "Semantics of Information" was devoted to talks by researchers in a wide range of disciplines: mathematics, computer science, systems biology, physics, and economic gam theory, all of which explored the relationship of computer science and its theory to their area