A Feshbach engine in the Thomas-Fermi regime

Bose-Einstein condensates can be used to produce work by tuning the strength of the interparticle interactions with the help of Feshbach resonances. In inhomogeneous potentials, these interaction ramps change the volume of the trapped gas allowing one to create a thermodynamic cycle known as the Feshbach engine. However, in order to obtain a large power output, the engine strokes must be performed on a short timescale, which is in contrast with the fact that the efficiency of the engine is reduced by irreversible work if the strokes are done in a non-adiabatic fashion. Here we investigate how such an engine can be run in the Thomas-Fermi regime and present a shortcut to adiabaticity that minimizes the irreversible work and allows for efficient engine operation.Comment: 8 pages, 7 figure

Fermionization of a Few-Body Bose System Immersed into a Bose-Einstein Condensate

We study the recently introduced self-pinning transition [Phys. Rev. Lett. 128, 053401 (2022)] in a quasi-one-dimensional two-component quantum gas in the case where the component immersed into the Bose-Einstein condensate has a finite intraspecies interaction strength. As a result of the matter-wave backaction, the fermionization in the limit of infinite intraspecies repulsion occurs via a first-order phase transition to the self-pinned state, which is in contrast to the asymptotic behavior in static trapping potentials. The system also exhibits an additional superfluid state for the immersed component if the interspecies interaction is able to overcome the intraspecies repulsion. We approximate the superfluid state in an analytical model and derive an expression for the phase transition line that coincides with well-known phase separation criteria in binary Bose systems. The full phase diagram of the system is mapped out numerically for the case of two and three atoms in the immersed component.Comment: 13 pages, 4 figure

Technology-Mediated Learning for Resilience

Resilience is a topic of steadily increasing interest. It particularly gains importance when discussing how communities (e.g. municipalities) can prepare themselves for potential future disruptions. A resilient community will overcome immediate shocks, such as an earthquake, as well as stresses, such as the successive outbreak of a pandemic. Due to the novelty of the topic, research particularly exists on theoretical aspects of resilience. Targeting learning - and thereby the local population - is a rather new emergence. To effectively reach, involve, and engage citizens, technology can play a key role. Based on four actual cases from communities we analyse the impact technology has on learning about resilience. We then scrutinize the effectiveness and propose future steps. Thereby, we seek to provide practical advice to local governments and to enrich the theory at the same time

Direct observation of the particle exchange phase of photons

Quantum theory stipulates that if two particles are identical in all physical aspects, the allowed states of the system are either symmetric or antisymmetric with respect to permutations of the particle labels. Experimentally, the symmetry of the states can be inferred indirectly from the fact that neglecting the correct exchange symmetry in the theoretical analysis leads to dramatic discrepancies with the observations. The only way to directly unveil the symmetry of the states for, say, two identical particles is through the interference of the original state and the physically permuted one, and measure the phase associated with the permutation process, the so-called particle exchange phase. Following this idea, we have measured the exchange phase of indistinguishable photons, providing direct evidence of the bosonic character of photons.Comment: 16 pages, 7 figure

Strong Lensing Model of SPT-CLJ0356-5337, a Major Merger Candidate at Redshift 1.0359

We present an analysis of the mass distribution inferred from strong lensing by SPT-CL J0356-5337, a cluster of galaxies at redshift z = 1.0359 revealed in the follow-up of the SPT-SZ clusters. The cluster has an Einstein radius of Erad=14 for a source at z = 3 and a mass within 500 kpc of M_500kpc = 4.0+-0.8x10^14Msol. Our spectroscopic identification of three multiply-imaged systems (z = 2.363, z = 2.364, and z = 3.048), combined with HST F606W-band imaging allows us to build a strong lensing model for this cluster with an rms of <0.3'' between the predicted and measured positions of the multiple images. Our modeling reveals a two-component mass distribution in the cluster. One mass component is dominated by the brightest cluster galaxy and the other component, separated by ~170 kpc, contains a group of eight red elliptical galaxies confined in a ~9'' (~70 kpc) diameter circle. We estimate the mass ratio between the two components to be between 1:1.25 and 1:1.58. In addition, spectroscopic data reveal that these two near-equal mass cores have only a small velocity difference of 300 km/s between the two components. This small radial velocity difference suggests that most of the relative velocity takes place in the plane of the sky, and implies that SPT-CL J0356-5337 is a major merger with a small impact parameter seen face-on. We also assess the relative contributions of galaxy-scale halos to the overall mass of the core of the cluster and find that within 800 kpc from the brightest cluster galaxy about 27% of the total mass can be attributed to visible and dark matter associated with galaxies, whereas only 73% of the total mass in the core comes from cluster-scale dark matter halos.Comment: 19 pages, 11 figures. Submitted to Ap

Modelling of long-term along-fault flow of CO2 from a natural reservoir

Geological sequestration of CO2 requires the presence of at least one competent seal above the storage reservoir to ensure containment of the stored CO2. Most of the considered storage sites are overlain by low-permeability evaporites or mudrocks that form competent seals in the absence of defects. Potential defects are formed by man-made well penetrations (necessary for exploration and appraisal, and injection) as well as (for mudrocks) natural or injection-induced fracture systems through the caprock. These defects need to be de-risked during site selection and characterisation. A European ACT-sponsored research consortium, DETECT, developed an integrated characterisation and risk assessment toolkit for natural fault/fracture pathways. In this paper we describe the DETECT experimental-modelling workflow, which aims to be predictive for fault-related leakage quantification, and its application to a field case example for validation. The workflow combines laboratory experiments to obtain single-fracture stress-sensitive permeabilities; single-fracture modelling for stress-sensitive relative permeabilities and capillary pressures; fracture network characterisation and modelling for the caprock(s); upscaling of properties and constitutive functions in fracture networks; and full compositional flow modelling at field scale. We focus the paper on the application of the workflow to the Green River Site in Utah. This is a rare case of leakage from a natural CO2 reservoir, where CO2 (dissolved or gaseous) migrates along two fault zones to the surface. This site provides a unique opportunity to understand CO2 leakage mechanisms and volumes along faults, because of its extensive characterisation including a large dataset of present-day CO2 surface flux measurements as well as historical records of CO2 leakage in the form of travertine mounds. When applied to this site, our methodology predicts leakage locations accurately and, within an order of magnitude, leakage rates correctly without extensive history matching. Subsequent history matching achieves accurate leak rate matches within a-priori uncertainty ranges for model input parameters

Service provision and barriers to care for homeless people with mental health problems across 14 European capital cities

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Time-Space Clustering of Human Brucellosis, California, 1973–1992 1

Infection with Brucella spp. continues to pose a human health risk in California despite great strides in eradicating the disease from domestic animals. Clustering of human cases in time and space has important public health implications for understanding risk factors and sources of infection. Temporal-spatial clustering of human brucellosis in California for the 20-year period 1973–1992 was evaluated by the Ederer-Myers-Mantel, Moran’s I, and population-adjusted Moran’s I procedures. Cases were clustered in concentrated agricultural regions in the first 5-year interval (1973–1977). Time-space clustering of human brucellosis cases in California late in the 20-year study period may reflect the distribution of Hispanic populations. Public health programs in California should focus on educating Hispanic populations about the risk of consuming dairy products, such as soft cheeses, made from unpasteurized milk

The ocean sampling day consortium.

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world's oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

Prior consumption of a fat meal in healthy adults modulates the brain’s response to fat

Background: Consumption of fat is regulated by reward and homeostatic pathways, but no studies have examined the role of the intake of a high fat meal (HFM) on subsequent brain activation to oral stimuli. Objective: We evaluated how prior consumption of a HFM or water load (WL) modulates reward, homeostatic and taste brain responses to subsequent delivery of oral fat. Methods: A randomized 2-way crossover design (1-week apart) was used to compare prior consumption of a 250mL HFM (520kcal) (rapeseed oil (440kcal), emulsifier, sucrose, flavor cocktail) or non-caloric WL on brain activation to the delivery of repeated trials of an oral flavored no-fat control stimulus (CS) or flavored fat stimulus (FS) in 17 healthy adults (11 male, age=25±2 years, BMI=22.4±0.8kg/m2). Analyses tested differences in brain activation to the CS and FS, and baseline cerebral blood flow (CBF), following the HFM and WL. Individual’s plasma cholecystokinin (CCK) concentration following the HFM was correlated with their BOLD activation. Results: Prior consumption of the HFM compared to the WL led to decreased anterior insula taste activation in response to both the CS (36.3%,P<0.05) and FS (26.5%,P<0.05). The HFM caused reduced amygdala activation (25.1%,P<0.01) in response to the FS compared to the CS (fat-related satiety). Baseline CBF significantly reduced in taste (insula (5.7%,P<0.01)), homeostatic (hypothalamus (9.2%,P<0.01), thalamus (5.1%,P<0.05))), and reward areas (striatum (9.2%,P<0.01)) following the HFM. Individual’s plasma CCK concentration negatively correlated with brain activation in taste, oral somatosensory and reward areas. Conclusions: To reduce obesity, policy in industry is to lower the fat content of foods. Our results in healthy adults show that a HFM suppresses BOLD activation in taste and reward areas compared to a WL. This understanding will help inform the reformulation of reduced-fat foods that mimic the brain’s response to high fat counterparts, and guide future interventions to reduce obesity