We report on the realization of long-range Ising interactions in a cold gas of cesium atoms by Rydberg dressing. The interactions are enhanced by coupling to Rydberg states in the vicinity of a Förster resonance. We characterize the interactions by measuring the mean-field shift of the clock transition via Ramsey spectroscopy, observing one-axis twisting dynamics. We furthermore emulate a transverse-field Ising model by periodic application of a microwave field and detect dynamical signatures of the paramagnetic-ferromagnetic phase transition. Our results highlight the power of optical addressing for achieving local and dynamical control of interactions, enabling prospects ranging from investigating Floquet quantum criticality to producing tunable-range spin squeezing.

We showed that the melatonin receptor subtype, MT1, is expressed in healthy and diseased human coronary arteries. As studies in experimental animals suggest that the MT2 melatonin receptor subtype is also present in the vasculature, we investigated whether the MT2 is expressed in human aorta and coronary arteries. Additionally, MT2 expression in human ventricular specimens was analysed, as melatonin was shown to affect myocyte function. Expression of the MT2-receptor was studied in sections of isolated coronary arteries, aorta and left ventricular specimens from healthy heart donors (control) and patients with dilated or ischemic cardiomyopathy. MT2 expression was found by reverse transcriptase (RT)-nested-polymerase chain reaction (PCR) in all of the specimens (aorta, left ventricle and coronary arteries) derived from controls. Also, visible evidence for receptor expression was found in 12 of 15 samples from cardiomyopathy patients and 10 of 15 of coronary heart disease patients. Additionally, the expression of MT2-receptor between aorta, left ventricle and coronary arteries varied among the individuals, some of them showing highest expression in the aorta while in others principal expression sites were coronary arteries or left ventricles. In conclusion, the MT2-receptor subtype is present in human arteries and left ventricles and it is suggested that in coronary heart disease MT2-receptor expression is altered. Furthermore, there is evidence for heterogeneous MT2 expression patterns in individual patients.

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We report on the creation of an array of spin-squeezed ensembles of cesium atoms via Rydberg dressing, a technique that offers optical control over local interactions between neutral atoms. We optimize the coherence of the interactions by a stroboscopic dressing sequence that suppresses super-Poissonian loss. We thereby prepare squeezed states of N = 200 atoms with a metrological squeezing parameter ξ 2 = 0.77(9) quantifying the reduction in phase variance below the standard quantum limit. We realize metrological gain across three spatially separated ensembles in parallel, with the strength of squeezing controlled by the local intensity of the dressing light. Our method can be applied to enhance the precision of tests of fundamental physics based on arrays of atomic clocks and to enable quantum-enhanced imaging of electromagnetic fields.