Three-body recombination at vanishing scattering lengths in an ultracold Bose gas

We report on measurements of three-body recombination rates in an ultracold gas of $^7$Li atoms in the extremely nonuniversal regime where the two-body scattering length vanishes. We show that the rate is well defined and can be described by two-body parameters only: the scattering length $a$ and the effective range $R_e$. We find the rate to be energy independent, and, by connecting our results with previously reported measurements in the universal limit, we cover the behavior of the three-body recombination in the whole range from weak to strong two-body interactions. We identify a nontrivial magnetic field value in the nonuniversal regime where the rate should be strongly reduced.Comment: Version with enhanced supplemental material

Nuclear-spin-independent short-range three-body physics in ultracold atoms

We investigate three-body recombination loss across a Feshbach resonance in a gas of ultracold 7Li atoms prepared in the absolute ground state and perform a comparison with previously reported results of a different nuclear-spin state [N. Gross et.al., Phys. Rev. Lett. 103 163202, (2009)]. We extend the previously reported universality in three-body recombination loss across a Feshbach resonance to the absolute ground state. We show that the positions and widths of recombination minima and Efimov resonances are identical for both states which indicates that the short-range physics is nuclear-spin independent.Comment: 4 pages, 2 figure

Calcium channel blockers in heart failure

AbstractThe rationale for the use of calcium enamel bleckers in patients with chronic heart failure lies in their vasodilator action, antiischemic effect, ability to lessen left ventricular diastole dysfunction and data showing their effect in preventing progression of myocardiai dysfunction in animals with cardiomyopathy. Despite initial studies reporting improvement of the hemodynamic profile with nifedipine, further evaluation showed variable results, with hemodynamic worsening seen in up to 29% of patients. Longer-term controued studies evaluating Symptoms and clinical status demonstrated worsening chronic heart failure in ~25% of patients within 8 weeks of nifedipine therapy. Although diltiazem has a lesser myo cardial depresseset effect and its short-term use was associated with less frequent hemodynamic and clinical worsening, long-tern exposure te the drug in a large group of paients with chronic heart failure due to left ventricular systolic dysfunction after myocardial infarction resulted in an increased incidence of cardiac events, with worsening heart failure and death. The use of verapamil in a simiar patient cohort showed the loss of its demostrated protective effect in patients with clinical evidence of heart failure.In an attempt to improve the safety of calcium channel blockers, the following approaches were suggested 1) use of second-generation drugs with less myocardial depressant effect; 2) concomitant use of angiotensin-converting enzyme inhibitors to prevent reported neurohormonal activation; and 3) development of drugs with favorable neurohormonal effects. These approaches led to mixed results. The use of some second-generation calcium channel blockers such as nisoldipine, felodipine and nicardipine resulted in no change or worsening of clinical status, which did not seem to be prevented by concomitant use of angiotensin-converting enzyme inhibitors. A recent study using amlodipine demonstrated improvement of both the clinical and neurohormonal profiles. Two large ongoing studies are evaluating the effects of felodipine and amlodipine on morbidity and mortality of patients with chronic heart failure and are likely to provide further information regarding the role of calcium blockers in the treatment of this condition

Observation of universality in ultracold 7Li three-body recombination

We report on experimental evidence of universality in ultracold 7Li atoms' three-body recombination loss in the vicinity of a Feshbach resonance. We observe a recombination minimum and an Efimov resonance in regions of positive and negative scattering lengths, respectively, which are connected through the pole of the Feshbach resonance. Both observed features lie deeply within the range of validity of the universal theory and we find that the relations between their properties, i.e. widths and locations, are in an excellent agreement with the theoretical predictions.Comment: 5 pages, 2 figure