Photoemission spectra of massless Dirac fermions on the verge of exciton condensation

Angle-resolved photoemission spectroscopy (ARPES) is a powerful probe of electron correlations in two-dimensional layered materials. In this Letter we demonstrate that ARPES can be used to probe the onset of exciton condensation in spatially-separated systems of electrons and holes created by gating techniques in either double-layer graphene or topological-insulator thin films.Comment: 5 pages, 3 figure

Photon-Mediated Interaction between Two Distant Atoms

We study the photonic interactions between two distant atoms which are coupled by an optical element (a lens or an optical fiber) focussing part of their emitted radiation onto each other. Two regimes are distinguished depending on the ratio between the radiative lifetime of the atomic excited state and the propagation time of a photon between the two atoms. In the two regimes, well below saturation the dynamics exhibit either typical features of a bad resonator, where the atoms act as the mirrors, or typical characteristics of dipole-dipole interaction. We study the coherence properties of the emitted light and show that it carries signatures of the multiple scattering processes between the atoms. The model predictions are compared with the experimental results in J. Eschner {\it et al.}, Nature {\bf 413}, 495 (2001).Comment: 18 pages, 15 figure

Joint versus separate inpatient rehabilitation treatment for patients with alcohol use disorder or drug use disorder : an observational study

Background: In many national treatment systems, patients with alcohol use disorders (AUD) and those with drug use disorders (DUD) are treated separately, while other systems provide joint treatment for both kinds of substance use disorders (SUDs). Regarding long-term rehabilitation treatment of DUD and AUD patients, there is however a lack of empirical studies on the comparison between a separate versus joint treatment modality. Methods: Data were gathered from 2 rehabilitation units located in small towns from the same German region. One unit provided treatment to a mixed group of AUD and DUD patients, while the other unit treated the 2 groups separately. Staffing, funding, and treatment programs were otherwise similar between facilities. Data were gathered from standardized routine documentation and standardized interviews. In order to understand correlates of premature treatment termination, a logistic regression analysis was performed, with treatment modality and type of SUD as main predictors, and a range of patient characteristics as covariates. Results: Patients (N=319) were diagnosed with AUD (48%), DUD (34%), or AUD plus DUD (18%). Patients in joint treatment showed a higher prevalence of lapses during treatment than those in separate treatment (26% versus 12%; p=0.009), but there was no significant difference in the prevalence of premature terminations (38% versus 44%, p=0.26). Treatment modality and interaction between modality and type of SUD was not significantly associated with premature termination. Joint treatment completers showed higher satisfaction with treatment than separate treatment completers ( p<0.001). Conclusion: We found no evidence here for a difference between treatment modalities in terms of premature termination rate. Satisfaction level was higher in those who completed joint treatment compared to separate treatment.Peer reviewe

Photonic spectrum of bichromatic optical lattices

We study the photonic spectrum of a one-dimensional optical lattice possessing a double primitive cell, when the atoms are well localized at the lattice minima. While a one-dimensional lattice with a simple Wigner-Seitz cell always possesses a photonic bandgap at the atomic resonance, in this configuration the photonic transmission spectrum may exhibit none, double or multiple photonic bandgaps depending on the ratio between the interparticle distance $\varrho$ inside the cell and the cell size $a$. The transmission spectra of a weak incident probe are evaluated when the atoms are trapped in free space and inside an optical resonator for realistic experimental parameters.Comment: 10 pages, 10 figures, to appear in PR

Light scattering by ultracold atoms in an optical lattice

We investigate theoretically light scattering of photons by ultracold atoms in an optical lattice in the linear regime. A full quantum theory for the atom-photon interactions is developed as a function of the atomic state in the lattice along the Mott-insulator -- superfluid phase transition, and the photonic scattering cross section is evaluated as a function of the energy and of the direction of emission. The predictions of this theory are compared with the theoretical results of a recent work on Bragg scattering in time-of-flight measurements [A.M. Rey, {\it et al.}, Phys. Rev. A {\bf 72}, 023407 (2005)]. We show that, when performing Bragg spectroscopy with light scattering, the photon recoil gives rise to an additional atomic site to site hopping, which can interfere with ordinary tunneling of matter waves and can significantly affect the photonic scattering cross section.Comment: 13 pages, 6 fig, (accepted in PRA

Percutaneous CT fluoroscopy-guided core biopsy of pancreatic lesions: technical and clinical outcome of 104 procedures during a 10-year period

Background: In unclear pancreatic lesions, a tissue sample can confirm or exclude the suspected diagnosis and help to provide an optimal treatment strategy to each patient. To date only one small study reported on the outcome of computed tomography (CT) fluoroscopy-guided biopsies of the pancreas. Purpose: To evaluate technical success and diagnostic rate of all CT fluoroscopy-guided core biopsies of the pancreas performed in a single university center during a 10-year period. Material and Methods: In this retrospective study we included all patients who underwent a CT fluoroscopy-guided biopsy of a pancreatic mass at our comprehensive cancer center between 2005 and 2014. All interventions were performed under local anesthesia on a 16-row or 128-row CT scanner. Technical success and diagnostic rates as well as complications and effective patient radiation dose were analyzed. Results: One hundred and one patients (54 women;mean age, 63.912.6 years) underwent a total of 104 CT fluoroscopy-guided biopsies of the pancreas. Ninety-eight of 104 interventions (94.2%) could be performed with technical success and at least one tissue sample could be obtained. In 88 of these 98 samples, a definitive pathological diagnosis, consistent with clinical success could be achieved (89.8%). Overall 19 minor and three major complications occurred during the intra- or 30-day post-interventional period and all other interventions could be performed without complications;there was no death attributable to the intervention. Conclusion: CT fluoroscopy-guided biopsy of pancreatic lesions is an effective procedure characterized by a low major complication and a high diagnostic rate

Changes in Memory before and after Stroke Differ by Age and Sex, but Not by Race

Post-stroke memory impairment is more common among older adults, women, and blacks. It is unclear whether post-stroke differences reflect differential effects of stroke per se, or differences in pre-stroke functioning. We compare memory trajectories before and after stroke by age, sex and race