The fraction of Bose-Einstein condensed triplons in TlCuCl3 from magnetization M(T,H)-data

In this study we calculate the fraction of condensed magnetic quasiparticles of TlCuCl3 from magnetization M(T,H)-data. It is independent of the direction of the magnetic field and slightly decreases with increasing magnetic field.Comment: 8 pages, 10 figure

Experimental tests for macroscopic phase coherence in magnetic-quasiparticle condensates of insulating spin systems

For most kinds of already known Bose-Einstein condensates experimental evidence for the existence of a macroscopic coherent quantum state has been provided, e.g., from the observation of interference phenomena, the formation vortices, the detection of Josephson effects, or even by the manifestation of superfluid behaviour. However, none of these hallmarks for a true, macroscopic phase-coherent state has ever been reported for any insulating spin system in a solid in which magnetic bosonic quasiparticles are thought to condense close to a quantum critical point. We describe an attempt to detect superfluid behaviour in TlCuCl3, and discuss in more detail a proposal for an experiment in which the a.c. Josephson effect can be probed by using a device composed of two weakly coupled magnetic insulators with different critical fields. We conclude that the detection of the a.c. Josephson effect is feasible for a proper choice of compounds with realistic material parameters.Comment: 6 pages, 2 figure

The effects of disorder in dimerized quantum magnets in mean field approximations

We study theoretically the effects of disorder on Bose-Einstein condensates (BEC) of bosonic triplon quasiparticles in doped dimerized quantum magnets. The condensation occurs in a strong enough magnetic field Hc, where the concentration of bosons in the random potential is sufficient to form the condensate. The effect of doping is partly modeled by delta - correlated disorder potential, which (i) leads to the uniform renormalization of the system parameters and (ii) produces disorder in the system with renormalized parameters. These approaches can explain qualitatively the available magnetization data in the Tl_(1-x)K_(x)CuCl_3 compound taken as an example. In addition to the magnetization, we found that the speed of the Bogoliubov mode has a peak as a function of doping parameter, x. No evidence of the pure Bose glass phase has been obtained in the BEC regime.Comment: Includes 19 pages, 5 figure

LaBaNiO4: a fermi glass

Polycrystalline samples of LaSr1–xBaxNiO4 show a crossover from a state with metallic transport properties for x = 0 to an insulating state as € x →1. The end member LaBaNiO4 with a nominal nickel Ni 3d7 configuration might therefore be regarded as a candidate for an antiferromagnetic insulator. However, we do not observe any magnetic ordering in LaBaNiO4 down to 1.5 K, and despite its insulating transport properties several other physical properties of LaBaNiO4 resemble those of metallic LaSrNiO4. Based on an analysis of electrical and thermal-conductivity data as well as magneticsusceptibility and low-temperature specific-heat measurements we suggest that LaBaNiO4 is a Fermi glass with a finite electron density of states at the Fermi level but these states are localize

Peripheral venous catheter fracture with embolism into the pulmonary artery

Peripheral vein catheterization is generally considered a harmless procedure. Venous catheter rupture associated with pulmonary embolism is an unlikely but potentially serious complication. We report a case of a peripheral venous catheter (PVC) fracture with pulmonary artery embolization in the left lower lobe treated successfully by a surgical approach. The positioning of a PVC is not always a harmless procedure. Every time there are difficulties in positioning or in removal of a catheter device, it should be carefully inspected to verify integrity. The advisability of removal of these small foreign bodies is debated; percutaneous retrieval is preferred, while surgery should be discussed case by case

Cardiac mesothelial/monocytic-incidental-excrescence: More than an artifactual lesion?

Mesothelial/monocytic incidental cardiac excrescence (MICE) is a benign finding made up of a mixture of cuboidal mesothelial cells, histiocytes and fibrine and is mainly found incidentally during open heart surgery, commonly after cardiac catheterization. Clinical importance of this lesion has been emphasized because of its potential confusion with malignancies, especially with metastatic carcinoma. We report a case of an asymptomatic 72-year-old man with incidental finding of a pericardial effusion and a small mass attached to the left appendage. \ua9 2008 Published by European Association for Cardio-Thoracic Surgery. All rights reserved

Papillary fibroelastoma of the aortic valve: incidental finding with intraoperative transesophageal echocardiography.

Papillary fibroelastoma is a benign but rare tumor of the heart, usually derived from the endocardium. Although rarely clinically symptomatic, fibroelastoma has a potential for valvular dysfunction and systemic embolization. In this article, we show the images of a previously undiagnosed mass that was surgically excised in a 73-year-old woman. \ua9 2007 Elsevier Inc. All rights reserved