Effect of dephasing on the current statistics of mesoscopic devices

We investigate the effects of dephasing on the current statistics of mesoscopic conductors with a recently developed statistical model, focusing in particular on mesoscopic cavities and Aharonov-Bohm rings. For such devices, we analyze the influence of an arbitrary degree of decoherence on the cumulants of the current. We recover known results for the limiting cases of fully coherent and totally incoherent transport and are able to obtain detailed information on the intermediate regime of partial coherence for a varying number of open channels. We show that dephasing affects the average current, shot noise, and higher order cumulants in a quantitatively and qualitatively similar way, and that consequently shot noise or higher order cumulants of the current do not provide information on decoherence additional or complementary to what can be already obtained from the average current.Comment: 4 pages, 4 figure

Acute respiratory distress syndrome in an uromastyx (uromastyx acanthinura nigriventris, 1820)

This article describes a case of acute respiratory distress syndrome (ARDS) in a 3-year-old Uromastyx acanthinura gravinensis. The lizard was presented to the veterinary hospital with an 8-day history of respiratory distress. After the initial physical examination, the patient was treated for the respiratory condition for three weeks and subsequently discharged. The bearded dragon died two weeks following release from the veterinary hospital, after an episode of acute dyspnea. Acute respiratory syndrome was diagnosed following histological examination of submitted tissue samples. The authors believe the condition was caused by possible environmental exposure to volatile organic compounds

Statistical model of dephasing in mesoscopic devices introduced in the scattering matrix formalism

We propose a phenomenological model of dephasing in mesoscopic transport, based on the introduction of random phase fluctuations in the computation of the scattering matrix of the system. A Monte Carlo averaging procedure allows us to extract electrical and microscopic device properties. We show that, in this picture, scattering matrix properties enforced by current conservation and time reversal invariance still hold. In order to assess the validity of the proposed approach, we present simulations of conductance and magnetoconductance of Aharonov-Bohm rings that reproduce the behavior observed in experiments, in particular as far as aspects related to decoherence are concerned.Comment: 6 pages, 6 figure

Rashba spin precession in quantum Hall edge channels

Quasi--one dimensional edge channels are formed at the boundary of a two-dimensional electron system subject to a strong perpendicular magnetic field. We consider the effect of Rashba spin--orbit coupling, induced by structural inversion asymmetry, on their electronic and transport properties. Both our analytical and numerical results show that spin--split quantum--Hall edge channels exhibit properties analogous to that of Rashba--split quantum wires. Suppressed backscattering and a long spin life time render these edge channels an ideal system for observing voltage--controlled spin precession. Based on the latter, we propose a magnet--less spin--dependent electron interferometer.Comment: 7 pages, 6 figure

An Ontological Framework for Representing Clinical Knowledge in Decision Support Systems, Journal of Telecommunications and Information Technology, 2014, nr 1

In the last decades, clinical evidence and expert consensus have been encoded into advanced Decision Support Systems (DSSs) in order to promote a better integration into the clinical workflow and facilitate the automatic provision of patient specific advice at the time and place where decisions are made. However, clinical knowledge, typically expressed as unstructured and free text guidelines, requires to be encoded into a computer interpretable form suitable for being interpreted and processed by DSSs. For this reason, this paper proposes an ontological framework, which enables the encoding of clinical guidelines from text to a formal representation, in order to allow querying, advanced reasoning and management in a well defined and rigorous way. In particular, it jointly manages declarative and procedural aspects of a standards based verifiable guideline model, named GLM-CDS (GuideLine Model for Clinical Decision Support), and expresses reasoning tasks that exploit such a represented knowledge in order to formalize integrity constraints, business rules and complex inference rules

Two-dimensional hole precession in an all-semiconductor spin field effect transistor

We present a theoretical study of a spin field-effect transistor realized in a quantum well formed in a p--doped ferromagnetic-semiconductor- nonmagnetic-semiconductor-ferromagnetic-semiconductor hybrid structure. Based on an envelope-function approach for the hole bands in the various regions of the transistor, we derive the complete theory of coherent transport through the device, which includes both heavy- and light-hole subbands, proper modeling of the mode matching at interfaces, integration over injection angles, Rashba spin precession, interference effects due to multiple reflections, and gate-voltage dependences. Numerical results for the device current as a function of externally tunable parameters are in excellent agreement with approximate analytical formulae.Comment: 9 pages, 11 figure