193 research outputs found

    Fermi liquid parameters in 2D with spin-orbit interaction

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    We derive analytical expressions for the quasiparticle lifetime tau, the effective mass m*, and the Green's function renormalization factor Z for a 2D Fermi liquid with electron-electron interaction in the presence of the Rashba spin-orbit interaction. We find that the modifications are independent of the Rashba band index rho, and occur in second order of the spin-orbit coupling alpha. In the derivation of these results, we also discuss the screening of the Coulomb interaction, as well as the susceptibility and the self-energy in small alpha.Comment: 9 pages, 1 fig. Corrected the result for the effective mass, and added a section IV.B. Corrected typos and updated reference

    Workplace personal exposure to respirable PM fraction: a study in sixteen indoor environments

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    AbstractThe present paper focuses on respirable particulate matter (RPM) measurements conducted at the breathing zone of adult volunteers in sixteen different working environments: two offices, a house, a chemical laboratory, a non–smoking shop, a pharmacy store, a car garage, a hairdresser's store, a photocopy store, a taxi, a gym, a mall, a restaurant, a bar, a kiosk and a school. The sixteen different cases were categorized according to the location, the type of the activities taking place indoors, the number of occupants, the proximity to heavy traffic roads, the ventilation pattern etc. According to the results, the maximum particle concentration (in average 285ÎŒg m−3) was recorded at the hairdresser store while the minimum concentration was measured in the cases of the housewife and the employee in the non–smoking shop (in average 30ÎŒg m−3). The results indicated smoking as a factor which strongly influences the exposure levels of both smokers and passive smokers. Furthermore, it was found that the building ventilation pattern comprises an important factor influencing the exposure levels especially in cases of buildings with great number of visitors (resuspension) and smoking

    Toy models of crossed Andreev reflection

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    We propose toy models of crossed Andreev reflection in multiterminal hybrid structures containing out-of-equilibrium conductors. We apply the description to two possible experiments: (i) to a device containing a large quantum dot inserted in a crossed Andreev reflection circuit. (ii) To a device containing an Aharonov-Bohm loop inserted in a crossed Andreev reflection circuit.Comment: 5 pages, 9 figures, minor modification

    Entanglement in Mesoscopic Structures: Role of Projection

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    We present a theoretical analysis of the appearance of entanglement in non-interacting mesoscopic structures. Our setup involves two oppositely polarized sources injecting electrons of opposite spin into the two incoming leads. The mixing of these polarized streams in an ideal four-channel beam splitter produces two outgoing streams with particular tunable correlations. A Bell inequality test involving cross-correlated spin-currents in opposite leads signals the presence of spin-entanglement between particles propagating in different leads. We identify the role of fermionic statistics and projective measurement in the generation of these spin-entangled electrons.Comment: 5 pages, 1 figur

    Differences and similarities in instant countertransference towards patients with suicidal ideation and personality disorders.

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    Previous findings showed that suicidal patients elicit mostly negative countertransference such as distress, hopelessness, feelings of inadequacy, and apprehension, and that a concurrent personality disorder is associated with more feelings of entrapment and mistreatment, among other adverse reactions. No studies were however conducted on instant countertransference (iCT), i.e., after a single encounter, for example in an emergency setting. We aimed to evaluate the impact of suicidal ideations, self-harm and presence of personality disorders on instant Countertransference (iCT). Caregivers rated their iCT with two validated and standardized questionnaires after a first emergency or outpatient consultation. Suicidal ideation, self-harm and personality disorders were tested as predictors for iCT in a multivariate and multilevel analysis. Thirty caregivers rated their iCT towards 321 patients. Personality disorders and suicidal ideation, but neither recent nor past history of self-harm, predicted iCT. Common iCT included tension, lack of self-confidence and feeling of being tied. iCT specifically associated with suicidal ideation included distress, lack of hope, confusion, and sense that the patient's life had little worth. In contrast, iCT towards patients with personality disorders suggested tension in the therapeutic relationship (low affiliation with patient, anger, disappointment, devaluation). Caregiver's characteristics were not considered in the analysis. Furthermore, while countertransference also includes unconscious phenomena, only conscious iCT was assessed. Patients with suicidal ideation and personality disorders elicit common but also specific negative iCT. Mental health institutions need to devote specific resources (such as clinical supervision and training) to help caregivers manage their iCT

    Coulomb scattering in a 2D interacting electron gas and production of EPR pairs

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    We propose a setup to generate non-local spin-EPR pairs via pair collisions in a 2D interacting electron gas, based on constructive two-particle interference in the spin singlet channel at the pi/2 scattering angle. We calculate the scattering amplitude via the Bethe-Salpeter equation in the ladder approximation and small r_s limit, and find that the Fermi sea leads to a substantial renormalization of the bare scattering process. From the scattering length we estimate the current of spin-entangled electrons and show that it is within experimental reach.Comment: 4 page

    Localization of interacting electrons in quantum dot arrays driven by an ac-field

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    We investigate the dynamics of two interacting electrons moving in a one-dimensional array of quantum dots under the influence of an ac-field. We show that the system exhibits two distinct regimes of behavior, depending on the ratio of the strength of the driving field to the inter-electron Coulomb repulsion. When the ac-field dominates, an effect termed coherent destruction of tunneling occurs at certain frequencies, in which transport along the array is suppressed. In the other, weak-driving, regime we find the surprising result that the two electrons can bind into a single composite particle -- despite the strong Coulomb repulsion between them -- which can then be controlled by the ac-field in an analogous way. We show how calculation of the Floquet quasienergies of the system explains these results, and thus how ac-fields can be used to control the localization of interacting electron systems.Comment: 7 pages, 6 eps figures V2. Minor changes, this version to be published in Phys. Rev.
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