8,091 research outputs found

    Dynamics of a classical Hall system driven by a time-dependent Aharonov--Bohm flux

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    We study the dynamics of a classical particle moving in a punctured plane under the influence of a strong homogeneous magnetic field, an electrical background, and driven by a time-dependent singular flux tube through the hole. We exhibit a striking classical (de)localization effect: in the far past the trajectories are spirals around a bound center; the particle moves inward towards the flux tube loosing kinetic energy. After hitting the puncture it becomes ``conducting'': the motion is a cycloid around a center whose drift is outgoing, orthogonal to the electric field, diffusive, and without energy loss

    Functional requirements for onboard management of space shuttle consumables, volume 1

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    A study was conducted to determine the functional requirements for onboard management of space shuttle consumables. A generalized consumable management concept was developed for application to advanced spacecraft. The subsystems and related consumables selected for inclusion in the consumables management system are: (1) propulsion, (2) power generation, and (3) environmental and life support

    Are there nodes in LaFePO, BaFe2_2(AsP)2_2, and KFe2_2As2_2 ?

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    We reexamined the experimental evidences for the possible existence of the superconducting (SC) gap nodes in the three most suspected Fe-pnictide SC compounds: LaFePO, BaFe2_2(As0.67_{0.67}P0.33_{0.33})2_2, and KFe2_2As2_2. We showed that while the TT-linear temperature dependence of the penetration depth λ(T)\lambda(T) of these three compounds indicate extremely clean nodal gap superconductors, the thermal conductivity data limT,H0κS(H,T)/T\lim_{T,H \rightarrow 0} \kappa_S (H,T)/T unambiguously showed that LaFePO and BaFe2_2(As0.67_{0.67}P0.33_{0.33})2_2 are extremely dirty, while KFe2_2As2_2 can be clean. This apparently conflicting experimental data casts a serious doubt on the nodal gap possibility on LaFePO and BaFe2_2(As0.67_{0.67}P0.33_{0.33})2_2.Comment: 11 pages, 5 figures A new section "4. Remark on the quantum oscillation (QO) experiments" is adde

    Microwave Conductivity of a High Purity d-wave Superconductor

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    The cusp-like behavior of the microwave conductivity observed in clean ortho-II YB2_{2}Cu3_{3}O6.50_{6.50} at low temperature and low frequency is shown to be related directly to a linear in frequency dependence of the impurity scattering rate with a negligibly small value at zero frequency. In the weak scattering limit, the conductivity decreases linearly with the frequency. In the vortex state, assuming a random (Gaussian) distribution of vortices, we show that the magnetic field profoundly alters the impurity scattering rate, which now acquires a finite zero frequency value. As a consequence, we predict a Drude-like line shape in the microwave conductivity at low frequency.Comment: 3 figure
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