Answer to the comment of Chudnovsky: On the square-root time relaxation in molecular nanomagnets

Answer to the comment of E. Chudnovsky concerning the following papers: (1) N.V. Prokof'ev, P.C.E. Stamp, Phys. Rev. Lett.80, 5794 (1998). (2) W. Wernsdorfer, T. Ohm, C. Sangregorio, R. Sessoli, D. Mailly, C. Paulsen, Phys. Rev. Lett. 82, 3903 (1999).Comment: 1 page

H.E.S.S. deeper observations on SNR RX J0852.0-4622

Supernova Remnants (SNRs) are believed to be acceleration sites of Galactic cosmic rays. Therefore, deep studies of these objects are instrumental for an understanding of the high energy processes in our Galaxy. RX J0852.0-4622, also known as Vela Junior, is one of the few (4) shell-type SNRs resolved at Very High Energies (VHE; E > 100 GeV). It is one of the largest known VHE sources (~ 1.0 deg radius) and its flux level is comparable to the flux level of the Crab Nebula in the same energy band. These characteristics allow for a detailed analysis, shedding further light on the high-energy processes taking place in the remnant. In this document we present further details on the spatial and spectral morphology derived with an extended data set. The analysis of the spectral morphology of the remnant is compatible with a constant power-law photon index of 2.11 +/- 0.05_stat +/- 0.20_syst from the whole SNR in the energy range from 0.5 TeV to 7 TeV. The analysis of the spatial morphology shows an enhanced emission towards the direction of the pulsar PSR J0855-4644, however as the pulsar is lying on the rim of the SNR, it is difficult to disentangle both contributions. Therefore, assuming a point source, the upper limit on the flux of the pulsar wind nebula (PWN) between 1 TeV and 10 TeV, is estimated to be ~ 2% of the Crab Nebula flux in the same energy range

Atomic correlations in itinerant ferromagnets: quasi-particle bands of nickel

We measure the band structure of nickel along various high-symmetry lines of the bulk Brillouin zone with angle-resolved photoelectron spectroscopy. The Gutzwiller theory for a nine-band Hubbard model whose tight-binding parameters are obtained from non-magnetic density-functional theory resolves most of the long-standing discrepancies between experiment and theory on nickel. Thereby we support the view of itinerant ferromagnetism as induced by atomic correlations.Comment: 4 page REVTeX 4.0, one figure, one tabl

Phenomenological analysis of K+ meson production in proton-nucleus collisions

Total and differential cross sections from literature, on the production of K+ mesons in pA interactions at projectile energies between T=0.8 and 2.9 GeV, covering the transition across the free nucleon-nucleon threshold at 1.58 GeV, have been investigated. From the target-mass dependence of the production cross sections no evidence for the expected change of the dominant reaction mechanism from two-step to direct kaon production was found. At T=1.0 GeV the A dependences of the total cross sections and of the most recent data from COSY-Juelich, differential cross sections measured under forward angles, are strongly different. The invariant K+ production cross sections show an overall exponential scaling behavior with the squared four-momentum transfer between the beam proton and the produced K+ meson for t< -0.05 GeV^2 independent of the beam energy and emission angle. The data from COSY-Juelich reveal a strongly different t dependence in the region of t>0 GeV^2. Further data at forward angles and different beam energies should be taken in order to explore this region of kinematically extreme conditions.Comment: 9 Pages, 11 Figure

Electronic thermal transport in strongly correlated multilayered nanostructures

The formalism for a linear-response many-body treatment of the electronic contributions to thermal transport is developed for multilayered nanostructures. By properly determining the local heat-current operator, it is possible to show that the Jonson-Mahan theorem for the bulk can be extended to inhomogeneous problems, so the various thermal-transport coefficient integrands are related by powers of frequency (including all effects of vertex corrections when appropriate). We illustrate how to use this formalism by showing how it applies to measurements of the Peltier effect, the Seebeck effect, and the thermal conductance.Comment: 17 pages, 4 figures, submitted to Phys. Rev.

'Hole-digging' in ensembles of tunneling Molecular Magnets

The nuclear spin-mediated quantum relaxation of ensembles of tunneling magnetic molecules causes a 'hole' to appear in the distribution of internal fields in the system. The form of this hole, and its time evolution, are studied using Monte Carlo simulations. It is shown that the line-shape of the tunneling hole in a weakly polarised sample must have a Lorentzian lineshape- the short-time half-width $\xi_o$ in all experiments done so far should be $\sim E_0$, the half-width of the nuclear spin multiplet. After a time $\tau_o$, the single molecule tunneling relaxation time, the hole width begins to increase rapidly. In initially polarised samples the disintegration of resonant tunneling surfaces is found to be very fast.Comment: 4 pages, 5 figure

Inclusive K^+ meson production in proton-nucleus interactions

The production of K^+ mesons in pA (A = D, C, Cu, Ag, Au) collisions has been investigated at the COoler SYnchrotron COSY-J\"ulich for beam energies T_p = 1.0 - 2.3 GeV. Double differential inclusive pC cross sections at forward angles theta < 12 degrees as well as the target-mass dependence of the K^+ momentum spectra have been measured with the ANKE spectrometer. Far below the free NN threshold at T_{NN}=1.58 GeV the spectra reveal a high degree of collectivity in the target nucleus. From the target-mass dependence of the cross sections at higher energies, the repulsive in-medium potential of K^+ mesons can be deduced. Using pN cross-section parameterisations from literature and our measured pD data we derive a cross-section ratio of sigma(pn -> K^+ X) / sigma(pp -> K^+ X) ~ (3-4).Comment: Accepted for publication in EPJ A; 17 pages, 10 figures, 11 table

The future of social is personal: the potential of the personal data store

This chapter argues that technical architectures that facilitate the longitudinal, decentralised and individual-centric personal collection and curation of data will be an important, but partial, response to the pressing problem of the autonomy of the data subject, and the asymmetry of power between the subject and large scale service providers/data consumers. Towards framing the scope and role of such Personal Data Stores (PDSes), the legalistic notion of personal data is examined, and it is argued that a more inclusive, intuitive notion expresses more accurately what individuals require in order to preserve their autonomy in a data-driven world of large aggregators. Six challenges towards realising the PDS vision are set out: the requirement to store data for long periods; the difficulties of managing data for individuals; the need to reconsider the regulatory basis for third-party access to data; the need to comply with international data handling standards; the need to integrate privacy-enhancing technologies; and the need to future-proof data gathering against the evolution of social norms. The open experimental PDS platform INDX is introduced and described, as a means of beginning to address at least some of these six challenges

Nonadiabatic Landau Zener tunneling in Fe_8 molecular nanomagnets

The Landau Zener method allows to measure very small tunnel splittings \Delta in molecular clusters Fe_8. The observed oscillations of \Delta as a function of the magnetic field applied along the hard anisotropy axis are explained in terms of topological quantum interference of two tunnel paths of opposite windings. Studies of the temperature dependence of the Landau Zener transition rate P gives access to the topological quantum interference between exited spin levels. The influence of nuclear spins is demonstrated by comparing P of the standard Fe_8 sample with two isotopically substituted samples. The need of a generalized Landau Zener transition rate theory is shown.Comment: 5 pages, 6 figure