1,585 research outputs found

    DAMPE space mission: first data

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    The DAMPE (DArk Matter Particle Explorer) satellite was launched on December 17, 2015 and started its data taking operation a few days later. DAMPE has a large geometric factor (∼ 0.3 m2 sr\sim~0.3\ m^2\ sr) and provides good tracking, calorimetric and charge measurements for electrons, gammas rays and nuclei. This will allow precise measurement of cosmic ray spectra from tens of GeVGeV up to about 100 TeV100\ TeV. In particular, the energy region between $1-100\ TeVwillbeexploredwithhigherprecisioncomparedtopreviousexperiments.Thevarioussubdetectorsallowanefficientidentificationoftheelectronsignaloverthelarge(mainlyproton−induced)background.Asaresult,theall−electronspectrumwillbemeasuredwithexcellentresolutionfromfew will be explored with higher precision compared to previous experiments. The various subdetectors allow an efficient identification of the electron signal over the large (mainly proton-induced) background. As a result, the all-electron spectrum will be measured with excellent resolution from few GeVuptofew up to few TeV$, thus giving the opportunity to identify possible contribution of nearby sources. A report on the mission goals and status is presented, together with the on-orbit detector performance and the first data coming from space.Comment: XXV ECRS 2016 Proceedings - eConf C16-09-04.

    Coordinate representation for non Hermitian position and momentum operators

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    In this paper we undertake an analysis of the eigenstates of two non self-adjoint operators q^\hat q and p^\hat p similar, in a suitable sense, to the self-adjoint position and momentum operators q^0\hat q_0 and p^0\hat p_0 usually adopted in ordinary quantum mechanics. In particular we discuss conditions for these eigenstates to be {\em biorthogonal distributions}, and we discuss few of their properties. We illustrate our results with two examples, one in which the similarity map between the self-adjoint and the non self-adjoint is bounded, with bounded inverse, and the other in which this is not true. We also briefly propose an alternative strategy to deal with q^\hat q and p^\hat p, based on the so-called {\em quasi *-algebras}.Comment: Accepted in Proceedings of the Royal Society

    Dynamics for a quantum parliament

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    In this paper we propose a dynamical approach based on the Gorini-Kossakowski-Sudarshan-Lindblad equation for a problem of decision making. More specifically, we consider what was recently called a quantum parliament, asked to approve or not a certain law, and we propose a model of the connections between the various members of the parliament, proposing in particular some special form of the interactions giving rise to a {\em collaborative} or non collaborative behaviour

    Study of neutron-rich calcium isotopes with a realistic shell-model interaction

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    We have studied neutron-rich calcium isotopes in terms of the shell model employing a realistic effective interaction derived from the CD-Bonn nucleon-nucleon potential. The short-range repulsion of the potential is renormalized by way of the V-low-k approach. The calculated results are in very good agreement with the available experimental data, thus supporting our predictions for the hitherto unknown spectra of 53-56Ca nuclei. In this context, the possible existence of an N=34 shell closure is discussed.Comment: 11 pages, 3 figures, to be published in Physical Review

    D{\cal D}-deformed harmonic oscillators

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    We analyze systematically several deformations arising from two-dimensional harmonic oscillators which can be described in terms of D\cal{D}-pseudo bosons. They all give rise to exactly solvable models, described by non self-adjoint hamiltonians whose eigenvalues and eigenvectors can be found adopting the quite general framework of the so-called D\cal{D}-pseudo bosons. In particular, we show that several models previously introduced in the literature perfectly fit into this scheme.Comment: in press in International Journal of Theoretical Physic
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