221 research outputs found

    Scaling of variables and the relation between noncommutative parameters in Noncommutative Quantum Mechanics

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    We consider Noncommutative Quantum Mechanics with phase space noncommutativity. In particular, we show that a scaling of variables leaves the noncommutative algebra invariant, so that only the self-consistent effective parameters of the model are physically relevant. We also discuss the recently proposed relation of direct proportionality between the noncommutative parameters, showing that it has a limited applicability.Comment: Revtex4, 4 pages; version to match the published on

    Comment on "Feynman Effective Classical Potential in the Schrodinger Formulation"

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    We comment on the paper "Feynman Effective Classical Potential in the Schrodinger Formulation"[Phys. Rev. Lett. 81, 3303 (1998)]. We show that the results in this paper about the time evolution of a wave packet in a double well potential can be properly explained by resorting to a variational principle for the effective action. A way to improve on these results is also discussed.Comment: 1 page, 2eps figures, Revte

    Astrophysical constraints on the confining models : the Field Correlator Method

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    We explore the relevance of confinement in quark matter models for the possible quark core of neutron stars. For the quark phase, we adopt the equation of state (EoS) derived with the Field Correlator Method, extended to the zero temperature limit. For the hadronic phase, we use the microscopic Brueckner-Hartree-Fock many-body theory. We find that the currently adopted value of the gluon condensate G2≃0.006−0.007GeV4G_2 \simeq 0.006-0.007 \rm {GeV^4}, which gives a critical temperature Tc≃170MeVT_c \simeq 170 \rm MeV, produces maximum masses which are only marginally consistent with the observational limit, while larger masses are possible if the gluon condensate is increased.Comment: 7 pages, 5 figure

    The LEBT Chopper for the Spiral 2 Project

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    International audienceThe Spiral 2 driver uses a slow chopper situated in the common section of the low energy beam transport line to change the beam intensity, to cut off the beam in case of critical loss and to avoid hitting the wheel structure of rotating targets. The device has to work up to 10 kV, 1 kHz repetition frequency rate and its design is based on standard power circuits, custom alarm board and vacuum feed-through. The paper summarizes the design principles and describes the test results of the final device which has been installed on the beam line test bench
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