75,494 research outputs found
Development of an infinite input impedance fluidic amplifier
Two-phase analog infinite input impedance high stable gain fluid amplifie
Critical view of the claimed pentaquark
We use a theoretical model of the reaction
adapted to the experiment done at LEPS where a peak was observed and associated
to the pentaquark. The study shows that the method used in
the experiment to associate momenta to the undetected proton and neutron,
together with the chosen cuts, necessarily creates an artificial broad peak in
the assumed invariant mass in the region of the claimed
. It is shown that the LEPS fit to the data, used to make the
claim of the , grossly distorts the background. An
alternative fit, assuming a background plus a fluctuation, returns a background
practically equal to the theoretical one and a fluctuation identical to the one
seen in the experimental spectrum of 2 significance.Comment: Conference Proceedin
An analytic Pade-motivated QCD coupling
We consider a modification of the Minimal Analytic (MA) coupling of Shirkov
and Solovtsov. This modified MA (mMA) coupling reflects the desired analytic
properties of the space-like observables. We show that an approximation by
Dirac deltas of its discontinuity function is equivalent to a Pad\'e
(rational) approximation of the mMA coupling that keeps its analytic structure.
We propose a modification to mMA that, as preliminary results indicate, could
be an improvement in the evaluation of low-energy observables compared with
other analytic couplings.Comment: 2 pages, 1 figure (double), to appear in the Proceedings of the VIII
Latin American Symposium on Nuclear Physics and Applications, Santiago,
Chile, 15-19 December 2009. Poster presented by H. E. Martine
Fermionic entanglement ambiguity in non-inertial frames
We analyse an ambiguity in previous works on entanglement of fermionic fields
in non-inertial frames. This ambiguity, related to the anticommutation
properties of field operators, leads to non-unique results when computing
entanglement measures for the same state. We show that the ambiguity disappears
when we introduce detectors, which are in any case necessary as a means to
probe the field entanglement.Comment: 9 pages, 4 figures. Revtex 4.1, added Journal referenc
Redistribution of particle and anti-particle entanglement in non-inertial frames
We analyse the entanglement tradeoff between particle and anti-particle modes
of a Dirac field from the perspective of inertial and uniformly accelerated
observers. Our results show that a redistribution of entanglement between
particle and anti-particle modes plays a key role in the survival of fermionic
field entanglement in the infinite acceleration limit.Comment: 10 pages, 5 figures, revtex4. Added journal referenc
Recommended from our members
Automatic Generation of Cognitive Theories using Genetic Programming
Cognitive neuroscience is the branch of neuroscience that studies the neural mechanisms underpinning cognition and develops theories explaining them. Within cognitive neuroscience, computational neuroscience focuses on modeling behavior, using theories expressed as computer programs. Up to now, computational theories have been formulated by neuroscientists. In this paper, we present a new approach to theory development in neuroscience: the automatic generation and testing of cognitive theories using genetic programming. Our approach evolves from experimental data cognitive theories that explain âthe mental programâ that subjects use to solve a specific task. As an example, we have focused on a typical neuroscience experiment, the delayed-match-to-sample (DMTS) task. The main goal of our approach is to develop a tool that neuroscientists can use to develop better cognitive theories
- âŠ