Reduced-dimension linear transform coding of distributed correlated signals with incomplete observations

We study the problem of optimal reduced-dimension linear transform coding and reconstruction of a signal based on distributed correlated observations of the signal. In the mean square estimation context this involves finding he optimal signal representation based on multiple incomplete or only partial observations that are correlated. In particular this leads to the study of finding the optimal Karhunen-Loeve basis based on the censored observations. The problem has been considered previously by Gestpar, Dragotti and Vitterli in the context of jointly Gaussian random variables based on using conditional covariances. In this paper, we derive the estimation results in the more general setting of second-order random variables with arbitrary distributions, using entirely different techniques based on the idea of innovations. We explicitly solve the single transform coder case, give a characterization of optimality in the multiple distributed transform coders scenario and provide additional insights into the structure of the problm

Evolution of Efimov states into the continuum in neutron rich (2n-core) nuclei - A general study

The nuclear three-body system, with two halo neutrons very weakly coupled to a heavy core, is studied to investigate necessary conditions for the occurrence of Efimov states. Extending the analysis to the scattering sector, we find that these states evolve into Feshbach type resonances. This behaviour is very similar to the 20C nucleus in which the occurrence of Efimov states evolving into resonances in the elastic scattering of n?19C system has been investigated in recent publications. This work, thereby, extends the study of the Efimov effect beyond 20C, showing that 32Ne and 38Mg exhibit a very similar dynamical structure. These nuclei are, therefore, also candidates for probing experimentally the Efimov effect. © 2011 Elsevier B.V

Efimov states and their Fano resonances in a neutron-rich nucleus

Asymmetric resonances in elastic n+$^{19}$C scattering are attributed to Efimov states of such neutron-rich nuclei, that is, three-body bound states of the n+n+$^{18}$C system when none of the pairs is bound or some of them only weakly bound. By fitting to the general resonance shape described by Fano, we extract resonance position, width, and the "Fano profile index". While Efimov states have been discussed extensively in many areas of physics, there is only one very recent experimental observation in trimers of cesium atoms. The conjunction that we present of the Efimov and Fano phenomena may lead to experimental realization in nuclei.Comment: 4 double-column pages, 3 figure

Adding Corrections to Global Spherical Potentials for Use in a Coupled-Channel Formulation

The coupled-channel technique augments a non-relativistic distorted wave born approximation scattering calculation to include a coupling to virtual states from the negative energy region. It has been found to be important in low energy nucleon-nucleus scattering. We modify the nucleon-nucleus standard optical potentials, not designed for a coupled-channel space, so they can be used in that setting. The changes are small and systematic. We use a standard scattering code to adjust a variety of optical potentials and targets such that the original fit to scattering observables are maintained as we incorporate the coupled-channel environment. Overall over forty target nuclei were tested from $A=12$ to $A=205$ and nucleon projectile energies from 1 MeV to 200 MeV. There is excellent improvement in fitting the scattering observables, especially for low energy neutron scattering.The corrections were found to be unimportant for projectile energies greater than 200 MeV. The largest changes are to the surface amplitudes while the real radii and the real central amplitude are modified by only a few percent, every other parameter is unchanged. This technique is general enough to be applied to a variety of inelastic theoretical calculations.Comment: Second draft, not yet submitted to a journal in this for

Re-integerization of fractional charges in the correlated quarter-filled band

Previous work has demonstrated the existence of soliton defect states with charges +/- e/2 in the limits of zero and of infinite on-site Coulomb interactions in the one-dimensional (1D) quarter-filled band. For large but finite on-site Coulomb interaction, the low temperature 2k_F bond distortion that occurs within the 4k_F bond-distorted phase is accompanied by charge-ordering on the sites. We show that a ``re-integerization'' of the defect charge occurs in this bond-charge density wave (BCDW) state due to a ``binding'' of the fractional charges. We indicate briefly possible implications of this result for mechanisms of organic superconductivity.Comment: 4 eps figure

Dynamics of a large extra dimension inspired hybrid inflation model

In low scale quantum gravity scenarios the fundamental scale of nature can be as low as TeV, in order to address the naturalness of the electroweak scale. A number of difficulties arise in constructing specific models; stabilisation of the radius of the extra dimensions, avoidance of overproduction of Kaluza Klein modes, achieving successful baryogenesis and production of a close to scale-invariant spectrum of density perturbations with the correct amplitude. We examine in detail the dynamics, including radion stabilisation, of a hybrid inflation model that has been proposed in order to address these difficulties, where the inflaton is a gauge singlet residing in the bulk. We find that for a low fundamental scale the phase transition, which in standard four dimensional hybrid models usually ends inflation, is slow and there is second phase of inflation lasting for a large number of e-foldings. The density perturbations on cosmologically interesting scales exit the Hubble radius during this second phase of inflation, and we find that their amplitude is far smaller than is required. We find that the duration of the second phase of inflation can be short, so that cosmologically interesting scales exit the Hubble radius prior to the phase transition, and the density perturbations have the correct amplitude, only if the fundamental scale takes an intermediate value. Finally we comment briefly on the implications of an intermediate fundamental scale for the production of primordial black holes and baryogenesis.Comment: 9 pages, 2 figures version to appear in Phys. Rev. D, additional references and minor changes to discussio

The curvaton scenario in the MSSM and predictions for non-Gaussianity

We provide a model in which both the inflaton and the curvaton are obtained from within the minimal supersymmetric Standard Model, with known gauge and Yukawa interactions. Since now both the inflaton and curvaton fields are successfully embedded within the same sector, their decay products thermalize very quickly before the electroweak scale. This results in two important features of the model: firstly, there will be no residual isocurvature perturbations, and secondly, observable non-Gaussianities can be generated with the non-Gaussianity parameter $f_\mathrm{NL}\sim {\cal O}(5-1000)$ being determined solely by the combination of weak-scale physics and the Standard Model Yukawas.Comment: 4 pages, no figure

Enhanced baryon number violation due to cosmological defects with localized fermions along extra dimension

We propose a new scenario of baryon number violation in models with extra dimensions. In the true vacuum, baryon number is almost conserved due to the localization mechanism of matter fields, which suppresses the interactions between quarks and leptons. We consider several types of cosmological defects in four-dimensional spacetime that shift the center of the localized matter fields, and show that the magnitudes of the baryon number violating interactions are well enhanced. Application to baryogenesis is also discussed.Comment: 12pages, latex2e, added references, to appear in PR