Decoherence-free quantum information in the presence of dynamical evolution

We analyze decoherence-free (DF) quantum information in the presence of an arbitrary non-nearest-neighbor bath-induced system Hamiltonian using a Markovian master equation. We show that the most appropriate encoding for N qubits is probably contained within the ~(2/9) N excitation subspace. We give a timescale over which one would expect to apply other methods to correct for the system Hamiltonian. In order to remain applicable to experiment, we then focus on small systems, and present examples of DF quantum information for three and four qubits. We give an encoding for four qubits that, while quantum information remains in the two-excitation subspace, protects against an arbitrary bath-induced system Hamiltonian. Although our results are general to any system of qubits that satisfies our assumptions, throughout the paper we use dipole-coupled qubits as an example physical system.Comment: 8 pages, 4 figure

A new microscopic nucleon-nucleon interaction derived from relativistic mean field theory

A new microscopic nucleon-nucleon (NN) interaction has been derived for the first time from the popular relativistic mean field theory (RMFT) Lagrangian. The NN interaction so obtained remarkably relate to the inbuilt fundamental parameters of RMFT. Furthermore, by folding it with the RMFT-densities of cluster and daughter nuclei to obtain the optical potential, it's application is also examined to study the exotic cluster radioactive decays, and results obtained found comparable with the successfully used M3Y phenomenological effective NN interactions. The presently derived NN-interaction can also be used to calculate a number of other nuclear observables.Comment: 4 Pages 2 Figure

New method for Calculating the Input Impedance of rectangular Patch Antenna

The cavity model has been modified to account for the impedance boundary condition at the edges of a  rectangular microstrip antenna. Results have been compared with those from the old cavity model and  experimental data

Applicability of shape parameterizations for giant dipole resonance in warm and rapidly rotating nuclei

We investigate how well the shape parameterizations are applicable for studying the giant dipole resonance (GDR) in nuclei, in the low temperature and/or high spin regime. The shape fluctuations due to thermal effects in the GDR observables are calculated using the actual free energies evaluated at fixed spin and temperature. The results obtained are compared with Landau theory calculations done by parameterizing the free energy. We exemplify that the Landau theory could be inadequate where shell effects are dominating. This discrepancy at low temperatures and high spins are well reflected in GDR observables and hence insists on exact calculations in such cases.Comment: 10 pages, 2 figure

Rotational Bands and Electromagnetic Transitions of some even-even Neodymium Nuclei in J-Projected Hartree-Fock Model

Rotational structures of even-even $^{148-160}$Nd nuclei are studied with the self-consistent deformed Hartree-Fock (HF) and angular momentum (J) projection model. Spectra of ground band, recently observed $K=4^{-}$, $K=5^{-}$ and a few more excited, positive and negative parity bands have been studied upto high spin values. Apart from these detailed electromagnetic properties (like E2, M1 matrix elements) of all the bands have been obtained. There is substantial agreement between our model calculations and available experimental data. Predictions are made about the band structures and electromagnetic properties of these nuclei. Some 4-qasiparticle K-isomeric bands and their electromagnetic properties are predicted.Comment: 20 page

First simultaneous lidar observations of sodium layers and VHF radar observations of E-region field-aligned irregularities at the low-latitude station Gadanki

Simultaneous observations of atmospheric sodium (Na) made by a resonance lidar and E-region field-alignedirregularities (FAI) made by the Indian MST radar, both located at Gadanki (13.5°N, 79.2°E) and horizontal winds acquired by a SKiYMET meteor radar at Trivandrum (8.5°N, 77°E) are used to investigate the relationship among sodium layer, FAI and neutral winds in the mesosphere and lower thermosphere region. The altitudes and descent rates of higher altitude (~ 95 km) Na layer and FAI agree quite well. The descending structures of the higher altitude Na layer and FAI are found to be closely related to the diurnal tidal phase structure in zonal winds observed over Trivandrum. At lower altitudes, the descent rate of FAI is larger than that of Na layer and zonal tidal phase. These observations support the hypothesis that the metallic ion layers are formed by the zonal wind shear associated with tidal winds and subsequently get neutralized to manifest in the form of descending Na layers. The descending FAI echoing layers are manifestation of the instabilities setting in on the ionization layer. In the present observations, the altitudes of occurrence of Na layer and FAI echoes being low, we surmise that it is quite possible that the FAI echoes are due to the descent of already formed irregularities at higher altitudes

Giant dipole resonance with exact treatment of thermal fluctuations

The shape fluctuations due to thermal effects in the giant dipole resonance (GDR) observables are calculated using the exact free energies evaluated at fixed spin and temperature. The results obtained are compared with Landau theory calculations done by parameterizing the free energy. The Landau theory is found to be insufficient when the shell effects are dominating.Comment: 5 pages, 2 figure

Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

In this paper, we present seasonal variation of E region field-aligned irregularities (FAIs) observed using the Gadanki radar and compare them with the seasonal variation of Es observed from a nearby location SHAR. During daytime, FAIs occur maximum in summer and throughout the day, as compared to other seasons. During nighttime, FAIs occur equally in both summer and winter, and relatively less in equinoxes. Seasonal variations of Es (i.e. ftEs and fbEs) show that the daytime activity is maximum in summer and the nighttime activity is maximum in equinoxes. No relation is found between FAIs occurrence/SNR and ftEs/fbEs. FAIs occurrence, however, is found to be related well with (ftEs-fbEs ). This aspect is discussed in the light of the present understanding of the mid-latitude Es-FAIs relationship. The seasonal variations of FAIs observed at Gadanki are compared in detail with those of Piura, which show a significant difference in the daytime observations. The observed difference has been discussed considering the factors governing the generation of FAIs

Carbide precipitates in solution-quenched PH13-8 Mo stainless steel: a small-angle neutron scattering investigation

This paper deals with the small-angle neutron scattering (SANS) investigation on solution-quenched PH13-8 Mo stainless steel. From the nature of the variation of the functionality of the profiles for varying specimen thickness and also from the transmission electron microscopy (TEM), it has been established that the small-angle scattering signal predominantly originates from the block-like metallic carbide precipitates in the specimen. The contribution due to double Bragg reflection is not significant in the present case. The single scattering profile has been extracted from the experimental profiles corresponding to different values of specimen thickness. In order to avoid complexity and non-uniqueness of the multi-parameter minimization for randomly oriented polydisperse block-like precipitate model, the data have been analyzed assuming randomly oriented polydisperse cylindrical particle model with a locked aspect ratio