Response to the comments of Dwivedi and Srivastava on the propagation and dissipation of Alfven waves in coronal holes

Chandra [1] made an attempt to show that the work of Dwivedi and Srivastava [2] (hereinafter DS) can be investigated even analytically and their results are erroneous. Dwivedi and Srivastava [3] picked up some values of Chandra [1] and tried to show that they are not physically acceptable. Some results of Chandra [1] are not physically acceptable, as these are the outcome of the wrong approach of DS. However, the results are numerically correct whereas the results of DS are numerically wrong.Comment: 3 page

Controversy on a dispersion relation for MHD waves

Kumar et al. (2006) obtained a fifth order polynomial in $\omega$ for the dispersion relation and pointed out that the calculations preformed by Porter et al. (1994) and by Dwivedi & Pandey (2003) seem to be in error, as they obtained a sixth order polynomial. The energy equation of Dwivedi & Pandey (2003) was dimensionally wrong. Dwivedi & Pandey (2006) corrected the energy equation and still claimed that the dispersion relation must be a sixth order polynomial. The equations (11) $-$ (19) of Dwivedi & Pandey (2006) and the equations (24) $-$ (32) Kumar et al. (2006) are the same. This fact has been expressed by Kumar et al. (2006) themselves. Even then they tried to show this set of equations on one side gives the sixth order polynomial as they got; on the other side, the same set of equations gives the fifth order polynomial as Kumar et al. (2006) obtained. The situation appears to be non-scientific, as the system of equations is a linear one. These are simple algebraic equations where the variables are to be eliminated. However, it is a matter of surprise that by solving these equations, two scientific groups are getting polynomials of different degrees. In the present discussion, we have attempted to short out this discrepancy.Comment: 5 page

A Fault-Tolerant Superconducting Associative Memory

The demand for high-density data storage with ultrafast accessibility motivates the search for new memory implementations. Ideally such storage devices should be robust to input error and to unreliability of individual elements; furthermore information should be addressed by its content rather than by its location. Here we present a concept for an associative memory whose key component is a superconducting array with natural multiconnectivity. Its intrinsic redundancy is crucial for the content-addressability of the resulting storage device and also leads to parallel image retrieval. Because patterns are stored nonlocally both physically and logically in the proposed device, information access and retrieval are fault-tolerant. This superconducting memory should exhibit picosecond single-bit acquisition times with negligible energy dissipation during switching and multiple non-destructive read-outs of the stored data

A Landau Primer for Ferroelectrics

In this review, we hope to give the reader a self-contained contemporary presentation of the application of Landau theory to ferroelectrics. We begin by developing Landau theory for homogenous bulk ferroelectrics and then consider the finite-size (thin film) case within the related Landau-Ginzburg approach. Next we discuss the treatment of inhomogeneity within this framework. We end with a number of open questions for future pursuits.Comment: 47 pages, 8 figures, 1 tabl

Composite Fermion Approach to Diquark and Heavy-Light Baryon Masses

A composite Fermion (CF) model of quasi particle has been used to describe a diquark. Considering baryons in quark-diquark configuration,the masses of the heavy light baryons like $\Lambda_{c}^{+}$, $\Sigma_{c}^{+}$, $\Xi_{c}^{0}$, $\Omega_{c}^{0}$ and $\Lambda_{b}^{+}$, $\Sigma_{b}^{+}$, $\Xi_{b}^{0}$, $\Omega_{b}^{-}$ have been computed using this CF model of the diquark. The results are found to be in good agreement with the corresponding experimental findings. It has been suggested that the diquark can be well described in the framework of CF model in a gauge invariant way

Fractal Space Time and Variation of Fine Structure Constant

The effect of fractal space time of the quantum particles on the variation of the fine structure constant $\alpha$ has been studied. The variation of fine structure constant has been investigated around De Broglie length $\lambda$ and compton length $\lambda_{c}$ and it has been suggested that the variation may be attributed to the dimensional transition of the particle trajectories between these two quantum domains. Considering the Fractal universe with a small inhomogeneity in the mass distribution in the early universe, the variation of the fine structure constant have been investigated between matter and radiation dominated era. The fine structure constant shows a critical behaviour with critical exponent which is fractional and shows a discontinuity. It has been suggested that the variation of the fine structure constant may be attributed to the intrinsic scale dependance of the fundamental constants of nature

Stress and heat flux for arbitrary multi-body potentials: A unified framework

A two-step unified framework for the evaluation of continuum field expressions from molecular simulations for arbitrary interatomic potentials is presented. First, pointwise continuum fields are obtained using a generalization of the Irving-Kirkwood procedure to arbitrary multi-body potentials. Two ambiguities associated with the original Irving-Kirkwood procedure (which was limited to pair potential interactions) are addressed in its generalization. The first ambiguity is due to the non-uniqueness of the decomposition of the force on an atom as a sum of central forces, which is a result of the non-uniqueness of the potential energy representation in terms of distances between the particles. This is in turn related to the shape space of the system. The second ambiguity is due to the non-uniqueness of the energy decomposition between particles. The latter can be completely avoided through an alternate derivation for the energy balance. It is found that the expressions for the specific internal energy and the heat flux obtained through the alternate derivation are quite different from the original Irving-Kirkwood procedure and appear to be more physically reasonable. Next, in the second step of the unified framework, spatial averaging is applied to the pointwise field to obtain the corresponding macroscopic quantities. These lead to expressions suitable for computation in molecular dynamics simulations. It is shown that the important commonly-used microscopic definitions for the stress tensor and heat flux vector are recovered in this process as special cases (generalized to arbitrary multi-body potentials). Several numerical experiments are conducted to compare the new expression for the specific internal energy with the original one.Comment: arXiv admin note: text overlap with arXiv:1008.481

Dissociation of 1 p quarkonium states in a hot QCD medium

We extend the analysis of a very recent work (Phys. Rev. {\bf C 80}, 025210 (2009)) to study the dissociation phenomenon of 1p states of the charmonium and bottomonium spectra ($\chi_c$ and $\chi_b$) in a hot QCD medium. This study employed a medium modified heavy quark potential which is obtained by incorporating both perturbative and non-perturbative medium effects encoded in the dielectric function to the full Cornell potential. The medium modified potential has a quite different form (a long range Coulomb tail in addition to the usual Yukawa term) compared to the usual picture of Debye screening. We further study the flavor dependence of their binding energies and dissociation temperatures by employing the perturbative, non-perturbative, and the lattice parametrized form of the Debye masses. These results are consistent with the predictions of the current theoretical works.Comment: 7 pages, 2 figures, 3 tables, two colum

Solitons in an effective theory of CP violation

We study an effective field theory describing CP-violation in a scalar meson sector. We write the simplest interaction that we can imagine, $${\cal L}\sim \epsilon_{i_1\cdots i_5}\epsilon^{\mu_1\cdots\mu_4}\phi_{i_1}\partial_{\mu_1}\phi_{i_2}\partial_{\mu_2}\phi_{i_3}\partial_{\mu_3}\phi_{i_4}\partial_{\mu_4}\phi_{i_5}$$ which involves 5 scalar fields. The theory describes CP-violation only when it contains scalar fields representing mesons such as the $K^*_0$, sigma, $f_0$ or $a_0$. If the fields represent pseudo-scalar mesons, such as B, K and $\pi$ mesons then the Lagrangian describes anomalous processes such as $KK\to \pi\pi\pi$. We speculate that the field theory contains long lived excitations corresponding to $Q$-ball type domain walls expanding through space-time. In an 1+1 dimensional, analogous, field theory we find an exact, analytic solution corresponding to such solitons. The solitons have a U(1) charge $Q$, which can be arbitrarily high, but oddly, the energy behaves as $Q^{2/3}$ for large charge, thus the configurations are stable under disintegration into elementary charged particles of mass $m$ with $Q=1$. We also find analytic complex instanton solutions which have finite, positive Euclidean action.Comment: 15 pages, 1 figur

A thermodynamic geometric study of R\'{e}nyi and Tsallis entropies

A general investigation is made into the intrinsic Riemannian geometry for complex systems, from the perspective of statistical mechanics. The entropic formulation of statistical mechanics is the ingredient which enables a connection between statistical mechanics and the corresponding Riemannian geometry. The form of the entropy used commonly is the Shannon entropy. However, for modelling complex systems, it is often useful to make use of entropies such as the R\'{e}nyi and Tsallis entropies. We consider, here, Shannon, R\'{e}nyi, Tsallis, Abe and structural entropies, for our analysis. We focus on one, two and three particle thermally excited configurations. We find that statistical pair correlation functions, determined by the components of the covariant metric tensor of the underlying thermodynamic geometry, associated with the various entropies have well defined, definite expressions, which may be extended for arbitrary finite particle systems. In all cases, we find a non-degenerate intrinsic Riemannian manifold. In particular, any finite particle system described in terms of R\'{e}nyi, Tsallis, Abe and structural entropies, always corresponds to an interacting statistical system, thereby highlighting their importance in the study of complex systems. On the other hand, a statistical description by the Gibbs-Shannon entropy corresponds to a non-interacting system.Comment: 26 pages, 23 figure