Signal estimation and threshold optimization using an array of bithreshold elements

We consider the problem of optimizing signal transmission through multi-channel noisy devices. We investigate an array of bithreshold noisy devices which are connected in parallel and convergent on a summing center. Utilizing the concept of noise-induced linearization we derive an analytical approximation of the normalized power norm and clarify the relation between the optimum threshold and the standard deviation of noises. We show that the optimum threshold value is 0.63 times the standard deviation of the noises. This relation is applicable to both subthreshold and suprathreshold inputs.Comment: 14 pages, 6 figure

Quantum description for a chiral condensate disoriented in a certain direction in isospace

We derive a quantum state of the disoriented chiral condensate dynamically, considering small quantum fluctuations around a classical chiral condensate disoriented in a certain direction $\vec n$ in isospace. The obtained nonisosinglet quantum state has the characteristic features; (i) it has the form of the squeezed state, (ii) the state contains not only the component of pion quanta in the direction $\vec n$ but also the component in the perpendicular direction to $\vec n$ and (iii) the low momentum pions in the state violate the isospin symmetry. With the quantum state, we calculate the probability of the neutral fraction depending on the time and the pion's momentum, and find that the probability has an unfamiliar form. For the low momentum pions, the parametric resonance mechanism works with the result that the probability of the neutral fraction becomes the well known form approximately and that the charge fluctuation is small.Comment: 19 page

Use of Hirsch Index for Measuring the Impact of IS Academic Research and Journals

This study examines the use of journal rankings and a relatively new method of measuring impact of research as a surrogate of scholarly impact: the Hirsch Index (Hirsch 2005). Journal rankings are a very important exercise in academia since they impact tenure and promotion decisions. Current methods employed to rank journal influence are shown to be subjective. We propose that the Hirsch Index be adopted as a more objective journal ranking method. To demonstrate the results of using the Hirsch Index, it is applied to the “pure MIS” journals ranked by Rainer and Miller (2005). The authors find substantial differences between the scholar rankings and those obtained using the Hirsch index. This provides weak support for the current journal ranking system but also suggests that other factors are at play

Parametric resonance at the critical temperature in high energy heavy ion collisions

Parametric resonance in soft modes at the critical temperature ($T_{c}$) in high energy heavy ion collisions is studied in the case when the temperature ($T$) of the system is almost constant for a long time. By deviding the fields into three parts, zero mode (condensate), soft modes and hard modes and assuming that the hard modes are in thermal equilibrium, we derive the equation of motion for soft modes at $T=T_{c}$. Enhanced modes are extracted by comparing with the Mathieu equation for the condensate oscillating along the sigma axis at $T=T_{c}$. It is found that the soft mode of $\pi$ fields at about 174 MeV is enhanced.Comment: 8 pages, 1 figure Some statements and equations are modified to clarif

Parametric amplification with a friction in heavy ion collisions

We study the effects of the expansion of the system and the friction on the parametric amplification of mesonic fields in high energy heavy ion collisions within the linear $\sigma$ model . The equation of motion which is similar to Mathieu equation is derived to describe the time development of classical fields in the last stage of a heavy ion collision after the freezeout time. The enhanced mode is extracted analytically by comparison with Mathieu equation and the equation of motion is solved numerically to examine whether soft modes will be enhanced or not. It is found that the strong peak appears around 267 MeV in the pion transverse momentum distribution in cases with weak friction and high maximum temperature. This enhancement can be extracted by taking the ratio between different modes in the pion transverse momentum distribution.Comment: 10 pages, 9 figures LaTeX: appendix adde

Description of a domain by a squeezed state in a scalar field theory

The author attempted to describe a domain by using a squeezed state in quantum field theory. An extended squeeze operator was used to construct the state. In a scalar field theory, the author described a domain that the distributions of the condensate and of the fluctuation are Gaussian. The momentum distribution, chaoticity and correlation length were calculated. It was found that the typical value of the momentum is about the inverse of the domain size, and that the chaoticity reflects the ratio of the size of the squeeze region to that of the coherent region. The results indicate that the quantum state of a domain is surmised by these quantities under the assumption that the distributions are Gaussian. As an example, this method was applied to a pion field, and the momentum distribution and the chaoticity were shown.Comment: 10 pages, 5 figures, a typographical error in the reference is correcte

Vertex operator approach for form factors of Belavin's (Z/nZ)(Z/nZ)-symmetric model

Belavin's $(\mathbb{Z}/n\mathbb{Z})$-symmetric model is considered on the basis of bosonization of vertex operators in the $A^{(1)}_{n-1}$ model and vertex-face transformation. Free field representations of nonlocal tail operators are constructed for off diagonal matrix elements with respect to the ground state sectors. As a result, integral formulae for form factors of any local operators in the $(\mathbb{Z}/n\mathbb{Z})$-symmetric model can be obtained, in principle.Comment: 24 pages, 4 figures, published in J. Phys. A: Math. Theor. 43 (2010) 085202. For the next thirty days from Feb 5 2010, the full text of the article will be completely free to access through our 'This Month's Papers' service (www.iop.org/journals/thismonth), helping you to benefit from maximum visibilit

Vertex operator approach for correlation functions of Belavin's (Z/nZ)-symmetric model

Belavin's $(\mathbb{Z}/n\mathbb{Z})$-symmetric model is considered on the basis of bosonization of vertex operators in the $A^{(1)}_{n-1}$ model and vertex-face transformation. The corner transfer matrix (CTM) Hamiltonian of $(\mathbb{Z}/n\mathbb{Z})$-symmetric model and tail operators are expressed in terms of bosonized vertex operators in the $A^{(1)}_{n-1}$ model. Correlation functions of $(\mathbb{Z}/n\mathbb{Z})$-symmetric model can be obtained by using these objects, in principle. In particular, we calculate spontaneous polarization, which reproduces the result by myselves in 1993.Comment: For the next thirty days the full text of this article is available at http://stacks.iop.org/1751-8121/42/16521

Compound basis arising from the basic A1(1)A^{(1)}_{1}-module

A new basis for the polynomial ring of infinitely many variables is constructed which consists of products of Schur functions and Q-functions. The transition matrix from the natural Schur function basis is investigated.Comment: 12 page