A new approach to the parametrization of the Cabibbo-Kobayashi-Maskawa matrix

The CKM-matrix V is written as a linear combination of the unit matrix I and a matrix U which causes intergenerational-mixing. It is shown that such a V results from a class of quark-mass matrices. The matrix U has to be hermitian and unitary and therefore can depend at most on 4 real parameters. The available data on the CKM-matrix including CP-violation can be reproduced by $V=(I+iU)/\sqrt{2}$. This is also true for the special case when U depends on \textit{only 2 real parameters}. There is no CP-violating phase in this parametrization. Also, for such a V the invariant phase $\Phi \equiv \phi _{12}+\phi_{23}-\phi_{13}$, satisfies a criterion suggested for `maximal' CP-violation.Comment: 8 pages, latex, no figure

Locality-Aware Hybrid Coded MapReduce for Server-Rack Architecture

MapReduce is a widely used framework for distributed computing. Data shuffling between the Map phase and Reduce phase of a job involves a large amount of data transfer across servers, which in turn accounts for increase in job completion time. Recently, Coded MapReduce has been proposed to offer savings with respect to the communication cost incurred in data shuffling. This is achieved by creating coded multicast opportunities for shuffling through repeating Map tasks at multiple servers. We consider a server-rack architecture for MapReduce and in this architecture, propose to divide the total communication cost into two: intra-rack communication cost and cross-rack communication cost. Having noted that cross-rack data transfer operates at lower speed as compared to intra-rack data transfer, we present a scheme termed as Hybrid Coded MapReduce which results in lower cross-rack communication than Coded MapReduce at the cost of increase in intra-rack communication. In addition, we pose the problem of assigning Map tasks to servers to maximize data locality in the framework of Hybrid Coded MapReduce as a constrained integer optimization problem. We show through simulations that data locality can be improved considerably by using the solution of optimization to assign Map tasks to servers.Comment: 5 pages, accepted to IEEE Information Theory Workshop (ITW) 201

Fermions obstruct dimensional reduction in hot QCD

We have studied, for the first time, screening masses obtained from glueball-like correlators in Quantum Chromodynamics with four light dynamical flavours of quarks in the temperature range 1.5T_c < T < 3T_c, where T_c is the temperature at which the chiral transition occurs. We have also studied pion-like and sigma-like screening masses, and found that they are degenerate in the entire range of T. These obstruct perturbative dimensional reduction since the lowest glueball screening mass is heavier than them. Extrapolation of our results suggests that this obstruction may affect the entire range of temperature expected to be reached even at the Large Hadron Collider.Comment: 4 pages RevTeX, 2 eps figures included; minor corrections: version for publicatio

Quark Number Susceptibilities & The Wroblewski Parameter

The Wroblewski parameter is a convenient indicator of strangeness production and can be employed to monitor a signal of quark-gluon plasma production : enhancement of strangeness production. It has been shown to be about a factor two higher in heavy ion collisions than in hadronic collisions. Using a method proposed by us earlier, we obtained lattice QCD results for the Wroblewski parameter from our simulations of QCD with two light quarks both below and above the chiral transition. Our first principles based and parameter free result compare well with the A-A data from SPS and RHIC.Comment: 5 pages, Plenary talk by R.V.G. at Hard Probes 2004, Ericeira, Portugal, Nov.4-10, 2004; Reference adde

The critical end point in QCD

In this talk I present the logic behind, and examine the reliability of, estimates of the critical end point (CEP) of QCD using the Taylor expansion method.Comment: Plenary talk at SEWM 06 by S