arXiv subjects

Rajiv V. Gavai

Publications and source records attributed to Rajiv V. Gavai.

58 records · Page 4Linked to original sources

arXiv1996

Lattice Computations of Small-x Parton Distributions in a Model of Parton Densities in Very Large Nuclei

Using weak coupling methods McLerran and Venugopalan~\cite{LV1} expressed the parton distributions in large nuclei as correlation functions of a two dimensional Euclidean field theory. The theory has the dimensionful coupling $g^2 μ$, where $μ^2\sim A^{1/3}$ is the valence quark color charge squared per unit area. We use a lattice regularization to investigate these correlation functions both analytically and numerically for the simplified case of $SU(2)$ gauge theory. In weak coupling ($g^2μL<< 5$), where $L$ is the transverse size of the nucleus, the numerical results agree with the {\it analytic} lattice weak coupling results. For $g^2μL>> 5$, no solutions exist at O($a^4$) where $a$ is the lattice spacing. This suggests an ill-defined infrared behavior for the two dimensional theory. A recent proposal of McLerran et al.~\cite{Kovner} for an {\it analytic} solution of the classical problem is discussed briefly.

hep-ph↗

arXiv1996

A Study of the Bulk Phase Transitions of the SU(2) Lattice Gauge Theory with Mixed Action

Using the finite size scaling theory, we re-examine the nature of the bulk phase transition in the fundamental-adjoint coupling plane of the SU(2) lattice gauge theory at $β_A = 1.25$ where previous finite size scaling investigations of the deconfinement phase transition showed it to be of first order for temporal lattices with four sites. Our simulations on $N^4$ lattices with N=6, 8, 10, 12 and 16 show an absence of a first order bulk phase transition. We find the discontinuity in the average plaquette to decrease approximately linearly with $N$. Correspondingly, the plaquette susceptibility grows a lot slower with the 4-volume of the lattice than expected from a first order bulk phase transition.

hep-lat↗

arXiv1995

Finite Temperature Phase Transition in SU(2) Lattice Gauge Theory with Extended Action

We study the three dimensional fundamental-adjoint $SU(2)$ lattice gauge theory at finite temperature by Monte Carlo simulations. We find that the finite temperature deconfinement phase transition line joins the first order bulk phase transition line at its endpoint. Moreover, across the bulk transition line, the Polyakov loop undergoes a discontinuous jump implying the existence of both confining and deconfining phases on its two sides. Implications for universality and the nature of the confining-deconfining transition are discussed.

hep-lat↗

arXiv1994

Universality and the Deconfinement Phase Transition in SU(2) Lattice Gauge Theory

We study the three dimensional fundamental-adjoint $SU(2)$ lattice gauge theory at non-zero temperatures by Monte Carlo simulations. On an $8^3 \times 2$ lattice, at $β_A = 1.1$, where $β_A$ is the adjoint coupling, we find no evidence of any transition at the location of a previously known bulk phase transition around $β= 1.33$. Moreover, the deconfinement transition at $ β_A = 1.1$ occurs at $β=1.20$ and is of first order for $β_A \ge 1.1$, thus implying a change of universality class from that of the Wilson action at $β_A=0$. Computations of the plaquette susceptibility and the temporal and spatial Polyakov loops on $8^3 \times 4$ and $16^3 \times 8$ lattices at $β_A = 1.1$ further support these conclusions and suggest that the previously claimed bulk transition around $β= 1.33$ is, in fact, the first order deconfinement transition. Simulations at larger $β_A$ and the measurements of the mass gaps from the correlation functions of temporal and spatial Polyakov loops also confirm the temperature dependent nature of the above transition. The consequences of our results on universality are discussed.

hep-lat↗