On Non-Abelian Structure From Matrix Coordinates

We consider the matrix quantum mechanics of N D0-branes in the background of the 1-form RR field. It is observed that the transformations of matrix coordinates of D0-branes induce on the Abelian RR field symmetry transformations that are like those of non-Abelian gauge fields. The Lorentz-like equations of motion for matrix coordinates are derived. The field strengths appearing in the Lorentz-like equations transform in the adjoint representation of U(N) under symmetry transformations. A possible relation between D0-brane dynamics in RR background, and the semi-classical dynamics of charged particles in Yang-Mills background is mentioned.Comment: 12 pages, no figures, LaTeX. v2: typos fixed, to appear in Phys. Lett.

D0-Branes As Light-Front Confined Quarks

We argue that different aspects of Light-Front QCD at confined phase can be recovered by the Matrix Quantum Mechanics of D0-branes. The concerning Matrix Quantum Mechanics is obtained from dimensional reduction of pure Yang-Mills theory to 0+1 dimension. The aspects of QCD dynamics which are studied in correspondence with D0-branes are: 1) phenomenological inter-quark potentials, 2) whiteness of hadrons and 3) scattering amplitudes. In addition, some other issues such as the large-N behavior, the gravity--gauge theory relation and also a possible justification for involving ``non-commutative coordinates'' in a study of QCD bound-states are discussed.Comment: 26 pages, LaTeX file, 3 .eps figures; v2: language is improved; v3: subsection 4.2 is changed- accepted for publication in EPJ.

First-Order Phase Transition by XY Model of Particle Dynamics

A gas-liquid type of phase transition is found based on the particle dynamics on radius-$R$ circle in which the coordinate appears as the angle-variable of 1D XY-model. Due to the specific appearance of compact-space radius (volume) in the present interpretation of XY-model, the ground-state develops a minimum at some critical radius, leading to the multi-valued Gibbs energy similar to systems with first-order phase transition.Comment: v1: LaTeX, 7 pages, 3 figs; v2: 9 pages, 5 figs, detailed comparison with magnetic system interpretation of XY-model is presented. Accepted for EP