Fuzzy Conifold YF6Y_F^6 and Monopoles on SF2×SF2S_F^2\times S_F^2

In this article, we construct the fuzzy (finite dimensional) analogues of the conifold $Y^6$ and its base $X^5$. We show that fuzzy $X^5$ is (the analogue of) a principal U(1) bundle over fuzzy spheres $S^2_F \times S^2_F$ and explicitly construct the associated monopole bundles. In particular our construction provides an explicit discretization of the spaces $T^{\kappa,\kappa}$ and $T^{\kappa,0}$

Monopoles On SF2S^2_F From The Fuzzy Conifold

The intersection of the conifold $z_1^2+z_2^2+z_3^2 =0$ and $S^5$ is a compact 3--dimensional manifold $X^3$. We review the description of $X^3$ as a principal U(1) bundle over $S^2$ and construct the associated monopole line bundles. These monopoles can have only even integers as their charge. We also show the Kaluza--Klein reduction of $X^3$ to $S^2$ provides an easy construction of these monopoles. Using the analogue of the Jordon-Schwinger map, our techniques are readily adapted to give the fuzzy version of the fibration $X^3 \rightarrow S^2$ and the associated line bundles. This is an alternative new realization of the fuzzy sphere $S^2_F$ and monopoles on it.Comment: version submitted to JHE

Fuzzy Cosets and their Gravity Duals

Dp-branes placed in a certain external RR (p+4)-form field expand into a transverse fuzzy two-sphere, as shown by Myers. We find that by changing the (p+4)-form background other fuzzy cosets can be obtained. Three new examples, S^2 X S^2, CP^2 and SU(3)/(U(1) X U(1)) are constructed. The first two are four-dimensional while the last is six-dimensional. The dipole and quadrupole moments which result in these configurations are discussed. Finally, the gravity backgrounds dual to these vacua are examined in a leading order approximation. These are multi-centered solutions containing (p+4)- or (p+6)-dimensional brane singularities.Comment: 36 pages, harvmac, no figures, two references adde

Twisted Conformal Symmetry in Noncommutative Two-Dimensional Quantum Field Theory

By twisting the commutation relations between creation and annihilation operators, we show that quantum conformal invariance can be implemented in the 2-d Moyal plane. This is an explicit realization of an infinite dimensional symmetry as a quantum algebra.Comment: 10 pages. Text enlarged. References adde

Quantum Entropy for the Fuzzy Sphere and its Monopoles

Using generalized bosons, we construct the fuzzy sphere $S_F^2$ and monopoles on $S_F^2$ in a reducible representation of $SU(2)$. The corresponding quantum states are naturally obtained using the GNS-construction. We show that there is an emergent non-abelian unitary gauge symmetry which is in the commutant of the algebra of observables. The quantum states are necessarily mixed and have non-vanishing von Neumann entropy, which increases monotonically under a bistochastic Markov map. The maximum value of the entropy has a simple relation to the degeneracy of the irreps that constitute the reducible representation that underlies the fuzzy sphere.Comment: 21 pages, typos correcte

A Matrix Model for QCD: QCD Colour is Mixed

We use general arguments to show that coloured QCD states when restricted to gauge invariant local observables are mixed. This result has important implications for confinement: a pure colourless state can never evolve into two coloured states by unitary evolution. Furthermore, the mean energy in such a mixed coloured state is infinite. Our arguments are confirmed in a matrix model for QCD that we have developed using the work of Narasimhan and Ramadas and Singer. This model, a $(0+1)$-dimensional quantum mechanical model for gluons free of divergences and capturing important topological aspects of QCD, is adapted to analytical and numerical work. It is also suitable to work on large $N$ QCD. As applications, we show that the gluon spectrum is gapped and also estimate some low-lying levels for $N=2$ and 3 (colors). Incidentally the considerations here are generic and apply to any non-abelian gauge theory.Comment: 16 pages, 3 figures. V2: comments regarding infinite energy and confinement adde

Thermal Correlation Functions of Twisted Quantum Fields

We derive the thermal correlators for twisted quantum fields on noncommutative spacetime. We show that the thermal expectation value of the number operator is same as in commutative spacetime, but that higher correlators are sensitive to the noncommutativity parameters $\theta^{\mu\nu}$.Comment: 4 pages, LaTeX. Reference added, typos corrected

Aspects of Boundary Conditions for Nonabelian Gauge Theories

The boundary values of the time-component of the gauge potential form externally specifiable data characterizing a gauge theory. We point out some consequences such as reduced symmetries, bulk currents for manifolds with disjoint boundaries and some nuances of how the charge algebra is realized.Comment: 15 page