On the Hierarchy Between Non-Commutative and Ordinary Supersymmetric Yang-Mills

Non-commutative supersymmetric Yang-Mills with rational Theta is dual to an ordinary supersymmetric Yang-Mills with a 't Hooft flux. It is believed that the simplest description is via the ordinary supersymmetric Yang-Mills. We claim, however, that the two descriptions form a hierarchy. The SYM description is the proper description in the ultra violet while the non-commutative description takes over in the infra red.Comment: 16 pages, 3 figures, references adde

Large branes in AdS and their field theory dual

Recently it was suggested that a graviton in $AdS_5 \times S^5$ with a large momentum along the sphere can blow up into a spherical D-brane in $S^5$. In this paper we show that the same graviton can also blow up into a spherical D-brane in $AdS_5$ with exactly the same quantum numbers (angular momentum and energy). These branes are BPS, preserving 16 of the 32 supersymmetries. We show that there is a BPS {\it classical} solution for SYM on $S^3\times R$ with exactly the same quantum numbers. The solution has non-vanishing Higgs expectation values and hence is dual to the large brane in AdS.Comment: 20 pages, 6 figures, minor change

Possible evolutionary transition from rapidly rotating neutron stars to strange stars due to spin-down

We present a scenario of formation of strange stars due to spin-down of {\it rapidly rotating} neutron stars left after supernova explosions . By assuming a process where the total baryon mass is conserved but the angular momentum is lost due to emission of gravitational waves and/or the magnetic braking, we find that the transition from rapidly rotating neutron stars to slowly rotating strange stars is possible; a large amount of energy $\sim 10^{53} ergs$ could be released. The liberated energy might become a new energy source for a delayed explosion of supernova. Furthermore, our scenario suggests that the supernova associated with gamma-ray bursts could become candidates for targets in the future observation of gravitational waves.Comment: 11 pages, 3 figures, Received November 5, 200

Finite volume QCD at fixed topological charge

In finite volume the partition function of QCD with a given $\theta$ is a sum of different topological sectors with a weight primarily determined by the topological susceptibility. If a physical observable is evaluated only in a fixed topological sector, the result deviates from the true expectation value by an amount proportional to the inverse space-time volume 1/V. Using the saddle point expansion, we derive formulas to express the correction due to the fixed topological charge in terms of a 1/V expansion. Applying this formula, we propose a class of methods to determine the topological susceptibility in QCD from various correlation functions calculated in a fixed topological sector.Comment: 22pages, references adde

Non-commutative gauge theory on D-branes in Melvin Universes

Non-commutative gauge theory with a non-constant non-commutativity parameter can be formulated as a decoupling limit of open strings ending on D3-branes wrapping a Melvin universe. We construct the action explicitly and discuss various physical features of this theory. The decoupled field theory is not supersymmetric. Nonetheless, the Coulomb branch appears to remain flat at least in the large N and large 't Hooft coupling limit. We also find the analogue of Prasad-Sommerfield monopoles whose size scales with the non-commutativity parameter and is therefore position dependent.Comment: 15 pages, 1 figure, reference adde

Nucleosynthesis in Type II Supernovae

Presupernova evolution and explosive nucleosynthesis in massive stars for main-sequence masses from 13 $M_\odot$ to 70 $M_\odot$ are calculated. We examine the dependence of the supernova yields on the stellar mass, ^{12}C(\alpha, \gamma) ^{16}O} rate, and explosion energy. The supernova yields integrated over the initial mass function are compared with the solar abundances.Comment: 1 Page Latex source, 10 PostScript figures, to appear in Nuclear Physics A, Vol. A616 (1997

Non-Linear/Non-Commutative Non-Abelian Monopoles

Using recently proposed non-linearly realized supersymmetry in non-Abelian gauge theory corrected to the order (alpha')^2, we derive the non-linear BPS equations in the background B-field for the U(2) monopoles and instantons. We show that these non-Abelian non-linear BPS equations coincide with the non-commutative anti-self-dual equations via the Seiberg-Witten map.Comment: 9 pages, LaTe