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Joseph A. Minahan

Publications and source records attributed to Joseph A. Minahan.

53 records · Page 3Linked to original sources
arXiv2000

Finite Temperature Effects in the Supergravity Dual of the N=1* Gauge Theory

We consider the supergravity dual of the N=1* theory at finite temperature by applying the Polchinski-Strassler construction to the black D3 brane solution of Type IIB supergravity. At finite temperature the 5-brane probe action is minimized when the probe falls to the horizon, although metastable minima with r>>r_H persist for a range of temperatures. Thermal effects on the 3-form source for the hypermultiplet mass m and its order m^2 back reaction on the other fields of the IIB theory are computed. We find unique solutions which are regular at the horizon and have the correct behavior on the boundary. For fixed temperature T, the horizon shrinks for increasing m^2 suggesting that there is a critical temperature separating the system into high and low temperature phases. In the high temperature phase 5-branes are unnecessary since there are no naked singularities. Using the order m^2 correction to the horizon area we calculate the correction to the entropy to be ΔS =-0.1714N^2m^2T, which is less than the free field result.

hep-th↗
arXiv1999

Asymptotic Freedom and Confinement from Type 0 String Theory

We argue that there are generic solutions to the type 0 gravity equations of motion that are confining in the infrared and have log scaling in the ultraviolet. The background curvature generically diverges in the IR. Nevertheless, there exist solutions where higher order string corrections appear to be exponentially suppressed in the IR with respect to the leading type 0 gravity terms. For these solutions the tachyon flows to a fixed value. We show that the generic solutions lead to a long range linear quark potential, magnetic screening and a discrete glueball spectrum. We also estimate some WKB glueball mass ratios and compare them to ratios found using finite temperature models and lattice computations.

hep-th↗
arXiv1998

Glueball Mass Spectra and Other Issues for Supergravity Duals of QCD Models

We derive WKB expressions for glueball masses of various finite temperature supergravity models. The results are very close to recent numerical computations. We argue that the spectra has some universality that depends only on the dimension of the AdS space and the singularity structure of the horizon. This explains the stability of the $0^{++}$ glueball mass ratios between various models. We also consider the recently proposed nonsupersymmetric model arising from the type 0 string. In the supergravity limit of this model, the heavy quark potential has an effective coupling with 1/(log u) behavior in the UV. Unfortunately, the supergravity solution implies that the heavy quark potential is still coulombic in the infrared, with an effective coupling of order 1. We also argue that the type 0 supergravity background solution does not have normalizable glueball solutions.

hep-th↗
arXiv1998

Duality Symmetries for N=2 Supersymmetric QCD with Vanishing beta-Functions

We construct the duality groups for N=2 Supersymmetric QCD with gauge group SU(2n+1) and N_f=4n+2 hypermultiplets in the fundamental representation. The groups are generated by two elements $S$ and $T$ that satisfy a relation $(STS^{-1}T)^{2n+1}=1$. Thus, the groups are not subgroups of $SL(2,Z)$. We also construct automorphic functions that map the fundamental region of the group generated by $T$ and $STS$ to the Riemann sphere. These automorphic functions faithfully represent the duality symmetry in the Seiberg-Witten curve.

hep-th↗
arXiv1998

Quark-Monopole Potentials in Large N Super Yang-Mills

We compute the quark-monopole potential for ${\cal N}=4$ super Yang-Mills in the large $N$ limit. We find an attractive potential that falls off as 1/L and is manifestly invariant under $g\to 1/g$. The strength of the potential is less than the quark-antiquark and monopole-antimonopole potentials.

hep-th↗
arXiv1996

Superconformal Fixed Points with E_n Global Symmetry

We obtain the elliptic curve and the Seiberg-Witten differential for an $N=2$ superconformal field theory which has an $E_8$ global symmetry at the strong coupling point $τ=e^{πi/3}$. The differential has 120 poles corresponding to half the charged states in the fundamental representation of $E_8$, with the other half living on the other sheet. Using this theory, we flow down to $E_7$, $E_6$ and $D_4$. A new feature is a $λ_{SW}$ for these theories based on their adjoint representations. We argue that these theories have different physics than those with $λ_{SW}$ built from the fundamental representations.

hep-th↗
arXiv1996

An N=2 Superconformal Fixed Point with E_6 Global Symmetry

We obtain the elliptic curve corresponding to an $N=2$ superconformal field theory which has an $E_6$ global symmetry at the strong coupling point $τ=e^{πi/3}$. We also find the Seiberg-Witten differential $λ_{SW}$ for this theory. This differential has 27 poles corresponding to the fundamental representation of $E_6$. The complex conjugate representation has its poles on the other sheet. We also show that the $E_6$ curve reduces to the $D_4$ curve of Seiberg and Witten. Finally, we compute the monodromies and use these to compute BPS masses in an $F$-Theory compactification.

hep-th↗
arXiv1996

$N=2$ Super Yang-Mills and Subgroups of $SL(2,Z)$

We discuss $SL(2,Z)$ subgroups appropriate for the study of $N=2$ Super Yang-Mills with $N_f=2n$ flavors. Hyperelliptic curves describing such theories should have coefficients that are modular forms of these subgroups. In particular, uniqueness arguments are sufficient to construct the $SU(3)$ curve, up to two numerical constants, which can be fixed by making some assumptions about strong coupling behavior. We also discuss the situation for higher groups. We also include a derivation of the closed form $β$-function for the $SU(2)$ and $SU(3)$ theories without matter, and the massless theories with $N_f=n$.

hep-th↗
arXiv1995

Hyperelliptic curves for Supersymmetric Yang-Mills

In this paper we discuss the hyperelliptic curve for $N=2$ $SU(3)$ super Yang-Mills with six flavors of hypermultiplets. We start with a generic genus two surface and construct the curve in terms of genus two theta functions. From this one can construct the curve for $m_i=u=0$. This curve is explicitly dual under a subgroup of $Sp(4,Z)$ which is not isomorphic to $Sp(2,Z)$. We then proceed to construct the curve for the general $SU(3)$ theory and discuss the duality properties of the theory. The results given here differ from those given previously.

hep-th↗
arXiv1994

Density Correlation Functions in Calogero Sutherland Models

Using arguments from two dimensional Yang-Mills theory and the collective coordinate formulation of the Calogero-Sutherland model, we conjecture the dynamical density correlation function for coupling $l$ and $1/l$, where $l$ is an integer. We present overwhelming evidence that the conjecture is indeed correct.

hep-th↗
arXiv1993

Interacting Fermion Systems from Two Dimensional QCD

We consider two dimensional U(N) QCD on the cylinder with a timelike Wilson line in an arbitrary representation. We show that the theory is equivalent to N fermions with internal degrees of freedom which interact among themselves with a generalized Sutherland-type interaction. By evaluating the expectation value of the Wilson line in the original theory we explicitly find the spectrum and degeneracies of these particle systems.

hep-th↗
arXiv1993

Equivalence of Two Dimensional QCD and the $c=1$ Matrix Model

We consider two dimensional QCD with the spatial dimension compactified to a circle. We show that the states in the theory consist of interacting strings that wind around the circle and derive the Hamiltonian for this theory in the large $N$ limit, complete with interactions. Mapping the winding states into momentum states, we express this Hamiltonian in terms of a continuous field. For a $U(N)$ gauge group with a background source of Wilson loops, we recover the collective field Hamiltonian found by Das and Jevicki for the $c=1$ matrix model, except the spatial coordinate is on a circle. We then proceed to show that two dimensional QCD with a $U(N)$ gauge group can be reduced to a one- dimensional unitary matrix model and is hence equivalent to a theory of $N$ free nonrelativistic fermions on a circle. A similar result is true for the group $SU(N)$, but the fermions must be modded out by the center of mass coordinate.

hep-th↗
arXiv1993

Summing Over Inequivalent Maps in the String Theory Interpretation of Two Dimensional QCD

Following some recent work by Gross, we consider the partition function for QCD on a two dimensional torus and study its stringiness. We present strong evidence that the free energy corresponds to a sum over branched surfaces with small handles mapped into the target space. The sum is modded out by all diffeomorphisms on the world-sheet. This leaves a sum over disconnected classes of maps. We prove that the free energy gives a consistent result for all smooth maps of the torus into the torus which cover the target space $p$ times, where $p$ is prime, and conjecture that this is true for all coverings. Each class can also contain integrations over the positions of branch points and small handles which act as ``moduli'' on the surface. We show that the free energy is consistent for any number of handles and that the first few leading terms are consistent with contributions from maps with branch points.

hep-th↗
arXiv1992

Integrable Systems for Particles with Internal Degrees of Freedom

We show that a class of models for particles with internal degrees of freedom are integrable. These systems are basically generalizations of the models of Calogero and Sutherland. The proofs of integrability are based on a recently developed exchange operator formalism. We calculate the wave-functions for the Calogero-like models and find the ground-state wave-function for a Calogero-like model in a position dependent magnetic field. This last model might have some relevance for matrix models of open strings.

hep-th↗
arXiv1992

Matrix Models and One Dimensional Open String Theory (Revised)

We propose a random matrix model as a representation for $D=1$ open strings. We show that the model is equivalent to $N$ fermions with spin in a central potential that also includes a long-range ferromagnetic interaction between the fermions that falls off as $1/(r_{ij})^2$. We find two interesting scaling limits and calculate the free energy for both situations. One limit corresponds to Dirichlet boundary conditions for the dual graphs and the other corresponds to Neumann conditions. We compute the boundary cosmological constant and show that it is of order $1/\log(β)$. We also briefly discuss a possible analog of the Das-Jevicki field for the open string tachyon. (n.b. This is a revised version of paper previously submitted to xxx@lanl.gov. The original version misidentified the Dirichlet and Neumann cases. This version also includes references to work by Yang that was missing in the original.)

hep-th↗
arXiv1991

Flows and Solitary Waves in Unitary Matrix Models with Logarithmic Potentials

We investigate unitary one-matrix models coupled to bosonic quarks. We derive a flow equation for the square-root of the specific heat as a function of the renormalized quark mass. We show numerically that the flows have a finite number of solitary waves, and we postulate that their number equals the number of quark flavors. We also study the nonperturbative behavior of this theory and show that as the number of flavors diverges, the flow does not reach two-dimensional gravity.

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