Test of the Skyrme Effective Field Theory Using Quenched Lattice QCD

The Skyrme effective field theory is tested by evaluating nucleon ground state matrix elements of the correlation functions for two flavor density operators and two pseudoscalar density operators in the Skyrme model and comparing them with results in quenched lattice QCD. The possiblility of using quenched lattice QCD to study higher-order terms in effective field theory is also discussed.Comment: 20 pages in TeX, 6 figures added using "figures", MIT-CTP-200

Insight into the Role of Instantons and their Zero Modes from Lattice QCD

Evidence from lattice QCD calculations is presented showing that instantons and their associated zero modes play a major role in the physics of light hadrons and the propagation of light quarks in the QCD vacuum.Comment: Proceedings of KEK Tanashi Symposium. 8 pages LaTe

Bijective Proofs of Gould's and Rothe's Identities

We first give a bijective proof of Gould's identity in the model of binary words. Then we deduce Rothe's identity from Gould's identity again by a bijection, which also leads to a double-sum extension of the $q$-Chu-Vandermonde formula.Comment: 4 page

Instanton Distribution in Quenched and Full QCD

In order to optimize cooling as a technique to study the instanton content of the QCD vacuum, we have studied the effects of alternative algorithms, improved actions and boundary conditions on the evolution of single instantons and instanton anti-instanton pairs. Using these results, we have extracted and compared the instanton content of quenched and full QCD.Comment: 3 pages, LaTeX file + 3 figures included, uses epsfig.sty and espcrc2.sty. Talk presented at LATTICE96(topology

Study of Instanton Contributions to Moments of Nucleon Spin-Dependent Structure Functions

Instantons are the natural mechanism in non-perturbative QCD to remove helicity from valence quarks and transfer it to gluons and quark-antiquark pairs. To understand the extent to which instantons explain the so-called "spin crisis" in the nucleon, we calculate moments of spin-dependent structure functions in quenched QCD and compare them with the results obtained with cooled configurations from which essentially all gluon contributions except instantons have been removed. Preliminary results are presented.Comment: LATTICE98(matrixelement), 3 pages, 1 figur

Instantons, the QCD Vacuum, and Hadronic Physics

A large body of evidence from lattice calculations indicates that instantons play a major role in the physics of light hadrons. This evidence is summarized, and recent results concerning the instanton content of the SU(3) vacuum, instanton contributions to the static potential, and a new class of instanton solutions at finite temperature are reviewed.Comment: 13 pages, 8 figures, Latex using Boxed EPS Macros, LATTICE98 Plenary Tal

Evidence for Possible Phase-Separations in RuSr2(Gd,Ce)2Cu2O10-delta

An unusual thermal-magnetic hysteresis was observed between a minor magnetic transition around 120 K and the main one at 80 K in superconducting RuSr2(R,Ce)2Cu2O10-delta (Ru1222R) samples, where R = Gd or Eu, down to a submicron length-scale. The observation suggests a possible phase-separation and is consistent with the very small but universal demagnetizing factor observed, which is difficult to reconcile with the canted spin-structure previously proposed. In such a scenario, the unusual superconducting properties of the Ru-based cuprates can also be understood naturally.Comment: 8 pages, 3 figures, submitted to Phys. Rev. B, "Rapid Communications" (September 26, 2001

30 Doradus - a Template for "Real Starbursts"?

30 Doradus is the closest massive star forming region and the best studied template of a starburst. In this conference paper we first summarize the properties of 30 Doradus and its stellar core, R136. We discuss the effects of insufficient spatial resolution and cluster density profiles on dynamical mass estimates of super star clusters, and show that their masses can be easily overestimated by a factor of ten or more. From a very simple model, with R136-like clusters as representative building blocks, we estimate typical luminosities of the order 10^11 L_o for starburst galaxies.Comment: To be published in "Starbursts: From 30 Doradus to Lyman Break Galaxies", eds. R. de Grijs & R.M. Gonzalez Delgad