14,336 research outputs found
The chiral condensate in a constant electromagnetic field
We study the shift of the chiral condensate in a constant electromagnetic
field in the context of chiral perturbation theory. Using the Schwinger
proper-time formalism, we derive a one-loop expression correct to all orders in
. Our result correctly reproduces a previously derived
``low-energy theorem'' for . We show that it is essential to include
corrections due to non-vanishing in order for a low energy theorem to
have any approximate regime of validity in the physical universe. We generalize
these results to systems containing electric fields, and discuss the regime of
validity for the results. In particular, we discuss the circumstances in which
the method formally breaks down due to pair creation in an electric field.Comment: 9 pages, 6 figures, LaTeX; removed extraneous section + minor
revision
Tangle and Brauer Diagram Algebras of Type Dn
A generalization of the Kauffman tangle algebra is given for Coxeter type Dn.
The tangles involve a pole or order 2. The algebra is shown to be isomorphic to
the Birman-Murakami-Wenzl algebra of the same type. This result extends the
isomorphism between the two algebras in the classical case, which in our
set-up, occurs when the Coxeter type is of type A with index n-1. The proof
involves a diagrammatic version of the Brauer algebra of type Dn in which the
Temperley-Lieb algebra of type Dn is a subalgebra.Comment: 33 page
The United States-Canadian Automotive Trading Relationship and the Legality of the Canadian Duty Remission Program
The automotive industry influences the entire U.S. economy. This huge industrial structure directly affects over four million jobs in the United States. In terms of foreign trade in 1985, the United States exported approximately $6 billion worth of new passenger cars to foreign nations; 96 percent of those automobiles went to Canada. This is an illustration of the U.S. automotive industry\u27s direct interest in the U.S.-Canadian trading relationship, and the desire to obtain the potential benefits of a broadened trading relationship between the two countries. Presently, the United States and Canada have a unique dutyfree automotive trading arrangement which is distinguishable from those of other automotive trading nations
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