WILSON LINES AND T-DUALITY IN HETEROTIC M(ATRIX) THEORY

We study the M(atrix) theory which describes the E-8 x E-8 heterotic s tring compactified on S-1 or equivalently M-theory compactified on an orbifold (S-1/Z(2)) x S-1, in the presence of a Wilson line, We formul ate the corresponding M(atrix) gauge: theory, which lives on a dual or bifold S-1 x (S-1/Z(2)). Thirty-two real chiral fermions must be intro duced to cancel gauge anomalies, In the absence of an E-8 x E-8 Wilson line, these fermions are symmetrically localized on the orbifold boun daries, Turning on the Wilson line moves these fermions into the inter ior of the orbifold, The M(atrix) theory action is uniquely determined by gauge and supersymmetry anomaly cancelation in 2+1 dimensions, The action consistently incorporates the massive IIA supergravity backgro und into M(atrix) theory by explicitly breaking (2+1)-dimensional Poin care invariance, The BPS excitations of M(atrix) theory are identified and compared to the heterotic string. We find that heterotic T-dualit y is realized as electric-magnetic S-duality in M(atrix) theory. (C) 1 997 Elsevier Science B.V.