Seminarium KMMF "Teoria Dwoistości"

It is at the heart of gauge theory that one cannot find potentials forthe massless Wigner +/-h field strength tensors which are (i) local,(ii) covariant, (iii) have 2 degrees of freedom and (iv) live on theWigner-Fock Hilbert space of their field strength. Typically, one keepslocality, introduces unphysical degrees of freedom and works on anindefinite Krein space in intermediate steps. However, one can alsointroduce non-local potentials which satisfy (ii)-(iv), for example"string-localized" potentials.I present recent results on the self- and matter-interaction ofstring-localized graviton potentials. The structure of theseinteractions is determined by the requirements that the physicalquantities, in this case the S-matrix, are local and string independent.Although only derived at tree level, the results are "purely quantum" inthe sense that they do not refer to the gauge invariance of anunderlying classical theory.