Sala 422 12:15 
Seminarium Instytutu

prof. dr hab. Krzysztof A. Meissner, UW

Conformal anomalies

We argue that the presence of conformal anomalies in gravitational theories can lead to observable modifications to Einstein’s equations via the induced anomalous effective actions, whose non-localities can overwhelm the smallness of the Planck scale. The fact that no such effects have been seen imposes strong restrictions on the field content of possible extensions of Einstein’s theory: all viable theories should have vanishing conformal anomalies. It turns out that a complete cancellation of conformal anomalies in D = 4 can only be achieved for N-extended supergravity multiplets with N > 4, as well as for M theory compactified to four dimensions.