# The extended algebra of observables for Dirac fields and the trace anomaly of their stress-energy tensor

Claudio Dappiaggi, Thomas-Paul Hack, Nicola Pinamonti
April 03, 2009
We discuss from scratch the classical structure of Dirac spinors on an arbitrary globally hyperbolic, Lorentzian spacetime, their formulation as a locally covariant quantum field theory, and the associated notion of a Hadamard state. Eventually, we develop the notion of Wick polynomials for spinor fields, and we employ the latter to construct a covariantly conserved stress-energy tensor suited for back-reaction computations. We shall explicitly calculate its trace anomaly in particular.

Keywords:
Dirac fields, QFT on curved spacetimes, trace anomaly