Negative Energy Density States for the Dirac Field in Flat Spacetime

Negative energy densities in the Dirac field produced by state vectors that are the superposition of two single particle electron states are examined. I show that for such states the energy density of the field is not bounded from below and that the quantum inequalities derived for scalar fields are satisfied. I also show that it is not possible to produce negative energy densities in a scalar field using state vectors that are arbitrary superpositions of single particle states. Introduction Recent work on wormholes [1, 2, 3] and the ‘warp drive’ [4] has generated interest in matter that violates the weak energy condition. Most discussions of such exotic matter occur within the context of quantum field theory and deal with bosonic fields [1, 2, 5, 6, 8, 9] (see [10, 11, 12] for a classical discussion and [7] for a discussion of