Lorentz invariance and the zero-point stress-energy tensor
  Some 65 years ago (1951) Wolfgang Pauli noted that the net zero-point energy density could be set to zero by a carefully fine-tuned cancellation between bosons and fermions. In the current article I will argue in a slightly different direction: The zero-point energy density is only one component of the zero-point stress energy tensor, and it is this tensor quantity that is in many ways the more fundamental object of interest. I shall demonstrate that Lorentz invariance of the zero-point stress energy tensor implies finiteness of the zero-point stress energy tensor, and vice versa. Under certain circumstances, (in particular, but not limited to, the finite QFTs), Pauli's cancellation mechanism will survive the introduction of particle interactions. I shall then relate the discussion to BSM physics, to the cosmological constant, and to Sakharov-style induced gravity. 
Matt Visser (Victoria University of Wellington)
gr-qc hep-th