Towards a solution of the cosmological constant problem

F. R. Klinkhamer^{#}, G. E. Volovik ^{*+ 1)}

^{#}Institute for Theoretical Physics, University of Karlsruhe, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany

^{*} Low Temperature Laboratory, Aalto University, FI-00076 AALTO, Finland

^{+} Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia

**Abstract**

The standard model of elementary particle physics
and the theory of general relativity can be extended by
the introduction of a vacuum variable which is responsible for
the near vanishing of the present cosmological constant (vacuum energy
density). The explicit realization of this vacuum variable can be via a
three-form gauge field, an aether-type velocity field, or any other field
appropriate for the description of the equilibrium state corresponding to the
Lorentz-invariant quantum vacuum. The extended theory has, without
fine-tuning, a Minkowski-type solution of the field equations with
spacetime-independent fields and provides, therefore, a possible solution of
the main cosmological constant problem.