Vacuum Energy Density in the Quantum Yang – Mills Theory

The following sections are included:

• Introduction

• The vacuum energy density

• The intrinsically non-perturbative vacuum energy density

• The bag constant

• Analytical and numerical evaluation of the bag constant

• The trace anomaly relation

• Comparison with phenomenology

• Numerical values for B_YM in different units

• Contribution of B_YM to the dark energy problem

• Energy from the QCD vacuum

• Conclusions

• Appendix: The general role of ghosts

• Problems