抄録
Dark energy indicated by the current acceleration of our universe is one of the greatest mysteries in modern cosmology. Although more than 70% of our universe is thought to be dark energy, we do not know what it really is. In this situation, it seems natural to ask whether we can modify gravity at long distances to address the mystery. Ghost condensation is an analog of Higgs mechanism in general relativity, and modifies gravity at long distances without pathologies like ghost instability or strong coupling. In this presentation I discuss gravity and cosmology with ghost condensate.
