  We discover that some unstable vacua have long memory. By that we mean that
even in the theories containing only massive particles, there are correllators
and expectation values which grow with time. We examine the cases of
instabilities caused by the constant electric fields, expanding and contracting
universes and, most importantly, the global de Sitter space. In the last case
the interaction leads to a remarkable UV/IR mixing and to a large back
reaction. This gives reasons to believe that the cosmological constant problem
could be resolved by the infrared physics.
