ABSTRACT
The measurement of a non-zero cutoff in the fluctuation spectrum directly impacts the viability of inflation to simultaneously solve the temperature horizon problem and account for the formation of structure in the early Universe. Our primary interest here, though, is the electroweak phase transition, because the properties of the Higgs field inevitably lead to another horizon problem, analogous to the cosmic microwave background temperature horizon problem. The electroweak horizon problem has become much more prominent in recent years, though the earliest signs of its potential impact on cosmology actually surfaced gradually, in various guises, over the past half century. This chapter raises the possibility that the electroweak horizon problem could be resolved with a modified expansion history of the Universe. The electroweak horizon problem arises from the observation that the same vacuum expectation value has emerged everywhere, even at distances exceeding the observer’s causal horizon.
