α-states in de Sitter space

Field theory in de Sitter space admits a one-parameter family of vacua determined by a superselection parameter α. Of these vacua, the Euclidean vacuum uniquely extrapolates to the vacuum of flat Minkowski space. States which resemble the α-vacua can be constructed as excitations above the Euclidean vacuum. Such states have modes α(k) which decay faster that k^(1-d)/2. Fields in such states exhibit nonlocal correlations when examined from the perspective of fields in the Euclidean vacuum. The dynamics of such entangled states are fully consistent. If an α-state with properties that interpolate between an α-vacuum and the Euclidean vacuum were the initial condition for inflation, a signature for this may be found in a momentum dependent correction to the inflationary power spectrum. The functional formalism, which provides the tool for examining physics in an α-state, extends to fields of other spin. In particular, the extension to spin-2 may proffer a new class of infrared modifications to gravitational interactions. The implications of superselection sectors for the landscape of string vacua are briefly discussed.