, basic to superfluidity, is
commonly formulated as the spatial long-range coherence in a
static correlation function involving only thermostatic
susceptibilities. Here we examine the corresponding dynamical
problem: to what extent is long-range coherence in time also
present in superfluids?It is a pleasure to dedicate this paper to Hermann Haken whose contagious fascination with - and fundamental contributions to - the problem of dynamical phase coherence in lasers in the 1960's launched and deeply influenced me on my own scientific trajectory
Key words: Bose-Einstein condensation, phase-fluctuations, off-diagonal long range order
