Narrow Results

While the accumulation of long wavelength modes during inflation wreaks havoc on the large scale structure of spacetime, the question of even observability of their presence by any local observer has lead to considerable confusion. Though, it is commonly agreed that infrared effects are not visible to a single sub-horizon observer at late times, we argue that the question is less trivial for a patient observer who has lived long enough to have a record of the state before the soft mode was created. Though classically, there is no obstruction to measuring this effect locally, we give several indications that quantum mechanical uncertainties censor the effect, rendering the observation of long modes ultimately forbidden.

We consider infrared dependences of chiral effects, like chiral magnetic effect, in chiral media. The main observation is that there exist competing infrared-sensitive parameters, sometimes not apparent. The value of the chiral effects depends in fact on the actual hierarchy of the parameters. Some examples have been already given in the literature. We argue that magnetostatics of chiral media with a non-vanishing chiral chemical potential μ₅ ≠ 0 is also infrared sensitive. In particular, the system turns to be unstable if the volume is large enough. The instability is with respect to the decay of the system into domains of non-vanishing magnetic field with non-trivial helicity.