# What is the physical interpretation of the Papadodimas/Raju mirror operators?

In this paper http://arxiv.org/abs/1310.6335, the authors discuss the firewall problem and contruct so called mirror operators appearing in the correlation function. The key part seems to be (2.6) where the horizon correlator is computed (using the field operators and their mirror images) only from 'one side' for a thermal, mixed, state (as if they traced over the interior). This ensures the smooth transition across the horizon (ignoring some subtle issues they discuss as well). So, the mirror operators have the nice properties that they act localy (inside or outside) and you can decide whether to calculate the correlator on the whole state ($\Psi_{tfd}$ being the Hawking state) or just on one branch (outside as in (2.6) or (2.7)).

Here comes my question(s): They often talk about doubling the degrees of freedom (inside vs outside or no tilde vs tilde in their notation). Does their construction imply that in reality there is some redundancy in the description of the black hole interior? What I mean is that if I imagine an evaporating black hole, I get a Hawking photon outside (no tilde) and this has a counterpart inside (tilde). But by emitting the photon, the black hole (I want to consider those formed by a gravitational collapse) should lose its mass (as if a particle tunneled through the horizon) and there should be no real counterpart inside.

Is this the picture suggested by the authors of the paper when they talk about doubling the degrees of freedom?

Is somebody (inside the black hole) actually holding the tilde degrees of freedom?