On Monday, May 7, 2018 at 12:39:45 AM UTC-5, Bruce wrote: > > > You are probably right. He is wrong about Hawking radiation in most > respects: particularly because he think it comes from vacuum loops near the > horizon -- there are no such loops containing only photons. Hawking > radiation comes about because the horizon mixes the positive and energy > frequency parts of the field, so the definition of the vacuum (zero > particle state) is different in the presence of the horizon. Nothing to do > with virtual loops. > > Bruce >
The loop at the intersection of two null lines in a Penrose diagram indicates something funny. The loop does not occur in a single causally complete region. It occurs across event horizons. For the accelerated observer the loop appears to slowly asymptotically emerge from the past horizon and then converge to the future horizon. This observer does not witness a complete loop. This accelerated observer witnesses locally an anti-de Sitter metric, and we know these spacetimes have closed loops. This loop can then be interpreted as a closed loop that enters a conformal patch that is causally complete according to the accelerated observer. This involves no quantum mechanical interpretation. That the loop is considered quantum mechanical does raise some subtle issues. In particular I think this suggests some connection between the causal structure of AdS spacetimes and quantum mechanics or QFT. We may then consider this loop as a virtual photon. This may then be a photon in an offshell configuration and which corresponds to amplitudes emitted to I^+ in the exterior region. There are some subtle things going on here. LC -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
