Wednesday, August 31, 2005 ... Deutsch/Español/Related posts from blogosphere

Entanglement entropy

One of the most interesting papers 24 hours ago was a paper by three authors from Santa Barbara, Israel, and Michigan claiming that the black hole entropy in all known examples in string theory may be entirely interpreted as

It is certainly true that not everyone has believed and believes that the whole entropy equals the entanglement entropy; others viewed entanglement entropy merely as one of the contributions. The total number of microstates of the interior counts the total entropy; but it is not necessarily true that each of them is entangled with a different state of the exterior degrees of freedom. The entanglement entropy could therefore be smaller. I am curious to hear comments from others.

Also,

offers a new proof of the CSW rules for the tree amplitudes based on the maximally helicity violating vertices. If someone can explain in what sense the proof is more direct than the BCFW proof, it may be interesting.


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reader Plato said...

If not in your surprize(?) I do not think you and Lee Smolin are too far apart?

Glast determination in "calorimeric views" would be consistent with attempts with "gluonic perception" at such levels?

It would be hard to know this starting point? Yet the blackhole seems to be where we must start:)?

Sorry for layman "point" of view


reader P.P. Cook said...

Hi Lubos,

First permit me to confess that I have not read the paper about entanglement entropy yet. However, from my unenlightened position, I find it very unlikely that all the entropy of a black hole comes from entanglement. My motivation is simple and probably naive: extremal black holes have no Hawking temperature but do have an entropy. I can only conceive entanglement (between states inside and outside the event horizon) occurring through Hawking radiation. So extremal black holes would have no degrees of freedom to explain their entropy. And even for a radiating non-extremal black hole, isn't the entropy of the black hole itself decreasing during the process? My apologies if these comments are daft, but I would appreciate your opinion/correction :)

Oh, and what do you think?

Best wishes,
Paul