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marcus

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http://arxiv.org/abs/gr-qc/0501027

Edgar1813 who sometimes drops in at PF is closely associated with the team of Gambini, Pullin, and Porto.

I am glad to see they are following up on their argument about decoherence (which would make the BH information paradox unobservable)

they have constructed a discrete quantum gravity which, I believe allows them to be more precise about the decoherence----which however was established in an earlier paper using a thought experiment with optimal quantum clocks

Rodolfo Gambini, Rafael Porto, Jorge Pullin

6 pages, to appear in the proceedings of DICE 2004 (Piombino, Italy)

"A recently introduced discrete formalism allows to solve the problem of time in quantum gravity in a relational manner. Quantum mechanics formulated with a relational time is not exactly unitary and implies a fundamental mechanism for decoherence of quantum states. The mechanism is strong enough to render the black hole information puzzle unobservable."

----a brief exerpt from the conclusions section at the end---

Summarizing, we have shown that unitarity in quantum mechanics only holds when describing the theory in terms of a perfect idealized clocks. If one uses realistic clocks loss of unitarity is introduced. We have estimated a minimum level of loss of unitarity based on constructing the most accurate clocks possible. The loss of unitarity is universal, affecting all physical phenomena. We have shown that although the effect is very small, it may be important enough to avoid the black hole information puzzle.

---end quote---

Edgar1813 who sometimes drops in at PF is closely associated with the team of Gambini, Pullin, and Porto.

I am glad to see they are following up on their argument about decoherence (which would make the BH information paradox unobservable)

they have constructed a discrete quantum gravity which, I believe allows them to be more precise about the decoherence----which however was established in an earlier paper using a thought experiment with optimal quantum clocks

**Fundamental decoherence in quantum gravity**Rodolfo Gambini, Rafael Porto, Jorge Pullin

6 pages, to appear in the proceedings of DICE 2004 (Piombino, Italy)

"A recently introduced discrete formalism allows to solve the problem of time in quantum gravity in a relational manner. Quantum mechanics formulated with a relational time is not exactly unitary and implies a fundamental mechanism for decoherence of quantum states. The mechanism is strong enough to render the black hole information puzzle unobservable."

----a brief exerpt from the conclusions section at the end---

Summarizing, we have shown that unitarity in quantum mechanics only holds when describing the theory in terms of a perfect idealized clocks. If one uses realistic clocks loss of unitarity is introduced. We have estimated a minimum level of loss of unitarity based on constructing the most accurate clocks possible. The loss of unitarity is universal, affecting all physical phenomena. We have shown that although the effect is very small, it may be important enough to avoid the black hole information puzzle.

---end quote---

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