It was not a classical computation. LC
On Sunday, December 4, 2022 at 4:17:35 PM UTC-6 [email protected] wrote: > Did you read Scott Aaronson's comments? > > Google’s Sycamore chip: no wormholes, no superfast classical simulation > either > December 2nd, 2022 > https://scottaaronson.blog/ > > Brent > > On 12/4/2022 6:57 AM, Lawrence Crowell wrote: > > There has been a lot of buzz over the supposed creation of a wormhole in a > quantum computer. I am going to comment on this from a middle ground > perspective. There are those who have condemned this as absolute nonsense, > Peter Woit for instance, and a lot of science media attention filled with > hype. I want to give some idea on what this is about and how on the one > hand this is an important result, but on the other hand we do not have a > real wormhole that we can travel across the universe with. In the end this > is just a demonstration of how quantum mechanics and general relativity > have a correspondence. Here the entanglement of many states has properties > corresponding to spacetime physics. This fairly remarkable. > > This experiment published in > https://www.nature.com/articles/s41586-022-05424-3 involves an extension > of the ER = EPR result of Maldacena and Susskind from nontraversable to > traversable wormholes. Below a discussion on the role of ER = EPR with > respect to the conservation of quantum information is given. The truncated > Penrose diagram illustrates a green region with fields interior to the > black hole entangled with fields in the interior. However, after the Page > time this region splits into the interior island, states entangled with the > observer and the exterior states. > > On arXiv:2006.06872 the paper "The entropy of Hawking radiation" by A. > Almheiri, T. Hartman, J. Maldacena, E. Shaghoulian, A. Tajdini examins this > problem by looking at a new approach to the entropy of a black hole. A > method for computing the fine-grained entropy of a black hole is employed > to compute entropy of Hawking radiation. This technique extends the > Bekenstein entropy S = k A/4ℓ_p^2 into S = k A/4L_p^2 + 〈 quantum > corrections 〉 so for small black hole these are corrections that maintain > unitary evolution of black hole dynamics and quantum evaporation. > > This is a way to use Cardy's 4-dimensional conformal geometry. The Penrose > diagram, taken from the paper by Almeheiri et al is show in figure 2. After > the page time the geometry is like what occurs to an observer in the pure > Penrose diagram. Nothing is labelled, but the island of interior entangled > states is identified with the left-hand blue region. The QES is the left > vertex between the blue and green where the additional particle is > localized, and the right vertex is the later Hawking particle. > > This is to be compared to Susskind’s ER = EPR hypothesis for a > nontraversable wormhole, or a pure conformal black hole. This is a theory > to two entangled blackholes that share the same interior. The unlabeled > diagram shows the black hole interior as the upper triangle, while the > lower triangle is the white hole. The two squares on the left and right are > two exterior regions or “universes” which contain a black hole. The two > interior regions, black hole and white hole, have analogues to the > absorption and emission of particles and their operators b and b^†. The > white hole produces radiation, and the black hole absorbs it. Susskind’s > hypothesis is that this is a form of quantum entanglement, and that > particles emitted by the black hole on the right are entangled with this > alternative region. > > The two diagrams are not mapped into each other. The one below is for a > pure spacetime region without matter sources for the black hole, while the > above is not conformally equivalent on the left. This truncated Penrose > diagram removes the white hole, which we do not expect to exist on a large > scale, and changes the topology of the spacetime. There is a timelike > boundary on the left and a I^+, I^- null boundary on the right. The two > have inequivalent information or are not conformally equivalent. What is > needed is gravitational radiation associated with the backreaction of the > metric. > > We may interpret the gravitational information propagated to I^+ is > carries the topology of the pure vacuum solution. The truncated diagram has > gravitational waves propagating to the I^+ boundary, and this carries the > topological quantum numbers that defines the pure vacuum solution. In work > that I did this role for gravitational information is shown to play a role > https://www.frontiersin.org/articles/10.3389/fphy.2022.734199/full In the > end the Susskind “octopus” of wormhole based entanglements are carried in a > spacetime manner by gravitons. A bipartite entanglement of a qubit with a > black hole is a 4-entanglement, where the other two quantum units are in > the polarization directions of a weak graviton. This theory is > approximately workable for weak gravitons that are linear and obey a > Schrödinger > equation. In the UV limit this theory will break down. > > The most important feature of wormholes in the ER = EPR paradigm is that > quantum information is conserved. The simplest way to think of this is that > an EPR pair, where one enters a black hole, never fundamentally loses > entanglement. The exterior qubit become entangled with the black hole. The > exterior observer, say Bob, loses contact with Alice and her state, but > this is not what happens from the standpoint of Alice. The two descriptions > are a matter of reference frame and are not fundamentally important. If > Alice attempts to teleport a state to Bob, Bob can never receive a signal > pertaining to the setting of an apparatus in order to properly read the > teleported state. Bob, however, can teleport a state to Alice. This issue > pertains to causal domains in spacetime, where a black hole is a trapped > region bounded by a congruence of null rays, called the event horizon. > Quantum entanglement is independent of causality. > > To consider this experiment in particular this does involve a quantum > computer entanglement experiment that has an ER = EPR correspondence with a > wormhole. Further, a phase shift on qubits simulates the negative energy > condition. This involves 2^7 = 512 qubits, which is far from the N → ∞ of > the SYK theory. This is the nontraversable wormhole. What follows is the > SYK theory for a traversable wormhole. A traversable wormhole requires a > negative vacuum energy, or a violation of the averaged weak energy > condition T^{00} ≥ 0. This might be arranged with a Casimir cavity with a > confined vacuum that has a lower energy than the vacuum of free space. This > is emulated by a magnetic field induce shift of qubits. Kip Thorne has even > suggested using this as a way to pull a wormhole out of the vacuum. A > sparse matrix-like method in 2 spatial dimensions resulted in a signature > of the occurrence of a transported quantum bit, like what is expected from > a wormhole. > > This result is interesting from an academic perspective, for it indicates > a correspondence between quantum states and spacetime physics. This is very > far from generating a real wormhole in spacetime. This does illustrate how > quantum states have a dualism with spacetime physics, which is interesting > since the nonlinearity of spacetime makes quantum mechanics problematic. > From that perspective this is an interesting result. This is though very > far from any spacetime engineering of a wormhole. > > LC > > > On Saturday, December 3, 2022 at 4:56:03 PM UTC-6 [email protected] wrote: > >> From Jamie Farnes of Oxford- >> >> >> He says it gots negative mass, which for me is yummy, crunchy-sweet for >> the Penrose-Hilbert Holidays, upcoming! Negative mass keeps the mouths of >> wormholes open & accessible for travel, and mine, shut. >> >> Either >> Bizarre ‘dark fluid’ with negative mass could dominate the universe – >> what my research suggests (universal-sci.com) >> <https://www.universal-sci.com/headlines/2018/12/5/bizarre-dark-fluid-with-negative-mass-could-dominate-the-universe-what-my-research-suggests> >> Or >> [1712.07962] A Unifying Theory of Dark Energy and Dark Matter: Negative >> Masses and Matter Creation within a Modified $Λ$CDM Framework (arxiv.org) >> <https://arxiv.org/abs/1712.07962> >> >> Fire up the Interocitor, and ignite the Bussard Ramjet field, folks, >> ahead, full speed! >> >> -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/8bcb809a-6d25-45ce-bb61-75f3e4d8cba8n%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/8bcb809a-6d25-45ce-bb61-75f3e4d8cba8n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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