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Counterfactual quantum cryptography (CQC) is used here as a tool to assess the status of the quantum state: Is it real/ontic (an objective state of Nature) or epistemic (a state of the observer's knowledge)? In contrast to recent approaches to wave function ontology, that are based on realist models of quantum theory, here we recast the question as a problem of communication between a sender (Bob), who uses interaction-free measurements, and a receiver (Alice), who observes an interference pattern in a Mach-Zehnder set-up. An advantage of our approach is that it allows us to define the concept of "physical", apart from "real". In instances of counterfactual quantum communication, reality is ascribed to the interaction-freely measured wave function (ψ) because Alice deterministically infers Bob's measurement. On the other hand, ψ does not correspond to the physical transmission of a particle because it produced no detection on Bob's apparatus. We therefore conclude that the wave function in this case (and by extension, generally) is real, but not physical. Characteristically for classical phenomena, the reality and physicality of objects are equivalent, whereas for quantum phenomena, the former is strictly weaker. As a concrete application of this idea, the nonphysical reality of the wavefunction is shown to be the basic nonclassical phenomenon that underlies the security of CQC.
The quantum world can be quite a strange one. Particles at opposite ends of a galaxy can instantaneously react to each other, and can exist in more than one place simultaneously. It now seems this world may be even more complicated, allowing communication to occur without a physical medium.
It's called counter-factual communication, and a group of researchers from Saudi Arabia's King Abdulaziz City of Science and Technology (KACST) and Texas A&M University in the US, have just published a paper in Physical Review Letters demonstrating it – at least in principle.
Imagine a communication channel between Alice and Bob, across which, normally something has to pass for communication to occur. But suppose Alice releases a photon – through an array of beam-splitters and mirrors – that Bob can choose to either block or not block.
What he does will rouse different detectors at Alice's end. In this way, Alice can infer Bob's action by checking her own detectors. But here is where it gets stranger: the photon didn't even have to leave Alice's side of the communication channel in order for her to know about Bob's choice.
One of the authors of the paper, Hatim Salih, a physicist at KACST, notes that, "unlike most communication protocols, in ours it is Bob who sends a message to Alice, not the other way round."
"This is a bit like Alice and Bob using pigeons to communicate – except that the pigeons never have to leave," says Zhenghong Li, one of the paper's authors.
As Salih says: "I believe the question of how information gets from Bob to Alice is a deep one speaking to the heart of the debate about the reality of the quantum state: if physical particles did not carry information between sender and receiver, what did?"
originally posted by: neoholographic
a reply to: mbkennel
This is the problem with blind materialist. You make these blind blanket statements that sound like gobbledy gook. This because QM doesn't support materialism.
You said:
No, quantum mechanics does NOT say any of that BS. Quantum mechanics is a physical theory of natural phenomena.
Show me the evidence that shows the wave function is physical.
An advantage of our approach is that it allows us to define the concept of "physical", apart from "real". In instances of counterfactual quantum communication, reality is ascribed to the interaction-freely measured wave function (ψ) because Alice deterministically infers Bob's measurement. On the other hand, ψ does not correspond to the physical transmission of a particle because it produced no detection on Bob's apparatus.
“I go into the Upanishads to ask questions.”
The wave-particle duality of electrons or photons does not collapse because we consciously consider that duality -- it collapses only after mechanical measurement, with the mechanical measurement causing the waveform to collapse (with "collapsing waveform" being a purely rhetorical way of describing it, considering it is more complicated than that).
Everything we call real is made of things that cannot be regarded as real.
I think that modern physics has definitely decided in favor of Plato. In fact the smallest units of matter are not physical objects in the ordinary sense; they are forms, ideas which can be expressed unambiguously only in mathematical language.
The observer is never entirely replaced by instruments; for if he were, he could obviously obtain no knowledge whatsoever.... Many helpful devices can facilitate this work...But they must be read! The observer’s senses have to step in eventually. The most careful record, when not inspected, tells us nothing.
“This life of yours which you are living is not merely a piece of this entire Existence, but in a certain sense the whole; only this whole is not so constituted that it can be surveyed in one single glance. This, as we know, is what the Brahmins (wise men or priests in the Vedic tradition) express in that sacred, mystic formula which is yet really so simple and so clear; Tat Tvam Asi, That Thou Art.”
theopendoorway.org...
What you are actually is beyond words, but it would be not untrue to say you are nothing whatsoever other than pure, infinite, disembodied consciousness/intelligence; a field of miraculous infinite light; God dreaming itself; an infinite point of pure potential; or the infinite implications of nothing whatsoever.
The immediate presentation of this unspeakable actuality is the field of your experience, which is an instantaneously appearing virtual field of Radiant Presence as apparent qualities. This is the actuality of which every/ and any/ thing that you think exists consists. This is inclusive and complete; nothing whatever other than this field exists. In short, the entirety of Reality is the "bubble" of YOUR experience, the field of Radiant Presence, which alone exists.
This is the totality of Reality. This is not theoretical, but is actually, immediately real; always the case right here right now.
Why can't the universe just be a materialistic place, doing its thing the same way before human thought came along, and will continue doing its thing after humans and human thought are extinct?
Ready for a mind-bending news story that will forever change your perception of life? Quantum physicists in Israel have successfully entangled two photons that don’t exist at the same time. They create one photon and measure its polarization, destroying it — they then create another photon, and though it never coexisted with the first, it always has the exact opposite polarization, proving they’re entangled.
originally posted by: FunkyContents
a reply to: Soylent Green Is People
Why can't the universe just be a materialistic place, doing its thing the same way before human thought came along, and will continue doing its thing after humans and human thought are extinct?
Do you have any proof that anything ever happens or happened, outside of conscious perception?
On the other hand, I can prove that everything happens inside of conscious perception.
originally posted by: Soylent Green Is People
If the universe seems as it is only due to our perception of it, then why do we perceive it the way it is -- i.e., unimaginably so huge that the Earth is a infinitesimally small bit of almost nothingness in comparison, and the time of humans on that Earth has occurred in an almost imperceptible and infinitesimally small blip of time. The universe we perceive is so huge and has existed so long that humans seem to not even matter. Why would we perceive such a universe if the universe wasn't really like that.
I don't feel I'm special in comparison to the universe. I don't think human thought is important to the workings of the universe, and I don't think humans are special or important enough that it would make a difference to the universe whether or not we were around to perceive it.
Why would I think I and humans are special? Especially considering how infinitesimal our existence is (in both space and time) in relation to a much much grander universe -- a universe that does its thing without any reliance on human thought.
There is no known method to communicate information between entangled particles. Maybe we will find a method to do so someday, but your statement seem to be saying that it is a fact that we can do so right now. We can't.
If the universe seems as it is only due to our perception of it, then why do we perceive it the way it is -
That's a bit of a circular argument...i.e., "I wrongly perceive the universe as being materialistic only because that's the way my consciousness is programed to perceive it"
I need some evidence that my consciousness is programmed that way. In fact, I need some evidence that a separate thing called 'consciousness" exists at all, other than an emergent construct within my own brain caused by the chemical processes in my brain.
I mean, sure, it's fun to think philosophically about the possibilities of consciousness being a separate entity that exists outside of brain chemistry. If we want to get really philosophical, then the only thing any person can be sure about is his/her own existence. It's entirely possible that while you may know you exist, there is no reason to believe that anyone/anything else exists outside of your brain. You may be the only being in existence, and the rest of the universe does not really exist, but instead is only a construct of your own mind.
Is it cool to consider those possibilities? Sure. Do I actually believe in them? No.
originally posted by: FunkyContents
a reply to: Soylent Green Is People
There is no known method to communicate information between entangled particles. Maybe we will find a method to do so someday, but your statement seem to be saying that it is a fact that we can do so right now. We can't.
We actually can communicate information between entangled particles, we just can't use it for "faster than light" communication. It does indeed require a classical means of communication to place the information in perspective.
With quantum teleportation entangled particles are "communicating". If you change the spin on one partner the other changes its spin to the opposite polarisation.
This is a given. There is just no accepted mechanism that explains how this communication happened. Accepted by mainstream science that is.