Just the facts, ma'am. Just the facts.
Posted on 12/18/2012 9:39:41 AM PST by Ernest_at_the_Beach
The stealth technology of America's fifth-generation jet fighters, the F-22 and the F-35, could be obsolete after a new discovery from the University of Rochester in New York.
One main goal of fifth-generation aircrafts is to slip through skies over enemy lines without being targeted. It's not invisible, but elusive, and digitally feisty.
The F-35's lineup of electronic tools, work toward that end, by using a variety of sophisticated and devastating radar defeating moves. Combined with internal weapons storage, special composite skin, and reduced angles of design, the fighter does all it can to work past the weaknesses in today's aircraft detection. Lockheed Martin designers, however, did not plan for this University of Rochester research.
The U of R doesn't look to use a radar wave but instead a quantum image gleaned through a string of photons that boomerang out and back, telling operators everything they've seen. This process can't be jammed, confused, or eluded and rather than get absorbed, reflected, or even restructured to look like something else the photons supposedly report back with only the facts.
(Excerpt) Read more at businessinsider.com ...
I don’t see how this will work. The same process they rely on to detect changes in the photons should change the photons as well. How could they then tell if the properties changed before they tried to measure them, or because they tried to measure them?
This is what I was taught when I learned Bell's Theorem in graduate school. However, in the last few years this claim has become controversial.
My understanding (and I was a condensed matter theorist and not an expert on quantum ontology or high energy physics by any means) is that current thinking is that certain kinds of purely quantum information can be transmitted at superluminal velocities.
The rather strong requirement that "information" (one assumes somehow rigorously and suitably defined) cannot be transmitted superluminally, has been replaced with the weaker requirement that whatever effects might be transmitted that could convey deterministic information must be Lorentz Invariant. [In other words, there is no reference frame in which deterministic state information could be seen to be travelling backwards in time.]
The weaker requirement is clearly necessary, or we have far bigger problems in the universe than nolocality; and to my knowledge it is the only one that people concerned with the conceptual philosophy of QM have ever insisted on.
of course it does ~ you know at a minimum if A got there ~
Just the facts, ma'am. Just the facts.
Thank you. IBD is probably not the place to find a story which explains something like this clearly or even entirely correctly so your comment is very “illuminating”.
Yes, exactly! This is why I’m stumped as to how this is supposed to work. They know the polarization of the photons they sent out, okay, I can see how they could know that. However, how can they know whether the polarization has changed when the photons come back? If they try to measure it, they may be changing the polarization just by the act of observation.
That’s not really transmitting any useful information though. If you know the distance between the sender and receiver, and the nature of the intervening medium, then you already know when the photon arrives, by simple arithmetic.
Besides, quantum teleportation is not really about sending the photon somewhere; it only comes into play once the photons are already in place in two locations. You only send the entangled photon a single time, and after that, you can perform the operations to achieve the quantum teleportation.
Once they’re in place, you could then tell if someone performed an operation on the other photon, but that’s the only superluminal information you might be able to get. You couldn’t tell specifically what operation was performed unless there are accompanying subluminal transmissions to provide you with the missing information you need.
“Not there” types of technologies spot stealth and have for several decades.
For the purpose intended, finding objects otherwise not readily detected with incoherent visible light, or radar, or similar frequencies, knowing ‘it’s there’ or ‘it’s not there’ is all the information you need. ‘it’s there’ means nothing happened ~ but if ‘it’s not there’ you have a different situation entirely. Now do that a million times a second with gazillions of split photons.
Yes, I don’t think there is any requirement for photons to be created in pairs. Particles absorb and emit single photons all the time.
“For the purpose intended, finding objects otherwise not readily detected with incoherent visible light, or radar, or similar frequencies, knowing ‘it’s there’ or ‘it’s not there’ is all the information you need.”
That’s not the intended purpose of this system. It’s meant to determine if there is an object there OR if the photons have been manipulated in an attempt to make it look as if an object is not there. So, that information is simply not enough for this system.
Hence the conclusion that it can't be used for purposes of communication, or the sending of information of any kind ~ or even for sending negative-information of nothing at all.
That does not mean we can't get around those limitations eventually. Scientific observation of aggregations/groups of entangled photons is a really new field and few can begin to guess what that will lead to.
As early as 1990 AT&T was working on using entanglement to assist in protecting encrypted messages. Last time I looked at that they'd overcome many hurdles ~ but the big idea was that sometimes no information is the answer.
My understanding is that entanglement can't be used for communication since the process presumably of interest to us is instantaneous and since nothing can exceed the speed of light, then it doesn't really exist, or it's a misunderstanding, or all sorts of other reasons why somebody doesn't want it to be of use.
I do believe research into entanglement has advanced way beyond that. But the top dogs aren't talking!
Some of us are old enough to remember how laser research and technology went underground for more than 20 years. Just flat out disappeared.
Now i remember that series.....LOL!
We need another internet where only the facts are allowed. It will be called the JackWebb. ;^)
Yes, the big issue is that people, at least lay people, want this to be some supraluminal technology, when it doesn’t appear to fit that purpose. That doesn’t mean it won’t be very useful in some other purpose though.
Personally, I think trying to cross the “light barrier” will prove to be foolish. People think of the speed of light as a speed limit, when really it is the only speed there is. Everything travels at the speed of light, including matter, when you look at things in Minkowski space. We are just constantly travelling at the speed of light (or quite near to it) in the time dimension, while photons are travelling at the speed of light in the spatial dimensions.
Once you realize that, then it also solves the question of why we experience only the current moment of time, and cannot see the future or the past (except reconstructed in our memory). Since we travel at near the speed of light in the time direction, that dimension will shrink to nearly a point due to length contraction, just like spatial distances shrink to a point for photons travelling at the speed of light.
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Yes...the waves emit photons across the electromagnetic spectrum.
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