Speed of LIght limit being broken - again?

I thought there was already a topic where some research seemed to indicate the speed of light being broken in confounding way{s} but I could not find it. This article {& ripped image} at Extreme tech is interesting in that sense {to me at least!}

Chinese physicists measure speed of Einstein’s ‘spooky action at a distance’: At least 10,000 times faster than light

At least, they said, and maybe instantaneous. Their equipment doesn't allow more precise measurement. Pretty cool.

Hi Dugs, OP.

There are still (not that I except any) no hint that matter or information have exceeded the speed of light. This seems to be some variant of Bells Hypothesis I suspect the media got hold of this one :-( and did its usual thing.

Okay, no.

The report a couple years ago about superluminal neutrinos turned out to be, as everyone vaguely familiar with physics expected it to be, completely wrong. (Problems with the clocks.)

And this is just standard-issue entanglement/Bell's Theorem stuff, as guido47 suggests. Nothing actually exceeded the speed of light, this cannot be used to transmit information, relativity remains unscathed.

Despite the naysayers it all seems to be following the grand design ;-)

http://www.librarything.com/topic/22475#327336

5> You can't use entangled particles for communication.

#6 I realize this is a very generic statement from the article but it seems your opinion is not shared by everyone "A lot of work is being done in this area, though, and some physicists believe that faster-than-light communication might be possible with some clever manipulation of entangled particles."

The idea must be to tempting to dismiss for some.

7>

Whatever. I'm not in this group to be insulted. Actually I'm not sure why I'm in this group at all anymore, since it seems to have become "Credulous nonsense!" "Calm science-based refutation." "Pouting!"

"A lot of work is being done in this area, though, and some physicists believe that faster-than-light communication might be possible with some clever manipulation of entangled particles."

The idea must be to tempting to dismiss for some.

The idea is easy to dismiss for anybody with basic knowledge of modern physics (specifically the no-cloning theorem). lorax is absolutely right that entanglement is consistent with relativity and cannot be used to transmit information faster than the speed of light. Even without modern physics, the following observation should suffice to reign in any over-exuberance: Any communication using entangled particles would require those particles themselves to be separated, and they can only move at or below the speed of light.

Unfortunately, there's a great deal of confusion and misinformation on this issue in the media, in some "pop sci" books, and from crackpots who proclaim themselves to be "some physicists". For example, the claim that entanglement violates relativity is one of the more egregious errors in Bill Byrson's Short History of Nearly Everything.

I would be surprised if we find incontrovertible evidence that violates Einstein in my lifetime. Relativity is one of the most tested and well-established principles in physics. On the other hand, there is a possibility, however small, that we may find discrepancies that lead to an even better theory. While great claims require great evidence, in science we make better and better models to account for the known data. Describing truth is a more complicated matter...

"Any communication using entangled particles would require those particles themselves to be separated, and they can only move at or below the speed of light." Good point daschaich. I always wonder how long the "entanglement" lasts when reading journalistic descriptions of the effect. I have never done much toward finding out but I am still curious.

I always wonder how long the "entanglement" lasts when reading journalistic descriptions of the effect. I have never done much toward finding out but I am still curious.

Well, the article you linked reports that the entangled photons were separated by about 15km, so say that each photon traveled roughly 10km after being entangled. Photons move at the speed of light, roughly 300,000km/s, so we're talking about an order of magnitude of 1/30000~0.00001 seconds (tens of microseconds).

It's possible for entanglement to last much longer than that in different conditions where the entangled particles don't move over large distances. A quick Google search for "entanglement time record" was dominated by a heavily publicized 2011 paper reporting "steady state" entanglement lasting about an hour (thousands of seconds). This requires continuously regenerating the entanglement, so it's not really the situation we're interested in. They mention, however, that without regeneration their large room-temperature system maintains entanglement for 0.04 seconds. I would expect smaller and colder systems to remain entangled for longer.

Sorry it took so long to say thanks for the reply daschaich! I have been busy with a lot of personal "issues".

Just read an article also about Hawking saying there "are no black holes" in that they would destroy information forever & violate the quantum theory in some way. He redefines the concept of black holes balancing quantum theory and general relativity. One article on the topic below, probably better ones out there. Also bending the definition of "information" into an area that is vague for me.

http://www.extremetech.com/extreme/175414-stephen-hawking-research-there-are-no-...

You might be interested in a book I read last year, The Black Hole War, in which the author describes a long-running dispute where, if I remember correctly, Hawking claimed that information was lost in a black hole and Susskind claimed that was impossible. It was a kind of argument between large-scale, cosmic, physics and quantum physics. At the end Hawking agreed with Susskind that information cannot be lost, so I guess this is Hawking's next response.

Maybe the black hole thing should be a separate thread. I think Lenny's book that jjwilson61 mentions is pretty good, and as a preview you can watch a recording of him telling its story here.

However, there have been more recent developments. Stated (too) briefly, Susskind (et al.)'s proposal that eventually won out over Hawking (et al.)'s position is based on a concept called complementarity. I won't take the time to explain what that means: it suffices to say that while this argument was pretty convincing, it was never rigorously proven, and some recent work has cast serious doubt on complementarity. This does not mean Hawking was right all along to claim that information is lost: the current consensus is that information is not lost, but it's not clear precisely how information is not lost. There is a good and much more detailed explanation here on Matt Strassler's Web site.

So while this is in a sense "Hawking's next response", he's responding most directly to that more recent work, which he cites in the first sentence (and almost every paragraph) of his paper. In fact, this "paper" is just the verbatim write-up of a talk that Hawking gave last summer at a workshop debating that recent work. If you want, you can watch the talk here. It's only about eight minutes long (followed by about 40 minutes of further discussion, mainly by the audience), and his write-up would only be about a page long if formatted in the usual style.

As far as the content of the talk/paper goes, it looks reasonable but far from conclusive. I should be clear that this is not my area of expertise, so this entire paragraph may be wrong. The bit about "there are no black holes" strikes me more as semantics than as physics. At its heart, this just seems to boil down to a statement that the predictions of classical (i.e., non-quantum) general relativity will be modified by quantum effects, which shouldn't shock anyone. The key is figuring out the correct modifications, which Hawking claims must (...in some way that doesn't seem to be explained...) make the classical event horizon merely an apparent horizon.

The bulk of the talk/paper really consists of arguments that the "recent work" I mentioned above is wrong. I happen to know one of the folks who did that work, Don Marolf. About a year ago, he quipped (I paraphrase): 'Dozens of people are arguing that we must have gotten something wrong, but no two of those critics seem to agree about what exactly that something is.' Given that Hawking doesn't mention any of those other critiques, I think this is another addition to that pile.

There is a good and much more detailed explanation here on Matt Strassler's Web site.

PS. Speak of Matt Strassler and he will write a post:
http://profmattstrassler.com/2014/01/30/did-hawking-say-there-are-no-black-holes...

I'm pleased to see that there don't seem to be any serious errors in what I wrote before. Matt provides many more details and background, also pointing out that the media itself is acting like a black hole: "information comes in, and after being completely scrambled beyond recognition, comes back out again through a mysterious process that makes no sense to anyone."

As others have mentioned there was the announcement that neutrinos might have exceeded the speed of light. I think that has been cleared up as experimental error.

The issue mentioned in the original post has to do with experimental evidence of non-separability of entangled particles. They do seem to break the speed of light barrier in restricted ways.

A third way of looking at the speed of light, as well as other "constants" such as the gravitational constant, is to ask if they are really as constant as say the number pi which have all its infinite digits precisely determined. Is the speed of light as fixed as pi or does it change after some point?

I suspect it changes, but I don't think anyone knows for sure because we have not tested it to many decimal places. This was one of the 10 items mentioned in Rupert Sheldrake's The Science Delusion when he questioned whether the laws of nature were fixed.

They entangled particles do seem to break the speed of light barrier in restricted ways.

This is mistaken, as discussed in previous posts in this thread.

Many experimental searches have been carried out for variations in apparent fundamental constants. These searches find so such variation.

Here's some information about variation in the "constant" Big G: http://www.sheldrake.org/about-rupert-sheldrake/blog/how-the-universal-gravitati...