Runaway pulsar has astronomers scratching their heads

[Xamonas Chegwé]

You are trying to use quantum computing to deny that quantum entanglement involves the transfer of information instantaneously.

No. I am not. I have never claimed that. I am stating that QE cannot be used to transmit useful information instantaneously. I am further stating that QC does not show that it can.

The measuring of a quantum properties in one particle (A) instantaneously fixes the same states in an entangled particle (B) irrespective of distance. But, since, until they are measured, the states of A cannot be predicted in any way, neither can the states of the corresponding properties in B. So you are instantaneously transmitting essentially random values! It is not a case of cause and effect - both values are unknown until measured.

[pErvinalia]

No. I am not. I have never claimed that. I am stating that QE cannot be used to transmit useful information instantaneously. I am further stating that QC does not show that it can.

Then you haven't read the progression of quotes properly.

It was my understanding that QC used quantum entanglement via qubits (instead of classical 'bits'), so the transfer of information (whether instantaneous or not) is resulting in the refutation of what JimC said (and what I was responding to) - "Information has a fairly technical meaning, but I think it comes down to whether a bit of information can potentially change something.". If a QC can complete an algorithm whose underlying information structure is contained in qubits, then that transfer of "quantum information" DOES lead to the "change [of] something". If you thought you were refuting something else (i.e. the "useful information" strawman), then you should perhaps have expanded on your slightly simplistic answer of "NO".

[Hermit]

I have a feeling that the constant attempts to find something (matter or information) that goes faster than the speed of light are akin to trying to find exceptions to the second law of thermodynamics, and create a perpetual motion machine......

Or rather, "I read something in teh Daily Blurb that says that pasta can travel faster than light and I read it so I am clevererer than Einstein even though I left school at 15 to become a burger chef. Burger chefs are COOL!"

Yes. And "I don't know how to do - or even follow - calculus, but that is no obstacle for me to comment authoritatively on the implications of quantum mechanics, which I will insist on abbreviating as QM just to show my intimate familiarity with and thorough understanding of it."

[pErvinalia]

I'm no fan of MM's scientific knowledge in other fields (most notably climate science) but in this case, criticism of what he has said is a bit unwarranted. Abbreviating Quantum Mechanics to QM is pretty fucking common, and is a really juvenile point to bring up in a pathetic attempt to discredit someone.

[Hermit]

Abbreviating Quantum Mechanics to QM is pretty fucking common

Agreed. It is common practice among forumites, in the blogosphere and many other commentators who lack even an approximate mathematical competence that might enable them to follow the formulae leading up to the conclusions contained in Einstein's paper titled On the Electrodynamics of Moving Bodies, let alone the mathematic steps that were necessary to come up with quantum mechanics.

[pErvinalia]

Nice non sequitur.

It's common among everyone with a certain minimum education/experience. How that relates to whether someone understands it or not, is specious nonsense. Is there a certain beautiful irony here in you criticising someone else for a common forum practice, while you yourself have showed the common level of ability to prosecute a reasoned logical argument?

[mistermack]

Well, my first criticism is that Xamonas' post was just a rant.

As I said, he included no quotes or links. He didn't quote what I wrote, he criticised things I didn't say. Basically, just a shitty rant.

And at the end of it all, he's pushing the no-communication theorem as if it's set in stone.
It's a theorem. It relies on many assumptions. Which, according to wiki, are ''reasonable''.

As far as the claim that entanglement can't be used to send useful information faster than light, I certainly didn't say that it could. Big fat strawman. We all know that.
There's a big difference between saying it can't be used, and it can NEVER be used.
We all know it can't be done now. That's not the question.

At the bottom of the no-communication theorem page in wiki, there is a section laying out the opposing viewpoint. Some people seem to have missed that.

Only time will tell if the theorem stands the test of further research.
And considering that we can already communicate perfectly well at the speed of light, why would people be studying entanglement, with a view to using it in communication, as my original wiki quote stated?

[pErvinalia]

I think using it in quantum computing is not related to the speed of decoherence, but to a more exponential scaling up of normal bitwise computing. Qubits have more possible states than a binary bit. So as qubits are added, the processing power increases exponentially (or something likewise) over ordinary computers. The other benefit is that a qubit takes up way less space than an ordinary classical bit. I'm not sure how much space the associated electronics will take up, but if they are the same or smaller than a normal computer, then that will reduce the space needed per operation.

Regarding XC, he seems to have got mixed up between us and not sure what he is responding to. I suspect it's alcohol o'clock over there...

[FBM]

So anyway, are they sending anybody to get the pulsar and bring it back home? Its parents must be worried sick by now.

[mistermack]

I'm no fan of MM's scientific knowledge in other fields (most notably climate science) but in this case, criticism of what he has said is a bit unwarranted. Abbreviating Quantum Mechanics to QM is pretty fucking common, and is a really juvenile point to bring up in a pathetic attempt to discredit someone.

I think he meant you, rEv.

I didn't say QM.

Not that I give a fuck.

[pErvinalia]

Just in case everyone has had enough of the derail and wants to move on, I thought i'd just add a bit first. Information isn't a material thing. It's an abstract concept. The fact that decoherence only fixes probabilistic states that already "existed", doesn't mean information hasn't been transferred. I think the problem some people are having is that they are imagining a literal "information particle" with some property flying across space. Information doesn't have to have a material basis. It's a concept.

[pErvinalia]

I'm no fan of MM's scientific knowledge in other fields (most notably climate science) but in this case, criticism of what he has said is a bit unwarranted. Abbreviating Quantum Mechanics to QM is pretty fucking common, and is a really juvenile point to bring up in a pathetic attempt to discredit someone.

I think he meant you, rEv.

I didn't say QM.

Yeah, I know. But both him and XC were criticising you too. Either way, it's lame.

[Hermit]

Just in case everyone has had enough of the derail and wants to move on, I thought i'd just add a bit first. Information isn't a material thing. It's an abstract concept. The fact that decoherence only fixes probabilistic states that already "existed", doesn't mean information hasn't been transferred. I think the problem some people are having is that they are imagining a literal "information particle" with some property flying across space. Information doesn't have to have a material basis. It's a concept.

Conceptually, information is the message (utterance or expression) being conveyed. Therefore, in a general sense, information is "Knowledge communicated or received concerning a particular fact or circumstance". In other words facts require some form of transport to become information. We may well speculate that some means of such transport can occur at speeds greater than that of light, and I do hope that at some time in the future evidence for it will turn up, but none such has emerged to date.

[pErvinalia]

Well knowledge has been communicated. Person B knows what Person A's particle spin (or whatever) is, when Person A observes their particle. The fact that it's largely useless information (perhaps there will be a way in the future to make use of such info, I don't know), is not relevant. Look at it this way: If I give you an envelope with a message in it, but tell you to wait till you reach point B before opening it. Is that still information? Of course. And it's analogous to the entanglement argument. Just because the contents of the envelope were known by someone well before it was opened, doesn't change the fact that you have some new information that you didn't have before you opened it. What if there was a delay of years (after you arrived at point B) before you opened it? What difference does the transport make in that case? How it got there is really inconsequential to the fact that it is information.

[Rum]

Which introduced ideas of consciousness and perception, living as we do mentally, as it were, in Newtonian space in important respects. The fact that observing phenomena alters or defines them in some way is fascinating and I'm not sure it has been explored enough in terms of consciousness, as opposed to physics.