Physicist Trying To Send a Signal Back In Time

phil reed writes "University of Washington physicist John Cramer is attempting to send a signal back through time." From the article: "We're going to shoot an ultraviolet laser into a (special type of) crystal, and out will come two. lower-energy photons that are entangled," Cramer said. For the first phase of the experiment, to be started early next year, they will look for evidence of signaling between the entangled photons. Finding that would, by itself, represent a stunning achievement. Ultimately, the UW scientists hope to test for retrocausality — evidence of a signal sent between photons backward in time. The test will involve sending one of the photons down 10 miles of fiber optic cable, delaying it by 50 microseconds, then testing a quantum-mechanical aspect of the delayed photon. Due to quantum entanglement, the non-delayed photon would need to reflect the measurement made 50 microseconds later on the delayed photon. In order for this to happen, some kind of signal would need to be sent 50 microseconds back in time from the delayed photon to the non-delayed photon. (Confusing? Quantum physics is like that.)

I heard about this

[alnapp]

Yesterday

Re:I heard about this

[Anonymous Coward]

and it was already a dupe!

Re:I heard about this

[ookabooka]

Yeah, I told you about it tomorrow.

A HA!

[lavid]

So this is how Bif gets rich. I knew there was no Sports Almanac.

Re:I heard about this

[Anonymous Coward]

2009 called and they want their joke back.

Slashdot posting time travel test

[Aim Here]

Test has succeeded!

Re:Slashdot posting time travel test

[Aim Here]

We at Aim Here Research laboratories are now about to begin a similar time travel experiment!

We are now going to attempt to post the reply to a slashdot thread BEFORE posting the first post in the thread!

Wish us luck, guys. This could revolutionise the internet!

Re:I am Positive, this cant work...

[MicrosoftRepresentit]

Yes, forget any of the laws of physics that might be violated here, the primary concern is this breaks the fundamental rule of the universe, the core axiom at the heart of space and time; it would allow people to cheat at the lottery.

Re:This makes no sense

[rifter]

You mean to tell me that it only just now occurred to someone to send an entangled photon through a spool of fiber and see how it affects its twin, which took a direct path?

Also, I thought entanglement couldn't be used to transmit information, as a consequence of Somebody or Another's Law.

Can anyone clarify just what this poorly-written and sensational article is actually saying?

No, this is Slashdot. You want real physicists, and you're probably barking up the wrong tree.

However you may receive several answers. They are statistically likely not to include the right answer to your question, but rather to fall into one of the following categories (in fact you may just get all of these):

1) Someone will pretend they know what they are talking about and give you a very long and detailed answer. Unfortunately it will be horribly wrong, but only people with the proper background will realize it (ie no one here). :D

2) Someone will post a completely offtopic ad hominem attack on you for no particular reason (brain hurt! must strike thing that make brain hurt!) for bonus it will probably have something to do with your sexual proclivities and/or your mother.

3) Someone will post a completely unrelated troll hoping to get people to actually read it.

4) Someone will post a smart-aleck comment predicting the reasons you will not receive your answer (Hi there!)

5) In Soviet Russia, ??? profits you!

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:I heard about this

[igny]

The major problem of time travel is grammar. See, you have already screwed been have it up .

Re: What about cause and effect?

[Anonymous Coward]

This would be like posting a response before the initial post

And who says that can't be done?

Re: What about cause and effect?

[Anonymous Coward]

This would be like posting a response before the initial post

Re:This makes no sense

[i_should_be_working]

You mean to tell me that it only just now occurred to someone to send an entangled photon through a spool of fiber and see how >it affects its twin, which took a direct path?

That's been done. I think the new thing here is that the photons are now outside of each other's light cone. Before with entanglement experiments the photons were still close enough to each other during the measurements that a naysayer could claim that when the first measurement was made a signal (traveling
Also, I thought entanglement couldn't be used to transmit information, as a consequence of Somebody or Another's Law.

Law of causality. If these systems could be used to transmit information, they could send information faster than the speed of light.

Can anyone clarify just what this poorly-written and sensational article is actually saying?

Take two entangled photons and send one really far away. Since it's known that measuring the state of the one far away will result in knowing what the state of the close one is one could claim
a) that the one far away sent an instantaneous signal to the close one, telling it what state to be in or
b) if you measure the close one first, that the one you sent away sent it's information from the 50 microsecond-in-the-future-measurement back in time to the moment you measured the close one.

I think the physicists working on this would say both of those interpretations are wrong.

Re: The Future

[ag0ny]

I don't think it's possible though, otherwise we would probably be getting messages from the future, wouldn't we?

Maybe we're already getting them.

http://en.wikipedia.org/wiki/John_Titor [wikipedia.org]

Re:Dear Mr Gates...

[xoyoyo]

Dear Mr Bush Now would be a really good time to consider adoption. Thanks The future

Re:I heard about this

[owlman17]

Testing testing. frist post. Oh wait, it didn't work. Folks, it doesn't work.

Re:I heard about this

[eclectro]

So when the dupe shows up tomorrow, we will know the experiment is a success today.

I await notification of my Nobel prize any moment now.

Re:I heard about this

[niktemadur]

A young rocket scientist named Wright
once travelled much faster than light.
He set out one day, in a relative way
and arrived on the previous night.

special type of crystal ?

[ei4anb]

I wonder if they are going to use resublimated thyotimoline?

Of course, in the clasical version of this experiment the crystal is usualy spherical with a diameter of about 20cm.

Re:I heard about this

[dewie]

Clearly you haven't read Dr. Dan Streetmentioner's Time Traveller's Handbook of 1001 Tense Formations. The correct tense is the Present Ultraconditional Subinverted Semi-active Past Subjunctive Deponent Aorist. So he willon on-have scrod it up.

HTH.

Re:special type of crystal ?

[OneSmartFellow]

I wonder if they are going to use resublimated thyotimoline?

Highly unlikely, the Nuntz coefficient is too high. More likely they would choose a lower Keyton class substance like floriumnated calpoproxylene.

damn

[Anonymous Coward]

For Petes sake, we need 1.81jiggawats for this to happen.

And keep in mind, DO NOT CROSS THE STREAMS!!!

Re: The Future

[muffen]

Why would you want to go back in time?
Going back in time would just mean you need to wait even longer for the Nintendo Wii to come out...

Re:I heard about this

[Mini-Geek]

or is that they want their joke forward?

Dear Me

[asjk]

Don't marry her.

Re: The Future

[peragrin]

Okay two questions come to mind. First you have to the ability in the past to receive said message, and then you have to follow said message, and send it again. If you sent it via email it would mostly likely end up in your spam filter and lost to you. hence useless.

As the mesage would be filled with phrases like buy IBM on this date, short sell MSFT on this date buy it back on this date. Buy Apple on this date, etc.

Re:Why send a signal back in time ?

[thenerdgod]

[past scientists] Hey future scientists, we totally got your message through the quantumly entangled photons you sent us!
[future scientists] (to past scientists, now present) You mean the message you sent us with the photons you sent into the future?
[past scientists] Awww maaan!
[future scientists] Yeah, causality's a mofo.
[past scientists] I wish we got invitations to the sorts of parties where the hostess's undergarments's wave functions were made to collapse 3 feet to the left.
[future scientists] can I borrow your hot cup of tea? I'm going to a party.

Grammar Nazi

[jdbartlett]

If you're going to have given people grammar advice, at least have done it correctly: you're using the the present ultraconditional subinverted sem-active past subjunctive deponent aorist, so that should have been "scrodding".

Re:Slashdot posting time travel test

[aplusjimages]

Not for the porn industry. People cumming before going to the site.

Re: The Future

[Nephilium]

AH-HA!

That's what all the gibberish spam is! It's us sending ourselves messages from the future!

Of course, this means that in the future, we will all need giant penises and breasts to fight off the alien invaders, but we can finance the purchasing of the pills needed by buying penny stocks, consolidating our bills, and refinancing our homes... Of course, it also means that we will all be impotant, and need to purchase viagra in order to keep our species going...

It's all so clear to me now...

Nephilium

"Even on Central Avenue, not the quietest dressed street in the world, he looked about as inconspicuous as a tarantula on a slice of angel food." -- Farewell, My Lovely (Chapter 1)

Re:Not the only scientist trying this

[LordLucless]

We'll finally have an answer to the Grandfather paradox.

Volunteers reqiured for scientific experiment to redefine time as we know it. Lack of attachment to grandparents a plus.

Re:I heard about this

[Ctrl-Z]

Didn't you already receive it?

Re:I am Positive, this cant work...

[Anonymous Coward]

It's a bit like the way a twin will instantly know when the other one is getting laid.

Not that big a feat. I always know when my twin sister is getting laid. It's kinda hard not to, since I'm the only guy she'll sleep with.

Re:I heard about this

[elrous0]

John Titor called two days ago and warned you not to make that comment.

-Eric

Re:I heard about this

[inviolet]

Clearly you haven't read Dr. Dan Streetmentioner's Time Traveller's Handbook of 1001 Tense Formations. The correct tense is the Present Ultraconditional Subinverted Semi-active Past Subjunctive Deponent Aorist. So he willon on-have scrod it up.

*golf clap*

I'm undone.

If you are located in Houston, please feel free to drop by my apartment to receive your free beer and backrub-by-nerdloving-chick. :)

Re:don't be too sure

[roaddemon]

Why is he looking for funding? It would be way more interesting if it was being funded by lottery winnings.

Of course this is possible!

[Schraegstrichpunkt]

A lot of my spam comes from the future!

Re:I heard about this

[Rufty]

No, no, NO! *This* is the dupe. The original was posted next week...

Re:I heard about this

[IAmTheDave]

you forgot to include your address.....

An address to a beer-having, backrub-giving, nerd-loving chick would see airline stock skyrocket as nerds around the world booked their tickets to Houston with the quickness, in hopes of reliving themselves of the damned iron mask that is virginity.

Re:I heard about this

[pilgrim23]

"One day while walking up the stair,
I met a man who wasn't there.
He wasn't there again today
I wish that man would go away!"

Re:don't be too sure

[whoop]

WTF!!? I read that whole link and don't see anywhere in there about how to get my Free Wii. Don't post such lies anymore.

Re:Grammar Nazi

[xENoLocO]

I may have missed something, but you grammar nazis are getting more and more difficult to understand.

Re: The Future

[SilentBob0727]

It's definitely possible to travel into the future in your own time line. In fact, it's pretty damn easy. I'll do it right now! Watch... ... ... ...

Voila, I'm in the future!

If you actually wanted me to travel "further" into the future, give me a spaceship that travels at 99.9999% of the speed of light and I'll see you in 1000 years. It's getting back that's the bitch.

Re:Grammar Nazi

[leshert]

Give him a break. He's obviously using the 2011 Revised Edition of Dr. Dan Streetmentioner's Time Traveller's Handbook of 1001 Tense Formation, back-published in 2090. The rules for deponent verbs were changed in the 2010 Third Revisionist Edition, which had willn't have beent back-publishent until 2071.

I understand that the rules for declension will have beent back-revised in the 2010 1/2 Fourth Revisionist Edition (Twice Removed), due for publication in a year that I can't yet mention, as the Unicode character set legally required by the "Second Enhanced Pan-Euro Metrification of Year Descriptors" has not yet beent post-back-ratifiedent in the current timestream. I shall have been gotting back to you sometime last week on that issue, which should clear things up a treat.

Re:Can't they just promise to do it?

[Chris Burke]

The third states that there are infinitely parallel universes with every possibly outcome occurring simultaneously (string theory?) and that the universe has many more dimensions than three or four, possibly ten or more dimensions.

I don't think it implies that there is a universe for every possible outcome... Infinite universes doesn't imply every universe, just like an infinite set of real numbers between 1 and 2 doesn't necessarily contain 1.5.

At least I hope that's true.

I'd hate to think that no matter where I am, no matter what I'm doing, there's a parallel universe in which I'm mere moments away from being raped by a heard of goats.

Was that a bleat I just heard?

Re: The Future

[mikael]

We could open a IPoST (IP over spacetime) daemon on jan 1 2009, and be able to receive messages from the future from that date on.

Being spammed from the present is bad enough, but being spammed from the future....

Imagine making payments - it would be like Douglas Adams's "Restaurant at the End of the Universe" - Just open a bank account under our name with a minimum deposit, and rest assured, your visit will have been fully paid from the accumulated interest over several billion years.

Re:I heard about this

[NeutronCowboy]

It's a test. Any real nerd would be able to not only find her real address, but would also create a Google Maps Mashup that would show all her past, present and future addresses. Especially if they're versed in time-travel grammar.

Re:I heard about this

[Reverend528]

I'm tagging your post "itsatrap"!

Re:I heard about this

[elgatozorbas]

So when the dupe shows up tomorrow, we will know the experiment is a success today.

No, because this experiment conveys no new information. We already know the story is going to be duped...

Re:I heard about this

[syukton]

That might be enough pasty white skin to compensate for the melting polar caps and beneficially alter the albedo of the earth, even if only for a few hours.

I always knew that nerds would ensure the end of global warming, just not quite like this...

Re:Damn

[An ominous Cow art]

I, for one, willed having beent welcomed our Future Grammer Nazi overlords.

Re:I heard about this

[a whoabot]

A Greek I.T. governor?

Re:I heard about this

[raehl]

If you are located in Houston, please feel free to drop by my apartment to receive your free beer and backrub-by-nerdloving-chick. :)

Interesting.. how many chins do you have?

Re:Grammar Nazi

[sunwolf]

I can't tell if this is actually an obscure reference to something or if there are just a lot of grammar school dropouts having a field day with verb tenses in here

surely this is some sick English professor's vision of Hell