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Scott Eklund / Seattle P-I file
University of Washington physicist John Cramer, seen here in a 2007 photo, has been working on a laser experiment to test whether causality can work backward in time.
Five years have flown by since University of Washington physicist John Cramer set out to determine whether the chain of cause and effect can go backward in time, with $40,000 from curious contributors — but the experiment is still stuck in suspended animation.
"No results to report," Cramer told me today in an email. He said the experiment, which looks into a theoretical phenomenon known as nonlocal quantum communication, is currently "mothballed" while he's traveling. Work will resume sometime after he returns to Seattle at the end of the month.
The experiment is spooky enough to qualify as a Halloween tale: It plays off the concept in quantum physics that you can link two photons in such a way that what you do to one photon is reflected in the state of the other photon as well, no matter how far apart the photons end up. Albert Einstein didn't like the concept, and called it "spooky action at a distance." But recent experiments have shown that the phenomenon is real — even when one of the photons has been sent across a distance of, say, 89 miles.
Cramer envisioned setting up a complicated laser apparatus to entangle two photons, send them along separate paths, and then manipulate one of them so that it takes on the definite characteristics of a wave or a particle. Whatever is done to that one photon should be reflected in the characteristics of the other photon as well. Thus, if you use a movable detector to observe one photon as a wave, the other photon should be detected as a wave as well. That's the "nonlocal communication" part of the experiment.
The spookier part of the experiment would involve sending the photon that's manipulated through an extra six miles (10 kilometers) of optical cable, so that it goes through Cramer's manipulating apparatus about 50 microseconds after the other photon hits the detector. Would the state of the manipulated photon be reflected in the other photon, 50 microseconds before the manipulation took place? It seems like something of a Catch-22, and Cramer suspects that something will always stand in the way of "quantum retrocausality." He just isn't sure what form the obstacle could take.
Maybe the universe is telling him something: Cramer has found that his equipment was too "noisy" to pick up the subtle signals from a single photon. He's run into other technical and financial difficulties as well. But there's still hope of finding an answer. Here's how Cramer explained the situation in his email:
"The status of the experiment is that my $10,000 Sacher 405 nm grating-stabilized laser failed in March. It would have cost $6,000 to have Sacher fix it, and I didn't have the funding for that. Therefore, my student and I spent April-June developing a new low-cost replacement. That is mostly done, and in early July I had a new high-power 405 nm 500 mW diode laser going, just before I left Seattle. ... It puts out more power than the old laser and can, in principle, be tuned to precisely 405.0 nm (required by the ppKTP down-conversion crystal) by stabilizing the diode's operating temperature to about 40 [degrees] C with feedback, but that isn't done yet.
"The principal experimental roadblock to a real test of nonlocal communication remains the fact that the avalanche photodiodes we had been using as detectors of the 810 nm entangled photons are simply too noisy for single photon detection. We tried cooling them all the way down to liquid nitrogen temperatures, but we could not beat down the noise enough. As the temperature drops, the avalanche threshold voltage goes down with the noise voltage, so the noise-detection rate does not change much.
"Fortunately, there is a new technology developed at NIST [the National Institute of Standards and Technology], superconducting transition edge detection, that involves driving superconducting junctions to normal conduction with the energy deposited by a single photon. The system has zero noise, and energy sensitivity good enough that they can distinguish detection events involving one photon, two photons, three photons, etc., from the deposited energy. My efforts when I get back to Seattle will be directed toward trying to get a pair of those detectors. It will not be cheap, but I think it's the only way the experiment might succeed."
Is it just coincidence that other researchers concluded in a recently published paper that quantum noise would head off any paradoxes associated with backward causality? It would be interesting to see whether those "zero-noise" devices suddenly start producing noisy results in Cramer's experiment. If Cramer is still having trouble in 2017, I just might start thinking that Stephen Hawking's "Chronology Protection Agency" has been hard at work.
More about quantum physics:
- Interactive: Cats and qubits
- How to spot quantum quackery
- Tales from the quantum frontier
- Millions invested in quantum weirdness
- Nobel Prize for quantum teleportation?
- Why 3-month-olds get quantum mechanics (and you don't)
- Distance record set for quantum teleportation
- Is the uncertainty principle misunderstood?
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.
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He may not succeed .
But he may stumble on an advanced method of cleaning up background noise for the radio frequency spectrum .
Thanks
Maybe he'll develop Quatum Radio? No need for broadcasting.
All our experience and evidence to date indicates that time goes in one direction naturally. Philosophers and Science Fiction Writers have long explored all the potentially dangerous pitfalls if time travel were possible. Maybe the probability of an unresolvable paradox is one reason why it doesn't happen. Trying to go against the flow of time is like trying to swim up Angel Falls. The probability of success is extremely low, so more productive pursuits are a better use of time.
Instead of trying to reverse something that doesn't want to reverse, maybe we should try to find out what the "one-way ratchet" mechanism is that prevents time from reversing. That may ultimately be more of a useful, and realistically achievable goal.
I dunno. In my quantum mechanics class in college we talked about the fact that mathematically, a positive electron could be seen as a normal electron moving backward through time. I don't think that moving backward in time, at least at the subatomic level, is impossible. Your one-way-ratchet mechanism may be nothing more than the limits of humans' normal three (or four)-dimensional perception.
The most prevelant theory for what the one-way ratchet is is the Second Law of Thermodynamics: Entropy. Since the the total chaos in a closed system will always move to a higher state, many believe that this one-way law is also the reason we never see eggs unbreak or remember the future. Time's arrow may be "baked" right into our universe's physical apparatus.
Trying to reverse something that doesn't want to reverse is precisely how we will end up finding out what is keeping it from going in reverse.
As the article stated,
Hmmm... and how exactly do you investigate the mechanism that prevents time from reversing without trying to reverse time?
Give Robert Heinlein's short story "All You Zombies" a read on how to become your own father *and* mother.
If information can be proven to be saved within a Black Hole, you have your route to go backward in time. Now prove THAT!
We can already prove that information can be saved within Microsoft Sharepoint, yet we are so far unable to go backward in time to a point before the Sharepoint existed.
Likewise, we do not know (and possibly may not ever know) the age of a black hole. Sure, we can make some educated guesses, but we're about as likely to be accurate as the guy that guesses age & weight for prizes at the county fair.
...any inferred analogy in this post that Microsoft Sharepoint is a black hole is "purely coincidental"....
Now that information is proven to be saved within a Black Hole, you now have a possible route for the photon to go back in time. Now prove THAT!
You have to qualify that statement...
First, it hasn't been proven that information is not lost when entering a black hole, that's just the latest theory.
Second, even according to this theory, the information isn't assembled the same way it was before entering the black hole, so even if the ingredients are there, reassembling them would be next to impossible.
Third, I fail to see the connection between the photon going back in time and your black hole comment.
I heard a few different things about this a long time ago, or something similar. Something about making a vortex with lasers or something. I thought they said they were able to detect what ever signal they were sending miliseconds before it sent. I don't think it had anything to do with entanglement though.
I believe you are thinking about Dr. Ronald Mallet's proposed experiment: en.wikipedia.org/wiki/Ronald_Mallett
He hasn't actually perfomed it yet though and many scientist don't believe that the basis for the experiment is on solid ground.
When I see the use of religion in the political arena, I do indeed take note. This is the most dangerous and pernicious form of propaganda in existence. Frankly, if any politician who might have his finger anywhere near the "nuclear button" starts making too much of his/her submission to "divine guidance" I really start to worry about the fate of the world. We have a recent example in the career of one George W. Bush. The account of his babbling to the French prime minister about Gog and Magog and how we were seeing the realization of bible prophesy playing out in the middle east made my blood run COLD!
It's high time that human beings realized that they ALONE are responsible for what happens on this planet. No "Man In The Sky", and certainly no dead rotting corpse of Muhammad, Jesus, or Moses, is going to save them. If you are a poor, ignorant slave today, you will be one tomorrow unless you get up off your ass and DO something about it. Praying is a wast of time. No one is listening.
I've never been able to understand why some people become so overwrought over other people's faith.
Become many people don't understand that faith is a personal decision that should not be used as a weapon to justify or nullify the actions of others. If you belive in God, great for you! But, your personal belief has absolutely no bearing on me and my life.
I agree with both Scott M and misterbeal. This is why I do not like the chair of the science committee in Congress to be somebody who uses their position simply to bash science in favor of religion. Science needs to be discussed in Congress, especially what is happening to the arctic ice that has been causing the jet stream to come to a standstill and massive droughts turning former grasslands and grain growing lands into deserts. The world population also needs to be addressed by Congress, and that isn't very popular either, especially since more people mean more votes. Congress and the Senate are the keys to this election: elect Republicans and you will have anti-science people heading science committees, or the scrapping of those committees and Cabinet positions altogether.
All things considered, the first step to solving these types of problems is to begin focusing on increasing overall reading comprehension, which at minimum should include encouraging students to read the titles of books, articles, and topics in "Cosmic Log", thereby greatly decreasing the probability of posting thoughts that truly are random, really . . .
Really! ;-p
Ignoring "noise" online is much easier - it can be done with a single click, but you have to select each bit to ignore individually (and it helps to realize that any 'noise' will contain something that isn't noise).
Please explain the beliefs and views of these so called progressive political watchdog!
Just what,who are these Progressives and why have they caused so much problems for the world and yet act like they are the heros, these people support some of the worst ideas and crack pot theories in history and hide behind others while stirring the pot and waiting to attack!
This guys views are kind of silly,if GODs all powerful then he'd create animals with the ability to adapt,evolve or these animals would become just like the Dinosuars and die out.
Evil they name is Progressive, failure and death follow all those that embrace these people and their evil ideas, plus their insurance really sucks!
What the hell does this post have to do with this story? TROLL!!
Well, the anti-progressives are anti-science, and put people as chairs of committees and Cabinet that might cut off research into any science project whatsoever. Or worse, fund only the projects which match their pre-conceived conclusions. People who think that Libertarians are all for science should realize that they will be the first to cut any funding. You might be able to make a paper airplane, but you won't be able to build a rocket that travels to other worlds or an off-world telescope without funding. When the super rich are done trashing the world's economy, there will be nothing left for science. You might make some money with a jacquard loom in your attic, but you will be milking your own cows, if you are lucky enough to own a cow.
So, why is this experiment starved for cash? It seems to me that this could have some impact on quantum cryptography, and there are several funding agencies that were granting big bucks for such info.
I agree Ben,
I have been following this story for years now and it seems like it is a very reasonable experiement, in terms of the knowledge that can be gained by the positive or negative results of it.
I would think that DARPA would want to fund this in a minute, considering:
1. Al the crackpot things they've funded in the past that had no value whatsoever.
2. The fact that, if it were to work, the possibilities would be unbelieveable.
You don't think that DARPA or others like them aren't already doing something similar?
Elizabeth-1372999, not necessarily.
Say, a scientist comes up with a result in a lab. Well, that woman's training and lab equipment basically determine what it is she can work on and can succeed at. If someone else wanted to do the same experiments they would have to spend a while to understand the experiment and replicate the result using whatever equipment they could get their hands on (maybe better, maybe worse, but most likely not identical).
Their best bet would be to funnel some money this guy's direction to get an experiment that is already started and a guy who has the knowledge to run it. On the other hand, since there national security issues in play, who knows what the NSA, DARPA, or military R&D think of him? But hey, I'm not sure what they think of me.....
@Elizabeth-1372999
I'm pretty sure they aren't. If they were, they'd shut this guy up quick!
I'm also unsure why this experiment is starved for cash. Dr. Cramer has been waiting a couple of years to fill his cash void. Because of the potential profound implications of his experiment it seems like other physicists would be standing in line to collaborate, both with funds and expertise. At a minimum I don't see why Dr. Cramer can't just borrow or lease the needed equipment for a short time instead of trying to buy it. Would be much cheaper.
Maybe part of the experiment is to see if he can get away with spending the intended donations on vacations prior to them actually arriving?
Toying with wibbly-wobbly timey-wimey stuff is dangerous.
paperbubble.com/wp-content/uploads/2011/01/back-in-time.jpg
I wish I had thought of it, I would be $40,000 dollars richer and then I could afford to travel around the world as well.
Why would you be 40,000 richer? You think the reasearch money is just getting pocketed?
Scott M - In this instance I would not be surprised. As $40,000 is hardly enough for seed money to buy equipment for the purpose of basically try to prove the possibility of an improbable quantum effect for retrocausality (or retro-causation). He is probably using the money for a little R&R while looking for other investers as well. Failing the ability to raise more capitol, the $40,000 investments will probably be just enough to cover his debts so far.
@Stephen J. Bauer
I hope you're not serious. Any scientist that wants to keep any hope of not being kicked out of the scientific community and not being black listed for future research money is never in a million years going to skim moeny for research into thier own pocket for personal reasons (unless the grant calls for a "salary" stipen).
$40,000 may not be a big amount by today's standards, but this is not an unbelievably complex set up and goes a long way toward setting the lab up. The problem is that more sensitive eqiupment is needed and that equipment isn't readily available for 40k.
"Undoing" is still time-progressive.
There is nothing like building one theoretical hypothesis upon another to support or qualify an equally abstract conceptual premise. While theories of special and general relativity suggest specialized local geometries of SpaceTime, or specific types of motion in space, to hypothesize time travel (i.e. into the past or future) if these geometries or motions were possible, these interpretations for Time Travel persist merely as an inept interpretation of time dilation. Time dilation postulate that the faster an object is moving, via extreme acceleration/deceleration - whether gravitational or thrust propelled, the slower time progresses for that object in relation to a stationary observer. The proof for this concept has been demonstrated via twin atomic clocks repositioned, one off Earth in outer Space and another remaining on Earth. Another experiment based its results on twin clocks placed on aircraft flying in opposing directions parallel with the spin of the Earth. The logic being the experiment was that gravitational acceleration follows the spin of the Earth. According to special relativity, the rate of a clock is greatest according to an observer who is at rest with respect to the clock. In a frame of reference in which the clock is not at rest, the clock runs more slowly. Considering this experiment in a frame of reference at rest with respect to the center of the earth, a clock aboard the plane moving eastward, in the direction of the Earth's rotation, had a greater velocity (resulting in a relative time loss) than one that remained on the ground, while a clock aboard the plane moving westward, against the Earth's rotation, had a lower velocity than one on the ground.
And yet time dilation has more to do with impractical interpretations rather than applied science. In physics, the twin paradox is a thought experiment in special relativity involving identical twins, one of which makes a journey into space in a high-speed rocket and returns home to find that the twin who remained on Earth has aged more. This result appears puzzling because each twin sees the other twin as traveling, and so, according to a naive application of time dilation, each should paradoxically find the other to have aged more slowly. However, this scenario can be resolved within the standard framework of special relativity (because the twins are not equivalent; the space twin experienced additional, asymmetrical acceleration when switching direction to return home), and therefore is not a paradox in the sense of a logical contradiction.
So how should we define the attribute of Time notable of the SpaceTime continuum? To understand time as a fourth dimension, it is necessary to recognize that any human attempt to "draw" or "represent" time beyond out immediate perception of it (basic, linear progression), is inherently flawed, because out mental capacity is limited to three dimensions. However, time, like space, is a dimension in itself, and objects can transverse it in a similar way as they do through the third dimension. A popular way of viewing time is using a coordinate set of axes, except instead of using a standard reference for 3 parts Space with simple x, y, and z axes, another axes is added from the convergence of the first three to represent 1 part Space. As a person walks forward, he is traveling through all three dimensions of space, and a fourth as he progresses forward through time. Thus, for humans, time travel (or traveling through the fourth dimension) is entirely possible, however, only in one direction. Relativity has shown us that it is possible to change our perception of time based on distance, gravitational dilation, or speed, but the direction of time has remained constant and singular.
The definition of time is how you use it to measure. Since Time is a relative concept that accounts for motion, velocity, and acceleration/deceleration within the universe, it more than enlivens our reality in existence. From my point of view, it actually shapes our reality conforming SpaceTime upon the concept for the convergences to provide for dimensional configurations upon which one perceives reality: space/time == flat space; space^2/time^2 == curved space; space^3/time^3 == spherical volume of space, space^4/time^4 == spherical density of space, etc. Whereupon each acquired configuration transitions to the next real-time event, the previous version is forever lost. Yet while I agree that the reality of our existence is based solely on the consecutive chaining of Present Time, where only Present Time expresses our reality, I do not believe that our traditional fourth dimensional experience should be the basis for what defines reality in other dimensional conditions. It has been said that from the dimensional perspective of a singularity, all Space and all Time exist as one point. I can only imagine that there would be also be an opposing condition as from the dimensional perspective of non-existence that would allow for No Space and No Time. If we consider the validity of reality varies by degrees of such dimensional configurations, then we might be able to assume that our existence is evolving from Minimum Space and Maximum Time toward Maximum Space and Minimum Time (consistent with our traditional fourth dimensional perspective of the expanding nature of our universe). So the 'Arrow of Time' is consistent with the evolving nature of our universe.
Think of it like this - If everywhere in the universe is residing in Present Time all at once, how is it that I can only see it Past Time? For that matter, if I stare at a spot on a blank wall, then why do I get bored? When I first notice the spot on the wall, my mind quickly searches to identify whether this is something new or not. If it is new, it is registered or impressed upon my memory. While I can change my perspective, it still remains a spot on the wall. Once the impression the spot on the wall causes no new connections to be made in memory, the echo of the impression lets us know that the vent has already happened (e.g. some time has passed). The mind is constantly maintaining an internal clock which allows us to separate and catalogue input on a per event basis. Probably an evolutionary mechanism that keeps seeking input for impressions of danger to support our need to survive, to continue to exist.
Another thought is that as the actual act of viewing the object, in what we would like to call real time, actually takes time to process (no matter how brief). Consequently we can only perceive and understand degrees of Past Time even while we exist in Present Time. Therefore while existence expresses only Present Time, our true reality is always in Past Time. Subsequently the Present Time always manifests itself to us as our Future Time. And although we can never experience Present Time, we still claim that it is real as the expression of the transitional event mitigating Future Time from Past Time. For more on this perspective, read the book - 'The Evolutioning of Creation - Volume 2'.
You understand that this experiement isn't about time-dialation at all, right? It's about quantum entanglement and temporal causality. Acceleration and gravity are not significant in this experiement.
@Scott. Your comment is spot on. But how can you rule acceleration and gravity insignificant before the experiment is concluded?
I assume that the entanglement of the photons might open a rift in the DeCartesian coordinate system. I always thought that prime numbers came from time singularities.
Scott M - Yes, I understand the acticle that Dr. Cramer's experiment are not about time dilation. However I draw upon the context of the misintepretation of this concept as providing the fuel for the pursuit of such experiments. Therefore my comment was crafted to be more general, than specific to the experiment in the article, because such articles are notorious for not providing a lot of research specifics. But as to the experiment in the article, the challenge that Dr. Cramer is unable to overcome will continue to plague his research as he is basing his theories on compounded hypotheses; like building one theoretical hypothesis upon another to support or qualify an equally abstract conceptual premise. While the underlying cause of quantum entanglement is a mystery, also known as the "spooky action", there are still also several interpretations for the quantum mechanics upon which these experiments are being. Philosophers of physics usually consider an interpretation of quantum mechanics as an interpretation of the mathematical formalism of quantum mechanics, specifying the physical meaning of the mathematical entities of the theory. So far the explanations for the basis of quantum entanglement do not violate the precedence of time per the notion of causality. While Cramer himself acknowledged that the concept of retro-causality doesn't seem to make sense ("but he doesn't understand why not."), he continues to explore why or why not. So it is no wonder that there is not a lot of money being thrown his way.
I'm sorry Stephen, but you may think that what you are writting has some bearing on this thread, but it's really just babble, some of which, is not even based in fact. That's why I pointed out that your earlier diatribe was in no way relevant to this experiement or conversation.
You say:
Which is utterly false. Quantum Entanglement is not a hypothesis. Nor is the ability to split a photon into two with one taking a longer path to the detector than the other. There is no piling of hypothesies onto each other. You start off with some fact and follow it up with an explanation that has no scientific merit and is just your personal feelings on the subject.
This simple problem here is money to set up the experiement with the appropriate equipment.
Scott M- While name given to the experimental effect for this "spooky action" has been dubbed quantum entanglement, it is not quantum entanglement that is the hypothesis. Rather it is the interpretation for the underlying quantum mechanics upon which these experiments are being designed. Sorry if I didn't make myself clear. Philosophers of physics usually consider an interpretation of quantum mechanics as an interpretation of the mathematical formalism of quantum mechanics, specifying the physical meaning of the mathematical entities of the theory.
Also you did not comment on - "So far the explanations for the basis of quantum entanglement do not violate the precedence of time per the notion of causality. While Cramer himself acknowledged that the concept of retro-causality doesn't seem to make sense ("but he doesn't understand why not."), he continues to explore why or why not. So it is no wonder that there is not a lot of money being thrown his way."
@Stephen,
This is yet another post that adds nothing to the thread. You point out that quantum entanglement is not the hypothesis here, which is exactly what I pointed out to you earlier, when you labled it as such. You next point out that I didn't omment on the fact that the explanations for quantum entanglement do not violate the precedence of time per the notion of causality. Why do you need a comment from me on this? This is simply a fact that makes the experiment worth doing in the first place.
Really, your way of restating the obvious or stating the unrelated is throwing the thread way off.
Say what you may, but God is True and His Word will stand. People may laugh and make fun of God , but i promise you, God will have the last Word. It matters not what people think up and make up, God is THE CREATOR and HIS SON JESUS CHRIST is the Only way to Heaven. He loves you my friend. If we want true answers, let us go to the correct source, Gods' Holy Word.
Keep that crap to yourself.
If you are so sure that God will have the last word, then shut up and let Him have it. We don't need to hear it from you.
dave & Scott -- Amen!
why is it that the religious nuts love to jump on science threads with their babbling nonsense?
I don't jump on religious threads and start disproving their ramblings
Which has...what to do with this?
thats a big promise
The "spooky action at a distance" as Einstein called it has important use in communication in real time. The first time that I have read about it was the use of calcium ions suspended in a magnetic field. When a pair of them were separated by a distance when you flipped one particle in it's magnetic trap the other would flip in reverse no matter what the distance. This would allow you to control robots on the moon in real time without the time lag and build a moon base without humans being put at risk. How about real time communications with robots on mars being controlled to build a mars base from earth all in real time with no 40 min time lag. I can imagine two sets of 256 traps separated by millions of miles instantly communicating with each other. This type of communications would allow you to have cable tv from the earth on mars.
Quantum entanglement has only been possible at the individual particle level, with relation to the particle's spin, not its electro-magnetic properties.
While I agree, Scott M, this does pose an interesting question. When we make astronomical observations of events light-years away, if any of the events were entangled, there should be an exact reflection some place else. I would assume that if any are entangled, some will be entangled, although not in a way necessarily controllable by humans. It would be interesting to find ways to sort out the noise in astronomical observations.
I can't really comment on the limits of the technology, generally it would be practically impossible to separate two entangled calcium ions, placing one on the moon and the other on the earth.
As was pointed out in the article, doing *anything* to the ions (including containing them in a box that is not at absolute zero) will generate quantum decoherence. The stronger the interaction, the faster the decoherence creeps in.
Great, that will will improve the economy by upping the sales of Intergalactic Vegematics as seen on TV.
Now, to find a civilization that needs them. Perhaps if we just go ahead and advertize the Intergalactic Vegematic they will come.
Reminds me of a Beastie Boys song.
@
Elizabeth-1372999
You wouldn't see a "reflection", you'd observe the exact same phonomenon happening in another location. Entaglement doesn't mean that you get a reflection of the other particle, it means that both particles are in the exact same physical state as each other. They are both real simultaneously. However, for astronomical events to have this quality, we need some unbelieveable amount of entangled particles to have any sense of it.
Very good work on a shoestring budget. Hopefully, he can encourage someone to come up with a few more bucks. It may not be possible but unless you try it will never be possible.
And how does your quantum ideas pan out before humans ever existed... when there is NO observer? The universe exists with or without an observer. Quantum mechanics is 90% mythical and 10% blury measurement.
The "observer" does not have to be a human. It's just a term used to exemplify "something interacting" with the item of interest. With that definition, the entire universe is being "observed" to some degree and always has been.
God created evolution. We all evolve, from the womb to the grave.
The Bastard...and all because he loves us so.
I am missing some point here. What is it that is supposed to induce the photon hitting the detector to take on the characteristics of the manipulated phonton 50 microsecs before manipulation? Wouldnt the detected photon have the charateristics of the unmaniputlated photon at the time it hits the detector. Are you saying the entangled phontons have retro causaltiy built into them? Why would this set up ever produce evidence of retrocausality? Just because the investigator says it will? If I stick my head outside I will prove it is raining only if it is raining.
See the movie "The Prestige." More than one photon would be observed at the beginning; the one about to be experimented on, and the one being sent backwards. There would be a glow before the experiment started.
R Bynum, this type of quantum manipulation is mindblowing. Even a simple example of quantum cryptography and why eavesdropping isn't practical is very hard to understand.
The real problem is not the math and physics. It is really what might be called the quantum-engineering, trying to figure out how you can relate the quantum elements to large-sized objects. A lot of the time this doesn't work well, so you get very difficult and nonsensical explanations.
I will have to have a think on the ideas behind the proposed experiment.....
I totally agree with you R Bynum.
r bynum and eric rose
admit it, you don't understand it so you claim it can't be real.
Yes I admit I dont understand this experiment as it is described in the article. Can you answer my questions Iseeconfusedpeople? Why is the particle detected supposed to have the charateristics of the particle manipulated 50 microsecs in the futue? That is not explained in the article. Somehow routing the manipulated particle and extra distance makes retrocausality? Please explain if you can. If not look at yourself in a mirror.
Also my limited understanding of entanglement seems to imply that when the detected photon is measured it should change the charateristics of the manipulated photon as well. Either simultaneously or if the experiment is true some time in the past. How would that affect the outcome of Cramer's experiment?
A great idea.
I fail to see how a positive result of this experiment would imply retro causality. Quantum entanglement implies a connection between two particles. If something changes the state of one of the particles and then the other particle mimics this change before undergoing the same conditions as the first, that only implies the connection was maintained, not that a future event acted retroactively to influence the past.
While I respect those who have undergone higher education in fields such as physics and mathematics, these people are none the less still very much human in the most normal sense of the word. They didn't achieve these degrees because they are somehow gifted beyond the reach of the average man, but because they had a personal interest in these fields and put in a lot of hard work to get where they are. The point I'm trying to make with this is that even though Dr. Cramer has a Ph.D. in physics, he is still prone to make very simple and basic mistakes in judgement when it comes to his line of reasoning, as is obvious by his definition of what incorporates "retrocausation".
This guy explains whatever he doesn't understand by saying it's the other person who misunderstands it. Lots of scientists appear to believe in the possibility of retro-causation. I don't, because it would violate the laws of sequential change. But then it may be that they're using time reversal sequentially and either don't realize it or see nothing wrong with doing so.
Although this guy knows for sure that when he's right, they are all wrong regardless..
Actually I understand this experiment perfectly, otherwise I wouldn't of bothered commenting. If you understood it as well you would agree with me. Also, sequential change is causality and time doesn't flow in reverse.
The fact is I actually am educated on these matters and I give detailed reasons as why I don't agree with certain ideas espoused in articles or comments. The vast majority of people on these forums really have no idea what they're talking about. The sad truth is a lot of you guys have an obvious interest in some of these ideas, but really don't understand them. That being the case, you shouldn't get upset when someone like myself tells you your ideas are crap and you're wrong.
Actually sequential change is NOT causality, unless you've reduced the term to meaninglessness in the sense that everything causes everything in sequence. And even them it's not the change that causes anything - just the reverse. And for someone that doesn't know that to try to tell a well known physicist that his ideas are crap because you think so is truly ridiculous. If you know why and how he's wrong, please tell us. But of course you can't.
Also time doesn't "flow" at all. And time symmetry at the quantum level is, in effect, change symmetry, but again it's an entirely different concept than that of sequentialism. Time symmetry and sequential change are not, however, contradictory phenomena.
Quote: "everything causes everything in sequence" Yes this is exactly what causality is. A causes b, b causes c etc. etc. You obviously need a lesson on what causality actually is. It's an extremely simple concept, which is why it amazes me that you can't comprehend it's actual nature. Every cause has a previous effect. Every effect goes on further to cause other effects, etc. etc.
As far as time symmetry goes... What the heck is that?! Seriously, are you referring to time moving one way versus another? I take it you read this idea in "The Universe in a Nut Shell" or "A Brief History of Time" by Stephen Hawking? The idea of time symmetry is baseless. There has never been any observed phenomenon to lend this "idea" gravitas. It is simply just an idea. Further, this idea is not derived from any currently known theories about how the universe works.
As far as Stephen Hawking goes... You know this guy's only contribution to physics has been the theory of "Hawking Radiation", right? He's not someone you want to derive ideas from. On a list of the top 20 greatest physicist of all time, Hawking wouldn't even be on the list. The guy is amazing given the fact that he's in a wheel chair and has written several books on physics, but that's the only reason.
It's clear that you really don't have any kind of personal, complete theory of how the universe works. You simply just repeat whatever you've read or heard as gospel. As I've said before on these forums, physicist are just like you and me. They're prone to mistakes and lapses in judement. For example, take into account all the different theories of quantum gravity. String theory, M theory, super symmetry, loop quantum gravity, etc. All of these theories are not compatible with one another, so at least one of them must be wrong. However, all of them have been created by and vouched for by multiple "experts" in the field. If physicist are infallible, then by definition of your beliefs all of these proposed solutions must be correct.
Wake up and smell the cold hard light of reality. All of the people working on these problems are just like you and me. There are no geniuses at work here, just regular people with a passion for this sort of thing. They're just as inherently intelligent as the rest of us. The thing that really separated Einstein from everyone else was his originality. His capability to see things from a different perspective other than his own. It wasn't some higher, God given ability to somehow reason better than the rest of us that allowed him his insight into relativity, it was simply approaching things from a different point of view.
A agree that most of the time, a trained physicist will have a better idea of what is going on in the universe than the rest of us, but when it comes to this particular matter and myself, it's simply not the case.
Also, I did explain how Dr. Cramer's experiment is faulty in the original post. How about you read the comment next time in full before going on a triad like this.
Obviously you haven't had much interaction with the average man, seriously. It does take a set of thinking skills that not everyone possesses, and I think you are giving yourself too much credit when you say you really understand the experiment.
Do I detect a bit of jealousy? Genius is a subjective term so you can throw that out, and the word intelligence is some what vague. When it comes to the specifics of understanding the math, the principles, the equipment you WOULD have a hard time teaching that to most people. Many people have passions, for example in music, writing, art, etc. but they just aren't very good at it. Passion, talent, and dedication are all required for success. I'm not saying that a physicist is somehow more intelligent than someone who is a brilliant economist or musician, but they do have brains with different wiring.
It implies retro causality because the state of the quantum system is absolutely indeterminate until it is "measured." Since the quantum state manipulation on the second entangled partner occurs after the first partner has ceased to exist, any effect of the state manipulation on the measured properties of the quantum state of the first partner requires causality to travel the "wrong way".
If you are thinking "well, just because we don't know what state the system is really in doesn't mean that Nature doesn't know it," you would be wrong. There are a lot of experiments that seem to support the idea that the "measurement" of a quantum system is just revealing quantum state information that Nature already knew (like measuring the polarization of light that is spontaneously emitted from an atom), but this type of thinking blows up when you start doing detailed experiments.
Eric - I tend to agree with you. Smart people often make stupid mistakes because they are unwilling to allow others to weigh in on their research; it is like proof reading your own work. Yet while smart people tend to go out on a limb to prove something simple based on mathemetics, Dr. Cramer has gone like two steps further in trying to come up with a prototype without a good design.
Indeed, while Dr Hawking is famous for promoting the notion of wormholes, even he has published arguments against the ability to allow for Time Travel (or retro-causation). However even Hawking leaves sci-fi fans with hope by noting that elsewhere (perhaps in some future SpaceTime configuration) Time Travel might only be possible in a region of SpaceTime that is warped in the correct way, and that if we cannot create such a region until the future, then Time Travelers would not be able to travel back before that date. Basically covering his basis by saying that if Time Travel were possible, there may be no evidence for it in our Present SpaceTime.
"currently "mothballed" while he's traveling" ... LOL! So basically he took all the money and went on an extended stay in the Bahamas.
I vote for Siberia. It is lovely in the summer and the return trip coincides with the onset of winter.... Also, what happens in Siberia only appears in history books 50 years later, just ask Stalin.
In response to Eric James Rose:
Classic. No geniuses at work, etc. Linear causation, etc., etc. Never heard of time symmetry - google it.
A wrong explanation is no explanation at all. And yes, there are a number of geniuses among the more prominent physicists, including Hawkings, and certainly Einstein, a super genius who comes along every 500 years. Did you know for example that he did all of his experiments in his head! To tell yourself and others these people are at the same level of intelligence as you are is a clear give away that contrary to our claim of equal intellect, you're nowhere near their levels. Hawkings has of course made some mistakes, but none that you could have detected on your own, and he still has the respect of his peers.
Apparently you're some sort of narcissist who projects his faults on all those who would otherwise be his betters. You don't know what you don't know and never will. And you won't get over it. Keep on babbling here. I like it that I can help everyone to see the kind of person that these insults are continually coming from.
They shouldn't and won't bother anyone once they know the weakness of the source.
Baron - Classic 'come back' - Trust in the scientist without question and assume no one else's opinion is worth anything. Then attack the integrity of the source without fielding the propose comment, and site some non-distinct reference to provide your comment with some worth. I don't see where providing an opinion on Dr. Cramer's should be cconsidered an insult. By the way, Time Symmetry is a theoretical premise that assumes a theoretical condition of Time Reversal Transformation, neither of which have ever been considered within the macroscopic persepctive of the universe; the observable universe itself does not show symmetry under time reversal, primarily due to the second law of thermodynamics.
First off, old Eric has been insulting others incessantly. Second, he claims he never hear of time symmetry, therefor I should not have mentioned it. But which has been discussed by David Albert in Time and Chance, and by numerous other scientific people at various places.
It does not support time reversal at a macro level. On a micro level it supports the equivalent. I mentioned sequential change on an earlier forum because that concept doesn't support any time reversal which portends to actually or completely reverse a sequence. You can quarrel with that if you like, but not by insulting those who have heard of it when you haven't.
By the way, if I called you a neo-Darwinist would that in and of itself insult you?
Baron - OK, fair enough; both Eirc and you need to consider the opinions of others without the insults. As for your comment about me being a neo-Darwinist, I would think it an ill used reference as nothing I have presented in my comments would lead you to such a conclusion and you can't possibly know enough about me unless you read all my books. By the way, did you mean it as an insult? It is the intent that counts, not the words you use to express your intent.
I simply asked a question to test your objectivity. You assumed I concluded the opposite of what was really the case. Basically you're biased toward those who agree with you , regardless of their reasons, and against those who don't agree, regardless of their reasons as well.
Baron - Sorry, what was the opposite? I commented that it was an ill-used reference. Now you're making things up.
Firstly, the "timey-wimey" nature of things is one directional only on the many body macroscopic level, in either classical or quantum mechanics time is a parameter marking states in an evolutionary sequence, nothing more. When the operators permit it "time" is perfectly symmetric, "reversible" (if you insist).
Secondly, the oddities of quantum entanglement that seem to imply causalities connected on space-like intervals, or with time sequences reversed, are at least flirting with the logical error of considering these "photons" to be distinct particles, they are not.
All such experiments "prepare the state" in a space-time volume totally consistent with normal causality, so that some property of that state can be transferred over space-time to be later "realized" in some measurement event. Quantum mechanics is for sure spooky in the sense that an interaction leading to a "realized" measurement appears to collapse all the manifold possibilities into that one outcome. The fact that the photons separate in no way alters this behavior, so it is no paradox that a bias implanted at "creation" would be manifest in a later measurement. Moreover, the influence or wave function for a photon of a precisely determined energy has no spatial localization whatever and no time localization whatever. This is Heisenberg's uncertainty principle, and if you admit some fuzz in the energy to allow that space-time localization, then you cannot sustain an "entangled" state.
So the photons are everywhere anyway, and if the properties are entangled then that correlation is only a statistical statement that every measurement realization will reflect the impressed entanglement. The whole class of experiments on spooky quantum computing or acausal time sequencing is a test or exploration of boundary conditions on an inherently statistical process and has nothing whatever to do with the imagined trajectories and "lifetime experiences" of individual particles.
Thanks for following up on this, Alan...