jonp

This,

 

http://www.black-holes.org/relativity1.html

 

by the way, seems to be the BEST explanation of Relativity I have yet to read.

It's not in the article, but in general space-time theory, that if you travel beyond space time you cross that bounday. Mine insertion.

Errr again, what is "General Space-Time theory"? I know of no such theory.

 

There is Einstein's Theories of Relativity (Special and General), which explains phenomena in terms of unified Space-Time. But there is no such thing called "General Space-Time theory" as far as I know.

 

Yes. But will it be a wave or a particle? It behaves as both, doesn't it? If it leaves the "sent" timeframe as a particle, will it enter as a particle 50 microseconds later?

Yes. It does, doesn't it?

 

Imagine the quantum flux to be the refraction factor of, say, water. Light enters water and gets refracted.

 

Then, the time-barrier is that point in time where an object achieves light velocity and starts to "travel" in time. Can a photon achieve this, when it is already at light speed? Can you even slow down light, or speed it up?

 

Sounds sci-fi, I know...

I didn't get that. For the last statement, light has been successfully slowed down and sped up, even stopped in its tracks. Articles about such experiments are easy to find on the 'Net.

 

The key principle to understand is http://en.wikipedia.org/wiki/Quantum_entanglement and as far as I understand, the experiment seeks to take advantage of this in order to demonstrate (or debunk) such entanglement propagating backwards in time.

There posed a question in the URL you've posted. A lot of people think it won't work, they just can't explain WHY it won't.

 

Well, if it works, once that photon crosses the space-time boundary, what will it be? A wave, or a particle?

I don't recall the article talking about any 'space-time boundary'. What are you referring to here?

 

The photon will still be a photon. It's what characteristic of it that will be detected that is at question here.

 

Also, since time technically moves forward, who will be there to DETECT the time-travelling photon? Nobody will be there, because that particular point in time no longer exists, and the photon hasn't been released, as such they won't be able to predict WHEN it'll turn up. It enters a point in time that IT DOESN'T exist yet. And regardless if they calculated the time of the delay, quantum flux generated from the breaking of the time barrier will eventually cause the photon to either end up way into the future, or sometime back in the past when it was NOT set up top be detected. A few milliseconds is a LOT of time for a quantum travelling photon, afterall.

What is a 'quantum flux'? What is a 'time barrier'? These sound like terms borrowed from scifi which do not have any precise scientific meaning.

 

 

 

They have been attempting this and similar experiments for years, if I recall correctly.

The Philadephia experiment seems to have succeded, if you're into that conspiracy stuff...

You are assuming that nature will permit "free will " of the experimenter.

It could be that every time he tries to do something contrary

the universe will flip him back to pre-ordained.

Well, the experimenter is certainly free to adjust detector #2 to detect photon #2 as either 'wave' or 'particle', so I don't see how the 'universe' can prevent that. We do have to understand how the experiment is supposed to work exactly, otherwise it's all just speculation. We are not sure if the description is not missing out some fine details. For example, what does it mean for a SINGLE photon to be detected as a 'wave'? The everyday language description of the reporter may have oversimplified the description to the point where the hypothetical scenario I gave (adjust detector #2 to give a contrary detection to detector #1, before the photon has reached the former) would not apply.

 

The english language description is simple: if detector #1 detects the first entangled photon as a 'wave', detector #2 MUST have also detected the second entangled photon as its complementary state. Entanglement holds that this principle cannot be violated. Detector #2 can be adjusted to detect the second photon as either 'wave' or 'particle', and the adjustment of detector #2 WILL directly affect how detector #1 (untouched) detects the first photon as. The relationship between what photon #2 and #1 is detected as can never be broken (supposedly).

 

The incredible thing here though is that detector #1 will 'register' photon #1 as 'wave' or 'particle' *BEFORE* photon #2 does so how the heck was it able to know that photon #2 was set to be detected as 'wave' or 'particle'?!? The experimenter, via adjustment of detector #2, forces the result of detector #1. But if the experiment succeeds, detector #1 will already 'know' the adjustment of detector #2 BEFORE photon #2 has even triggered it!

 

It sounds crazy, but the double-slit experiment already provides a precedent for such a crazy result.

You are assuming that nature will permit "free will " of the experimenter.

It could be that every time he tries to do something contrary

the universe will flip him back to pre-ordained.

Well, that's exactly what we'd like to find out. But before anything else, we have to understand how the experiment is supposed to work exactly, otherwise it's all just speculation. We are not sure however, if this description is not missing out some fine details. For example, what does it mean for a SINGLE photon to be detected as a 'wave'? The everyday language description of the reporter may have oversimplified the description to the point where the hypothetical scenario I gave (adjust detector #2 to give a contrary detection to detector #1, before the photon has reached the former) would not apply.

 

The english language description is simple: if detector #1 detects the first entangled photon as a 'wave', detector #2 MUST have also detected the second entangled photon as its complementary state. Entanglement holds that this principle cannot be violated. Detector #2 can be adjusted to detect the second photon as either 'wave' or 'particle', and the adjustment of detector #2 WILL directly affect how detector #1 (untouched) detects the first photon as. The relationship between what photon #2 and #1 is detected as can never be broken (supposedly).

 

The incredible thing here though is that detector #1 will 'register' photon #1 as 'wave' or 'particle' *BEFORE* photon #2 does so how the heck was it able to know that photon #2 was set to be detected as 'wave' or 'particle'?!? The experimenter, via adjustment of detector #2, forces the result of detector #1. But if the experiment succeeds, detector #1 will already 'know' the adjustment of detector #2 BEFORE photon #2 has even triggered it!

 

It sounds crazy, but the double-slit experiment already provides a precedent for such a crazy result.

Then the interaction of particle pairs will cease and the universe

will have to cease to exist to maintain parity.

 

KIDS, DO NOT TRY THIS AT HOME!!

 

:cool:

Hmmm... the universe's 'laws' do not really change only our conception of what we assume to be the universe's laws.

 

Now, since I'm too lazy to try to figure out the diagrams here -> http://www.flickr.com/photos/kathryncramer...57594379836957/ , assuming the news article is accurate in the sense that it all boils down to the photon "being detected as wave or particle" (A lot of the people in physicsforum.com do not buy Cramer's experiment, but what lends him legitimacy is that he was able to secure funding. Also, remember that in the double slit experiment, the so-called wave nature of light is not manifest until a lot of photons get shot at the plate behind the slit, so obviously some very complicated explanation is involved when the experiment claims to be able to detect a single photon as a 'wave' or a 'particle' using only a single photon), I would expect some totally mystifying/surprising results along the lines of the double slit experiment where the photon seems to 'know' if an attempt is being made to detect it as a particle or not and manifest as the former if so, and as a wave if not.

 

I'm almost sure that english or any other traditional human language is failing to capture the essence of the experiment correctly, (it already fails somewhat in the case of the double-slit experiment). In english understanding this is the best I can explain as to what is going on, and a paradox definitely arises:

 

a) it is possible to create 'entangled' photon pairs for which certain properties of each one totally determine the other. If, for example photon #1 is detected as 'black', photon #2 will always be detected as 'black' as well. If photon #1 is detected as 'white', photon #2 will always be detected as 'white' also. ('black' and 'white' being totally fictitoius properties).

 

it does not matter how far away the 2 photons are. The theory goes that you could send photon #2 to the other end of the galaxy and if the detector at the other end registers it as black, photon #1 will also be detected as black. Experimentally however, they have been able to confirm this phenomenon over hundreds of miles, iirc.

 

c) now, the above by itself would not be remarkable at all since photon #1 could already be 'black' from the beginning, and the act of detection merely confirms it. But this is NOT what is going on. Because of the Heisenberg uncertainty principle (I hope I'm not making this up), the experimenter can CHOOSE to make a particular property appear depending on the way he measures the particle. In other words, in some very very technical way (which I have only the foggiest notion of), he is able to choose to detect one of the photons as 'black' or 'white'.

 

d) the moment he does that, for some reason the other photon will then have to follow suit. If experimenter chose to detect photon #1 as 'black', then photon #2 cannot help but also be detected as 'black', and vice versa.

 

e) what is remarkable is that supposedly it does not matter how far away the photons are. The property of the 2nd photon is determined instantaneously by how the first one was chosen to be measured. This is supposed to be impossible because nothing travels faster than the speed of light, and yet there is instantaneous information transfer between the 2 photons.

 

f) Cramer's experiment ultimately seeks to confirm this absurdity even further, making the entanglement relation hold not only across great distances but across time. The experiment sets up photon #2 to be forcibly (according to my understanding) detected as 'black' or 'white' at (t+50) microseconds. At time t however, photon #1 is already being measured for whether it is 'black' or 'white' and the expectation is that entangled photon #1 will already exhibit the properties that the detector for photon #2 is set to discover only 50 microseconds later.

 

Now assuming the above understanding does not miss any vital points, you could push the envelope even further, by delaying detecting of photon #2 at time t plus, say, 10 seconds. I am wondering if it would be correct to speculate that the experiment could allow us to see whether photon #1 gets detected as 'black' or 'white' and THEN adjust the detection of photon #2 to be detected as the contrary.

 

That would violate the entanglement which I doubt is possible, so what the heck would actually happen?? Would nature show that it already knows what you're going to do before you do it (similarly to how the photon in the double-slit experiment knows if it was being detected as a particle)??? But how does that affect the free will of the experimenter since he can know in advance what nature is supposed to know about *his* future action *and* can then go ahead to do something contrary???

One URL describing the John Cramer experiment is described here:

 

http://seattlepi.nwsource.com/local/292378_timeguy15.html

 

The way I understand it, "adjusting the position of the detector that captures the second photon (the one sent through the cables) [to determine] whether it is detected as a particle or a wave" is the act of 'free will' that will only get consummated 50 microseconds into the future.

 

In principle, this act will already have been _decided_ beforehand (e.g. the experimenter's decision to set up the detector to detect the second photon as particle or wave). However, the actual detection will not occur until 50 microseconds in the future.

 

But before the 2nd photon's detection has occurred, the first photon's measurement will already corroborate the experimenter's (ostensibly free-will) decision.

 

 

Now, assuming the above is a correct understanding of what's going on, and if the so-called retrocausality is demonstrated successfully then that's pretty remarkable. Now here's a little thought experiment:

 

Lengthen the fiber optic cable to a length such that the second photon will take many seconds before it will hit the movable detector. Enough seconds such that the experimenter can see first whether photon #1 gets detected as a particle or a wave

and THEN adjust the movable detector.

 

What the heck would then happen in such a case?? Remember, the entanglement dictates that if photon #1 gets detected as either particle or wave, it should constrain photon #2 to be detected as likewise (or opposite, not sure which, but the relationship is concrete and pre-determined). But the adjustment of the second movable detector is supposed to be able to control detection as the experimenter wills it! If photon #1 is already detected as wave and if in such a case entangled photon #2 has GOT to be detected as a wave also, what happens if the experimenter tries to move the detector in such a way as to 'force' photon #2 to be detected as a particle??!?

 

 

 

Of course, there is the possibility that I really have no idea what the heck i'm talking about here and have missed some very fundamental point...

Suffice it to say that the new science of Chaos and Complexity Theory looks at everything in a holistic viewpoint rather than fragmented parts of the whole.

A clue to why probability plays such a big role may lie in that statement.

 

Probability/statistical measurements do not manifest themselves unless a large enough sampling is made. Believeing that the principle of cause and effect can explain everything discounts the notion that there are some kind of 'holistic' aspects that are impossible to analyze or make sense out of in isolation (because cause and effect is all about 'isolated' causes being responsible for isolated effects).

 

The notion of probability is absent when an event is looked at in isolation.

anyone out there interested in this sstuff? its actually a great read and the daily applications is phenomenal...

What I find most profound is the destruction of the principle of determinism. That there are events for which there is no traceable cause.

 

For some reason, the human mind is wired for searching the proper cause to assign to an effect, e.g. we seem to be wired to need to consider cause and effect as the overriding principle of reality. For early humans, no matter how primitive the culture, no matter how limited the science, the need to assign causes to particular effects was still there.

 

Slowly we taught ourselves that every supposed phenomena (effect) has a traceable non-supernatural origin (cause). But realize that, with this view comes the paradox of what then gets assigned as the First Cause, an uncaused cause. It is a paradox because an "uncaused cause" completely violates of the principle of cause and effect.

 

Now, with science, we are actually observing phenomena (at the quantum scale) for which the principle cause and effect clearly does not apply, with events just happening for no reason at all. However, the central feature of these events is that while they have no assignable cause they have the very remarkable property of being statistically/probabilistically consistent.

 

Einstein could not believe that 'God would play dice', but apparently 'GOD' seems to be nothing but a bunch of dice!

 

This means that probability, something that seems to be so intangible, seems to be intimately involved with the core of our current universe-view. A rigorous philosophical analysis of the notion of probability might be one way to point to put our understanding of physics on a more solid footing.

anyone out there interested in this sstuff? its actually a great read and the daily applications is phenomenal...

What I find most profound is the destruction of the principle of determinism. That there are events for which there is no traceable cause.

 

Our (present) human mind's tendency is to consider cause and effect as the overriding principle of reality. For early humans the cause they assigned to particular effects was very crude. The universe around them was NOT subject to scientific laws but rather to the whims of gods or whatever. Still, right here we see that for some reason Man's mind is wired for searching for the proper cause to assign an effect.

 

Slowly we taught ourselves that every supposed phenomena (effect) has a traceable non-supernatural origin (cause). With that view comes the paradox of what then gets assigned as the First Cause, an uncaused cause. It is a paradox because an "uncaused cause" completely violates of the principle of cause and effect.

 

Now, with science, we are actually observing phenomena (at the quantum scale) for which the cause and effect clearly does not apply, with events just happening for no reason at all. However, the central feature of these events is that while they have no assignable cause they have the very remarkable property of being statistically/probabilistically consistent.

 

Einstein could not believe that 'God would play dice', but apparently 'GOD' seems to be nothing but a bunch of dice!

 

This means that probability, something that seems to be so intangible, seems to be intimately involved with the core of our current universe-view. A rigorous philosophical analysis of the notion of probability might be one way to point to put our understanding of physics on a more solid footing.

When I was a kid studying in a fundamentalist school I was very afraid of God and all the mean things he is said to be able to do to people with very little justification, such as turning someone into a pillar of salt (Lot's wife) merely for looking back when he was destroying Sodom and Gomorrah.

 

Now I realize it was all just a cock-and-bull story.

 

Back then I couldn't understand why God would not want anyone to look at what he was supposed to be doing to these 2 cities. Now I can say the suspicion that was always at the back of my mind... it was the suspicion that God was actually joining in the homosexual orgies which was why He did not want anyone to look back and find him out!!