Language Subjects

[Alien1]

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.

 

The speed of light is only a limiting factor for mass particles, a massless

or negative mass particle "tachyon" travels faster than the speed of light

and cannot drop below it.

 

It should be noted that while Einstein's theory of special relativity prevents (real) mass, energy, or information from traveling faster than the speed of light c (Lorentz et al. 1952, Brillouin and Sommerfeld 1960, Born and Wolf 1999, Landau and Lifschitz 1997), there is nothing preventing "apparent" motion faster than c (or, in fact, with negative speeds, implying arrival at a destination before leaving the origin). For example, the phase velocity and group velocity of a wave may exceed the speed of light, but in such cases, no energy or information actually travels faster than c. Experiments showing group velocities greater than c include that of Wang et al. (2000), who produced a laser pulse in atomic cesium gas with a group velocity of . In each case, the observed superluminal propagation is not at odds with causality, and is instead a consequence of classical interference between its constituent frequency components in a region of anomalous dispersion

 

"If it works it will be interesting to see what happens"

Motto of MAD SCIENTISTS INC

[Alien1]

Formula didn't post

Group velocity is (-310+/-5)c

[mason_rod]

hello guys! can i join in the discussion? im very much interested to learn what this quantum mechanics concept is all about. what turns me off and what confuses me are what i read in pop books or watch in docu movies (like the 'What d bleep do they know'?) which to my mind r full of s@%t coz they co-mingle the physics principles with pseudo-zen buddhist concepts, fuzzy new age logic and jz knight/ramtha channeling (tagalog: "sinasaniban") philosophy!

 

I get your point, some people sometimes drag Quantum Physics into the equation despite lack of perspective.

 

I’m not an expert, but Quantum Physics grew out of failures of Classical Physics which found some quantum remedies in the Planck Hypothesis and Wave Particle Dualities and generated new ideas like the Uncertainty Principle and Quantum Statistics.

 

[X]

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:

Wow!

 

You've tried it?

[X]

One URL describing the John Cramer experiment is described here:

 

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?

 

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.

 

So the two conditions negate each other, preventing the paradox.

 

Hence, this may be the proof that will explain why time travel REALLY is not possible, especially at the quantum level.

 

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

Edited January 13, 2007 by X

[jonp]

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.

[jonp]

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.

[jonp]

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...

[X]

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

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.

 

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

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?

 

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.

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...

 

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

The Philadelphia experiment was a coverup for Nuclear testing. Besides, the test was supposed to be for cloaking a ship, rendering it invisible, NOT for moving it back (or forward) in time.

[jonp]

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.

[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.

[belisarius]

i'm still reading my beiser book (physics 73) on the part explaining why photons have zero rest mass but start having mass and increasing as they reach c whereupon mass becomes an undefined 0/0.

[X]

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.

Same thing actually. My bad on the term.

 

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.

Yes. But will it STILL be light?

 

A particle moving faster than light is no longer light. It's theoritical term is a tachyon.

 

Slow down a photon, and it's no longer light.

 

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.

Simply put, it's one photon's behaviour relative to another.

[naru2ako]

I'm planning to take arabic....

[rodstryker]

i never had one. gusto ko mag aral ng french.