German scientists have broken the light barrier
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Oh definitely, while I REAAAAAAALY wish this was true, being off by a hundredth of a percent is a massive difference. Lets see them repeat this, and then make me a flying car that makes me younger by driving 
For what it's worth, the speed of light isn't all that fast from the perspective of modern hardware - between two clock ticks of a 3ghz CPU, light only travels about 4 inches. Put differently, if you were to watch the clock ticking in your CPU, by the time you can observe a given clock tick, the CPU is already a few cycles ahead!
You're comparing speed with frequency?
Also, your formula doesn't make sense.
c = 3e8 [m/s]
f = 3e9 [Hz]
L = Lambda = wavelength [m]
We know that c = fL -> c/f = L.
So, what you did was you first found the wavelength of light at 3Ghz and then multiplied it by 1s, giving you dimensions of [m*s] for your final answer. This isn't quite right.
I think what you wanted to do was the following.
T = Time taken to complete 1 cycle = 1/f = 3.33e-10
Distance covered in that time = 3e8[m/s]*3.333e-10
Hence, at 3 GHz in 1 clock cycle, light would have traveled 0.1m or approx. 4 in. Although numerically the answers are identical (since you picked 1s), your method was slightly off.
I posted this in Slashdot, as well...
"You're not getting it. This is quantum mechanics/physics, not conventional.
They're using quantum tunneling to change the photons position rather than making it "travel" faster than light moves on its own. The photons in this experiment are not "traveling" in our definition of the word, they're leaving regular space and instantly appearing somewhere else. If the particles/matter we wish to transport can leave conventional space, they no longer need to follow the rules that state "matter with mass cannot move faster than light". Also, photons actually do have mass... Look it up.
Our entire understanding of why objects behave the way they do in regular space has been limited to our own percievable surroundings up until the last century. We're finally starting to see that our visible universe is only the cover sheet to a much more vast and complicated system. There are levels of existence that have different rules and structures that we cannot see yet, but we're just starting to poke them with our scientific stick, so to speak.
Personally, I'm hoping to see quantum tunneled (or something similar) matter within the next two decades, and I don't believe I'm giving my hopes up when I say that... So long as we don't fuck everything up by killing each other and/or dropping into another religiously provoked dark age, I think we're in for some absolutely rediculous scientific advancements in the next 20 years."
"You're not getting it. This is quantum mechanics/physics, not conventional.
They're using quantum tunneling to change the photons position rather than making it "travel" faster than light moves on its own. The photons in this experiment are not "traveling" in our definition of the word, they're leaving regular space and instantly appearing somewhere else. If the particles/matter we wish to transport can leave conventional space, they no longer need to follow the rules that state "matter with mass cannot move faster than light". Also, photons actually do have mass... Look it up.
Our entire understanding of why objects behave the way they do in regular space has been limited to our own percievable surroundings up until the last century. We're finally starting to see that our visible universe is only the cover sheet to a much more vast and complicated system. There are levels of existence that have different rules and structures that we cannot see yet, but we're just starting to poke them with our scientific stick, so to speak.
Personally, I'm hoping to see quantum tunneled (or something similar) matter within the next two decades, and I don't believe I'm giving my hopes up when I say that... So long as we don't fuck everything up by killing each other and/or dropping into another religiously provoked dark age, I think we're in for some absolutely rediculous scientific advancements in the next 20 years."
As far as I can tell this is just yet another experiment performed by experimentalists that do not fully understand what they are doing. This kind of "result" pops up from time to time (usually in the news, since no scientific journal will publish "results" like this for obvious reasons) and I can assure you that it does NOT violate special relativity.
QM tunnelling might be "strange" but it IS fully understood and current theories are fully verified in experiments. ALL known experiments are in full agreement with special relativity (relativistic quantum mechanic is quite complicated, but it has been around for over 60 years).
Manowar821 is partly right in that you can't think of this as "particles" moving FTL in the classical sense since the full QM description needed; however there is nothing mysterious about this.
Also, more importantly tunnelling does NOT allow us to transfer information (or matter) FTL.
In a way this is somewhat similar to the difference between phase and group velocity. The former can quite easily be made to exceed c in e.g. certain waveguides (note that this is a purely classical effect) since it conveys no information; the group velocity is,however, always smaller than c. This distinction is quite frequencly lost on some people leading to claims about FTL information transfer.
QM tunnelling might be "strange" but it IS fully understood and current theories are fully verified in experiments. ALL known experiments are in full agreement with special relativity (relativistic quantum mechanic is quite complicated, but it has been around for over 60 years).
Manowar821 is partly right in that you can't think of this as "particles" moving FTL in the classical sense since the full QM description needed; however there is nothing mysterious about this.
Also, more importantly tunnelling does NOT allow us to transfer information (or matter) FTL.
In a way this is somewhat similar to the difference between phase and group velocity. The former can quite easily be made to exceed c in e.g. certain waveguides (note that this is a purely classical effect) since it conveys no information; the group velocity is,however, always smaller than c. This distinction is quite frequencly lost on some people leading to claims about FTL information transfer.
No. I was pointing out that light takes its sweet time to travel a few feet, relative to the time periods all of our PCs are based on. The OP seemed to be looking at the claim intuitively and thinking "light is really fast - it must be very hard to measure its speed over a short distance like a few feet"; I was pointing out that we have lots of technology that operats on timescales short enough that a few feet is far.
I wanted to find out how fast light goes in 1/3rd of a nanosecond. I took c and divided it by unitless 3 billion (so I still actually got a result in m/s). This was a shortcut; to keep the units in line, I should have divided it by 3 billion seconds^-1. Since I didn't feel like figuring out how to convey that to Google quickly, I just multiplied by a second (which is mathematically identical - I stuck seconds^+1 in the numerator instead of seconds^-1 in the denominator). You'll also note that Google, which tracks units, says I got a distance as a result and not a distance*velocity (m*s) as you are saying (I'm not sure where you're getting that).
Wavelength is mostly irrelevant. Any light will travel ~4in per clock cycle. You're right that the wavelength of the "light' your CPU clock would emit is about 4 inches, but while obviously lambda = distance/c = [other permutations of c, freq, distance], it's not of any relevance here.
Farmer
Diamond Member
- Dec 23, 2003
- 3,334
- 2
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Here's a standard fare problem you get when you take relativity:
Suppose you have a searchlight. Recall the arclength equality, s for arclength, r for radius, w for angle:
s = rw
Let's take a time derivative, holding r constant WRT time.
d/dt (s = rw) = (ds/dt = r dw/dt);
Make (dw/dt) a reasonable, humanly feasible number. Make radius a huge number (i.e., let's say we are shining the light on Neptune), s.t., r dw/dt >> c.
Does the spot of light actually travel faster than light? I would argue that, yes, amazingly, the spot does travel faster than light. But then I would become extremely confused, and ask, what does that even mean, what exactly is traveling faster than light, and does any law forbid it from doing so?
Honestly, I only took one class on special relativity, and am not really even a physics major. I have absolutely no hope of understanding the research you linked to.
Suppose you have a searchlight. Recall the arclength equality, s for arclength, r for radius, w for angle:
s = rw
Let's take a time derivative, holding r constant WRT time.
d/dt (s = rw) = (ds/dt = r dw/dt);
Make (dw/dt) a reasonable, humanly feasible number. Make radius a huge number (i.e., let's say we are shining the light on Neptune), s.t., r dw/dt >> c.
Does the spot of light actually travel faster than light? I would argue that, yes, amazingly, the spot does travel faster than light. But then I would become extremely confused, and ask, what does that even mean, what exactly is traveling faster than light, and does any law forbid it from doing so?
Honestly, I only took one class on special relativity, and am not really even a physics major. I have absolutely no hope of understanding the research you linked to.
silverpig
Lifer
- Jul 29, 2001
- 27,703
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Farmer, there is no law saying things can't travel faster than c, it's just that they can't carry information with them. Here's one that I like to use:
Imagine a row of people lined up beside each other 10 feet apart, stretching from the north pole to the south pole. Let's say you want to send a message from Santa to a penguin so you have the first person clap. The second person then claps once they hear the first person, then the third claps once they hear the second etc. Eventually the signal will reach the south pole, and assuming that the people have 0 response time, the signal will travel at the speed of sound.
Doing the same with flashlights, and again assuming 0 response time, Santa can send a signal to the south pole at the speed of light using his human wire.
But can you make the people light up faster than light? Yes.
Let's give them all atomic clocks, and tell them all that Santa will turn his light on at 12:45:00 exactly, and we'll tell the second guy to turn on his light at exactly 1 100-trillionth of a second later. We'll arrange for the nth person down the line to turn on his flashlight n 100-trillionths of a second after Santa does.
Now to someone observing, the lights will light up in a wave traveling faster than c, however because the turn on times were all pre-determined, they don't carry any information with them.
Imagine a row of people lined up beside each other 10 feet apart, stretching from the north pole to the south pole. Let's say you want to send a message from Santa to a penguin so you have the first person clap. The second person then claps once they hear the first person, then the third claps once they hear the second etc. Eventually the signal will reach the south pole, and assuming that the people have 0 response time, the signal will travel at the speed of sound.
Doing the same with flashlights, and again assuming 0 response time, Santa can send a signal to the south pole at the speed of light using his human wire.
But can you make the people light up faster than light? Yes.
Let's give them all atomic clocks, and tell them all that Santa will turn his light on at 12:45:00 exactly, and we'll tell the second guy to turn on his light at exactly 1 100-trillionth of a second later. We'll arrange for the nth person down the line to turn on his flashlight n 100-trillionths of a second after Santa does.
Now to someone observing, the lights will light up in a wave traveling faster than c, however because the turn on times were all pre-determined, they don't carry any information with them.
Farmer
Diamond Member
- Dec 23, 2003
- 3,334
- 2
- 81
silverpig:
I guess that's a keen example, esp. if you take all the 'human' factors, like being on Earth (which places people at motion WRT each other, an in an accelerating frame), and having people do things.
If you just say there are just a bunch of lights floating in deep space, at rest WRT to eachother, seperated by some small distance, and are programmed to do what you said, I would say that example works. I mean, I wouldn't say, it carries no information, I would just say everything that carries information (i.e., light, and anything else) never needs to travel faster than c to do what you described.
I guess that's a keen example, esp. if you take all the 'human' factors, like being on Earth (which places people at motion WRT each other, an in an accelerating frame), and having people do things.
If you just say there are just a bunch of lights floating in deep space, at rest WRT to eachother, seperated by some small distance, and are programmed to do what you said, I would say that example works. I mean, I wouldn't say, it carries no information, I would just say everything that carries information (i.e., light, and anything else) never needs to travel faster than c to do what you described.
Any links to the original published article? I checked Europhysics Letters, Optics letters and PROLA. Found nothing.
This looks like the paper. I can't download it from home, but the abstract seems to fit.
edit: That pdf is actually a book chapter with a copyright of 2002...
One paper is available on the arXiv, dated 5 Aug 2007 so it should be the right paper
http://arxiv.org/abs/0708.0681
I had a quick look at it, and it basically confirmed what I wrote above.
I seriously doubt any good journal will publish this.
http://arxiv.org/abs/0708.0681
I had a quick look at it, and it basically confirmed what I wrote above.
I seriously doubt any good journal will publish this.
Out of curiosity, would this theoretical 'faster-than-light' wave appear to an observer to simply travel backwards (from the North Pole to the South Pole)? Or would the Santa's light turn on, and then the first light would turn on back in the South Pole, and the wave would travel in the 'forward' direction?
Not sure what you're getting at here. Yes, it could be interpreted as an infinitely fast wave, but it would carry no information. In order for the lights to light up at exactly the same time, they would have had to have been programmed to do so. No causal interactions would have created this wave, and thus it cannot convey any information.
I thought I read an article in Discover a few years ago about this. Something about shifting the mass of the particle slightly forward, so it registered on the sensor sooner than the unaltered particle.
Quantum tunneling doesn't allow object with mass to exceed C, they just get to take a different course, one that appears much shorter that in obvious to us therefore the overall trip vs obvious distance appears to be faster than C.
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