Slashdot Mirror
Data Transfer Has A Speed Limit
ChrisHanel writes "Yahoo News is reporting that despite the infinite climb data speeds seem to be making, scientists at Stanford say we'll eventually hit a barrier due to the inability to keep the data stable after a certain transfer speed. But no worries just yet; the watermark they've set is still 1,000 times faster than what we have now." Apparently: "The scientists confirmed this problem by firing up the particle accelerator at Stanford University and blasting electrons at a piece of the magnetic material used to store computer data."
While it does say that using the current magnetized bit storage system has a speed limit that is 1000 times the current, it is only with this method of storage. Hopefully by the time we could hit this limit we will have a new method of storage. Besides, if my data could be written at 1000x the max of current maybe I won't need memory any more (or maybe our storage will be memory). Anyone have any ideas what we will be storing at that speed? (other than everything happening around us and everyone else so we have instant replay on life).
Actually, no
The problem comes from the transfer itself due to the limits of magnetic storage. While this isn't mentioned in the summary, if you were to RTFA then you would see that the problem arrives when you fire electrons at a magnetic storage material fast enough (approaching the speed of light) they stop behaving in the expected way, and start producing random results. This of course is unacceptable for a storage medium, because if you increase the increase the pulses to write to the disk to near the speed of light it will result in random bits being flipped here and there and corrupt your data.
-geoff313
I might point out that all natural laws are derived strictly through empirical observation. In fact, that's the very definition of such a law.
Moore's Law is what an engineer would call a "rule of thumb." Something which is understood not to be a law, but within certain constraints can be treated as if it were. This observation is included in the full version of Moore's Law, as actually written by Moore himself.
Like Newton's Law of Gravity, which can be applied as if it were law, so long as you are not Mercury, as was in noted by Newton himself in his original statement of his law.
The writers of laws are not to be held accountable for the misinterpretations of others.
None of this has much of anything to do with the article either (nor does the heading under which the story appears, which is what the OP was responding to, which is perfectly valid). However, I do not believe STFU is an argument, so I will not apply it to myself, or you for that matter.
Post on, McDuff.
KFG
Comment removed based on user account deletion
No. You are wrong. Quantum entanglement does not lead to faster-than-light data transfer. See here: http://curious.astro.cornell.edu/question.php?numb er=612
The grandparent poster seems to be confusing things a bit. Let's try to clarify...
Except for the Lorentz transformation, the most important equation in Special Relativity theory is the Energy-Momentum relation:
(This is true for all inertial reference frames, and embodies the fact that the contraction of the energy-momentum 4-vector for a particle is an lorentz invariant. The Dirac equation, the Klein-Goron equation, and much of modern quantum field theory is rooted in this equation.)
Another important equation of SR involves the velocity:
From these, we can see that
(i) if v < c (sub-luminal), then pc/E < 1, so E^2-(pc)^2 > 0, which means m^2 > 0. This case is true for normal, boring matter. Note that the converse is also true: m^2 > 0 implies v < c .
(ii) if v = c (luminal), then E = pc, and m^2 = 0. This holds for (massless) photons and gluons, and used to be assumed true for neutrinos. The converse ( m^2 = 0 implies v = c ) is also true.
(iii) if v > c (super-luminal), then m^2 < 0. Conversely, m^2 < 0 implies v > c . There is no known type of matter that is described by this case, but physicists have given such hypothetical particles the name "tachyons". One could say that mass is imaginary in this case, as m^2 < 0, but physicists rarely actually speak like this.
Anyway, the parent poster is right in correcting the grandparent poster that it is negative mass *squared*, not negative mass, that makes something a tachyon (v > c). But this
is not quite correct. From F=ma, we can see that it is true a negative mass would cause a particle experiencing a force in one direction to actually accelerate in the *opposite* direction! (Imagine that. You push something away with your finger, but it comes closer, increasing the force you're exherting on it, which increases the acceleration, ad infinitum. Physicists really hate thinking about the instabilities involving negative inertia, so we don't like to talk about negative mass at all.)
The problem with the parent post's suggestion is that althought this strange behavior would happen with an electrical force (such as your finger), it need not hold for gravity! In boring old Newtonian Gravity, a particle a distance r away from another mass M feels the force F = GmM/r^2 . But the acceleration would be a = GM/r^2, whether the mass is negative or not, because m completely cancels out of the equation. A similar thing happens in General Relativity, Einstein's theory of gravity -- the particle still follows the local geodesic of the spacetime metric generated by M.
To get back on the topic of information transfer, it's pretty clear that without nontrivial spacetime topologies (eg, wormholes) superluminal information transfer shouldn't happen except in the tachyon case. But does it really happen in this case?
The problem is that real life is quantum mechanical, wherein "particles" are described by evolving wavefunctions in a Hilbert space. A particle is a sort of propagating localized disturbance. The equation that should describe the propagation of a (scalar) tachyon is the Klein-Gordon equation. I quote the last paragraph from this discussion of the KG equation in the tachyon case:
First, X-rays are definitely particles, as has been shown in various experiments. Also, X-rays are definitely waves, as has been shown in other various experiments. Light is both wave and particle.
Anyway, he wasn't talking about the X-rays themselves, or the microwaves themselves as the particles. What he meant was an X-ray tube is a particle accelerator. It operates by accelerating electrons through several hundred kilovolts, and slamming them into a metal target (tungsten). Hence it is a particle accelerator.
A microwave operates by a magnetron device, which is a circular chamber with a high voltage between the inner cathode and the outer walls. Electrons are emitted from the cathode and are accelerated toward the walls. However, a magnetic field causes them to spiral and create a rotating radial electric field which sweeps through a number of resonant cavities, which then resonate at microwave frequency. Hence a magnetron is a particle accelerator.