I Think You Mean. Duh.
According to particle physicists, the permiability and permittivity of free space are just the 1-st order approximation of the quantum- mechanical field that gives rise to photons. Their product _has_ to be related to the speed of light, because photons are massless and thus _have_ to go at the speed of light (no faster, no slower).
-- Tim Wescott Control systems, embedded software and circuit design I'm looking for work! See my website if you're interested http://www.wescottdesign.com
I played with this idea when I first found out about negative inductance and capacitance "simulator" circuits.
Short answer, it doesn't work.
Mark L. Fergerson
Your write. How very annoying.
Annoying that I'm wrong, that is :)
I'm overwhelmed by the Sheer Cosmicness of It All. ;)
Cheers
Phil Hobbs
They can't break c, but nonlinear transmission lines, shock lines, are fun. They propagate high frequencies faster than low ones, so a step gets faster as it moves down the line. They can use varicaps or saturating magnetics as the nonlinear elements.
IC versions can have hundreds of inductor-varicap stages and make output edges with single-digit-picosecond rise times. Really fast samplers and comb generators use them.
Some discrete ones can make kilovolt fast steps, too.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I've seen people fool themselves into thinking they can break c, by timing from the midpoint of a slow rise to the midpoint of a fast rise, with some nonlinear element reshaping the rise.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
Speaking of...
Suppose you construct a cosmic transmission line (or waveguide, or just beam waves out, unconfined), and you dump enough energy -- about the mass of a star's worth -- into it, in a fairly short time.
Time dilates inside the path, because of the immense energy density. From the outside, time appears to go slower. (In case you're wondering: yes, energy warps space-time, too -- light has mass-energy, and mass-energy is what warps it. Light just has zero rest mass, so it can never be at rest.)
So, space itself seemingly supports inverse shockwaves: they slow down rather than speed up.
Which is kind of damning for warp drive, because the best guesses we have right now require large negative masses (and/or oscillating masses, but I forget if the oscillating conditions are able to fully do away with the "exotic negative matter" part). Which... sounds suspiciously like plugging negative inductors and capacitors into an inverse transmission line, which....yeah.
Not that there's necessarily anything in circuit theory preventing negative inductors or capacitors from existing, but they're all larger than their negative length would save(?), and all have finite bandwidth (whereas space has an absurdly high bandwidth limit*).
*I suppose that would be a gamma ray so energetic, it's on the verge of a black hole. Probably wavelength = Planck length, or something like that.And not that there's necessarily anything in relativity preventing negative mass from existing, but... uh... yeah.
Analogies are fun..
Tim
-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
I had a case where I was forced to specify delay of a level shifter from 50%-to-50%. Of course it came out with a negative delay. Management didn't see the problem with it. It went into the document system with a negative delay.
So that it cannot escape itself?
-- Reinhardt
Or people who don't understand the difference between phase and group velocity.
-- Reinhardt
There's more to it than making high frequencies faster than low ones. It has to create extra high-frequency components. Of course, that's exactly what non-linearities do nicely.
I tried this in LTspice: A chain of 20 or so LC sections of 2nH with MV2201 varactors steepen a 1ns 10V edge down to 200ps. I could include the .asc, but it's pretty simple to reproduce. Terminate the end with 17 Ohms.
Nice.
(For this sort of thing, I'd want the .asc format to be more like a real programming language.)
Jeroen Belleman
I'll try that and get back to you.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
High-voltage versions have been done with crappy-dielectric ceramic capacitors as the nonlinear elements, and even a line made from a couple of strips of metal with a continuous nonlinear dielectric between.
You can copy one LC section, then copy two, then four...
-- John Larkin Highland Technology, Inc lunatic fringe electronics
Or the difference between group delay and true delay. (An RC lowpass has the one but not the other, for instance.)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
That's what I did. Exponential growth comes naturally.
Jeroen Belleman
eam
Requiring what, Kardashev II 1/2 level technology?
m
.)
Like laser beams self-focusing in air?
Wait, why would they slow down? Air isn't vacuum.
Hrm. Could it be seen in the gravitational wave signature of merging blac k holes? If we're gonna discuss how fast spacetime can transfer information ...
That last bit is yet another handwave that hasn't been shown to meet the only criterion that lends Alcubierre credibility- nobody's proven that it s atisfies the relevant Einstein fields equations. It *might* (produce exotic
-matter-equivalent vacuum states) if the vacuum becomes nonlinear when you stress it hard enough with strong (strength we can't generate yet) time-var ying fields.
Robert L. Forward looked into that sort of thing but died before he got a nywhere AIUI. Since he actually built stuff and wrote (gasp!) science ficti on in his spare time, "real" physicists don't seem interested in following him up.
The "simulator" circuits I played with had all sorts of inconvenient inte rnal delays that prevented anything fun from happening. However I understan d *real* negative effects have been demonstrated in ferroelectrcs recently.
ve
ce
The papers I've looked at on ferroelectrics contain too much math above m y pay grade to be easily penetrable but I suspect you're right.
OTOH nonlinear vacuum effects would have finite bandwidth too, but if you can get FTL signaling in a finite band it's *still* FTL.
t.
In that range the photon energy itself becomes slightly indeterminate so it might or might not collapse on itself. Now that's confusing. I suspect u nphysical singularities in the math but I'm not competent to pick them apar t. Maybe there's a UV-catastrophe type resolution?
ve
They're also like ropes. ;>)
Mark L. Fergerson
Something like that...
Just a little weekend project. :-)
Hmmm yes, should be. The "index of refraction" of space is always? positive, so it would tend to self-focus as well. At least, within the beam.
At the wavefront (supposing a fairly sharp rising edge on a relativistic-train-wreck-sized gulp of energy), does the spacetime warp travel with it, or lag behind, because, you know, speed of light is speed of light? The warping should be equivalent to saying there's a tremendous bow wave of gravity waves there, I think?
It's not intuitively clear to me, whether it should be self-maintaining (a soliton... oh, relevant now: ), or if the wavefront will disperse or diverge.
Well, the trainwreck speeds up, from its perspective.
But that's kind of not a useful observation, because it's pure energy, and light doesn't have a clock at all, which is...why it is light...
"Time flows slower inside a gravity well", to use common language.
It would be interesting, perhaps, to probe the environment of such a beam, but placing particles anywhere near it would surely not end well. With the intense electromagnetic field in the beam, lone protons would be ripped apart. Well, hell, space itself would be ripped apart; perhaps such a beam would lose energy quite quickly, due to pair production. (Its mass-energy remains constant, but if the pairs leave the beam, the beam itself will disperse. Perhaps the wave could be designed to confine particles anyway. Hmm.)
Anyway... surely such a concept extends so deeply into unknown physics that, even if we know (or think we know) relativity pretty well, there are untold rules preventing such a thing. Not to mention the engineering challenge, for what amounts to a "f*ck this solar system in particular"-blaster. :-)
Hmm...
It's interesting that black hole merge transients aren't fully hyperbolic. (Actually, maybe they are, or at least, more so than we can see because of LIGO's finite bandwidth?) The animations all show the waves stopping at a finite frequency and amplitude, at least.
It's perhaps the case that, once the BHs get close enough together, the rest of the death spiral (which does ultimately lead to the singularities merging) falls beneath their common event horizon, thus trapping whatever energy remains of the event.
I wonder what the exact timing is, as far as amplitude and frequency versus time. For a decaying pair without relativity, it should increase inversely, and end in a singularity (infinite frequency and amplitude). Since the waves radiate away from a curved source, and the mass distribution of that source is changing, the real curve should be distorted in subtle ways from that curve, no?
The end of the transient would be the most interesting, because it could end with a DC offset, so to speak, which is the result of the last amplitude peak being trapped on the event horizon, never to fully emerge. The exact way the transient freezes in its tracks, so to speak, might be interesting (particularly if we can measure it with much better SNR?).
Tim
-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
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