Boffins have constructed a new LIGHT SABRE. Their skills are complete Top boffins in the US say they have managed to make light behave in the same way as solid matter – and they've saved us the trouble by suggesting that this is pretty much the same as building a working Jedi light sabre. "It's not an inapt analogy to compare this to light sabers," boasts Harvard physics prof Mikhail Lukin, one …
"Read the link might be an idea?"
That's not really fair to say to someone when the article is behind a paywall, now is it? OK, so in this case an example did happen to be in the abstract, but still not everyone has a subscription to every journal. Of course, the authors could have gone open access, as we all should these days.
"I wonder how much support the Harvard-MIT Center for Ultracold Atoms receives from the US government."
If the research was US Government funded and not classified, it'd not be behind a pay wall. It would be openly available for all to read.
Forget what law that was that required that one.
For classified stuff, all bets are off, save that it wouldn't end up published for a generation or so.
In uni we worked out that the "Light" and the crystal were probably a laser which supplied the energy to create the plasma and keep it hot.
The trigger activates the magnetic bottle, releases enough matter to become plasma which is then excited by the laser, electrons are diverted to one end of the bottle and possibly allowed to escape, where they interact with the atmosphere (creating the hiss-crackle as the blade is extended). The energy and mass lost when the blade interacts with the environment is why the laser has to be kept on and the blade continues to crackle as it's used.
Might have been a sad git at uni. Probably still am.
I gave a lot of thought to this myself, but concluded there was no way a sabre effect could be achieved.
I have designed a force field, though. I think it would work. It just has a few minor practical issues, like requiring the entire output of a power station to generate a field big enough to block a corridoor, an a tendency to incinerate anything that touches it. But the theory would work: You could flip marbles at it and they would just bounce off.
One day I will find a way to build it. I think I could run a small-scale prototype off no more than twenty kilowatts or so.
Not to mention the fact that lightsabers are HOT. They're hot enough to cauterize the wounds they make instantly, to melt blast doors, and to scorch pretty much anything they cut through. For that matter they don't really 'cut' so much as instantly melt a microscopic path through whatever they're used on. That's how hot they are.
This light-matter stuff, on the other hand, sounds like it's cold. And by that I mean superconductor range temperatures. Which is pretty much the opposite of a lightsaber.
Mine's the one with the Star Wars Encyclopedia in one pocket and the empty address book in the other.
One way I figured to build an actual light sabre would use a laser that, when focused, would be powerful enough to heat air to plasma.
Then using a piezoelectric lens so that the focal point would be swept back and forth to generate the 'blade'.
It'd look like a light sabre, burn through stuff, and make the crackling and vroom sounds.
Unfortunately, sword fights wouldn't work, the 'blades' would pass through each other.
Two major drawbacks:
The handle would need to be hooked up to a rather unwieldy power source and cooling air supply. You'd look like you were dragging a vacuum cleaner around by the hose.
Air tends to produce some nasty to breath compounds at that temperature, you'd need to wear a respirator to use it!
The handle would need to be hooked up to a rather unwieldy power source and cooling air supply. You'd look like you were dragging a vacuum cleaner around by the hose.
Canonically the first lightsabers (a few thousand years before Exar Kun and something like ten or fifteen thousand years before the movies) had a bulky backpack power supply about the size of a vacuum cleaner and a fat power cable going to the handle, so you're on the right track.
*Yes, I truly am sad enough to know that much about the history of the Star Wars universe. As I've mentioned before I had way too much time on my hands when I was younger. This is just further proof of the fact.
"Personally I've always considered light sabres to be magnetically confined plasma."
Briefly considered that back in the 1980's. Then, I considered how magnetic fields don't maintain annular confinement beyond a magnetic coil.
Then, I considered multiple standing waves and a holographic reflector at the point...
Finally, I considered it a matter of, "To hell with that idiocy. A blaster puts out a greater volume of fire."
... yeah - wholly out of light that is strongly coupled to rubidium atoms. So not /only/ out of light, which is what is strongly implied by "wholly out of light".
I look forward to the Star Wars pre-pre-pre-prequels where proto-jedi whack each other over the head with clubs made out of ultracold-atom vacuum systems. :-)
The only way you get light to not travel at lightspeed is to make it interact with something. E.g. in water, visible light interacts with the water molecules, and it slows by about 30% (hence the refractive index of 1.5). To make light really slow, you have to get it to interact very strongly - in this case, using a specific frequency of light tuned to specific transitions in carefully managed rubidium atoms.
This "slow light" therefore, is a rather misleading name - it isn't just light - it's a strongly coupled light-matter system, which some would prefer to call a polariton.
I can therefore only assume the down votes were for the poor quality joke.
"Now where is my hoverboard?"
Actually the technology for that should have arrived about a decade ago, when scientists worked out the genetics of the "flagellum motor," and how to tweak it so it could be mounted to a framework.
1 motor generates about 1 nano Newton of force.
stick about 1000 billion of them on a framework (that's about the size of a full stop on a page), supply regularly with ATP and hey presto you have lift off..
The control problem (bit like the Segway but much tougher) is left as an exercise.
"They only generate that much force when immersed in a liquid. Wouldn't work in air."
And you know this because...?
I'll also point out that if their air thrust is 1/1000 that of a liquid then you'd need about 1000x more of them.
So enough full stops to be visible on the base of your board.
In chemical synthesis people deal in moles of a substance.
1 mole => 6x10^23 units (atoms or molecules).
100Terra motors is not that big a number.
"The physics of what's happening in these molecules is similar to what we see in the movies"
We don't see no physics happening in the movies, only cool medieval magic in the first tirlogy, and senseless rationalising crud in the followup.
"Here we demonstrate a quantum nonlinear medium inside which individual photons travel as massive particles with strong mutual attraction, such that the propagation of photon pairs is dominated by a two-photon bound state"
This is actually the same idea that says that particles get their rest mass from interaction with the surrounding mediumvacuum, via the Higgs field.
Particular applications of this technique include all-optical switching, deterministic photonic quantum logic and the generation of strongly correlated states of light
Hell yeah. That sounds useful at least.
... the photons are not so much 'bound together' but are constrained to act in a certain way due to some fundamental requirement involving allowed energy levels in what is some kind of quantum solid (the ultra cold rubidium). The overall effect is that they have to hold hands inside the rubidium 'crystal' I think a similar thing happens with Cooper pairs of elecrons in a superconductor. Life is never simple is it?
Think of it as a dry-dock for a ship? Once they leave the rubidium the structure will collapse and the photons will carry on travelling on their own again. The point is: Is it possible to construct a structure complex enough, that the structure would "survive" exiting the rubidium and remain in its "shape"
Instead of using light to shepherd particles, vice versa. And the article even lists some IT uses as well.
I've always wondered why no one seems to have gone the other way and built complex molecules using this technique. I'm sure there are some syntheses that have such poor yields (many steps and no good catalyst for example) that it would actually pay to do it this way.
Sadly I think the synthetic chemists don't talk to the kinds of physicists who do this sort of thing much :(
Thumbs up for a clever hack and hopefully many new applications.
"A synthesis would have to have an awfully poor yield indeed to justify building the product molecules one-by-one in some sort of cryo workbench."
I think you'll find that's a misconception.
In this context "temperature" is a measure of how fast molecules move. Normal atoms move at 100s to 1000s of m/s. Historically lasers of the right frequency have been fired at Rubidium vapour and the atoms have slowed down. They are still a vapour (most people would call a vapourized metal "hot") but their "temperature" is close to 0 K.
Low synthetic yield compounds are the obvious candidates but also "impossible" molecules.
A classic which AFAIK remains unmade is N8. That's a Nitrogen ring with 8 atoms.
Believed to be capable of storing as much energy as liquid Hydrogen/Oxgen can release in burning, it is one of a class of "highly energetic materials."
Yes Nanotechnological "mechanosynthesis" would be the great hope for (low cost high volume) mfg.
But "assemblers" seem to remain as far away as ever.
Unless you happen to have a reliable controllable reciprocating linear actuator that can be mounted to a "molecular scaffolding"?
.You could build a lot of stuff with such a combination.
This is light in a basic form that can be picked up and transported. What sort of information or power density could be developed from this? If you get enough energy density into this and release it at one time, would it move the crystalline storage up above the ground state? Could you make it lase when it reverts to ground state? I want my blaster...
Without reading all the details, if this is matter made out of photons, I'm guessing it wouldn't radiate photons, therefore wouldn't glow like a light saber? What colour would it be I wonder? I guess that depends on what colour light it reflects? Would matter made of light reflect light at all? If it doesn't reflect light and is actually cold, maybe we should call it a Dark Saber.
And when it is eventually released, will it just be made of metal or will it come in multiple colours?
Light is rebounding off a surface....lets say....a shed.
It hits this layer of super-cooled Rubidium in a transparent case and comes to an abrupt halt.
I am standing this side of the Rubidium layer.
Do I now have an "invisible" shed?
(yeah I know it'd block all light from everywhere not just the shed so you'd get a big black square where the rubidium is - but I still can't see the shed right?)
There are simpler ways to stop the light reflecting off your shed from reaching your eyes. Note that we do not refer to them as "invisibility".
When I stand on the opposite side of my house from my shed, the light reflecting off my shed (in my direction) hits the side of the house and heads off in various1 directions. I have no visual way to determine whether that light was reflected, refracted, or absorbed (as indeed some of it is); it doesn't get to me, and that's all that matters.
And, of course, said super-cooled Rubidium has this nifty effect on particular wavelengths, not on all of your common-or-garden-variety light.
1Insofar as my house is covered in a diffusing layer, which I quaintly refer to as "paint".
you can make realistic looking lightsabers unfortunately they are not capable of cutting through anything but can be used for dueling, a quick webserch should turn up several online shops offering the parts, or indeed assembeled non lethal (unless you hit someone over the head with the heavy metal handle) light sabre type objects
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