How Curved Spacetime Can Be Created In a Quantum Optics Lab 89
KentuckyFC writes: One way to explore the link between quantum mechanics and general relativity is to study the physics that occurs on a small scale in highly curved spacetimes. However, these conditions only occur in the most extreme environments such as at the edge of black holes or in the instants after the Big Bang. But now one physicist has described how it is possible to create curved spacetime in an ordinary quantum optics lab.
The idea is based on optical lattices, which form when a pair of lasers interfere to create an eggbox-like interference pattern. When ultracold atoms are dropped into the lattice, they become trapped like ping pong balls in an eggbox. This optical trapping technique is common in labs all over the world. However, the ultracold atoms do not stay at a fixed location in the lattice because they can tunnel from one location to another. This tunneling is a form of movement through the lattice and can be controlled by changing the laser parameters to make tunneling easier or more difficult.
Now, a physicist has shown that on a large scale, the tunneling motion of atoms through the lattice is mathematically equivalent to the motion of atoms in a quantum field in a flat spacetime. And that means it is possible to create a formal analogue of a curved spacetime by changing the laser parameters across the lattice. Varying the laser parameters over time even simulates the behavior of gravitational waves. Creating this kind of curved spacetime in the lab won't reveal any new physics but it will allow researchers to study the behavior of existing laws under these conditions for the first time. That's not been possible even in theory because the equations that describe these behaviors are so complex that they can only be solved in the simplest circumstances.
The idea is based on optical lattices, which form when a pair of lasers interfere to create an eggbox-like interference pattern. When ultracold atoms are dropped into the lattice, they become trapped like ping pong balls in an eggbox. This optical trapping technique is common in labs all over the world. However, the ultracold atoms do not stay at a fixed location in the lattice because they can tunnel from one location to another. This tunneling is a form of movement through the lattice and can be controlled by changing the laser parameters to make tunneling easier or more difficult.
Now, a physicist has shown that on a large scale, the tunneling motion of atoms through the lattice is mathematically equivalent to the motion of atoms in a quantum field in a flat spacetime. And that means it is possible to create a formal analogue of a curved spacetime by changing the laser parameters across the lattice. Varying the laser parameters over time even simulates the behavior of gravitational waves. Creating this kind of curved spacetime in the lab won't reveal any new physics but it will allow researchers to study the behavior of existing laws under these conditions for the first time. That's not been possible even in theory because the equations that describe these behaviors are so complex that they can only be solved in the simplest circumstances.
Damn (Score:2)
Re:Damn (Score:5, Informative)
It's not meant to be brain hurting territory.
It's like how zero gravity isn't possible on earth, but if you take a plane, and fly it in a parabolic curve matching G, the inside operates a lot like zero gravity.
This is like that, but for arbitrarily curved space-time, instead of zero G.
Headline Is Missing The Word "Highly" (Score:2)
Re: (Score:2)
Spacetime is always locally flat ... for varying definitions of locally.
A distinction that makes no difference. It's also always locally curved, for other definitions of "locally".
Re:Headline Is Missing The Word "Highly" (Score:5, Funny)
I'd like to see people try to keep pedantry off of slashdot!
Re: (Score:2)
How should I mod this? It deserves a downvote, but it is not flamebait, not overrated (rated 0) nor a troll. It's not even redundant.
It's just plain wrong.
Re: (Score:2)
I meant to attach that comment to the grandparent. The comment to which I replied was the correct one.
Re: (Score:1)
It's also always locally curved, for other definitions of "locally".
Yes, for wrong definitions. Curvature is a global property, not local.
Hate to break it to you but every property is 'local' in general relativity, even the speed of light. In any absolute frame GR defines the speed of light as variable or non-defined.
If you want to replace general relativity with an absolute frame physics you need three things -
- An absolute frame - an FTL 3D hyperspace with an FTL Simultaneity backbone.
- To restrict the maximum size of dimensional time and 4D space time to quantum scales.
Re: (Score:2)
Yes, for wrong definitions. Curvature is a global property, not local.
No. Curvature is a local property. It is what creates gravity, according to Einstein.
In "the vastness of space", as the saying goes (I mean far out, not in orbit), you feel only micro-gravity. Because you are far from significant masses. But here on Earth, for example, you experience the sensation of gravity. Because that gravity is local to Earth.
On other scales, say very small compared to a human, it can "look" flat again.
So it all depends on scale. For some definitions of "locally", you will see
Re: (Score:2)
Fundamental to general relativity is the principle of equivalence, which equates gravity in one reference frame to uniform acceleration in another one. It's why old-school space stations are big wheels -- they create gravity without using mass, by spinning. In the right coordinate system - one that rotates relative to the lab - the ultracentrifuge in a biochemistry lab creates a highly curved spacetime equivalent to 6 times the gravity at the surface of a white dwarf. (2 million g vs 350,000 g).
Curved o
Re: (Score:2)
A distinction that makes no difference. It's also always locally curved, for other definitions of "locally".
How should I mod this? It deserves a downvote, but it is not overrated (rated 0), not flamebait, nor a troll. It's not even redundant.
It's just plain wrong.
Re: (Score:2)
It's just plain wrong.
Really? Can you demonstrate to us how it is wrong?
GP's comment, to the effect that space is always locally flat "for some definition of locally" is a kind of a joke. His comment itself implies that if you increase the scale, it isn't flat.
And it isn't. The more you increase the scale, the more "non-flatness" you will observe, due to large masses. Even where it isn't tightly curved, it will be at least slightly curved by some mass in your universe.
Flatness only occurs on a relatively small scale, aw
Re: (Score:2)
Hi Jane. After some deliberation I see that you are in fact correct. I apologize for the comment, and I encourage those with mod points to downvote GPP (my post):
http://slashdot.org/comments.p... [slashdot.org]
Re: (Score:3)
Re: (Score:1)
It's not meant to be brain hurting territory.
It's like how zero gravity isn't possible on earth, but if you take. . . p>
Its funny, as I understand it zero gravity isn't really possible anywhere inside our universe. In things like parabolic dives or orbital trajectories there is no change in actual gravity, the vehicle is merely accelerating to compensate. One of the main reasons why you cant do sensible gravity engine research within about 1 to 2 Earth diameters of the planets surface.
Re:Damn (Score:4, Insightful)
Stop making my brain hurt!
I think that's the point. It's too complex to model but if you have a playground that you can
play with you can explore interactions without having to do a ton of math.
Most people can't grasp certain complex stuff. Even something as simple as combining
green light and red light to make yellow confuses people as it goes against their grade school intuition.
Allow people to get a chance to play with it in a lab and then it just clicks.
Re: (Score:2)
I spent two weeks teaching relativity and quantum mechanics to an illiterate redneck.
It only took two weeks.
Next week, I teach a vocal class for pigs.
I get paid a subsidy and hope to be very annoying.
Re: (Score:2)
Green light + red light = black light.
How do you think we made the Jimi Hendrix posters on the walls of our rooms glow so brightly, back in the 70s, when UV fluorescent technology was prohibitively expensive for those of us in junior high?
Re: (Score:2)
Green light + red light = black light.
How do you think we made the Jimi Hendrix posters on the walls of our rooms glow so brightly, back in the 70s, when UV fluorescent technology was prohibitively expensive for those of us in junior high?
Um, No, It's yellow. Also, you're referring to a UV light which is a specific frequency of light. Combining the visual attributes
of light doesn't change the underlying frequency. You can't create ultraviolet light by combining visible light.
Re: (Score:2)
Stop making my brain hurt!
It will have to come out.
Re: (Score:1)
Sometimes thinking "outside the box" solves things that would be near impossible.
For example, collecting elephants is usually hard, they are big and weight too much.
Here's a problem easy to solve using the correct tools; a jar with lid, binoculars and a pair of tweezers.
If done correctly, the problem of elephant collection becomes easy.
First find an elephant (the hardest part of the collection process).
Once located, look at the elephant through the wrong end of the binoculars, you will see that the elephant
Re: (Score:2)
I'm crushing your head! I'm crushing your head, silly little anonymous coward guy!
"ordinary" quantum optics lab (Score:2)
Because there's one on every block! 7-11 has real competition now!
Re: (Score:2)
Eh, it's the kinda thing any physics department at a doctorate granting university would have. As opposed to a cyclotron, or other sorts of high-energy physics tools.
But is it worth doing? (Score:1)
OK, so they found something that, according to their models, is a model for curved spacetime. Why not just use the original model?
Re: (Score:2)
Because you only have to mathematically prove the model, then you can run arbitrarily complex pragmatic experiments on it. Rather than proving the arbitrarily complex thing you're testing.
Re: (Score:3)
That's not what quantum tunneling is. Tunneling has to do with the phase-state of particles, and how it implicates their ability to cross force barriers that should reverse them under classical understanding.
It's a bit like if your car blinked into and out of existence every couple seconds, you could sometimes drive through a brick wall.
Re: (Score:2)
Re:Need more explination of the tunneling (Score:5, Funny)
Argh, it's like I've been sucked into Star Trek, and everyone just uses science terms for whatever, as if they're all related.
No. Not the zero point field. Not at all.
Re: (Score:2)
Well duh. Zero point devices are for powering the Atlantis.
Re: (Score:2)
Anyway, I'm not aware of many other instances where particles wink in and out of existence (virtual particles)
Re: (Score:2)
You even provided a car analogy...
Pearls before swine, I guess.
Re: (Score:2)
I feel that analogy might just be more complicated than the actual math.
Re: (Score:2)
My very layman's understanding that may be quite wrong. Yes? No?
Overweight (Score:3)
Since all mass curves spacetime I can curve spacetime simply by existing and being a bit overweight. Its just too bad that I'll have to wait until 2015 for the nobel prize!
Re: (Score:2)
Since all mass curves spacetime I can curve spacetime simply by existing and being a bit overweight. Its just too bad that I'll have to wait until 2015 for the nobel prize!
Alas, you only get the prize if you manage to curve spacetime either more or less than what would ordinarily result from your particular fatness.
Re: (Score:2)
"Hey Baby! My space-time curvature deviates from the standard model... wanna come back to my place and distort physics??"
Obligatory Abstruse Goose (Score:2)
"Hey Baby! My space-time curvature deviates from the standard model... wanna come back to my place and distort physics??"
Go for it, but be careful what you say about your partner's space-time curvature [abstrusegoose.com].
Don't leave us hanging! (Score:2, Funny)
Re: (Score:3)
I've calculated it's precisely the day after you die, which is also when immortality is invented. Tough break, duder.
Re: (Score:2)
Never. This is is only building a model for something which might not even exists (GR may lose to quantum effects in extremely curved spacetime)
Title is even wrong, curved spacetime is NOT created by the hypothesised experiments.
mathematically equivalent ? (Score:5, Insightful)
Now, a physicist has shown that on a large scale, the tunneling motion of atoms through the lattice is mathematically equivalent to the motion of atoms in a quantum field in a flat spacetime.
mathematically equivalent ?
So they haven't created curved spacetime in a Quantum Optics Lab. They have done something that is a model of how they think curved space time would behave.
Re: (Score:2)
Re: (Score:2)
While we are at it, remember that scientists have recently shown that black holes don't have to exist and may not exist. Further, the Expanding Quantum Vacuum theory for the evolution of the Universe discounts the need for a big bang.
Interesting surely, but this theory is trying to build upon two theories that have some very good scientific competition.
Re: (Score:2)
Which is why this line was included in the description:
"Creating this kind of curved spacetime in the lab won't reveal any new physics but it will allow researchers to study the behavior of existing laws under these conditions for the first time."
Re: (Score:2)
At the risk of being snarky, you seem to have no idea what you're talking about. So why did you bother with the post?
Re: (Score:1)
Except that they will only be tiny little blobs of quantum stuff.
Chevron 7 Locked (Score:2)
Komptria!
Indeed.
Jaffa kree!
Sha'kaaaaaaaaaaaa.
If you immediately know the candlelight is fire, the meal was cooked a long time ago.
Does it say "Colonel" anywhere on my uniform?
Analogue (Score:3)
Re: (Score:2)
I don't want to have to memorize a bunch of new kings.
Grow a pair and move to the US of A.
Here, the only king you need to memorize is the Almighty Dollar.
What equations? (Score:2)
Creating this kind of curved spacetime in the lab won't reveal any new physics but it will allow researchers to study the behavior of existing laws under these conditions for the first time. That's not been possible even in theory because the equations that describe these behaviors are so complex that they can only be solved in the simplest circumstances.
Are they talking about general relativity equations?
Re: (Score:3)
Are they talking about general relativity equations?
That's included, but I think the article and summary are actually getting it right for once. The equations in question are ones that reconcile GR with Quantum Mechanics, and that, in general, means variations on various String or Brane Theories, and quite possibly specifically Supersymmetry, if that's not being completly discarded by the researchers just because CERN is finding preliminary evidence that the simplest and lowest energy Supersymmetry model do
Re: (Score:2)
Yes, that's exactly what is being referred to here. The Einstein Equation [youtube.com] is a horrible differential equation which can only be solved analytically for a few idealized cases. However, they can be solved numerically [youtube.com] (taking several thousand CPU hours for a common case like two colliding black holes, I think). So it's not quite right to say that we can't solve them in complex circumstances - only that's it's quite slow.
While quantum mechanics is involved in setting up this analogy (e.g. to describe the atoms
Wrong links! (Score:2)
Oops, I somehow used the wrong link twice there. I'll try again:
The innocent-looking but really horrible Einstein equation [wikipedia.org], and how to solve it numerically [einsteintoolkit.org] on your friendly local supercomputer.
Wording (Score:3)
ordinary quantum optics lab
Something about the wording in that phrase gives me the urge to search Instructables for a how-to...
Re: (Score:2)
We're so used to breakthroughs only coming from the extraordinary quantum optics lab.
not so accurate headline (Score:1)
Re: (Score:2)
And here I was hoping the iPhone 7
Will curve its localized space-time if you put it in your back pocket and sit on it.
Physical vs Non Physical (Score:2)
No eggs where damaged during this experiment (Score:2)
Which is kind-of-a shame, since I'd have liked them, sunny side up.
big picture (Score:1)
Best summary of this result (Score:2)
Really excellent succinct and easy to follow summary.
And that on /. of all places, where article summaries usual go to die.
Me too. (Score:2)