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An Experiment Could Determine Whether Gravity Is Quantized (forbes.com)
TheAlexKnapp writes: Physicist Brian Koberlein explains an experimental proposal by Großardt et al, which would attempt to determine whether gravity is quantized. "Their idea," explains Koberlein, "is to take a charged disk of osmium with a mass of about a billionth of a gram and suspend it an electric field. This is small enough that its energy levels in the electric field would take on quantum behavior when cooled to temperatures a fraction of a Kelvin above absolute zero, but its also massive enough that its gravitational pull would affect the quantum behavior."
The two primary approaches to a quantum gravity, the "perturbative approach" and "the semi-classical method," predict different results from this type of interaction. So the results of the experiment, could, in principle, elucidate the right approach for developing future theories of quantum gravity.
The two primary approaches to a quantum gravity, the "perturbative approach" and "the semi-classical method," predict different results from this type of interaction. So the results of the experiment, could, in principle, elucidate the right approach for developing future theories of quantum gravity.
Proposed experiment: arXiv:1510.01696.
More detailed theory: arXiv:1510.01262.
See also blog post.
Not much gravity ... or anything else on Forbes
Does Time come in quanta?
There's a good explanation by a physicist who thinks about experimental validation of quantum gravity here.
It's not about gravity, it's investment advice. Long osmium?
shut up and do the experiment already!
Better known as 318230.
Physicists are quantized, so they want everything else to be quantized.
Or, better, behave unexpectedly, contradicting all known theories.
Just google it.
Mass is quantized, therefore gravity has to be as well.
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Not trying to poop on it, far from it. But could someone explain just what this should prove or show? What insights will this give us?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
How the charge of a single electron was measured back in the early 1900's - good luck to these scientists.
sigs are for losers (except to point out that sigs are for losers)
It would seem that gravity would be quantized at the level of the smallest particle having mass. Any bulk mass is ultimately made up of these smallest particles and the expression of the gravity of the bulk mass would be the sum of that of all the smallest particles making up that mass. One problem with gravity for the smallest particles is distinguishing it from the much larger kinds of interactions such as electric charge, etc.
In a time of universal deceit, telling the truth is a revolutionary act. George Orwell
gravitons exist? (I remember reading the problem with gravitons is that they were basically impossible to detect because their interactions were so weak.)
Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
Why is the site covered in cheap clickbait and list articles? Are they that desperate for clicks that they'd list "Grid Girls, Pit Girls photo collection" and "Fame Was The Worst Things That Happened To These 10 Former Child Stars" on the page?
I think those are just advertisments that are deceptively made to look like part of the host site, which is almost worse.
thumby.grvcdn.com, you're going on my blocked DNS lookups list.
most interesting. ... thus there cannot exist a source of gravity from 1.5 plank-mass?
plank-length, plank-time and plank-mass, so there's no 1.5 plank-mass
a source of gravity can only be multiples of 1 plank-mass? or 2? or 3?
so, maybe it is possible for space-time to "represent" the gravity of 1.5 plank-mass but since 1.5 plank-masses cannot exist, space-time is sad ^_^
because momentum is quantized. In fact everything is quantized.
That is not what's meant by gravity being quantized. Quantum gravity would mean the gravitation interaction between particles is quantized: i.e. if particle A pulls on particle B (and vice-versa), the energy exchange between them occurs in discrete packets. The alternative would be that the gravitational forces between them are a continuous interaction, so that A pulls on B to change the energy state of both constantly. To use an analogy: the former is like an object rolling down a staircase, where the objects level jumps as it falls down a step, while the latter is like a ramp, where the object's level takes on all continuous values of the ramp.
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So... a fraction of a Kelvin then.
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"Oh dear, Watson, I just fell up!"
Table-ized A.I.
If Gravity is nothing more than a curvature of spacetime and objects moving through it fowls "straight" lines, then why do people still also say that gravity is a force? Or try to unify it with the other forces? Or tat it can be quantized?
If you reply, do so only to what I explicitly wrote. If I didn't write it, don't assume or infer it.
What is an example of something that takes less than a Planck time to transpire? Can you point to an example where Planck time isn't the frame rate of reality?
All there needs to be is a process that takes 23 quadrillion + .333333 Planck units of time to resolve, or any amount greater than 1 Planck but ending in a fraction.
At this time we don't have the tools necessary to actually prove any specific fundamental measurement of real time so we use "Planck" as a tool of convenience for practical purposes. To say otherwise is to show that for you Science is really just a Religious process in your mind where you have "Faith" in unproven things that are being taught to you by your elders. Sadly many people who think they are defenders of science behave in very religious ways regarding their institutional beliefs.
Were that to be the case, you'd need to worry about the gravity of neutrinos, as they are currently the least massive particle known. But good luck trying to measure the mass accurately, or trying to get one to change it's speed, or even bend its path.
I think we've pushed this "anyone can grow up to be president" thing too far.
It's turtles all the way down!
Like, monitor a speck of dust near a mountain. I'm convinced we don't have "gravity" here, it's just "density". But then I'm also convinced the world is flat.
Read "Zetetic Astronomy" for convincing arguments, experiments, and proof: http://www.sacred-texts.com/ea...
I feel fantastic, and I'm still alive.
Umm, an experiment like that can be done in any undergrad lab course (or in a well equipped high school physics course). A torsion balance is sensitive enough to pick up the gravitational force between metal spheres, as in ones the size your hand, and have been used as an estimate of the gravitational constant back to the end of the 18th century. More modern methods using micro-mechanical structures like microscopic vibrating bars are even more sensitive, although less accessible (well, cheap ones are used in a lot of cheap consumer electronics, but the highly sensitive ones are less common). But the older method is something you can build yourself from hardware store parts.
Or, to put it another way, and probably horribly inaccurately to boot, 'quantized' gravity is like constantly throwing a ball at something, only when that ball hits the object, it casues the object to move towards, instead of away from, the direction of impact.
Non-quantized gravity is like everything being attached to everything with ropes, constantly pulling on everything.
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