Gravity effect on wave function (from Looking at the Spacetime Uncertainty Relation as an Approach to Unify Gravity)

[swansont]

On 9/22/2017 at 0:13 AM, Dubbelosix said:

I was made aware of some research with some results just out:

 

''Manipulating rubidium atoms with lasers, scientists led by researchers from Italy gave the atoms an upward kick and observed how gravity tugged them down. To compare the acceleration of normal atoms with those in a superposition, the scientists split the atoms into two clouds, put atoms in one cloud into a superposition, and measured how the clouds interacted. These clouds of atoms behave like waves, interfering similarly to merging water waves. The resulting ripples depend on the gravitational acceleration felt by the atoms.The scientists then compared the result of this test to one where both clouds were in a normal energy state. Gravity, the researchers concluded, pulled on atoms in a superposition at the same rate as the others — at least to the level of sensitivity the scientists were able to probe, within 5 parts in 100 million.''

 

 

It seems gravity can affect a wave function!!! This is crucial information, as it tells us gravity does tug on the superpositioned states. This proves that gravity could induce the gravitational collapse.

 

https://www.sciencenews.org/article/key-einstein-principle-survives-quantum-test

I don't think so. If you take an ensemble of atoms and put them in a superposition of the ground states and toss them up, gravity will bring them back down without inducing a collapse of the wave function. We make clocks that work this way. Gravitational collapse of the wave function would introduce a bias in such a clock's frequency. If it's happening, it's happening at a level where we can't measure it happening. Somewhere below a part in 10^16.

The conclusion from the description in the article is that gravity has no effect on the superposition, and the superposition has no effect on how gravity interacts with the atoms.

[Dubbelosix]

On 11/11/2017 at 5:48 PM, swansont said:

I don't think so. If you take an ensemble of atoms and put them in a superposition of the ground states and toss them up, gravity will bring them back down without inducing a collapse of the wave function. We make clocks that work this way. Gravitational collapse of the wave function would introduce a bias in such a clock's frequency. If it's happening, it's happening at a level where we can't measure it happening. Somewhere below a part in 10^16.

The conclusion from the description in the article is that gravity has no effect on the superposition, and the superposition has no effect on how gravity interacts with the atoms.

 

That's not what I got from the paper, what I got was that gravity acts on all energy states in the same way. That didn't mean gravity has no effect on superpositioned particles. 

40 minutes ago, Vmedvil said:

Oh, I agree it is happening on the Planck Scale, which is why I wanted to see what that "Toy Model" said on the Planck Scale.

You're not understanding what was being discussed. If you read it again, you will (maybe) understand, my toy model is a theory of the Planck Space in terms of non-commutative phase space. 

[swansont]

1 hour ago, Dubbelosix said:

That's not what I got from the paper, what I got was that gravity acts on all energy states in the same way. That didn't mean gravity has no effect on superpositioned particles. 

That agrees with what I said. But you said "gravity affects the wave function" earlier, which is not the same as "gravity affects the particles"

[Dubbelosix]

Just now, swansont said:

That agrees with what I said. But you said "gravity affects the wave function" earlier, which is not the same as "gravity affects the particles"

 

By default it would if gravity affects atoms all in the same way no matter what the energy level. This of course is to be expected to satisfy the weak equivalence principle. 

The work clearly states they were trying measure the acceleration of the superpositioned particles. Note, you cannot talk about gravity affecting the wave function and not the particles at the same time, since by principle the supepositioned states means the system is not local. It is like projecting the particle in different states through space by smearing the wave function. That implies you have a many-body problem. 

 

[swansont]

Just now, Dubbelosix said:

 

By default it would if gravity affects atoms all in the same way no matter what the energy level. This of course is to be expected to satisfy the weak equivalence principle. 

The work clearly states they were trying measure the acceleration of the superpositioned particles. Note, you cannot talk about gravity affecting the wave function and not the particles at the same time, since by principle the supepositioned states means the system is not local. It is like projecting the particle in different states through space by smearing the wave function. That implies you have a many-body problem. 

 

The statement that gravity affects the wave function implies that the wave function evolves owing to gravity, and it doesn't at a level measurable by atomic clocks.

1 hour ago, Vmedvil said:

Oh, I agree it is happening on the Planck Scale, which is why I wanted to see what that "Toy Model" said on the Planck Scale.

That has nothing to do with this discussion.

[Dubbelosix]

The statement that gravity affects the wave function implies that the wave function evolves owing to gravity, and it doesn't at a level measurable by atomic clocks

 

 

Not always, a wave function need not evolve due to gravity to have conditions which may satisfy gravitational interpretations. For instance, here is an interesting thought experiment. In an ideal experiment where you can isolate a single superpositioned particle such that there was no forces acting on it, could you calculate a decay time for a gravitational collapse due to a non-equilibrium in the gravitational binding of the system?

Note then, a wave function could evolve without any gravitational influence, but the collapse may be a different story when you consider a nice thought experiment like this above.

Edited November 29, 2017 by Dubbelosix