Exploring the Casimir Effect: The Archimedes Experiment

[hyksos]

TL;DR Summary

Carlo Rovelli and Enrico Calloni are going to a cave under Sardinia to have vacuum energy tilt a high-precision balance.

Vacuum energy is predicted by Quantum Field Theory, and also independently corroborated by recent observations in cosmology involving accelerated expansion. More corroboration occurs in superconducting cuprates exhibiting quantum criticality, and in the Casimir effect

The island of Sardinia sits west of Italy, and abandoned mines there are ripe ground for seismically quiet passages. Scientists Enrico Calloni (et al) are going to set up a type of interferometer that operates by a high precision balance. One of the hanging bob masses will change its electrical properties, while the other one remains the same. Because of cancellations in vacuum energy, via Casimir effect, it is proposed that the cantilever will tilt by nanometers, detectable to the interferometer. The amount of difference in force between the two bobs is estimated at 10^-16 Newtons.

When a large solid mass is submersed in water, it will experience a buoyant force upwards equal to the amount of water its volume displaces. This principle was first discovered by Archimedes many centuries ago. Analogously, the Casimir effect can cancel out certain wavelengths of vacuum fluctuations, in which case the net impinging vacuum energy on a bob will create a vacuum buoyant force . The experiment in Sardinian caves is allegedly going to measure this force. Thus, this project is dubbed The Archimedes Experiment.

• https://www.scientificamerican.com/article/how-much-does-nothing-weigh/
• https://arxiv.org/abs/1511.00609
• https://ui.adsabs.harvard.edu/abs/2016NIMPA.824..646C/abstract

 

[hyksos]

I have created this thread to discuss the physics of the the upcoming Archimedes Experiment to be performed in Sardinia. Interesting in its own right, including issues on whether Casimir cavities will have varying masses; whether vacuum energy interacts with gravity; and purely engineering interests involving precision interferometry.

My own interest in this experiment comes from the apparatus itself. A macroscopic portion of the balance will undergo a torque that is only measurable with the most precise interferometers in the world. If the experiment is a success, this will be even more observational evidence for the physical effects of vacuum energy on objects far larger than electrons.

 

[Vanadium 50]

First, while this measurement may be interesting and important, it is in no way weighing vacuum energy. The Casimir effect does not require vacuum energy to explain it - see Jaffe.

Second, people who conduct precision balance experiments usually find that saying one will reach a certain level of precision is a lot easier than actually doing it. Expect a slow start.

 

[hyksos]

>> see Jaffe

Tell me what you meant by see Jaffe. Is this a reference of some kind?

 

[berkeman]

>> see Jaffe

Tell me what you meant by see Jaffe. Is this a reference of some kind?

Found with a simple Google search of Jaffe vacuum energy (there are likely others):

https://arxiv.org/abs/hep-th/0503158

 

[hyksos]

In that preprint, Jaffe says,

Certainly there is no experimental evidence for the “reality” of zero point energies in quantum field theory (without gravity). Perhaps there is a consistent formulation of relativistic quantum mechanics in which zero point energies never appear. I doubt it.

Still, no known phenomenon, including the Casimir effect, demonstrates that zero point energies are “real”.

Is the Archimedes Experiment an attempt to demonstrate such a phenomena?

 

[Vanadium 50]

Is the Archimedes Experiment an attempt to demonstrate such a phenomena?

1. You were the one who brought it up. "You guys hunt down what this is all about and explain it to me" is a pretty big ask.
2. ZPE and vacuum energy are not synonyms. For example, a pendulum is obviously not a vacuum but has ZPE.
3. In real science, we don't play the game of dueling quotes. We try and understand what the authors have to say and not score points for our "team".
4. See my message #3.

 

[hyksos]

1. You were the one who brought it up. "You guys hunt down what this is all about and explain it to me" is a pretty big ask.

Then let me ask it this way. Is what is suggested to occur in the Archimedes Experiment perfectly consistent with your understanding of the physical world?

 

[Vanadium 50]

Doesn't it make sense to make the measurement first and explain it second?

 

[PeterDonis]

Moderator's note: Thread moved to Quantum Physics forum.

 

[PeterDonis]

Is what is suggested to occur in the Archimedes Experiment perfectly consistent with your understanding of the physical world?

What is your answer to this question?