Penrose-Dosi Model

[Ssnow]

TL;DR

What is the opinion of the validity of Penrose -Dosi model

Hi to all! I want to ask the opinion of the forum about the conjecture on the collapsing wave function $\psi$ due to the presence of the gravity as assumed in the model of Penrose-Dosi ... It seems the only "true" way to understand the quantum mechanics (at least it is possible to verify it recently experimentally ...)
I think the theory of string or the quantum loop gravity (QLG) are elegant theories that for the moment it is impossible a verification. In the opposite the theory of Penrose-Dosi has not the complete condivision of all expert in the field ... Possible the true is in the "middle" ...
Ssnow

 

[PeterDonis]

the model of Penrose-Dosi

Can you give a link?

 

[renormalize]

Can you give a link?

The OP is presumably referring to the Diósi–Penrose model:
https://en.wikipedia.org/wiki/Diósi–Penrose_model

​

 

[physika]

An Objetive Collapse Model.

https://plato.stanford.edu/entries/qm-collapse/
https://www.nature.com/articles/s41567-020-1008-4
https://arxiv.org/abs/2111.13490

 

[Matterwave]

An Objetive Collapse Model.

https://plato.stanford.edu/entries/qm-collapse/
https://www.nature.com/articles/s41567-020-1008-4
https://arxiv.org/abs/2111.13490

Nice, it looks like they are attempting to test the theory.

But it does seem like maybe the most simple version of the theory has been ruled out experimentally. See attached image from the Arxiv paper.

Just my personal opinion (and I give it here only because OP explicitly asked for "the opinion of the forum") -- I think this gravitation-based collapse theory is an interesting way to try to bring in gravity to quantum mechanics from a different angle, but ultimately, objective collapse theories (incl. GRW here) seem a bit "ugly" and "arbitrary" to me. It feels to me like nature just goes with Schroedinger, unitary, evolution and collapse is a mathematical artifact of our theories in order to connect the quantum world to the classical world where our measurements take place. Introducing collapse as a fundamental tenet of quantum theory just rubs me as a bit ugly in that sense.

Just my opinion though. I think Penrose himself has not allowed this result to deter him from pursuing the idea further.

 

[Ssnow]

Hi @Matterwave thanks for your opinion, I think that the original model of Penrose is a ''good idea'' in order to understand quantum mechanics in the theory of Newtonian-Relativistic gravity instead the inverse that is the "quantization of the gravity" (think about the geometric quantization program, or string theory or loop quantum gravity ...). I think that the Penrose model is in fact extremely simple and it seems as a little toy instead a rigorous theory ... but I think this direction can be considered, I belive it is possible an evolution of the Penrose model with the introduction of the pobability and the chaos ... at least in this direction we can think about expreriment; an important key is to understand as the collapse works, in this direction we can understand better the QM teory and, at the same time (if it exists ), the gravity and the gravitational field ...

Ssnow

 

[Ssnow]

An Objetive Collapse Model.

https://plato.stanford.edu/entries/qm-collapse/
https://www.nature.com/articles/s41567-020-1008-4
https://arxiv.org/abs/2111.13490

Thanks for references ....

 

[Matterwave]

Hi @Matterwave thanks for your opinion, I think that the original model of Penrose is a ''good idea'' in order to understand quantum mechanics in the theory of Newtonian-Relativistic gravity instead the inverse that is the "quantization of the gravity" (think about the geometric quantization program, or string theory or loop quantum gravity ...). I think that the Penrose model is in fact extremely simple and it seems as a little toy instead a rigorous theory ... but I think this direction can be considered, I belive it is possible an evolution of the Penrose model with the introduction of the pobability and the chaos ... at least in this direction we can think about expreriment; an important key is to understand as the collapse works, in this direction we can understand better the QM teory and, at the same time (if it exists ), the gravity and the gravitational field ...

Ssnow

I feel he had a nice idea -- gravity causes collapse. He put out some heuristics on how to look for it. The experimental community (based on that last paper) went and took a look but didn't find the effects and rules out the most naive, parameter-free version of the theory.

This is healthy science to me.

If there's a few more experiments and such that people can think of to test a few variants of the theory, that's great too. But, for my opinion, given the rather "arbitrariness" of objective collapse I (personally) wouldn't sink too much more time into the theory. It doesn't matter though since I'm no longer a practicing research physicist. :P

I don't begrudge Sir Penrose from being more stubborn about his theory and I would support those who want to investigate further. New avenues, beyond the standard theories, are always worth while.

 

[bhobba]

I don't begrudge Sir Penrose from being more stubborn about his theory and I would support those who want to investigate further. New avenues, beyond the standard theories, are always worth while.

Well said. And, at least in principle, it is experimentally testable.

Plus, listening to a scientist of his stature is always a joy.

Thanks
Bill

 

[flippiefanus]

TL;DR: What is the opinion of the validity of Penrose -Dosi model

Hi to all! I want to ask the opinion of the forum about the conjecture on the collapsing wave function $\psi$ due to the presence of the gravity as assumed in the model of Penrose-Dosi ... It seems the only "true" way to understand the quantum mechanics (at least it is possible to verify it recently experimentally ...)
I think the theory of string or the quantum loop gravity (QLG) are elegant theories that for the moment it is impossible a verification. In the opposite the theory of Penrose-Dosi has not the complete condivision of all expert in the field ... Possible the true is in the "middle" ...
Ssnow

This topic intrigues me, and I think this approach to address the larger problem of quantum gravity is closer to the way physics works and therefore more likely to make progress in a scientific manner than other attempts. The idea of collapse due to an instability caused by gravity is in fact close to the question why we don't see macroscopic superpositions.

To that end, one can perform a simpler investigation to study the properties of superpositions that would in principle be able to become entangled with the geometry of spacetime due to the effects of gravity. In doing so, one finds that there are different scenarios that can emerge in which such macroscopic superpositions do not so much collapse but are instead prevented form being formed in the first place. It also includes a scenario where the superposition is too small to make a difference.

So imagine that, although macroscopic objects can form superpositions, such superpositions are not discernable from the no-superposition case. In such a case the effect of gravity would not be able to affect the different terms in the superposition in different ways. In effect, the superposition remains pre-collapsed.

Anyway, I'm just sharing some ideas I had on the topic. Curious what others may think of it.

 

[PeterDonis]

Moderator's note: Thread moved to the Beyond the Standard Models forum since it is about a model that goes beyond current QM.

 

[Matterwave]

Anyway, I'm just sharing some ideas I had on the topic. Curious what others may think of it.

Is it a personal theory or are you just sharing your thoughts on what the Penrose-Diosi model says?

which such macroscopic superpositions do not so much collapse but are instead prevented form being formed in the first place.

So imagine that, although macroscopic objects can form superpositions, such superpositions are not discernable from the no-superposition case.

Isn't this contradictory? Or are you imagining different scenarios?