11 ms·

How David Bohm and Hugh Everett changed quantum theory

72 points by anarbadalov 2y ago

microtherion 2y ago
There are some biographical glimpses of Hugh Everett's family life in his son's autobiography, "Things the Grandchildren Should Know" https://en.wikipedia.org/wiki/Things_the_Grandchildren_Should_Know https://en.wikipedia.org/wiki/Things_the_Grandchildren_Shoul... The son, Mark Oliver Everett, is better known as E, the leader of the Eels.
- JKCalhoun 2y ago
  I highly recommend the documentary on Hugh Everett, hosted by his son, Mark: https://youtu.be/0LroZS97VjA https://youtu.be/0LroZS97VjA It's an odd thing to have a bio piece on what amounts to a "failed" phycist — at least while he was alive. Not all of life's stories have happy endings.
adolph 2y ago
For anyone interested in MWI in a novel, Stephenson’s Anathem is quite nice. I think I may start a reread this evening. https://en.wikipedia.org/wiki/Anathem https://en.wikipedia.org/wiki/Anathem
jessenichols 2y ago
"Claims that the standard procedure for testing scientific theories is inapplicable to Everettian quantum theory, and hence that the theory is untestable, are due to misconceptions about probability and about the logic of experimental testing. Refuting those claims by correcting those misconceptions leads to an improved theory of scientific methodology (based on Popper's) and testing, which allows various simplifications, notably the elimination of everything probabilistic from the methodology (‘Bayesian’ credences) and from fundamental physics (stochastic processes)." – David Deutsch pdf, The Logic of Experimental Tests, Particularly of Everettian Quantum Theory https://www.sciencedirect.com/science/article/pii/S135521981530023X/pdfft?md5=f65c229a83e03215c5619fb2821c29ac&pid=1-s2.0-S135521981530023X-main.pdf https://www.sciencedirect.com/science/article/pii/S135521981...
randomtoast 2y ago
I think interpretations fall more within the realm of philosophy. What physicists wants are theories that can yield correct and precise predictions. For instance, if we have, let's say, 10 different interpretations of QM, all of them unfalsifiable, yet all of them provide the same accurate physical predictions, then in terms of theory, they are equally suitable approximations of reality. What is of greater interest are innovative theories that can generate improved and more specific predictions, such as those for higher energy scales where gravity comes into play and other areas. Therefore, as a physicist, I would concentrate on developing theories that can yield more accurate and precise predictions.
- deleted 2y ago
  [deleted]
- zeroonetwothree 2y ago
  I wouldn’t say it’s philosophy so much as a split in what you think the goal of physics is. Is the goal to create the most accurate models or to understand how the universe actually works?
  - mensetmanusman 2y ago
    You are describing philosophy: because we can’t measure the goals anywhere in the universe; the universe (in the form of humans) has to decide with its consciousness what is more valuable (this is philosophy).
  - rthnbgrredf 2y ago
    The notion that we can fully understand how the universe works may be a overly optimistic belief. There's no inherent reason to assume the universe is structured in a way that human brains can comprehend. Even if we are fortunate enough to have a universe that is understandable by humans in principle, there is no guarantee that a falsifiable theory that explains everything exist. Some people assume that we could eventually formulate a theory of everything or have a complete understanding of QM, but there is no scientific evidence to support this belief. All we have are equations, like the Schrödinger equation, which provide accurate predictions of physical phenomena.
pjs_ 2y ago
The storyline that “science now accepts their ideas” is questionable editorializing imho. Neither Bohmian mechanics nor many worlds are falsifiable, they are just interpretations. They are cool but they aren’t really something you can reject. And to be honest, an unscientific sample of the physicists I know has the majority basically subscribing to some version of “shut up and calculate”
- mistermann 2y ago
  You just rejected them!
- superposeur 2y ago
  Agreed that “science accepts their ideas” is a mischaracterization (indeed Everett annd Bohm are probably mutually exclusive so couldn’t both be “accepted”). Better to say that the community now takes both seriously as contenders for a completion of quantum mechanics. I deliberately say “completion”, not “interpretation” since, without further elaboration, Copenhagen quantum mechanics is only a piece of a model.
- nico 2y ago
  Don’t know the specifics about this particular case However, this is a typical dichotomy in academic/research settings The interplay between the practical (like “calculate” or “build”); and searching for meaning (like coming up with a new model for some phenomenon) My impression is that the majority in a particular field, usually focus on the practical, applying known “tried and true” models to novel things And then, there are only a few who are successful at convincing others of using their models There are a lot of people who are technically capable of creating new models. But it is incredibly difficult to make them go mainstream
- mr_mitm 2y ago
  Technically, if you find a system that doesn't satisfy the Schrödinger equation, you have falsified many worlds. On the other hand, is the wave function collapse falsifiable? Note that MWI makes less assumptions than Copenhagen.
  - 2y ago
fidrelity 2y ago
For anyone interested in other theories that were not mentioned and not satisfied with the unfalsifiability of Many Worlds I can recommend reading Carlo Rovelli's book Helgoland and his Relational Quantum Mechanics[0]. [0]: https://plato.stanford.edu/entries/qm-relational/ https://plato.stanford.edu/entries/qm-relational/
- notfed 2y ago
  Copenhagen isn't any more satisfiable than Many Worlds. They both say similar things: that the wavefunction evolves according to the Schrodinger equation. One leaves the equation intact (Many Worlds), while the other involves randomly selecting certain parts of it to be "real" or "unreal" without any explanation of how or why that choice is made (Copenhagen).
- lanstin 2y ago
  https://arxiv.org/abs/2101.11052 https://arxiv.org/abs/2101.11052 claims to have derived an experimentally verifiable prediction from many worlds (namely that energy is only conserved in the linear progression of the wave function, and not necessarily in the "branched" or "collapsed" bit that we observe; and so in certain circumstances it might be possible to observe an interaction that fails to conserve energy.
nico 2y ago
I love these sort of paradoxes in physics: multiple models, multiple interpretations, multiple meanings and realities, out of seemingly the same experiments and measurements, sometimes even the exact same mathematical formulas Sometimes it can definitely be seen as a bit ridiculous, like if maybe a formula is taken to mean something slightly different, it could mean the whole Universe is upside down! However, sometimes creating alternative models, even if weird when taken at face value, can actually make a difference in making better predictions and even finding new practical applications In the end, all of our models are made up by us

72 points by anarbadalov 2y ago

There are some biographical glimpses of Hugh Everett's family life in his son's autobiography, "Things the Grandchildren Should Know" https://en.wikipedia.org/wiki/Things_the_Grandchildren_Should_Know https://en.wikipedia.org/wiki/Things_the_Grandchildren_Shoul... The son, Mark Oliver Everett, is better known as E, the leader of the Eels.

JKCalhoun 2y ago
I highly recommend the documentary on Hugh Everett, hosted by his son, Mark: https://youtu.be/0LroZS97VjA https://youtu.be/0LroZS97VjA It's an odd thing to have a bio piece on what amounts to a "failed" phycist — at least while he was alive. Not all of life's stories have happy endings.

adolph 2y ago

For anyone interested in MWI in a novel, Stephenson’s Anathem is quite nice. I think I may start a reread this evening. https://en.wikipedia.org/wiki/Anathem https://en.wikipedia.org/wiki/Anathem

jessenichols 2y ago

"Claims that the standard procedure for testing scientific theories is inapplicable to Everettian quantum theory, and hence that the theory is untestable, are due to misconceptions about probability and about the logic of experimental testing. Refuting those claims by correcting those misconceptions leads to an improved theory of scientific methodology (based on Popper's) and testing, which allows various simplifications, notably the elimination of everything probabilistic from the methodology (‘Bayesian’ credences) and from fundamental physics (stochastic processes)." – David Deutsch pdf, The Logic of Experimental Tests, Particularly of Everettian Quantum Theory https://www.sciencedirect.com/science/article/pii/S135521981530023X/pdfft?md5=f65c229a83e03215c5619fb2821c29ac&pid=1-s2.0-S135521981530023X-main.pdf https://www.sciencedirect.com/science/article/pii/S135521981...

randomtoast 2y ago

I think interpretations fall more within the realm of philosophy. What physicists wants are theories that can yield correct and precise predictions. For instance, if we have, let's say, 10 different interpretations of QM, all of them unfalsifiable, yet all of them provide the same accurate physical predictions, then in terms of theory, they are equally suitable approximations of reality. What is of greater interest are innovative theories that can generate improved and more specific predictions, such as those for higher energy scales where gravity comes into play and other areas. Therefore, as a physicist, I would concentrate on developing theories that can yield more accurate and precise predictions.

deleted 2y ago
[deleted]
zeroonetwothree 2y ago
I wouldn’t say it’s philosophy so much as a split in what you think the goal of physics is. Is the goal to create the most accurate models or to understand how the universe actually works?
- mensetmanusman 2y ago
  You are describing philosophy: because we can’t measure the goals anywhere in the universe; the universe (in the form of humans) has to decide with its consciousness what is more valuable (this is philosophy).
- rthnbgrredf 2y ago
  The notion that we can fully understand how the universe works may be a overly optimistic belief. There's no inherent reason to assume the universe is structured in a way that human brains can comprehend. Even if we are fortunate enough to have a universe that is understandable by humans in principle, there is no guarantee that a falsifiable theory that explains everything exist. Some people assume that we could eventually formulate a theory of everything or have a complete understanding of QM, but there is no scientific evidence to support this belief. All we have are equations, like the Schrödinger equation, which provide accurate predictions of physical phenomena.

pjs_ 2y ago

The storyline that “science now accepts their ideas” is questionable editorializing imho. Neither Bohmian mechanics nor many worlds are falsifiable, they are just interpretations. They are cool but they aren’t really something you can reject. And to be honest, an unscientific sample of the physicists I know has the majority basically subscribing to some version of “shut up and calculate”

mistermann 2y ago
You just rejected them!
superposeur 2y ago
Agreed that “science accepts their ideas” is a mischaracterization (indeed Everett annd Bohm are probably mutually exclusive so couldn’t both be “accepted”). Better to say that the community now takes both seriously as contenders for a completion of quantum mechanics. I deliberately say “completion”, not “interpretation” since, without further elaboration, Copenhagen quantum mechanics is only a piece of a model.
nico 2y ago
Don’t know the specifics about this particular case However, this is a typical dichotomy in academic/research settings The interplay between the practical (like “calculate” or “build”); and searching for meaning (like coming up with a new model for some phenomenon) My impression is that the majority in a particular field, usually focus on the practical, applying known “tried and true” models to novel things And then, there are only a few who are successful at convincing others of using their models There are a lot of people who are technically capable of creating new models. But it is incredibly difficult to make them go mainstream
mr_mitm 2y ago
Technically, if you find a system that doesn't satisfy the Schrödinger equation, you have falsified many worlds. On the other hand, is the wave function collapse falsifiable? Note that MWI makes less assumptions than Copenhagen.
- 2y ago

fidrelity 2y ago

For anyone interested in other theories that were not mentioned and not satisfied with the unfalsifiability of Many Worlds I can recommend reading Carlo Rovelli's book Helgoland and his Relational Quantum Mechanics[0]. [0]: https://plato.stanford.edu/entries/qm-relational/ https://plato.stanford.edu/entries/qm-relational/

notfed 2y ago
Copenhagen isn't any more satisfiable than Many Worlds. They both say similar things: that the wavefunction evolves according to the Schrodinger equation. One leaves the equation intact (Many Worlds), while the other involves randomly selecting certain parts of it to be "real" or "unreal" without any explanation of how or why that choice is made (Copenhagen).
lanstin 2y ago
https://arxiv.org/abs/2101.11052 https://arxiv.org/abs/2101.11052 claims to have derived an experimentally verifiable prediction from many worlds (namely that energy is only conserved in the linear progression of the wave function, and not necessarily in the "branched" or "collapsed" bit that we observe; and so in certain circumstances it might be possible to observe an interaction that fails to conserve energy.

nico 2y ago

I love these sort of paradoxes in physics: multiple models, multiple interpretations, multiple meanings and realities, out of seemingly the same experiments and measurements, sometimes even the exact same mathematical formulas Sometimes it can definitely be seen as a bit ridiculous, like if maybe a formula is taken to mean something slightly different, it could mean the whole Universe is upside down! However, sometimes creating alternative models, even if weird when taken at face value, can actually make a difference in making better predictions and even finding new practical applications In the end, all of our models are made up by us