Or as Dustin Lazarovici reacted to the paper: "A group of physicists claims to have found experimental evidence that there are no objective facts observed in quantum experiments. For some reason, they have still chosen to share the observations from their quantum experiment with the outside world.
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In particular, it doesn’t mean that measurement outcomes, once obtained, are not objective. It rather reminds us that a measurement is not a purely passive perception but an active interaction that “brings about” a particular outcome and can affect the state of the measured system in the process."
Basically, the only way we would have to let go the assumption of an objective reality is if we were to insist on locality (against this and other experimental results) in which case nothing really exists but thank God it's local! (pace Tim Maudlin) — Benkei
Quantum particles are even smaller, aka subatomic particles, and not properly described as particles but that's language for you. — Benkei
Sure, QM is consistent with special relativity, but I don't think it's correct to call the properties of a photon "physical". A photon has an effect on physical things, and it might have a physical cause, and it is described by mathematics, but according to special relativity, light does not have spatial-temporal properties. The speed of light is the limit to spatial-temporal properties. So how exactly would you describe these "physical properties" which light quanta have? How does something which is only described by mathematics have physical properties? Say for example "2+6=8", that's something only described by mathematics. How does that have physical properties, other than the symbols which represent the mathematical idea?There is no implication of non-physical properties. In QM, light quanta (photons) have physical properties. And QM is consistent with special relativity. — Andrew M
Putting this together with your earlier comment that you are not attached to locality, it sounds like you have an affinity to the 'non-local hidden variables' school, of which David Bohm's 'pilot wave' interpretation of QM is perhaps the best-known. In most other popular interpretations, the imprecision about location is not just epistemological.I'm saying that wave function collapse is a matter of knowledge. — Benkei
I dare say you are right.The trouble is that the word 'objective' is inextricably connected to the concept of an 'object'. — Wayfarer
In what way do you think QM puts an independent reality radically to question? And independent from what? — Benkei
Sure, QM is consistent with special relativity, but I don't think it's correct to call the properties of a photon "physical". A photon has an effect on physical things, and it might have a physical cause, and it is described by mathematics, but according to special relativity, light does not have spatial-temporal properties. The speed of light is the limit to spatial-temporal properties. So how exactly would you describe these "physical properties" which light quanta have? — Metaphysician Undercover
I have a rough time with this distinction. Something not real can still be used to describe a real thing. It just isn't the actual thing. — noAxioms
On this view, the universal wave-function Ψt of the system of particles at a given time is a mathematical object that represents the disposition to move in a certain manner at that time. This disposition is a holistic property of all the particles in the universe together – that is, a relational property that takes all the particles as relata. It induces a certain temporal development of the particle configuration, that development being its manifestation. In other words, given a spatial configuration of the particles (actual or counterfactual) and the disposition of motion at a time as represented by the wave-function as input, the Bohmian law of motion yields the velocities of the particles at that time as output.
That doesn't follow from either interpretation of the wave function. It seems to require an additional postulate. — noAxioms
He was shunned by the physics community after his PHD and went into the defense industry instead, but was asked to present his work 5 years after the paper was published. Somewhere around that time DeWitt coined the MWI term from Everett's original "relative state formulation" which sounds an awful lot like RQM. — noAxioms
That works given a postulate of such selection going on. My statement was an opinion, not an assertion. — noAxioms
It seems that some objective collapse interpretations might fit the bill:
On the other hand, it is shown that dynamical collapse models, of the type originally proposed by Ghirardi-Rimini-Weber, can be re-interpreted as set selection criteria within a quantum histories framework, in which context they appear as candidate solutions to the set selection problem.
- Quantum Histories - Adrian Kent — Andrew M
Even eighteenth-century dictionaries still preserved echoes of this medieval usage, which rings so bizarrely in modern ears: “Hence a thing is said to exist OBJECTIVELY, objective, when it exists no otherwise than in being known; or in being an Object of the Mind.”" (Daston and Galison, Objectivity). — StreetlightX
Putting this together with your earlier comment that you are not attached to locality, it sounds like you have an affinity to the 'non-local hidden variables' school, of which David Bohm's 'pilot wave' interpretation of QM is perhaps the best-known. In most other popular interpretations, the imprecision about location is not just epistemological. — andrewk
I like Bohm. I have his book 'Quantum Theory' which is interesting because it was written before the modern Dirac notation for QM with 'bras' and 'kets' became standard. — andrewk
FWIW Bohm was quite a mystic, and had a famous series of public discussions with Krishnamurti about physics and spirituality. — andrewk
The physical properties of a photon are able to be measured in the same way as for any other particle. If you want to know a photon's position or speed, you set up an experiment and measure it. — Andrew M
It occurs to me that the notion of QM undermining the notion of 'objective reality' only makes sense if one insists that only particles, not waves, can be objective. — andrewk
If different observers give different accounts of the same sequence of events, then each quantum mechanical description has to be understood as relative to a particular observer. Thus, a quantum mechanical description of a certain system (state and/or values of physical quantities) cannot be taken as an “absolute” (observer independent) description of reality, but rather as a formalization, or codification, of properties of a system relative to a given observer. Quantum mechanics can therefore be viewed as a theory about the states of systems and values of physical quantities relative to other systems. — StreetlightX
The physical properties of a photon are able to be measured in the same way as for any other particle. If you want to know a photon's position or speed, you set up an experiment and measure it.
— Andrew M
What is measured is the effect of the photon. — Metaphysician Undercover
It's worth noting that superpositions have been created for objects with up to trillions of atoms (as in the case of the piezoelectric "tuning fork"). Probably most physicists would consider QM to be a universal physical theory (i.e., applicable to everything). Which is part of the point of the Schrodinger's Cat and Wigner's Friend thought experiments. — Andrew M
That supposition was rejected more than a century ago given the results of the Michelson-Morley experiment. There is no medium in the model for electromagnetic waves.a wave without a medium doesn't make sense. — Metaphysician Undercover
So you see it like - everything is a quantum system, just sometimes the corrections from quantum mechanics to macroscopic systems are sometimes negligible? — fdrake
If so, then it would seem that the same principle should apply to an electron. One would be measuring the effect of the electron (on a measurement device), not a property of the electron itself.
Are you singling out the measurement of photons as unique here or claiming a general principle for the measurement of all particles and, by extension, all physical objects? — Andrew M
That supposition was rejected more than a century ago given the results of the Michelson-Morley experiment. There is no medium in the model for electromagnetic waves. — andrewk
Not in physics. In physics a wave is a phenomenon that behaves in accordance with the wave equation.That's what a wave is — Metaphysician Undercover
In physics a wave is a phenomenon — andrewk
Yes, I think that is the case, electrons are measured as effects, and most forms of measurement are like this. — Metaphysician Undercover
I don't think physics provides any reason to doubt that the elementary particles (as described in the Standard Model) exist — Andrew M
To complicate matters, the 'wave function' is, I believe, a misnomer. It's not a 'wave' in the way waves are understood either in physics or in everyday discussion. It is an element of a Hilbert space, and there's really no more user-friendly way to describe it than that. It has nothing to do with electromagnetic waves, gravity waves, sound waves or any other sort of wave, and it's not a solution to the wave equation.The big mystery with the wave function is precisely its ontological status, whereas the same can’t be said for water or sound waves, as they propagate through a medium; they are indeed ‘phenomena’. — Wayfarer
Isn’t the ontological status of fundamental particles also precisely what is at issue in all this? The ‘Copenhagen interpretation’ does, after alll, say that ‘the particle doesn’t exist until it’s measured.’ — Wayfarer
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