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61

I'm not a quantum cosmologist, but I am an early-universe cosmologist, so I can give you my opinion after having read this paper. The article claims that Bohmian trajectories is a valid replacement for geodesics. This was claimed in the very beginning of the paper and not much is offered in the way of defense for this assumption. That's not to say that it's ...


26

While this work certainly investigates an interesting point, I think simply replacing geodesics in GR with similarly looking quantum trajectories does not solve the issues here. Finding the Friedmann equations while assuming large-scale homogeneity and isotropy is no surprise to me. There are a number of people working on so-called Big-Bounce Cosmologies. ...


14

When dealing with a single quantum mechanical particle, both the wavefunction and the electric field appear to belong to the familiar class of "fields", both $\mathbf{E}(x)$ or $\psi(x)$. This analogy completely breaks down when you consider multiple particles, in which case the wavefunction depends on all of the particle coordinates, i.e. ...


10

You can, in principle, measure the electric and magnetic field strength at every point in space and time. Thus, the EM field is real in the the sense that its value can be determined uniquely by measurements, and thus, also excitations of it - the EM waves - are real. You cannot, in principle, measure the wavefunction at any point. The true quantum state ...


8

There are a number of models for the universe over the years. The Big Bang as you show it in the figure has become the "standard model" for the creation of the observed universe as we know it because it fits observations, i.e. data, using known theories and behaviors from elementary particle theories. This model has been evolving as data are added in our ...


6

The question is whether quantum computing necessarily implies that the many worlds interpretation of quantum mechanics is correct. This issue is dealt with in the question How much is quantum computation changing the interpretation of quantum theory, and, if at all, how?, though I suspect the discussion there is too deep for non-physicists. The simple ...


3

If the wave-function is a real thing or not, that doesn't depend on how many particles you put in a single wave-packet. If the wave-packet is of very low intensity, you should produce many copies of it. If the wave-function is a real thing, so it is for a thousand particles in a wave-packet, or for a single one particle. If the wave-function is a real-thing ...


3

There is no correct criticism of treating the wave function as real if by that you mean treating the equations of motion of quantum systems as if they describe how those systems actually work. There are many criticisms of treating the wave function as real that are no good: some examples follow. If quantum mechanics is a correct description of how ...


3

The debate over evidence for the many worlds interpretation is largely misconceived. Suppose that you take quantum mechanical equations of motion seriously and apply them to all physical systems, including macroscopic systems like detectors. When you do this, you find that it implies the existence of multiple versions of all those systems. Those multiple ...


2

This is not a "real" answer to your question but rather points you should consider while making a mental picture of the wavefunction. "as every respectable physics professor I've ever encountered has treated the wavefunction as an indisputably non-real mathematical tool" Quantum Mechanics, as taught in undergrad and early graduate courses, deals ...


2

The view that wave function is only a mathematical object rather than a real object is, unfortunately, only a (probably) majority view but it is not agreed upon universally. This is in part because not all people agree that mathematical object is not a real object. There are people who prefer to think mathematical objects can be real objects. This is partly ...


2

To me, the whole subject feels somewhat like a comedy of errors, and your question reveals some misconceptions. Hopefully, I'll be able to clear up some of them without just spreading my own misconceptions ;) Let's start off with de Broglie, who wanted to represent matter as physical waves. But when quantum mechanics emerged, we did not end up with matter ...


1

I will expand on my comment, answering the title: “Reality” of EM waves vs. wavefunction of individual photons - why not treat the wave function as equally “Real”? What does Real mean in physics It is instructive to look at the definition of fields for physics: "A field is a physical quantity that has a value for each point in space and time." ...


1

Yes, as long as you're assuming a local hidden variables theory it can be shown that even allowing the outcome to be determined by any arbitrary amount of prior events in the past light cone will not allow for violations of Bell inequalities. Bell demonstrates this for example in his paper "La nouvelle cuisine" which is reprinted in the collection Speakable ...



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