“Things” like electrons are neither particles nor waves, and this not merely in the sense that they behave neither like traditional particles nor like traditional waves, but in the more radical sense that they lack intrinsic behavior. Classically conceived particles or waves behave the way they...
There is no such thing as matter in physics. :surprised That is to say, there is no symbol for matter in the entire formalism of physics. There is a symbol for mass, which isn't the same as matter. Basically mass and energy are the same thing, simply measured in different units. The natural...
We had a long discussion about this. You still haven't gotten my point. Of course there is more than the algorithm. How else could there be so much stuff on my website about the ontological implications of the mathematical formalism of the theory? What I object to is the naive transmogrification...
Absolutely. They are weighted averages over possible measurement outcomes. The outcomes are real, the weights (probabilities) are real, so the expectation value has to be real. By the way, this is why the operators associated with observables are self-adjoint. The eigenvalues of operators...
MWI is what you get if you reject the symptom (the collapse postulate) without rejecting the underlying disease, which is the belief that quantum states or wave functions represent evolving instantaneous states of affairs. The time dependence of a quantum state is the dependence of an algorithm...
A universe with one particle is no universe at all. :bugeye: All positions, all momenta, are relatively defined. In a universe with only one particle there are neither positions nor momenta. And so there is no space. And so there is no universe. Besides, it is time that we learn to distinguish...
There are no interactions that don't involve measurements. :bugeye: Our description of the quantum world is entirely in terms of correlations between measurement outcomes. If two systems interact, it means that their probability distributions over the possible outcomes of possible measurements...
Hi Vanesch, in my previous post I just collected my thoughts on the subject; I didn’t mean they are all equally relevant to your challenge, though they certainly have a bearing on it.
I just had a look at what must be your bible (I'm kidding) - The many-worlds interpretation of quantum...
Hi vanesch, let me begin by noting a few points. They may have been raised already in this thread, but if so they bear repetition.
As said, there is no commutation relation for energy and time operators because there is no time operator.
All measurements are ultimately position measurements...
Please lock this thread, too, ZapperZ.
Once again you make me say what I didn’t. In your place I would have asked whether I think that surgery is too important to be left to the surgeons. (Of course I could then have countered that ethical issues are involved, and that surgeons are certainly...
A measurement, by my definition, is any actual event or state of affairs from which the truth value of a proposition "S has property P" or "O has value V" can be inferred. There is nothing in this definition that prevents you from analyzing the physics of a measurement apparatus to your heart's...
I didn’t. So you are saying that what appears in Foundations of Physics is not suitable for this quantum physics forum. Has anyone else something to comment on this?
Why does it have to be there? He's got dozens of "mumbo-jumbo" articles in American Journal of Physics, Physics Today, etc. Are...
There you go again with your time evolution. A stationary state (like any ket or quantum state) is a tool for calculating the probabilities of possible measurement outcomes on the basis of actual outcomes (the "preparation"). The time dependence of this tool is a dependence on the time of the...
I have 4 papers of this mumbo-jumbo published in Foundations of Physics, not to mention those published by AJP and IJQI. Prof. A. van der Merwe wouldn’t by happy if you told him that it doesn’t belong in your heavy-handedly moderated physics forums.
Mermin quotes a "distinguished Princeton...
philosophical mumbo jumbo = what goes over your head?
You said: "It is only after you understand what superposition means can you handle entanglement issues." A superposition is a mathematical expression that is used to calculate joint probability distributions over measurement outcomes and...
ZapperZ: Before I respond to your kind words, I would like to state (so that everyone knows) that you (or some other moderator) keep(s) removing links from my posts. The last two of these links refer to discussions of the Bell inequality (following Mermin) and the GHZ experiment (following...
The mathematically rigorous treatment of something that is profoundly mysterious doesn’t make it any less mysterious. The problem can be stated with the simplest mathematics possible, and no amount of mathematical sophistication can improve our understanding of what is going on in reality (as...
Quantum Mechanics: the dreams that stuff is made of. — Unknown
Exquisite poetry, Daryl, and as true as only poetry can be. But don’t be too hard on the physicists. Their work is highly demanding, either technically or mathematically, and their field highly competitive. They don’t get tenure...
As there are several wrong uses, so there are several correct uses, as Hilgevoord points out in the aforementioned article. Foremost among these is the relation between the energy width and the lifetime of a quantum state. Note that there is a completely analogous relation between the momentum...
If by "more experienced folks" you mean physicists, they don’t think about the fundamental nature of matter, at least not in their capacity as physicists. Note that the mathematical formalism of contemporary physics has no symbol form "matter". Physicists don’t talk about matter. They talk about...
Michel, the concepts that feature in classical physics have their roots in the mathematical features of the quantum-mechanical probability algorithms. The classical concepts of energy and momentum are rooted in the time and space dependence of the phases of quantum-mechanical probability...
Daniel, right you are, but there is nothing sacrosanct about those axioms. You can choose others as long as they give you the same probability assignments. These days, post string theory and Susskind's landscape, anthropic arguments are again en vogue. Quoting Jeffrey Bub,
the fact that we find...
Molu, uncertainty has nothing to do with disturbances. To see this, we just have to remember that the quantum-mechanical probability algorithm is time-symmetric. It allows us to assign probabilities not only to the possible outcomes of future measurements (on the basis of actual outcomes of...
IMO, there is an even better book: The Quantum Challenge by George Greenstein and Arthur G. Zajonc. It even contains all the maths you need, which is indeed not all that hard.