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OF THE MANY counterintuitive features of quantum mechanics, perhaps the most challenging to our notions of common sense is that particles do not have locations until they are observed. This is exactly what the standard view of quantum mechanics, often called the Copenhagen interpretation, asks us to believe. Instead of the clear-cut positions and movements of Newtonian physics, we have a cloud of probabilities described by a mathematical structure known as a wave function. The wave function, meanwhile, evolves over time, its evolution governed by precise rules codified in something called the Schrödinger equation. The mathematics are clear enough; the actual whereabouts of particles, less so. Until a particle is observed, an act that causes the wave function to “collapse,” we can say nothing about its location.
Bohmian mechanics was worked out by Louis de Broglie in 1927 and again, independently, by David Bohm in 1952, who developed it further until his death in 1992. (It’s also sometimes called the de Broglie–Bohm theory.) As with the Copenhagen view, there’s a wave function governed by the Schrödinger equation. In addition, every particle has an actual, definite location, even when it’s not being observed. Changes in the positions of the particles are given by another equation, known as the “pilot wave” equation (or “guiding equation”). The theory is fully deterministic; if you know the initial state of a system, and you’ve got the wave function, you can calculate where each particle will end up. That may sound like a throwback to classical mechanics, but there’s a crucial difference. Classical mechanics is purely “local”—stuff can affect other stuff only if it is adjacent to it (or via the influence of some kind of field, like an electric field, which can send impulses no faster than the speed of light). Quantum mechanics, in contrast, is inherently nonlocal. The best-known example of a nonlocal effect—one that Einstein himself considered, back in the 1930s—is when a pair of particles are connected in such a way that a measurement of one particle appears to affect the state of another, distant particle. The idea was ridiculed by Einstein as “spooky action at a distance.” But hundreds of experiments, beginning in the 1980s, have confirmed that this spooky action is a very real characteristic of our universe.
“The universe seems to like talking to itself faster than the speed of light,” said Steinberg. “I could understand a universe where nothing can go faster than light, but a universe where the internal workings operate faster than light, and yet we’re forbidden from ever making use of that at the macroscopic level—it’s very hard to understand.
But as far as i can reckon there's Copenhagen View which states the position of a subatomic particle can only be expressed as a probability
“The universe seems to like talking to itself faster than the speed of light,” said Steinberg. “I could understand a universe where nothing can go faster than light, but a universe where the internal workings operate faster than light, and yet we’re forbidden from ever making use of that at the macroscopic level—it’s very hard to understand.
That's not exactly what Bohmian mechanics proposes as the article explains, and it also claims that most rejections of Bohmian mechanics are based on misunderstandings of the Bohmian mechanics model.
originally posted by: dashen
But as far as i can reckon there's Copenhagen View which states the position of a subatomic particle can only be expressed as a probability vs Bohmian mechanics which say all particles are in definite positions .
In the Bohmian view, nonlocality is even more conspicuous. The trajectory of any one particle depends on what all the other particles described by the same wave function are doing. And, critically, the wave function has no geographic limits; it might, in principle, span the entire universe. Which means that the universe is weirdly interdependent, even across vast stretches of space. The wave function “combines—or binds—distant particles into a single irreducible reality,” as Sheldon Goldstein, a mathematician and physicist at Rutgers University, has written.
Photons travel at the speed of light so they generally don't travel across the universe any faster than that (they can appear to travel across short distances in a lab faster in quantum tunneling experiments). What they can do is interact with other photons in other parts of the universe faster than the speed of light, or at least observations of of distant entangled photons are correlated, because another model mentioned in your source, "Many worlds" says there's no interaction and that observation is local, and that experimental results are explained because we don't know which universe we are going to be observing, which gives the appearance of non-locality under other interpretations such as DeBroglie-Bohm and Copenhagen.
Does that mean a photon could potentially shoot offa Across the Universe if the amplitude of the wave was large enough?
Have you noticed that Bohm believes (as de Broglie did, by the way, 25 years ago) that he is able to interpret the quantum theory in deterministic terms? That way seems too cheap to me. But you, of course, can judge this better than I.
So if we're ok with wave-function collapse because we understand it through this decoherence, what's wrong with the idea that nature is probabilistic? Why do we have to have that every possibility is realized? Quantum mechanics is probabilistic, that's the way nature is, and just because our classical intuition tells us that we enjoy a deterministic existence, that doesn't mean quantum mechanics has to behave like that, it doesn't mean nature has to behave like that, it just means day to day that's how it seems to behave, but truly it's probabilistic. And that's fine, ok. It doesn't mean that every possibility has to be realized.
Quantum mechanics, in contrast, is inherently nonlocal. The best-known example of a nonlocal effect—one that Einstein himself considered, back in the 1930s—is when a pair of particles are connected in such a way that a measurement of one particle appears to affect the state of another, distant particle. The idea was ridiculed by Einstein as “spooky action at a distance.” But hundreds of experiments, beginning in the 1980s, have confirmed that this spooky action is a very real characteristic of our universe.
If it's bull then how do you explain the bands forming when the electrons are fired one at a time? Yes if you only look at one electron you only get one dot, but when you do that over and over again the one dots add up to form a band pattern. What's your explanation for the interference pattern if you don't accept the scientific explanation?
originally posted by: masterp
Another example is this: "each electron spreads out like a wave, passes through both slits simultaneously, and interferes with itself to form the bright and dark bands on the detector screen".
Well, that's wrong. If a single electron is fired, a single dot will appear on the detector screen, not a band. A band will appear after a stream of electrons is fired onto the slits.
Which means the whole thing is totally 100% bull#.
This means that the electrons are simply slingshot to certain positions when passing through the slits, due to the slits being narrow enough to not allow an electron to fully pass through it.
When a detector is put in between the electron gun and the slits, the electron is somewhat modified in such a way that it no longer has a problem fitting the slit.