Gravity is unlikely to be the cause of quantum collapse, experiment suggests (opens in new tab)

As soon as it says "here or there" the writer is clearly trying to make it binary again. It isn't "here or there" but a function of probability between those two "places." It's an infinite number of possible "locations," but we narrow it down to a large number of decimal places because otherwise we wouldn't be able to make use of it at all. If things were as written here, you could do all quantum calculations with a straight up coin toss (although some might argue that can with an adequately tiny coin, but that still only gets at the most basic understanding of "spin" and only becomes an accurate analogy if the coin is flipped randomly in zero-g).

Our higher level concept of gravity (at least in the classical sense) has been known to break down to the point that it doesn't apply to quantum mechanics for quite a long time now. The writer should just google "quantum gravity" to discover what a complicated subject that becomes.

I am not a physicist but isn't it an instance of "if you think you understand quantum mechanics, you don't understand quantum mechanics"?

The measurement problem, which deals with collapse is still unsolved. It is also the reason why there are so many weird interpretations of quantum mechanics and that even top physicists can't agree on one. In fact the same physicists tend to sweep the problem under the rug and instead focus on the equations that, to be fair, did a lot more to science and technology than trying to solve the measurement problem.

>Collapse is only mysterious to people who never learned thermofield theory, or non-equilibrium quantum dynamics.

Oh yeah? Then what is the physical explanation for collapse?

For the past several decades Penrose has been a fountain of nothing but frivolous fringe theories. Physicists are like investments: past performance is not indicative of future returns ;P

(Nobody is sure about the graviton, but IMHO it is a good bet.)

Electromagnetism is also mediated by particles (photons) and the quantum states can survive a lot of electromagnetic interactions without collapsing. One of my favorites https://en.wikipedia.org/wiki/Stern%E2%80%93Gerlach_experime...

My second sentence?

It seems continuous and unitary when the experimenter takes a lot of care to create a simple and very isolated system. When it's brought into contact with the mess that is the rest of the world it changes character very quickly, and interactions with the rest of the world completely swamp the internal dynamics.

I interpret KS backward from what you're saying. From my understanding, KS says that there is no sense in which the experiment involves an objective revelation of hidden state.

After the experiment, the experimenter did not "learn" or "reveal" some objective fact about reality, ie that the true state was UP rather than DOWN. Instead, after the experiment the experimenter becomes entangled with the UP/DOWN system in such a way that the experimenter measured both UP and DOWN, but all observables relating to the experimenter are either wholly consistent with UP or wholly consistent with DOWN.

I've always been content to know that after measurement, the quantum system that includes both me and the device has a certain quantum state which is a superposition of all the measurement eigenstates, but by construction that state couldn't be measured in such a way that I would have ever experienced an inconsistency.

There's no work QM is saving: it doesn't delay work or get to do less until when you physically look at something and then get to skip work for things you don't look at. * Things that are in superposition would require more computation for all their many alternate versions (most of which aren't meaningfully interacted with), not less, and the extra work for managing superpositions continues forever if MWI is right. All particles are constantly entering new superpositions, not just individual particles in fancy lab experiments. Only the very simplest of particle interactions (like two individual hydrogen atoms interacting) are feasible to simulate with full quantum mechanics on classical computers. * "Observation" happens through any physical interaction at all, including particle collisions. Outside of some individual particles inside carefully controlled experiments, most particles end up transitively interacting with most other particles near them.

If the universe was at all optimized for simulation costs for human experience, we probably wouldn't expect there to be be trillions of galaxies with hundreds of millions of stars each, for the smallest particles to be on the scale of billion-billionths compared to humans, or for QM to work anything like it does.

QM-as-RNG for a simulated universe has been one of my favorite "for fun" pet theories over the years. Finding whether the electron went through slit A or slit B during the double-slit interference tests just feels a bit too much like running a Monte Carlo sim to me. I know it's just my human brain really trying to find an explanation that makes rational sense but it's a fun thought experiment.

I mean, quantum fluctuations during inflationary expansion are (in my understanding) what's responsible for the tiny differences in mass distribution that led to the eventual formation of gas clouds/stars/galaxies. The negative gravity during expansion worked to keep the matter in an extremely low-entropy (highly ordered) state, but those unfathomably small quantum fluctuations were blown up by the same unfathomably massive proportions as everything else.

Universe needed that RNG.