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Are the Mysteries of Quantum Mechanics Beginning to Dissolve?

69 points| wjb3 | 4 hours ago |quantamagazine.org

76 comments

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yoyohello13|1 hour ago

Im fully willing to believe I just don’t “get it” but I took a pretty deep dive into quantum computing and the underlying mechanics and I kind of got the sense (with QC) that nobody really knows what they are talking about. I got this feeling so strongly that stopped studying the topic all together.

I’m probably way off base and I’m probably missing some insights that I could get by going to school or something but that’s was just my experience with the subject.

beloch|19 minutes ago

"I think I can safely say that nobody understands quantum mechanics."

--Richard Feynman

You're far from alone. Quantum physics is tricky because it frequently doesn't agree with our physical intuition. Humans are used to dealing with macroscopic objects. They surround us for our whole lives. Matter behaves in surprisingly different ways at the level of single quanta. Seemingly impossible things flop out of the math and then clever experiments show that reality is consistent with the math, but we struggle to reach the point where that reality feels correct. When we try to translate the math into human language, we often wind up overloading words and concepts in a way that can be misleading or even false.

Perhaps we just haven't reached the point where things are sufficiently well explained and simplified, but it may be be that quantum physics will always seem strange and counter-intuitive.

superposeur|1 hour ago

These debates over the interpretation of Quantum Mechanics (i.e. what ultimately happens when a “measurement” takes place) are important but don’t bear on the effectiveness of quantum computing. Regardless of your favorite interpretation (almost) everyone agrees that quantum computers should work and be able to do things classical computers cannot.

sampo|44 minutes ago

> I’m probably way off base and I’m probably missing some insights that I could get by going to school

A school would usually teach the "shut up (about philosophy) and calculate" approach. These philosophical problems about the meaning of quantum mechanics have been with us for 100 years, and mainstream physics sees them as too hard or even intractable, and thus as waste of time.

blueprint|11 minutes ago

> nobody really knows what they are talking about

Could you form a specific question that you're wondering about? (Have you looked at condensed matter physics yet?)

colechristensen|1 hour ago

>nobody really knows what they are talking about

The mathematics of QM works extremely well.

The interpretations of what the math is saying happens a varied and sometimes contradictory.

We can predict what's going to happen extremely well, we just can't tell the story of what's happening. And there's been a century of trying to avoid the weirdness and failing. The problem might just be our brains evolved in a world that behaves so much differently that we can't understand.

danbruc|1 hour ago

Do I get this right? Wave function collapse due to measurements is not real, the wave function evolves unitarily all the time. But as quantum states get amplified into the macroscopic world, superposition states are somehow amplified asymmetrically which makes it look like wavefunction collapse.

superposeur|1 hour ago

Yes, except for the “asymmetrically” part. In other words, Many Worlds.

jadbox|2 hours ago

How does "quantum darwinism" effectively select a state? Like how does that work in principle- what is the selection criteria.

superposeur|1 hour ago

It doesn’t. Decoherence is the technical step in the Everett picture defining what a “classical branch” even is and explaining how the state vector branches. Every claim that “Decoherence” somehow offers a distinct interpretation to Everett is pure confusion.

goatlover|2 hours ago

The article asks the same question in the last part, wondering whether it's just randomly selected. MWI proponents have always argued decoherence leads to the entire world being put into superposition as decoherence just spreads entanglement to the environment. The math never says entanglement destroys superposition beyond a certain point of complexity (many different entangled systems forming the environment).

The author does say the approach is a combination of Copenhagen and MWI, removing the outlandish parts of both. Seems to preserve the randomness of the former though.

outlace|53 minutes ago

Highly recommend looking at Jacob Barandes’ formulation of quantum mechanics as non-Markovian stochastic processes. It was the first introduction to quantum mechanics I could actually follow.

https://www.jacobbarandes.com/

suhputt|49 minutes ago

might make sense to link to the actual material you're referring to

lukol|2 hours ago

opens coat Hey kid, wanna try some superdeterminism?

A_D_E_P_T|2 hours ago

The Block Universe Theory, which relativity all but demands, makes that a pretty potent drug!

scotty79|1 hour ago

> How, for example, are we supposed to think about the domain in which all possibilities still exist before decoherence? How “real” is it?

The quantum function is the real object. Little balls we like to imagine the particles as are just perception of quantum functions very narrowed down by entangling with macroscopic objects. The way we measure anything is through the entanglement between the measured entity and our macroscopic instruments.

kikokikokiko|1 hour ago

To me, the fact that quantum mechanics is intrinsically "random" and unknowable beforehand, is what makes living bearable in this universe as a sentient being. If we, two legged viruses that we are, could reach a level of understanding that could show the universe to be fully deterministic and every future state to be knowable given that you know the current states, then this human condition would be impossible to stand. I love the fact that we just can't predict the future. It's what makes existing be a good thing instead of a bad one.

lukol|33 minutes ago

#1: You do not want randomness. You may believe you do until the Titanic crashes into your front yard and your significant vanishes into thin air. You want quite a lot of predictability, up to a degree where it might not even matter if things at the lowest level of existence are not perfectly deterministic.

#2: What's so bad about thinking about life as an exciting rollercoaster ride? The tracks are laid but the ride is still fun.

kykat|1 hour ago

Fully agree, feels good to say that it's all just kind of random.

phacker007|59 minutes ago

I knew you were going to say that.

Nevermark|2 hours ago

> None of the leading interpretations of quantum theory are very convincing. They ask us to believe, for example, that the world we experience is fundamentally divided from the subatomic realm it’s built from. Or that there is a wild proliferation of parallel universes, or that a mysterious process causes quantumness to spontaneously collapse.

Actually, the "many worlds" "interpretation", simply treats the highly successful equations as meaning what they say.

And it is misnamed. The field equations describe a highly interconnected "web universe" of "tangles" (what I call spans of entangled interactions) and "spangles". (My shorthand for superpositions, i.e. disjoint interactions of particles. Think of all the alternate lines leading from and two distinguishable states, like star patterns.) Basically, a graph of union and intersection relations where all combinations, individually and en masse, are determined exactly by the laws of conservation.

That's an amazingly good property for a theory. And we have it.

By including all consistent versions, no external information is required by the theory. It is informationally complete. A successful objective explanation. With deep experimental support that entanglement and superposition actually exist, because their interactions are easily testable.

In fact, entanglement doesn't "violate" locality, it is the more general case which explains locality. Locality is just tightly coupled entanglement/interaction. Not a fundamental constraint on connections. There is no fundamental "distance", just loose and dense connections. Locality is just what we see wherever there are patterns of dense connections. They are an effect, not a constraint.

Even in the classical world of large (highly tangled) objects, we take it for granted that dependent objects can separate over arbitrarily vast dimensions of space and time and yet return together. If that isn't entanglement over vast distances, what is it? It is a basic property of classical physics. Quantum mechanics reveals more subtlety in those maintained connections, including interactions between connections, but it didn't originate them.

Forces disappear. They become passive in an interesting way. Histories where information cancel, leave structured distribution patterns behind, which to us look like forces. Cancellation is just information being conserved. Not an active force. But the results appear active.

In a similar way to how the evolutionary umbrella seems very smart and creative, when really, it is just poorly adapted individual creatures independently cancelling themselves out blindly, leaving a distributional improvement behind.

There is no additional information needed to explain the effect of quantum "collapse" because it is already explained by the fast bifurcation of disjoint tangles when lots of particles interact in an unorganized manner. It is thermodynamics being thermodynamics.

Anyone attempting to invent a mechanism for "collapse" is like someone trying to explain why the spherical Earth appears "flat" by introducing additional speculative theories. Despite the spherical world theory already explaining why it looks flat locally.

And the only reason to not take the experimentally verified field equations as a plain reading, is the result is "too big" for someone's imagination.

Our everyday experience doesn't limit reality, despite humans having trouble with theories that reveal a bigger reality, over and over and over.

Bluntly: The total field equations preserve information - that is the plain implication and guarantee for having both unions (tangles) and intersections (spangles) of interactions.

Anything else requires a universal firehose of magically appearing information to choose collapses, i.e. particular interactions, in order to explain something already explained. In other words, dressed up voodoo. And by "re-complicating", uh, "re-explaining" the already explained, introduces a ridiculous new puzzle: Where does all that pervasively intrusive relentless injection of information (that determines every single extricable particle interaction!), come from? (Occam is spinning like a particle accelerator in his grave.)

Saying it "Just Happens" is like someone "explaining" their pet version of a creator with "Just Is". It is a psychological non-taulogy for "Don't Ask Questions".

spot5010|2 hours ago

The part that I have trouble wrapping around with many worlds interpretation is how I as an observer end up in one of the many bifurcations. Any links you can share that will help me with understanding that is welcome!

The Stanford Encyclopedia of Philosophy (https://plato.stanford.edu/entries/qm-manyworlds/) goes into this in some depth, and it seems like the right way to think about it is say that "I" in one branch is a different entity than the "I" in a different branch. I have somehow not been able to grok it yet.

And I agree about the naming. I really dislike the name "many worlds interpretation", which seems to imply that we have to postulate the existence of these additional worlds, whereas in fact they are branches of the wavefunction exactly predicted by standard quantum mechanics.

prmph|1 hour ago

I think the MWI is actually the just-so explanation you claim to avoid.

Is it falsifiable?

If you have a theory that seems unassailable by any logic, that's a good signal it is tautological and not very useful.

uh_uh|2 hours ago

Isn't there a magical moment needed still when a single qubit "touches" the rest of the universe?

borissk|2 hours ago

I think you're right, the many worlds interpretation makes the most sense. Unfortunately out current technology is very far from delivering any experimental confirmation or denial of any of the mainstream interpretations.

borissk|2 hours ago

Are the Mysteries of Quantum Mechanics Beginning to Dissolve? I don’t think so.

Zurek’s Decoherence and Quantum Darwinism is thought-provoking, but it’s still speculation without broad buy-in from researchers. We might need ASI to crack these mysteries — our brains weren’t built for this kind of problem.

vladms|2 hours ago

I think the brains of our stone age ancestors were not built for relativity either. In the end the normal sequence of generations (having children and then die at some point) offers "re-trainings" of the brains. So, besides waiting/hoping for artificial intelligence, we should continue to make (and train) children. Worked great so far.

wongarsu|2 hours ago

What we need are tractable experiments to test these theories.

Maybe ASI can help design these. Until it can, it will just be another voice arguing for one position over another on pretty weak arguments. Right now my money would be more on human researchers finding those experiments, but even among those few are even trying

general_reveal|2 hours ago

Quite frankly, Quantum is probably known or solved by a nation state (probably the United States). Similar to AI, they will release it in a safe roll out (as they deem it).

andirk|2 hours ago

Maybe, but the AI we see in the mainstream today -- generative image/video/text creations and Large Language Model chatbots -- were done via non-governmental public and private companies. And a lot of the work hitting the scene loudly and somewhat prematurely. My understanding is the amount of and type of compute needed for Quantum is pretty intense, so there'd be a huge footprint from its manufacturing to keep it hidden.

Noaidi|2 hours ago

"Thus the wave function can’t tell us what the quantum system is like before we measure it. "

Nothing is a particle, all measured things are a probability that we make a certainty when we measure them.

When you stop looking at things as things, but instead, see them as probabilities, it will all make sense. My hand and the beer bottle I pick up are both probabilities. Since the mind cannot navigate the world based on probabilities it turns them into certainties.

Physical science is is the only way we can perceive quantum science. There is no "collapse" outside of our brains perception.

tux1968|1 hour ago

Why does a probability taste so good after work on a hot day?

artrockalter|1 hour ago

It would be interesting if most of our confusion with quantum mechanics came from treating probabilities as independent when they are actually highly correlated. I don’t really know any physics, but I’m familiar with probability and this type of problem seems to be the most common error in interpreting probabilities.

butILoveLife|1 hour ago

I don't have any skin in the game, but people should be aware of Induction vs Deduction.

Induction had the earth at the center of the solar system and had the best calculations to predict where Mars was. Copernicus said earth was at the center, the equations were simpler, but were worse at predicting the location of planets.(until we figured out they moved in ellipses)

When we say "All swans are white, because I've never seen a black swan." Its probabilistically true. That is induction. If we found swans didn't have the gene to make black feathers, that would be deduction.

Deduction is probably the most true, if it is true. (But it is often 100% wrong)

Induction is always semi true.

Quantum mechanics seems to be in the stage of induction. Particles are like the earth at the center of the solar system. We need a Copernican revolution.

Findeton|1 hour ago

I wonder how this work relates to Jacob Barandes’s indivisible stochastic processes.