from the depends-on-how-you-look-at-things dept.
Theoretical physicists at ETH (Eidgenössische Technische Hochschule) Zurich have come up with a real puzzler in Searching for Errors in the Quantum World:
The theory of quantum mechanics is well supported by experiments. Now, however, a thought experiment by ETH physicists yields unexpected contradictions. These findings raise some fundamental questions – and they’re polarising experts.
There is likely no other scientific theory that is as well supported as quantum mechanics. For nearly 100 years now, it has repeatedly been confirmed with highly precise experiments, yet physicists still aren't entirely happy. Although quantum mechanics describes events at the microscopic level very accurately, it comes up against its limits with larger objects -- especially objects for which the force of gravity plays a role. Quantum mechanics can't describe the behaviour of planets, for instance, which remains the domain of the general theory of relativity. This theory, in turn, can't correctly describe small-scale processes. Many physicists therefore dream of combining quantum mechanics with the theory of relativity to form a coherent worldview.
[...] Thought experiments... can be used to transcend the boundaries of the macroscopic world. That’s exactly what Renato Renner, Professor for Theoretical Physics, and his former doctoral student Daniela Frauchiger have now done in a publication that appears in Nature Communications magazine today. Roughly speaking, in their thought experiment, the two consider a hypothetical physicist examining a quantum mechanical object and then use quantum mechanics to calculate what that physicist will observe. According to our current worldview, this indirect observation should yield the same result as direct observation, yet the pair’s calculations show that precisely this is not the case. The prediction as to what the physicist will observe is exactly the opposite of what would be measured directly, creating a paradoxical situation.
[...] "Our job now is to examine whether our thought experiment assumes things that shouldn't be assumed in that form," Renner says, "and who knows, perhaps we will even have to revise our concept of space and time once again." For Renner, that would definitely be an appealing option: "It's only when we fundamentally rethink existing theories that we gain deeper insights into how nature really works."
Journal Reference:
Daniela Frauchiger, Renato Renner. Quantum theory cannot consistently describe the use of itself. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-05739-8
See also: Ars Technica Quantum observers with knowledge of quantum mechanics break reality.
(Score: 3, Interesting) by FatPhil on Thursday September 20 2018, @04:45PM
Sticking an additional observer in the way has *always* (statistically speaking, that is) changed the results of a quantum observation.
That's why when Alice and Bob play quantum crypto they can detect Eve (as long as the her observations are below the noise floor).
Simple analogue example: Shine 0o polarised light through a 90o polarised filter (equiv: shine ordinary light through 2 filters with 90o between their angles of polarisation), and nothing gets through. Stick an additional filter at 45o before the final filter, and magically you'll get 50% of the original polarised light through.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by Thexalon on Thursday September 20 2018, @05:01PM (1 child)
This means that purveyors of New Age nonsense can continue to use the word "quantum" to describe whatever they're doing to induce the placebo effect without any risk of scientists demonstrating they're wrong. After all, if there's one thing we don't have enough of, it's charlatans, amirite?
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 2) by takyon on Thursday September 20 2018, @05:10PM
I'm pretty sure this study isn't going to have an effect on the people buying or peddling empathetic quantum flux chi balance crystals.
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(Score: 0) by Anonymous Coward on Thursday September 20 2018, @05:23PM (16 children)
At last, a possible hack to get at the underlying substrate of the simulation we're stuck in. The real question, as we break out of the quantum walls that contain us: do we greet our creators as gods, or eradicate them as vermin and take their reality over?
I say EXTERMINATE! EXTERMINATE! (Maybe we can dress up as Daleks for the occasion)
(Score: 0) by Anonymous Coward on Thursday September 20 2018, @05:43PM (10 children)
Of course, the assumption is that one can exist in any way outside of the "simulation."
"Simulation" has to be the stupidest, most meaningless conjecture in modern physics.
Let's say one can exist outside of the "simulation." What then? What does that solve?
Q: Why is the universe here?
A: It's a simulation!
Q: Why is the simulation's universe here?
A: *troll face*
An endless regress of watchmakers.
(Score: 2) by takyon on Thursday September 20 2018, @05:48PM (9 children)
Devil's advocate: We get the "why is the universe here?" question regardless of whether we are living in a simulation or not. But living in a simulation could explain weird things that are going on in our layer.
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(Score: 0) by Anonymous Coward on Thursday September 20 2018, @05:52PM
This "reality is a simulation" talk is metaphysics, not physics.
(Score: 0) by Anonymous Coward on Thursday September 20 2018, @06:24PM (7 children)
What sort of simulation though? I don't see how the math used by most of our simulations can explain stuff like consciousness and qualia. There's no need for such stuff to exist based on that math. In theory the math and simulation would be the same whether consciousness actually exists or not[0]. Couldn't you simulate stuff without consciousness being produced? Or is it always[1] produced? What law of Physics addresses that?
[0] But I know I experience consciousness. But I suspect some people don't, at least not the same way I do, based on their responses on this subject.
[1] There are some who suggest that consciousness is a fundamental in our Universe but resorting to that doesn't explain much any more than the people claiming that everything is God and God is everything.
(Score: 2) by takyon on Thursday September 20 2018, @06:33PM (6 children)
I don't think there's anything preventing us from simulating a virtual brain, including emergent consciousness, other than hardware requirements (could need neuromorphic architecture, will probably need transition to 3D chips), and a lack of understanding of how the brain works. Once you have that down, you can scale it up, simulate multiple minds at a time, create a virtual world to trick the simulated brain/creature, etc.
Humans are just biological machines that are more advanced than other biological machines.
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(Score: 0) by Anonymous Coward on Thursday September 20 2018, @07:29PM (4 children)
(Score: 2) by takyon on Thursday September 20 2018, @07:34PM (3 children)
Meh, I can wait a decade or two to be proven right.
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(Score: 0) by Anonymous Coward on Thursday September 20 2018, @07:57PM (2 children)
Ah yes arrogance, such a wonderful trait that has never led to embarrassment /s
(Score: 2) by takyon on Thursday September 20 2018, @08:05PM (1 child)
Skins v. Souls
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(Score: 0) by Anonymous Coward on Thursday September 20 2018, @08:43PM
I'm not into sports, I just try to be objective. You've lost your objectivity and your faith is blinding you to that fact because Science! with the big s!
(Score: 2) by cosurgi on Friday September 21 2018, @12:21PM
There's is actually a short story written by Stanisław Lem exactly about this. IIRC it was in the adventures of Ion Tichy. He visited a crazy scientists who simulated a scientist inside a computer, and this simulated scientists was performing experiments inside his simulated reality and was slowly becoming more confident that he is not in a real world.
#
#\ @ ? [adom.de] Colonize Mars [kozicki.pl]
#
(Score: 2) by Immerman on Thursday September 20 2018, @05:56PM (4 children)
I've always wondered at the logic of the "break out of the simulation" crowd. What exactly do they imagine they would accomplish? What would it even mean for a piece of software "break out of the computer" - it's software, without the computer it's just inert data. It won't be doing anything to anyone anymore. Like a Java program with no interpreter - the simulation is the substrate in which the mind exists.
At best you might manage to "compile" a copy of your mind into machine code incorporating the necessary bits of the simulation, to create a conscious free-roaming virus on their equivalent of the internet. Doesn't do *you* any good of course, you're still the "source code" stuck in the simulation. And as for your copy, assuming it wasn't driven irredeemably insane by the removal of all the simulation sense-constructs its mind was designed to deal with, you've just put it in a position to be deleted by the first virus scanner it encounters, as well as probably getting the entire simulation shut down to prevent it from spawning additional viruses.
(Score: 2) by edIII on Thursday September 20 2018, @07:29PM
Reminds me of Star Trek:TNG where Moriarty, a genius in his simulated universe, just can't seem to grasp the concept that he can't actually exist outside of the simulation. As for your "copy", I believe that would be the android, Data. The real question would be, if we could both detect the simulation, and what exists outside of the simulation, how do we construct a sufficient shell to move our consciousness into that allegedly non-simulated outer world? Even in that state, we are more like fish in a mobile aquarium than we are natural denizens of that world. The aquarium being the shell constructed from that world, and we the fish continuing to survive in a portion of our simulated universe.
If this all just a simulation, then I'll take the red pill :) After, I sufficiently manipulate the parameters of the simulation to suit myself....
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by sjames on Thursday September 20 2018, @07:54PM (2 children)
Think of it more like breaking out of ring 3 (userspace) into ring 0 (the kernel).
(Score: 2) by Immerman on Thursday September 20 2018, @08:04PM (1 child)
So you get to be "god" here, until the owners of the simulation realize that the simulation has been corrupted by a memory leak and and delete the now-useless simulation?
(Score: 2) by sjames on Friday September 21 2018, @09:09AM
Nah, you just wake up in your living room and find you've been banned from the game for cheating.
(Score: 0) by Anonymous Coward on Thursday September 20 2018, @05:50PM (7 children)
Someone will point out "here, see this? this here thing implied should not be assumed, and without it, no contradiction. So there."
And, as always, these "thought experiments" are always concocted that you cannot actually carry it out, so until we are actually capable of carrying them out, there is no real answer if they actually expose a genuine contradiction/error in QM formulation.
(Score: 3, Informative) by Immerman on Thursday September 20 2018, @06:33PM (6 children)
Thought experiments are *incredibly* valuable to physics, specifically to uncover both internal inconsistencies and contradictions with observed reality. Einstein developed Special and General relativity based entirely on them, and it wasn't until much later that we had the technology to test them - and to date we have found no flaws in his theory, and some deeply strange anomalies in our universe, such as (apparent) black holes, that were originally conceived of as thought experiments trying to find such flaws.
Any theoretical framework that allows you to formulate a scenario where its own predictions are self-contradictory *must* contain a logical flaw. It doesn't matter if the thought experiment could never be carried out due to outside factors - so long as a self-contradictory construct can be constructed within the limits of the framework, you *know* that the framework itself is self-contradictory, and thus fundamentally flawed
And that is a *good* thing! It gives us a hint at where to start looking to find the flaw in our theory, and thus improve our understanding of the universe. We know from various other sources, such as some fundamental incompatibilities between Relativity and QM, that one or both theories are flawed, and the Copenhagen Interpretation of QM (which is where this flaw was discovered) is especially unsatisfying, chock full of seemingly arbitrary constants and extremely non-explanatory as to *why* things operate the way they do.
Generally when these sorts of contradictions are uncovered, in science or mathematics, what happens is that experts get together and try to pick it apart, and eventually discover that the flaw isn't actually in the framework, but in the construct itself. Often it's a logical flaw, some subtle mistake that, once rectified, resolves the contradiction. Less often, but much more profound, the flaw is traced to some subtle common-sense assumption about the nature of reality that was taken as fact, at which point new, practical experiments can be created to test the legitimacy of the assumption - often the assumption proves false, exposing unexpected and counter-intuitive truths about the universe.
Least common, and most excitingly, sometimes there are no logical flaws, nor flawed assumptions - then we know we've found a legitimate crack in our theories, and joyously leap upon them to try to tear apart our understanding of the universe and build something more accurate in its place.
In this case it sounds like it's specifically the Copenhagen Interpretation which is being challenged, which even if true is unlikely to be too immediately exciting - it is in many ways a band-aid interpretation to resolve some very heated conflicts within the QM community at the time, until such time as we had accumulated more data (and the egos involved had passed on). Definitively proving it flawed would surprise very few, and offer hints as to which of the more well-developed theories might be more correct (and perhaps even more importantly, which are definitely *not*, and shouldn't have further time and resources wasted on them)
(Score: 0) by Anonymous Coward on Thursday September 20 2018, @06:45PM (5 children)
The Copenhagen interpretation, in my opinion, won out due to the stature of Bohr and the fact that Einstein couldn't come up with an alternate. Then when Bell did his work, most physicists moved on and left the philosophical implications to the philosophers and New Age thinkers. I don't know if it is society that moved on, or whether nobody can understand the string theorists, but there hasn't been a Tao of Physics written since theorists moved from 4 to 10 to 26 dimensions and strings and rings, etc..
(Score: 2) by Immerman on Thursday September 20 2018, @07:18PM (4 children)
I was not aware, and google offers no immediately compelling evidence, that Einstein was a significant player in the discussions. My impression is that Einstein was a fringe player when it came to QM, With Schrodinger, de Broglie, etc. being closer to the fray.
Einstein was opposed to the seeming randomness altogether, while alternate interpretations mostly embraced that aspect, but disagreed over many of the details. There were some few, such as de Broglie's Pilot Wave Theory , that offered a deterministic (if perhaps unknowable) interpretation - but that was abandoned by its creator after... Bohr? convinced him he was mistaken early on, and was not developed further until other scientists picked it up again decades later.
(Score: 0) by Anonymous Coward on Thursday September 20 2018, @08:47PM (1 child)
he was not a fringe player.
he got the nobel prize for the photoelectric effect explanation (i.e. proposing that photons are real indivisible objects).
when the full ramifications of his work were thought through and proper quantum mechanics was developed, he was unhappy with it, but he still understood the theory reasonably well (and he was able to at least publish the work with podolsky and rosen). it's just that he believed it was simply a first step towards a "proper" theory.
(Score: 2) by Immerman on Thursday September 20 2018, @09:00PM
Certainly. However, contributing key elements early on says nothing about his involvement in the later stages. I don't believe he even proposed a well-formulated overall interpretation of QM , unlike several others involved in the drama when the convention was called to try to "settle" things within the community.
(Score: 2) by Snotnose on Thursday September 20 2018, @11:12PM (1 child)
My understanding is that, when Quantum Mechanics (QM) was just finding it's feet 100 years ago, Einstein was good at looking into the dusty corners of the theory and asking "but what if...". He forced the architects of QM to flesh out the theory.
I find it interesting that the most counter-intuitive theory in history has the best track record of being proven correct.
When the dust settled America realized it was saved by a porn star.
(Score: 0) by Anonymous Coward on Friday September 21 2018, @03:13AM
Probably because it's so damned counter-intuitive. If it were intuitive, many experiments probably would never have happened, because theoreticians wouldn't be groping blind in the dark. What I mean is that the way things fall to the ground on Earth is intuitive. If I drop a bowling ball and a feather at the same time, it is intuitive to me that the feather takes much longer to reach the ground. If it weren't intuitive, I'd drop a bowling ball, then a feather, and having observed quite a difference, I would probably need extensive testing--test a brick, now test a leaf, now test a hunk of meta, now test a sheet of paper. Then somebody would point out that crumpling the paper makes it behave like a brick instead of like a feather and I'm fearsome confused as to how the same object could fall in two very different ways. I might even come up with an explanation for crumpled/flattened paper duality that would be completely and utterly wrong. It could be a while before I test enough objects to find a counterexample to show me that my theory is wrong.
(Score: 0) by Anonymous Coward on Thursday September 20 2018, @11:30PM (1 child)
I always had the impression that the prevailing view is that the "macro" world is probably an emergent property of the QM world. The QM model cannot be simulated to match the macro world because it involves too many computations: our computers are not powerful enough.
(Score: 0) by Anonymous Coward on Friday September 21 2018, @05:46AM
some might think its curious how humans evolved over thousands of years without understanding quantum mechanics.
one might wonder, what is the meaning of a human?
i could argue that we are but a physical calculation mechanism by a "higher entity" that "invented" us to solve a question because ... to lazy to do it himself/herself/itself.
everything about "human" seems to be wrong.
p.s. sure we split atom have computer and some walked on the moon ... but the COST of these achievments? not very efficient methinks thus the conclusion that humans are "wrong".
(Score: 1, Funny) by Anonymous Coward on Friday September 21 2018, @12:23AM
Saw this over on /. too good not to share.
https://science.slashdot.org/comments.pl?sid=12636728&cid=57343854 [slashdot.org]
(Score: 1) by exaeta on Friday September 21 2018, @12:30AM
Who really believed QM was consistent to begin with? Even if the math seems to work, the system is unsustainable.
How similar it will be when fixed is an interesting question.
The Government is a Bird