SoylentNews is people
SoylentNews
from the will-this-help-me-win-the-lottery? dept.
A team in Australia turned thought experiment into lab reality by using lasers. Their subject matter was not a photon but a helium atom. The lasers they used served as a pair of grates, one before the other, with the second grate randomly dropped in.
What they found is weirder than anything seen to date: Every time the two grates were in place, the helium atom passed through, on many paths in many forms, just like a wave. But whenever the second grate was not present, the atom invariably passed through the first grate like a particle. The fascinating part was, the second grate's very existence in the path was random. And what's more, it hadn't happened yet.
In other words, it was as if the helium particle "knew" whether there would be a second grate at the time it passed through the first.
Also covered at: phys.org. An abstract is available; full report is pay-walled. The original news article is at Australian National University
Original Submission
(Score: 2) by Immerman on Tuesday June 16 2015, @03:56PM
Well, if you want to bring philosophers into a scientific discussion you'll be there all night and probably never reach any conclusions - regardless of the topic. Modern philosophy has largely degenerated into mental gymnastics - it's great for developing strength and flexibility, but isn't actually directly useful for much. It just hasn't been the same since science and religion split off and took most of the practical questions with them.
Just because philosophers can't agree on whether anything beyond themselves doesn't mean there's no meaningful definition to be found - in fact it's a largely orthogonal question. Even if we had a perfect definition, we'd still run afoul of Descarte's evil-demon hypothesis and be unable to claim with certainty that anyone else even exists, much less is conscious.
You seem to see my point though -we could as easily define consciousnes by tautology: "a system which causes quantum wavefunctions to collapse when interacted with". In fact if we could find some way to detect exactly when the wavefunction collapsed, that might form the basis of a consciousness detector.
As for your cog-driving Geiger counter, of *course* the wheels are quantum devices - *everything* is a quantum device - what we call "classical physics" is the unexplained anomaly. How does combining a bunch of tiny quantum systems into ever-larger quantum systems eventually create something that appears to be governed by much simpler rules to a degree far beyond what can be explained by statistical averaging?
As for your speed question? If my preposition is correct then there would be no issue - the wheels would themselves would be in a superposition of states, having both rotated and not rotated as they interacted with the superposed measurement signal. The question is only whether the superposition collapses when it interacts with some poorly defined "macroscopic system", or if it continues to expand until it interacts with something conscious, or some other criteria is met, or even if it never actually collapses at all. There have been researchers who have managed to create mm-scale superpositions, so clearly it's not just "too many atoms involved", but as yet we really don't know what that criteria may be - it's *all* speculation. But clearly it doesn't simply end with the interaction of the initial superposed particle - far too many experiments have managed to transfer that superposition to other, often much larger, systems.
Enjoy the mountains, it's been too long since I spent a good chunk of time in them. I'll be around.
(Score: 2) by Zinho on Monday June 29 2015, @08:28PM
Thanks for the well thought-out answer! And your patience as well; I've been back for over a week now, but too busy catching up to spend time giving your response the consideration it deserves.
From what I read in your last post, I believe you and I are very close to each other philosophically, and perhaps talking past/around each other. I like your idea of a consciousness detector based on quantum waveform collapse; I even am open to the idea that we'll make startling discoveries, with many things we consider "inanimate" being detected as conscious. That would make for interesting news headlines, and perhaps a few amusing activist groups. [schlockmercenary.com]
That being said, I think I'm expressing myself poorly regarding my attitude towards consciousness. There are plenty of people willing to talk about consciousness who have more scientific street cred than philosophers; neuroscientists are a prime example. Even for them, though, it is a "hard problem". [livescience.com] Quantum mechanics is a difficult enough field to research, study, or understand; we do ourselves no favors be importing intractable problems from other fields. As a result, I find consciousness to not be useful as a tool in quantum mechanics.
Even if it were true, though, that conscious observation were the determining factor in waveform collapse, the mechanism by which that occurs would fall deeply into the field of untestable metaphysics. To restate one of my earlier ideas, how does the decaying atom know whether or not Schrodinger's cat is conscious? If the cat is asleep would it not be poisoned? If the cat doesn't count as conscious, how does the system know when/how/if/by whom it has been observed? If this is what's real, testing could/should be performed to determine its limits and explore it as a possible means of long-distance communication. If such testing is not possible, though, then it again isn't very useful as an analytical tool or avenue of research.
I mentioned Occam's razor in a different discussion thread, and I want to use (perhaps over-use?) it here. Instead of "observation" I prefer "measurement" as the collapsing action. Quantum entanglement is a delicate state, short-lived and easy to destroy. Certain types of interactions with an entangled system result in a determination of its state (e.g. measurement of polarization), which forces the waveform to subsequently act in a coherent manner for the entire entangled system (assuming that many particles are entangled). It is easy for me to believe that components of entangled systems behave consistently when measured because their entanglement requires it - if the measurements were going to be inconsistent, the particles wouldn't have been entangled in the first place. This is where the razor comes in - if I believe that the system is internally consistent from the beginning of the experiment, there is no need for me to be spooked out by measurements of widely separated entangled particles being consistent with one another.
Back to the article topic, my over-use of the razor in this case leads me to believe that the atoms of the experiment didn't need prescience or metaphysical awareness of the experimenter. If there are two grates and a detector, then the atoms will interact with grate A the same way every time that interaction takes place. If grate B is lowered, then the atoms interact with it; if it isn't, then they don't. At the detector, the atoms interact with the detector in a manner consistent with their history of previous interactions. This only causes problems if I want to believe things like that the atom has a specific position or path that it's following between grate A and the detector. That specific incorrect belief is what is disproved by this experiment. I am perfectly wiling to believe that grate B's interaction with the atom shifts it later behavior to be more wavelike than particle-like, and that there may not have been a specific path from grate A to detector in the first place.
Please understand that I'm not ruling out large-scale entangled systems. I'm actually quite looking forward to commercialized quantum computing systems, which rely on just such mass entanglements. I'm also looking forward to quantum cryptography, which may be needed to protect our privacy in a world with ubiquitous quantum computing; since good Q. crypto requires long-distance transmission of entangled pairs, I rather hope that entanglement over long distances (as has been repeatedly demonstrated) is not only possible, but practical and that we understand it well. I'm simply skeptical of interpretations of lab results which imply overly-complicated and untestable concepts of how the world works when much simpler explanations are readily available.
(Score: 2) by Immerman on Tuesday June 30 2015, @03:00PM
If we are talking about "useful tools", then yes, I agree - for the time being at least discussions of interactions between consciousness and QM are unlikely to be terribly productive. That does not mean it's inherently untestable however, only that nobody has yet thought of the tests needed. If, however, someone *does* think of such a test (and a testable link is discovered) it's likely to have far-reaching implications for both QM and consciousness research. But that requires that someone with a suitably subtle intellect not dismiss the possibility out of hand. There may even be non-dimissive conversations with peers required.
I have no answers as to the mechanism and limits of such an interaction, at the moment I can't even think of any well-formed speculations. But then formulating and testing such hypotheses is the whole point of scientific research, is it not? Though I will admit I have my doubts that the addition of consciousness would have any impact on the potential for long-distance communications.
> Instead of "observation" I prefer "measurement" as the collapsing action.
And as a practical short-term matter, that is likely the most productive approach. I think it's important though to remember that that is a completely untested preference, a matter of faith, and should be treated as such in a scientific discussion, lest your confidence spread and discourage the explorations that might yield definitive results.
Occams Razor is a wonderful tool for formulating useful explanations, but I think it's important to consider that in a scientific context it has pretty much invariably led to false, or at least incomplete, theories. Arguably often among the best theories that could be reasonably expected to emerge from the constraints of the culture and technology of the time, but nevertheless theories that have since been proven fundamentally flawed.
(Score: 2) by Zinho on Tuesday June 30 2015, @05:34PM
I completely agree with everything you just said, I think we're talking the same language now.
There is plenty of room for speculation on what is and is not going on in QM, and plenty of areas where we're really not sure what's happening because our efforts to measure anything change the systems we're measuring. Research into those areas of our ignorance will require subtle minds open to new ideas and careful consideration of new possibilities.
As long as we know that's where our discussion is sitting, I have no problem with that. Given that I am an amateur in this field (I took the course in college, but that's not what I'm paid to do today) I tend not to have a lot of discussions at that depth. In most discussions of QM I try to restrict myself to things that I firmly understand (or at least, think that I do) and theory that is at least consistent with my textbooks if not widely accepted in the field.
As a result, I do tend to get a bit snippy in tone on occasion. As an example, when someone finds a way to test for quantum entanglement being passed to measurement instruments and/or requiring a conscious observer for the expanded entangled system to collapse there will literally be a pair of PHDs waiting for them at the end of the project, plus a mention in two different fields' textbooks. I'll be honest, I get a bit nervous about how people with a shaky grasp of the topic will interpret speculation along those lines when discussing things like that in public forums. Thanks, by the way, for pointing out how I was coming across; it gave me an opportunity to think through why I was reacting the way I did and consider better ways to express myself. Hopefully this paragraph is a more tone-neutral way of expressing the same sentiments.
Speaking of faith, I've actually found this conversation a bit surreal; I often find myself at the other end of it. I'm a man of faith, and believe that the universe we inhabit is a large-scale engineering project created to make a home for conscious beings like ourselves. I suspect, based on other components of my faith's philosophy, that it is possible that animals, the earth, and even sub-atomic particles may possibly have intelligence of a sort at a level we don't fully understand (as if we even understand our own intelligence or consciousness). Discussions of such things in scientific circles generally elicits immediate derision and out-of-hand dismissal on the basis that my beliefs are based wholly upon superstition and must therefore be false. In our conversation I feel like I've been playing devil's advocate, struggling to balance between respectfully (and, regretfully at times, silently) agreeing with your sentiments and trying to point out where they over-reach the current state of the art as I understand it.
Thanks again for taking the time and patience to have a well thought-out discussion. I'm not sure that I have much more to contribute to this one, so respond or not at your leisure. I'll be watching for your future posts, and look forward to more engaging conversations when the opportunities arise.
"Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin