Oh dear, I haven’t blogged all day, have I? Bad Cheryl.
More books tomorrow, but for now here’s something much more weird. In my Google Reader feeds today I found this post about a new type of experiment in quantum physics. One of the really odd things about quantum theory is that particles can behave as either waves or particles, which to our eyes is hugely inconsistent of them. The new experiment, if I understand it correctly, says that we are wrong, not the particles. That is, particles have a consistent nature but, due to our flawed understanding, or possibly perception, of the universe, we can only see them as having this odd dual nature.
Er, can someone who understands physics better than I do please check to see if I have understood this correctly?
And talking of dual natures, Demon Knights #4 is out. Paul Cornell has been trailing this as featuring the origin of the Shining Knight, and so it does, but we don’t really learn much. For those of you not following the book, the Shining Knight is a) Welsh and b) apparently trans or intersex. You can see why I am interested. DC and the other characters in the book consistently refer to the Knight as “she”, but the Knight is drawn fairly androgynously and rejects the female label. Well, in the new issue we find out how the Knight got super powers and a quest, but not much more than that. There’s one key panel in which Marlin says, “You interest me, young squire. You have two natures”. And that’s all we are getting, for now.
Wave/particle. Male/female. Maybe we are not just looking properly.
And if that hasn’t broken your brains, here’s Andrej Pejic being fabulous.
“That is, particles have a consistent nature but, due to our flawed understanding, or possibly perception, of the universe, we can only see them as having this odd dual nature.”
Oh gods, let this be true. I’ve been praying for someone to say this for years, because it’s always seemed so frodding obvious to me; if our results are inconsistent, then obviously it’s our results that are at fault, not something voodooey and imponderable about the universe itself. I’m so fed up with scientists being mystagogues. The universe makes sense. It has to.
Thank you for mentioning this.
The purpose of the paper was to re-wire physicists minds into accepting wave-particle duality, not to change our perception of the very real, very measurable duality itself. The article you linked to was actually not very well written, and this article from the APS does a lot better job at explaining what exactly was accomplished:
Quantum physics tells us that a photon isn’t strictly a particle or strictly a wave. And yet most of us will revert back—whenever we can—to familiar concepts of billiard balls or vibrating strings when picturing photons in our heads.
That’s the perception that leads us in physics to still entertain some unlikely hypotheses called “hidden variable theories”, where the paradoxes we encounter in QM arise from stuff we have not discovered or measured yet.
In fact what this experiment reveals is either that we are lousy experimentalists, or quite possibly that we can’t, with equipment we build from groups of atoms that exhibit statistical mechanics properties, rather than quantum ones, build a machine that measures both properties at the same time.
The physics paper was actually an attempt to demolish those hidden variable theories once and for all. It didn’t quite do that, but it certainly did provide more evidence they are not good theories:
But this new, simpler thought experiment allows a direct analysis of the information flows between experimental elements, Ionicioiu says. Within this simplified framework, the theorists evaluated certain alternative theories to standard quantum mechanics known as “hidden variable†theories and showed that they would have to be absurdly complicated to reproduce the results of their quantum delayed-choice experiment.
Older thinking used to use somewhat anthropomorphic images: when the photon passes the beam splitter, it somehow “knows” which path to travel to hit either the wave or particle detector. That was demolished a few years ago, when our electronics got fast enough to make the choice in detection only after the photon was already on its way – in those experiments the photon still behaved the way the detector expected it to – meaning that both properties were always present, and we just can’t measure both at once right now.
But even back in the 90s when I was a grad student we thought of atoms and photons as having both properties at once, so this isn’t really anything new, but it is a nice way to visualize the information flow between 2 quantum systems, and a good reminder not to fall back on those simple models when we think about these systems:
We know very well that quantum phenomena cannot be described by hidden-variable theories, unless they have utterly implausible and unacceptable properties,†says Berthold-Georg Englert of the National University of Singapore. Marco Genovese of the Italian Metrological Institute (INRIM) in Turin agrees that the basic concepts here are not new. But he still very much likes this simple thought experiment for the way it points out the paradoxes that emerge from treating the photon as a classical particle or wave.
As an aside to your other commenter, the fact that our brains are made of aggregates of atoms that obey the laws of statistical mechanics may mean that there are parts of the universe we can’t understand. Ever. I’m not saying this is the case here, but it’s certainly a possibility that there will be parts of the universe that can never make sense to us. There may be no God to play dice, but something may have placed our Universe’s chip on the cosmic craps table.
Thank you, that was very helpful.
Well, if it’s a possibility that parts of the universe will never make sense to us, then it’s a possibility that there’s a God. I don’t see how one can deny the latter while admitting the former, at least not while our understanding of the universe remains incomplete as it is.
Personally, I don’t accept the first possibility; we may not be able to understand everything now, and if we fall back on “it just is that way” when confronted by something that doesn’t make sense, we never will, any more than if we fall back on “it’s God’s will.” But we will understand it, some day.
Zander, I don’t understand how the “God in the Gaps” argument is connected to whether or not we can fundamentally understand the entire universe. The universe may (or may not) be infinitely complicated. Our minds contain a finite number of neural connections. It may not be possible to understand one using the other.
Think of it this way. Using an old Univac from the 50s, there is absolutely no way to do some of the mathematics we now routinely do with computers in physics. There just were not enough logic gates in the computer to complete all the operations. That may be a good analogy for our brains versus the problems we want to solve.
Now it may be possible that humans evolve or develop or human / machine thinking interfaces capable of understanding more than even the best and brightest of homo sapiens can understand right now, but there still might come a time when we need simply more processing power than we can assemble to understand the entire universe. And a good question for an SFinal story might be to consider whther such evolved beings or machine / human hybrids would be close enough to us that we would even consider using the pronoun “we” when describing them.
When physicists say that a fundamental building block is like something, what that means is it has a behavior which can be modeled by math that resembles math that applies to some other thing. Photons do some things that can be mathematically represented with equations that apply to wave behaviors, and they do some other things which can be mathematically represented in a similar way to particle behaviors. But they aren’t waves, they aren’t particles, and they aren’t some spooky mystical combination of both; they’re photons, which don’t have an exact parallel in the macroscopic world.
A better analogy than male/female would be seeing shapes in clouds. Look, it looks like a bird! Now it looks like a horse! Is it some incredible mixture of animals which defies the understanding of the human mind? No, it’s a bunch of water vapor, and if you really want to understand how it works, you’re better off tackling it on that basis than trying to enumerate its avian and equine characteristics.
And I’m not dismissing the possibility of a cultural shift in viewing male/female duality, I stress, I’m just saying that if there is one, it’s a completely different kind of non-duality than this wave/particle business.
Petrea, in this case it’s not just that the math used to describe photon resembles the equations used to describe both a wave and a particle, experimentally it is true as well: photons do generate intereference patterns, have a frequency and wavelength which defines them as a wave. They also have momentum and may have a mass (this is an open experimental question) like particles. It’s not just the math that makes this so, we see those properties experimentally.
But I agree there is no parallel in the macroscopic world. I would add that electons can also generate an interference pattern in double slit experiments, so it’s not just light that exists at its fundamental level in a state we can not model macroscopically.
Furthermore, I agree that the physics analogy can be taken too far to male / female duality, but I would add that light looks more like a wave with some particle properties, and electrons look more like a particle with some wave properties, which with a substitution of nouns I submit would describe the gender of most humans.