Scientists have created a "quantum Cheshire Cat" by separating a particle from one of its physical properties. Named after the cat in Alice in Wonderland that vanishes leaving only its grin, a beam of neutrons was used to separate them from their magnetic moment.
From Nature:
From its very beginning, quantum theory has been revealing extraordinary and counter-intuitive phenomena, such as wave-particle duality, Schroedinger cats and quantum non-locality. Another paradoxical phenomenon found within the framework of quantum mechanics is the 'quantum Cheshire Cat': if a quantum system is subject to a certain pre- and postselection, it can behave as if a particle and its property are spatially separated. It has been suggested to employ weak measurements in order to explore the Cheshire Cat's nature. Here we report an experiment in which we send neutrons through a perfect silicon crystal interferometer and perform weak measurements to probe the location of the particle and its magnetic moment. The experimental results suggest that the system behaves as if the neutrons go through one beam path, while their magnetic moment travels along the other.
(Score: 5, Interesting) by sudo rm -rf on Wednesday July 30 2014, @02:09PM
I have enough of Quantum Physics. I tried to understand, I really did. And now there is this guy telling me, like, look, there goes the car straight to the city, but its color takes the scenic route.
There's not even a plausible car analogy!
(Score: 3, Insightful) by frojack on Wednesday July 30 2014, @05:40PM
+1 insightful, +1 funny.
Probably the best summary I've seen, all the while protesting too much.
No, you are mistaken. I've always had this sig.
(Score: 4, Funny) by MrGuy on Wednesday July 30 2014, @02:26PM
...that Brad Pitt and Edward Norton were the same person the whole time!
The first rule of quantum physics is that you do not talk about quantum physics.
The second rule of quantum physics is sometimes the first rule of quantum physics.
(Score: 0) by Anonymous Coward on Wednesday July 30 2014, @02:47PM
"separating a particle from one of its physical properties"?
if you bang a permanent magnet long enough it too will lose one of its "physical properties".
(Score: 0) by Anonymous Coward on Wednesday July 30 2014, @02:52PM
you're a moron ... they measurably remove the property and recombine it. it's not "lost".
unfortunately what is conveniently (yet again) ignored and not mentioned is that a atom had to
"die" to get the neutron.
so maybe nature was so sad about this once again and just decided to say "fuck it", do whatever you want.
(Score: 2, Funny) by turgid on Wednesday July 30 2014, @07:52PM
So they remove it and recombine it? I think this is not quite what they're doing. Or, at least, I'd like it not to be what they're doing. Perhaps they are producing a wave function for the probability of the position of the particle that means that "if you look over here at this point in time you have a 90% chance of observing these properties of the particle and if you look over there at the same time you have a 90% probability of observing all the other probabilities that you couldn't see at the other place." But it would be too easy just to explain it like that... So I haven't even bothered to read up on what they actually did: too old and cynical.
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 0) by Anonymous Coward on Wednesday July 30 2014, @06:58PM
"if you bang a permanent magnet long enough..."
Whatever floats your boat mate.
(Score: 2) by Oligonicella on Wednesday July 30 2014, @02:54PM
The article apparently contradicts the heading. From Nature:
(Score: 5, Interesting) by MrGuy on Wednesday July 30 2014, @03:15PM
While I can't follow everything in the paper, the one thing I note is that they do one run, looking for position. In that run, the particles appear to travel in path A. Then, with the same setup, they do a second run at a later time, looking for magnetic moment. In that run, the magnetic moment appears to travel in path B.
While that's super cool, there are a lot of really weird results in quantum mechanics where it appears that what you get depends on what you measure. Electrons have been observed behaving like a particle as opposed to a wave if you're using a particle detector, but behave like a wave otherwise. ("A physicist is an atom's way of knowing about other atoms." - G Wald)
What they have NOT observed, apparently, is the moment traveling in one path and the position traveling in the other path AT THE SAME TIME. When we look for position (and not moment) it's in one place. When we look for moment (and not position) it's somewhere else. The talk a bit in the article about WHY they used separate runs, and I'll let someone who knows the Deep Magicks more than I comment on whether it's a big deal or not.
(Score: 0) by Anonymous Coward on Wednesday July 30 2014, @04:34PM
" is the moment traveling in one path and the position traveling in the other path AT THE SAME TIME."
Isn't this just re-stating the Uncertainty principle?
(Score: 3) by mendax on Wednesday July 30 2014, @05:24PM
I prefer a "quantum evil cat analogy" better. It's far more realistic. In this case, my evil black cat slowly disappears leaving only her claws and fangs embedded in my tender flesh, the echo of her unholy yowl slowly fading. To me, this makes a lot more sense given that she is Darth Sophie, the Dark Lord of the Hiss.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 3, Insightful) by jimshatt on Wednesday July 30 2014, @09:55PM