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I was going to ask a question this evening in the thread where the OP was like "ask me random physics questions," & found that it had been archived: http://forums.somethingawful.com/showthread.php?threadid=3349860 So I searched the first three pages of A/T for the word "physics" & didn't find anything. So I figured since that other thread got a lot of pages, then there might still be interest in a random physics questions thread. So I'm posting this thread. Anyway my starter question is this: Has anyone tried to measure the velocity of the information that is transmitted between entangled quantum particles? Like, is there even a way to measure that? Or is it truly instantaneous?
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Oct 15, 2015 05:01
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There is no information travelled they are mathematically like two sides of a single coin
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Oct 15, 2015 15:18
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You may be interested in the Physics Question Thread in the Science, Academics, and Languages subforum of A/T.
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Oct 15, 2015 17:20
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clammy posted:I was going to ask a question this evening in the thread where the OP was like "ask me random physics questions," & found that it had been archived: http://forums.somethingawful.com/showthread.php?threadid=3349860 Instantaneous is not a meaningful concept in a relativistic universe.
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Oct 16, 2015 03:30
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Spazzle posted:Instantaneous is not a meaningful concept in a relativistic universe. But it is a meaningful concept when talking about your sex life.
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Oct 16, 2015 05:08
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clammy posted:Anyway my starter question is this: Has anyone tried to measure the velocity of the information that is transmitted between entangled quantum particles? Like, is there even a way to measure that? Or is it truly instantaneous? The terminology you are using is a bit iffy - describing it as information transmitted between entangled quantum particles is problematic as it suggests that it the mechanism could be used to transmit information, and being instantaneous is not a useful concept in a relativistic setting as it is frame dependent. I'm not a physicist but my understanding experiments have shown that it doesn't have a actual velocity; it has been tested in labs ~140km apart with space-like separation. This implies that you can choose a frame in which the measurements were instantaneous.
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Oct 16, 2015 10:58
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clammy posted:Anyway my starter question is this: Has anyone tried to measure the velocity of the information that is transmitted between entangled quantum particles? Like, is there even a way to measure that? Or is it truly instantaneous? 1. There's no information transmitted. 2. People have tried to measure the speed of "wavefunction collapse" and (duh) they find it has to be near instantaneous, because Everett was right.
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Oct 16, 2015 13:39
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Quantum Entanglement is pretty cool but currently useless. As others have said, no information is relayed, it's just synchronized particle dancing. One day it could (will) have many uses, though, and we may live to see some of them so that's pretty awesome.
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Oct 16, 2015 16:39
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clammy posted:Anyway my starter question is this: Has anyone tried to measure the velocity of the information that is transmitted between entangled quantum particles? Like, is there even a way to measure that? Or is it truly instantaneous? No information is transmitted. Quantum entanglement can be used in for example quantum teleportation, but you need to send classical info along with messing with entangled stated for that.
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Oct 18, 2015 10:58
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I don't get why entanglement is a big deal. If I buy a pair of shoes and send each one to different places, as soon as one person looks at their shoe they instantly know what the other one is, no matter how far away it's located. Not at all a big deal. How is entanglement different from that?
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Oct 20, 2015 18:00
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Ozymandiaz1260 posted:I don't get why entanglement is a big deal. If I buy a pair of shoes and send each one to different places, as soon as one person looks at their shoe they instantly know what the other one is, no matter how far away it's located. Not at all a big deal. How is entanglement different from that? Those are simply correlated particles. Entangled particles share a joint quantum mechanical state that behaves differently.
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Oct 20, 2015 18:55
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Ozymandiaz1260 posted:I don't get why entanglement is a big deal. If I buy a pair of shoes and send each one to different places, as soon as one person looks at their shoe they instantly know what the other one is, no matter how far away it's located. Not at all a big deal. How is entanglement different from that? If you roll one shoe around on the floor the second shoe doesn't roll around also.
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Oct 21, 2015 01:58
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Sheep-Goats posted:If you roll one shoe around on the floor the second shoe doesn't roll around also. Entangled particles stay entangled even after one is messed with? That seems counterintuitive even for quantum mechanics.
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Oct 21, 2015 07:33
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Grundulum posted:Entangled particles stay entangled even after one is messed with? That seems counterintuitive even for quantum mechanics. That's why they are cool. If you invert one the other will change to compensate for that inversion regardless of physical distance between them ( in theory). It's pretty sweet.
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Oct 29, 2015 18:48
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Crazyeyes posted:That's why they are cool. If you invert one the other will change to compensate for that inversion regardless of physical distance between them ( in theory). It's pretty sweet. Not really
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Oct 29, 2015 19:03
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Crazyeyes posted:That's why they are cool. If you invert one the other will change to compensate for that inversion regardless of physical distance between them ( in theory). It's pretty sweet. Yes, but there needs to be an observer for that to happen, like a non-blind scientist.
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Oct 29, 2015 19:07
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For some odd reason, I found this show fascinating: https://en.wikipedia.org/wiki/The_Mechanical_Universe I never took any courses beyond algebra in high school, but I found this program to be very informational, educational, and entertaining as a teenager. The cartoon-like computer graphics did a great job of explaining the concepts of the lessons so that a pure novice could understand, and everything I know about physics comes from this series exclusively.
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Oct 31, 2015 05:35
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Ozymandiaz1260 posted:I don't get why entanglement is a big deal. If I buy a pair of shoes and send each one to different places, as soon as one person looks at their shoe they instantly know what the other one is, no matter how far away it's located. Not at all a big deal. How is entanglement different from that? Particles, like shoes, are quantized, i.e. they are either right or left and nothing like 'half left' or whatever. When you measure particles you get a random answer from a statistical probability i.e. 50% of the time up and 50% of the time down, this is kinda different from shoes. If I put a left shoe in a box it's always a left shoe. You can exploit this difference to see if the particle does something different from shoes. The concept for how to exploit it is called Bell's inequalities.
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Oct 31, 2015 12:28
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The important distinction is better made with a compass, maybe it's a special one with a digital readout rather than one you look at that can spin in any direction. The compass can detect you facing in any orientation, 360 degrees, but the readout is really simple so that it can only display a single cardinal direction: North, East, South, or West. Oh and the compass is designed in a lovely way so it has two modes, North/South or East/West. In North/South mode it will simply tell you if you're facing more north by displaying "N", or more south with "S". Likewise in East/West mode. Keep in mind that the compass is actually quite sophisticated, it can detect any orientation very accurately, it just sucks at relaying the exact orientation in one reading. Okay so you're facing due north and you put it in north/south mode and you get a reading, it's "N". In fact you try it several times and you always get "N". Makes sense. But you want to check if it's really due north or maybe slightly north east. So you try East/West mode and get "E". Try again and get "W". The compass has no '0' reading, it's either E or W. Try some more, two more "E", and two more "W". No matter how many times you test it you get an equal number of random E's and W's, so you can be pretty sure you don't have an east or west bearing. Remember that the compass can only say "N" "E" "S" or "W", so if you have no east or west bearing but are in East/West mode, it will simply alternate both directions so that it seems your average has no east or west bias. But what if you were facing NE? NE is not quite north, and so you seem to get a few souths in your north/south mode. Same thing for east/west mode, there's a few wests. If the compass only said N for even a vaguely northern orientation you'd have less to go on. The compass can relate much more precise coordinates if you take lots of samples and average them out. Start in North/South mode. Make notes where N=+1 and S=-1. Average them out when facing NE and and your average will be 1/√2. Same for your east/west average, depending of if you chose E or W to be negative. If you know some trig, you'll know that those are the Sin and Cos of 45°, and a NE heading on a compass would be 45° from north. Anyway long story short if you entangle two of these compasses like particles you'll find that if one gives a reading of 'N' the other will read 'S'. Same for E and W, they always report the opposite of each other and according to the statistics above. But what if I measure in North/South while you measure East/West? Because they are perpendicular they don't seem to really have an effect. What if instead we had a compass that could only say "N", "SE" and "SW"? Those directions make it seem like +1 and -1 will not work anymore for finding our heading. Would the averaging statistics from before still let us calculate the real orientation? That kinda segues into this, If you already know what spin, entanglement and quantization are watch this without reading my analogy. Also I am not a real science person so maybe I am making poo poo up. https://www.youtube.com/watch?v=7zfnvGXpy-g Modest Mao fucked around with this message at 13:18 on Oct 31, 2015 |
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Oct 31, 2015 13:14
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jackyl posted:But it is a meaningful concept when talking about your sex life. 
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Nov 3, 2015 21:47
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