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I'm trying to find a way to visualize entangled states, as might be used in a quantum computer. The various articles I can find, and my physics textbook, make vague references to polarized light as a simple model for a qubit. I can understand the one-qubit case, since the components of the electric wave in two orthogonal axes for a coherent beam of light or a single photon will consist of two phasors, represented as two complex numbers, where overall amplitude and phase can be ignored. What's left is the two dimensions of polarization, representing angle and eccentricity. Gates are passing through eg a fluid that rotates polarization, and measurement is passing through a polarizing filter. So a two-qubit register should be two beams of light, or perhaps a beam of light with two colors. I haven't found anything that specifies which it is. Where I get lost is understanding how these bits can become entangled, and where the process can go from there. Black Carrot ( talk) 00:30, 1 May 2012 (UTC)
Our article says that the core is 0.2 ly. Obviously it doesn't burn like a star, so what defines the core? And how large is the entire nebula? Even a ballpark figure would help me. Thanks, -- T H F S W ( T · C · E) 05:19, 1 May 2012 (UTC)
Assuming a normal family car was submerged without it being smashed about, and there was one adult inside, roughly how long could they survive on air trapped in the vehicle?
If they inflated the air bags and punctured them, would that help, and if so, to what extent? -- Dweller ( talk) 09:36, 1 May 2012 (UTC)
Interesting. The engine is the heaviest part of the car, so I guess it would nose-dive, leaving whatever air there is against the back window. In a saloon car with no hatchback, there's no door seals there. Would there be as much as a minute's worth of air, or more? -- Dweller ( talk) 10:49, 1 May 2012 (UTC)
Mythbusters did a number of submerged car escape myths (you can google for videos). Based on their videos the engine pulls the car down nose first and it seems to take about 30-40 seconds for the front to fill and 60-75 total seconds for the air to also escape from the back seat. Of course, the precise time will vary with the make of the car, etc. Dragons flight ( talk) 11:50, 1 May 2012 (UTC)
Googling for something like cubic meter breathe air suffocate suggests that for a person in rest, one cubic meter of air should last about two hours until it has too little oxygen and too much carbon dioxide. Heavy physical activity can cut that time by a factor of ten; I imagine the stress of being in a submerged car will cause you to breathe heavily. If your car's interior volume is, say, three cubic meters, that would be of the order of a couple of hours. If partially filled with water, adjust accordingly. If your head is barely above surface, in a bubble of a couple of bucketfuls of air, let's call it one minute per bucket tops. 88.114.124.228 ( talk) 16:13, 1 May 2012 (UTC)
165.212.189.187 ( talk) 13:04, 1 May 2012 (UTC)
As far as I know, electromagnetic waves, or radiation, can penetrate any region of space. So, the statement does not make sense to me either. Plasmic Physics ( talk) 13:16, 1 May 2012 (UTC)
Electromagnetic waves of frequencies up to up to microwaves are dramatically attenutated by magnetic shielding and by faraday cages - see http://en.wikipedia.org/wiki/Faraday_cage. It is quite simple to make a faraday cage to reduce incident radiation to levels too low to measure. The next thing after microwaves is infrared thru to light - which is blocked by all sorts of things including metals. Gravitational waves are predicted to penetrate all these things. Keit 58.164.230.165 ( talk) 13:46, 1 May 2012 (UTC)
Could it be worded better? 165.212.189.187 ( talk) 14:12, 1 May 2012 (UTC)
But do faraday cages block ALL radiation? 165.212.189.187 ( talk) 15:47, 1 May 2012 (UTC)
Touche. I was particularly thinking of a solid one to rule out the light issue. Then the word "should" should be removed bc we know it DOES, right? 165.212.189.187 ( talk) 17:17, 1 May 2012 (UTC)
Ok I get it. SVT is the best theory so far. 165.212.189.187 ( talk) 18:06, 1 May 2012 (UTC)
Do quadriplegics need to have their limbs amputated sometimes? Why doesn't the blood clot, if they necessarily won't be moving their limbs? — Preceding unsigned comment added by 188.76.235.0 ( talk) 13:22, 1 May 2012 (UTC)
A few months ago I noticed a wasp in a cupboard in my house. I don't know how long it had been there, but it looked pretty dead to me. I didn't get rid of it because, well, I couldn't be bothered to and it wasn't affecting me. A few weeks later I go in the cupboard again and it's still there, exactly the same as before, it hasn't moved at all. So I am now certain it is dead. Again I just leave it because I'm really lazy. Today, I noticed a wasp buzzing around the house so I opened a window and let it go. Then I thought.. no way, it couldn't be the wasp in the cupboard, could it? I checked and it's gone. So.. do wasps hibernate or something? I'm assuming it was the same wasp, although I can't be certain. It looked like a normal wasp to me and not a big queen wasp. — Preceding unsigned comment added by Waspgirl03 ( talk • contribs) 20:32, 1 May 2012 (UTC)
From the 'deep hibernation' behaviour of the specimen which you have described it is very important to be sure. You should carefully check through you whole house, the kind of wasp that you describe can only be one of a few kinds if it is actually the same wasp. I do believe it is a north american native, and if it has made it's way in a shipping container by sea, or otherwise made it's way to the United kingdom it can do very serious ecological damage. The north United States Government centre for disease control has procedures in place for outbreaks of this kind, however if you are in Asia, or even worse, in the United Kingdom, the situation is dire, and I cannot stress this enough, you need to prepare your household according to this guide FIRST. before you inform the authorities. DO IT NOW. Penyulap ☏ 10:22, 6 May 2012 (UTC)
Science desk | ||
---|---|---|
< April 30 | << Apr | May | Jun >> | May 2 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
I'm trying to find a way to visualize entangled states, as might be used in a quantum computer. The various articles I can find, and my physics textbook, make vague references to polarized light as a simple model for a qubit. I can understand the one-qubit case, since the components of the electric wave in two orthogonal axes for a coherent beam of light or a single photon will consist of two phasors, represented as two complex numbers, where overall amplitude and phase can be ignored. What's left is the two dimensions of polarization, representing angle and eccentricity. Gates are passing through eg a fluid that rotates polarization, and measurement is passing through a polarizing filter. So a two-qubit register should be two beams of light, or perhaps a beam of light with two colors. I haven't found anything that specifies which it is. Where I get lost is understanding how these bits can become entangled, and where the process can go from there. Black Carrot ( talk) 00:30, 1 May 2012 (UTC)
Our article says that the core is 0.2 ly. Obviously it doesn't burn like a star, so what defines the core? And how large is the entire nebula? Even a ballpark figure would help me. Thanks, -- T H F S W ( T · C · E) 05:19, 1 May 2012 (UTC)
Assuming a normal family car was submerged without it being smashed about, and there was one adult inside, roughly how long could they survive on air trapped in the vehicle?
If they inflated the air bags and punctured them, would that help, and if so, to what extent? -- Dweller ( talk) 09:36, 1 May 2012 (UTC)
Interesting. The engine is the heaviest part of the car, so I guess it would nose-dive, leaving whatever air there is against the back window. In a saloon car with no hatchback, there's no door seals there. Would there be as much as a minute's worth of air, or more? -- Dweller ( talk) 10:49, 1 May 2012 (UTC)
Mythbusters did a number of submerged car escape myths (you can google for videos). Based on their videos the engine pulls the car down nose first and it seems to take about 30-40 seconds for the front to fill and 60-75 total seconds for the air to also escape from the back seat. Of course, the precise time will vary with the make of the car, etc. Dragons flight ( talk) 11:50, 1 May 2012 (UTC)
Googling for something like cubic meter breathe air suffocate suggests that for a person in rest, one cubic meter of air should last about two hours until it has too little oxygen and too much carbon dioxide. Heavy physical activity can cut that time by a factor of ten; I imagine the stress of being in a submerged car will cause you to breathe heavily. If your car's interior volume is, say, three cubic meters, that would be of the order of a couple of hours. If partially filled with water, adjust accordingly. If your head is barely above surface, in a bubble of a couple of bucketfuls of air, let's call it one minute per bucket tops. 88.114.124.228 ( talk) 16:13, 1 May 2012 (UTC)
165.212.189.187 ( talk) 13:04, 1 May 2012 (UTC)
As far as I know, electromagnetic waves, or radiation, can penetrate any region of space. So, the statement does not make sense to me either. Plasmic Physics ( talk) 13:16, 1 May 2012 (UTC)
Electromagnetic waves of frequencies up to up to microwaves are dramatically attenutated by magnetic shielding and by faraday cages - see http://en.wikipedia.org/wiki/Faraday_cage. It is quite simple to make a faraday cage to reduce incident radiation to levels too low to measure. The next thing after microwaves is infrared thru to light - which is blocked by all sorts of things including metals. Gravitational waves are predicted to penetrate all these things. Keit 58.164.230.165 ( talk) 13:46, 1 May 2012 (UTC)
Could it be worded better? 165.212.189.187 ( talk) 14:12, 1 May 2012 (UTC)
But do faraday cages block ALL radiation? 165.212.189.187 ( talk) 15:47, 1 May 2012 (UTC)
Touche. I was particularly thinking of a solid one to rule out the light issue. Then the word "should" should be removed bc we know it DOES, right? 165.212.189.187 ( talk) 17:17, 1 May 2012 (UTC)
Ok I get it. SVT is the best theory so far. 165.212.189.187 ( talk) 18:06, 1 May 2012 (UTC)
Do quadriplegics need to have their limbs amputated sometimes? Why doesn't the blood clot, if they necessarily won't be moving their limbs? — Preceding unsigned comment added by 188.76.235.0 ( talk) 13:22, 1 May 2012 (UTC)
A few months ago I noticed a wasp in a cupboard in my house. I don't know how long it had been there, but it looked pretty dead to me. I didn't get rid of it because, well, I couldn't be bothered to and it wasn't affecting me. A few weeks later I go in the cupboard again and it's still there, exactly the same as before, it hasn't moved at all. So I am now certain it is dead. Again I just leave it because I'm really lazy. Today, I noticed a wasp buzzing around the house so I opened a window and let it go. Then I thought.. no way, it couldn't be the wasp in the cupboard, could it? I checked and it's gone. So.. do wasps hibernate or something? I'm assuming it was the same wasp, although I can't be certain. It looked like a normal wasp to me and not a big queen wasp. — Preceding unsigned comment added by Waspgirl03 ( talk • contribs) 20:32, 1 May 2012 (UTC)
From the 'deep hibernation' behaviour of the specimen which you have described it is very important to be sure. You should carefully check through you whole house, the kind of wasp that you describe can only be one of a few kinds if it is actually the same wasp. I do believe it is a north american native, and if it has made it's way in a shipping container by sea, or otherwise made it's way to the United kingdom it can do very serious ecological damage. The north United States Government centre for disease control has procedures in place for outbreaks of this kind, however if you are in Asia, or even worse, in the United Kingdom, the situation is dire, and I cannot stress this enough, you need to prepare your household according to this guide FIRST. before you inform the authorities. DO IT NOW. Penyulap ☏ 10:22, 6 May 2012 (UTC)