"As I remember, you are correct about the particles only having spin. But I also remember that it is possible to change the spin on said particle, thereby changing the spin of the entagled particle"
No, that's not what entanglement means. Entanglement means that you have two particles occupying states which have some relationship to one another, but you don't know which state either one is in... yet. However, because of the relationship between the two particles states, you know that if you observe one, you immediately know the others state, wherever it is. However, if you change the state of one particle or the other, you break the entanglement.
Also, if you want an example of entanglement occuring naturally, here is one: two anti-particles (such as an electron and positron) anihilate one another, and release the energy as photons (you gotta have two photons to uphold conservation of momentum). Let's say that the positron and electron had opposite spins, so the total spin of the system was zero. Now, for conservation of momentum, the two photons created must have opposite spin from one another. Of course, you don't know for either particular one whether it is spin up down or zero... al you know is that if it is spin up, the other is down; if it is down the other is up, and if it is zero, so is the other.
(For anyone too anal to see that I rattled this off quickly, please forgive any minor errors... like, I don't know off the top of my head if there some restriction in the example above that you can't get two spin-zero photons out of this mess... and I know that I oversimplified things a bit)
"it doesn't even matter how far apart they are in the universe; they'll always do the same things at the same times no matter where they are in the universe"
Wrong wrong wrong wrong wrong. Quantum entanglement says that the two particles *started off the same (or opposite or some such relationship of the initial states). It follows, then that if you do not *observe* either particle for quite some time, and take the two of them far distant from one another, then the instant that you *observe* the state of one particle, you immediately *know* the state of the other particle (wherever it is).
This gives at first pass the illusion that you have gotten information at faster than the speed of light... I mean, you did just *instantaneously* learn the state of a particle far, far away, right? That's gotta mean that you communcated with that thing way over there, right? No. Not at all.
Now, what makes this interesting is the fact that quantum mechanics tells us that if you don't *observe* either particle's state, then neither particle has actually "picked" a state yet. So, it's as though the one particle *told* the other one that "hey I was observed at state A, so you must now occupy state B". So, now it appears that information has traveled faster than the speed of light... and I won't argue that point, because last I knew better scientists than me were still duking that one out.
However, one thing that anyone with a basic understanding of this can agree upon is the fact that there is no way to *use* the possible information transfer involved in the collapse of a wave function to TRANSMIT INFORMATION. Why? Well, there is no way to observe a wave function directly. You can only measure some operator on a wave function (like energy, position, spin), and by doing so, you collapse the wave function into an eigenfunction of that operator. However there is no way to tell whether the eigenfunction you observe is the result of *your* observation or someone elses. In other words, you can't tell if you collapsed the wave function or if someone else did, and quantum entanglement doesn't *do* anything other than pre-collapse the wave-fcuntion for you.
1. Copper/WiFi: Buildout of copper (or fiber!) is expensive as hell... several dollars a FOOT. Think about that, and compare to spending maybe a few hundred dollars on some point-to-point antennae and covering a few miles with higher throughput than a T1.
2. CAT5 in the wall: I rent. I sure as hell can't drill holes in the wall or floor. What if I want to use a computer in a different room than the cable drop? What if I have roommates, and we don't want to or can't run CAT5 all over the friggin house? Don't get me wrong, the room with the cable-drop has CAT5 all over it... switches, routers, servers... I'm a geek. But I still want to jack in on the first floor of my house.
3. This has become my new kick: community networks: Say I wanna share my cable modem and set up a small neighborhood network with my friends a few houses over? Am I supposed to run CAT5 over there? I don't think so.
Don't get me wrong, I'm not slamming you. I'm just trying to answer your question of "why bother".
OK, this is embarassing, and I don't really blame the manufacturer... but here is the story:
I bought one of these things when they were still fairly new, and I loved it. I used it for over a year.
Once 802.11b started to become ubiquitous, I bought a WAP and PCMCIA card. I went ahead and bought linksys... yes, I know that the chipset in linksys hardware is not as good as Lucents, for example... but I had a gift certificate, also I was really impressed with the router, and figured I'd support a company that I was beginning to like.
Anyway, the linsksys WAP had the exact same form-factor as the router, including divets in the top matching the legs in the bottom (like legos in reverse), so I stacked them. Of course, the ventilation for the router is on the top, and the WAP can get kind of warm...
Anyway, as I said, it's embarassing, and I consider myself smarter than this, but what's done is done. In the end, though, I think it was good, because it forced me to set up a spair linux machine as a router/NAT/firewall/DHCP daemon. Fun with patching and compiling the kernel. Now I've got my wireless net on one interface, my wired net on another interface, and my uplink (cable modem) on a third interface. The wireless NIC would be bound to FreeS/WAN... only I really want to use the Cisco VPN client with it and it just won't work (even with the x509 patch). Oh, well... getting further and further offtopic.
It would be interesting to see if more people started running alternate routes through friends houses and what not. A guy I work with has a p2p 802.11b link to another guy I work with's cable modem 5 miles away, despite having DSL himself. I know that when I pulled my (late) linksys router out of the box, I was surprised to see that it supported RIP.
The truth is that it is really not that hard to run multiple routes out of your bedroom. If you use *nix for your router (like I do since I burned up my linksys), it's as easy as dropping in another NIC (wireless, or ethernet, or modem, or whatever) and configing the new interface.
There's also the growing trend in community nets (particularly wireless community nets)... these could link themselves together fairly cheaply by setting up additional wireless links with directional antennae pointed at other peer community nets.
Anyway, I'd be curious to see how many new routes start springing up between these 2nd-class (and no-class) networks. The beauty of Internet Protocol is that this really works.
That's actually how radar was invented/discovered... not with 802.11b, obviously... but disruptions in radio traffic between islands and shore when ships passed between.
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"As I remember, you are correct about the particles only having spin. But I also remember that it is possible to change the spin on said particle, thereby changing the spin of the entagled particle"
No, that's not what entanglement means. Entanglement means that you have two particles occupying states which have some relationship to one another, but you don't know which state either one is in... yet. However, because of the relationship between the two particles states, you know that if you observe one, you immediately know the others state, wherever it is. However, if you change the state of one particle or the other, you break the entanglement.
Also, if you want an example of entanglement occuring naturally, here is one: two anti-particles (such as an electron and positron) anihilate one another, and release the energy as photons (you gotta have two photons to uphold conservation of momentum). Let's say that the positron and electron had opposite spins, so the total spin of the system was zero. Now, for conservation of momentum, the two photons created must have opposite spin from one another. Of course, you don't know for either particular one whether it is spin up down or zero... al you know is that if it is spin up, the other is down; if it is down the other is up, and if it is zero, so is the other.
(For anyone too anal to see that I rattled this off quickly, please forgive any minor errors... like, I don't know off the top of my head if there some restriction in the example above that you can't get two spin-zero photons out of this mess... and I know that I oversimplified things a bit)
Wow... I don't even know where to start...
"it doesn't even matter how far apart they are in the universe; they'll always do the same things at the same times no matter where they are in the universe"
Wrong wrong wrong wrong wrong. Quantum entanglement says that the two particles *started off the same (or opposite or some such relationship of the initial states). It follows, then that if you do not *observe* either particle for quite some time, and take the two of them far distant from one another, then the instant that you *observe* the state of one particle, you immediately *know* the state of the other particle (wherever it is).
This gives at first pass the illusion that you have gotten information at faster than the speed of light... I mean, you did just *instantaneously* learn the state of a particle far, far away, right? That's gotta mean that you communcated with that thing way over there, right? No. Not at all.
Now, what makes this interesting is the fact that quantum mechanics tells us that if you don't *observe* either particle's state, then neither particle has actually "picked" a state yet. So, it's as though the one particle *told* the other one that "hey I was observed at state A, so you must now occupy state B". So, now it appears that information has traveled faster than the speed of light... and I won't argue that point, because last I knew better scientists than me were still duking that one out.
However, one thing that anyone with a basic understanding of this can agree upon is the fact that there is no way to *use* the possible information transfer involved in the collapse of a wave function to TRANSMIT INFORMATION. Why? Well, there is no way to observe a wave function directly. You can only measure some operator on a wave function (like energy, position, spin), and by doing so, you collapse the wave function into an eigenfunction of that operator. However there is no way to tell whether the eigenfunction you observe is the result of *your* observation or someone elses. In other words, you can't tell if you collapsed the wave function or if someone else did, and quantum entanglement doesn't *do* anything other than pre-collapse the wave-fcuntion for you.
Well, here's why:
1. Copper/WiFi: Buildout of copper (or fiber!) is expensive as hell... several dollars a FOOT. Think about that, and compare to spending maybe a few hundred dollars on some point-to-point antennae and covering a few miles with higher throughput than a T1.
2. CAT5 in the wall: I rent. I sure as hell can't drill holes in the wall or floor. What if I want to use a computer in a different room than the cable drop? What if I have roommates, and we don't want to or can't run CAT5 all over the friggin house? Don't get me wrong, the room with the cable-drop has CAT5 all over it... switches, routers, servers... I'm a geek. But I still want to jack in on the first floor of my house.
3. This has become my new kick: community networks: Say I wanna share my cable modem and set up a small neighborhood network with my friends a few houses over? Am I supposed to run CAT5 over there? I don't think so.
Don't get me wrong, I'm not slamming you. I'm just trying to answer your question of "why bother".
OK, this is embarassing, and I don't really blame the manufacturer... but here is the story:
I bought one of these things when they were still fairly new, and I loved it. I used it for over a year.
Once 802.11b started to become ubiquitous, I bought a WAP and PCMCIA card. I went ahead and bought linksys... yes, I know that the chipset in linksys hardware is not as good as Lucents, for example... but I had a gift certificate, also I was really impressed with the router, and figured I'd support a company that I was beginning to like.
Anyway, the linsksys WAP had the exact same form-factor as the router, including divets in the top matching the legs in the bottom (like legos in reverse), so I stacked them. Of course, the ventilation for the router is on the top, and the WAP can get kind of warm...
Anyway, as I said, it's embarassing, and I consider myself smarter than this, but what's done is done. In the end, though, I think it was good, because it forced me to set up a spair linux machine as a router/NAT/firewall/DHCP daemon. Fun with patching and compiling the kernel. Now I've got my wireless net on one interface, my wired net on another interface, and my uplink (cable modem) on a third interface. The wireless NIC would be bound to FreeS/WAN... only I really want to use the Cisco VPN client with it and it just won't work (even with the x509 patch). Oh, well... getting further and further offtopic.
It would be interesting to see if more people started running alternate routes through friends houses and what not. A guy I work with has a p2p 802.11b link to another guy I work with's cable modem 5 miles away, despite having DSL himself. I know that when I pulled my (late) linksys router out of the box, I was surprised to see that it supported RIP.
The truth is that it is really not that hard to run multiple routes out of your bedroom. If you use *nix for your router (like I do since I burned up my linksys), it's as easy as dropping in another NIC (wireless, or ethernet, or modem, or whatever) and configing the new interface.
There's also the growing trend in community nets (particularly wireless community nets)... these could link themselves together fairly cheaply by setting up additional wireless links with directional antennae pointed at other peer community nets.
Anyway, I'd be curious to see how many new routes start springing up between these 2nd-class (and no-class) networks. The beauty of Internet Protocol is that this really works.
That's actually how radar was invented/discovered... not with 802.11b, obviously... but disruptions in radio traffic between islands and shore when ships passed between.
The real problem wasn't the high latency, it was the packet loss on the return trip. Also, the Brittish failed to up their TCP_WINDOW to 2000 pounds.
For a related (but somewhat less evil, and sadly more real) joke look at the rfc for IP-over-homing-pigeon: http://www.blug.linux.no/rfc1149/
So sad... they don't have their own top-level domain name. :-(
I'd pay $35 for a .cr (or is that czech republic?)