|
|
|
|
NubiWan
Skeptic Friend
USA
424 Posts |
 Posted - 05/14/2003 : 12:22:17
|
With my daughter being in Iraq, and delighting in receiving a phone call from her on Mother's Day, bumped into the limitations of our current communication's net tech level. Even at near light speed, there was a noticeable delay, causing our conversation to stutter, with many false starts and overlaps. It made the experience a bit confusing, although the primary message, never actually spoken, came though loud and clear, she was alright.
To the possible rescue, comes quantum physics and that "spooky action at a distance," as Einstein called what we now refer to as "quantum entanglement." Current investigations are centered around its applications towards "quantum computting," but its potential for instantaneous communications, holds the most exciting possibilities for me. If me understands this point at all, the universal speed limit of light speed, isn't actually violated by the seeming passing of data faster than light could travel, because the data doesn't really "travel" at all, but it is "inferred" or "implied."
To quote, "Textbook quantum entanglement scenario: Two formerly united photons fly off in different directions. We measure one photon, an act that, in keeping with quantum law, forces it to assume a distinct state, complete with a quantifiable property known as "spin." Here's the strange part: The other photon—even if it's now miles away—immediately assumes the opposite spin. Why? Because an obscure quantum bylaw dictates that the sum of the photons' spins always be zero."
"When Einstein suggested this experiment, he was trying to subvert quantum physics—which he never entirely accepted—with a kind of reductio ad absurdum. He thought that, if anyone ever conducted the experiment, this outcome—though predicted by quantum theory—wouldn't actually ensue; it was just too weird. After all, how could an event in one part of the world influence information in another part of the world instantaneously—with no physical stuff passing from one place to the other to carry the "message"? Unfortunately for Einstein's attempted reductio, physicists eventually did the experiment, and the "absurd" outcome transpired."
Confess this is all "FM" to me, (F***king Magic), but should our attempts to exploit this "spooky action" pan out, think of the impact on the human verses robotic exploration of space debate. Our virtual astronauts could then man their T-1 pods, perhaps located even in a corner of their den at home, boot up their assigned robotic-avatars, to explore Mars, the moons of Jupiter, wherever, in real time. It would be much like piloting one of those deep sea submersibles, today, would imagine. Should a candidate for a viable colony be discovered, then a 'follow on' mission with real people could then be launched with real confidence of what we'll find upon arriving.
|
 |
|
|
Dave W.
Info Junkie
USA
26031 Posts |
 Posted - 05/14/2003 : 13:03:46 [Permalink]
|
Unfortunately, NubiWan, the effect cannot be "exploited" to transmit information, except in fiction (see Ender's Game by Orson Scott Card, specifically the "Ansible").
In the classic fictional scenario, you capture a pair of entangled particles somehow. One person, Alex, takes one captured particle with him, while Bev takes the other particle with her. They travel far apart, but by tweaking the state of his particle, Alex can communicate (say, through Morse code) with Bev (since her entangled particle will mirror the one Alex has) instantaneously, far faster than the speed of light.
The problem is, you cannot force a particle into a particular state without it becoming disentangled. You also can't tell, prior to measuring the particle (per your quote), which state it will enter. It is random, and thus useless for transmitting information.
|
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
 |
|
|
NubiWan
Skeptic Friend
USA
424 Posts |
Posted - 05/14/2003 : 16:36:52 [Permalink]
|
| Umm.., bummer. Well Dave, are ya saying "It can't be done," or we don't know how to do it? How long have we been fooling around with this 'entanglement' effect, anyways? Don't know how ya would seperate out and contain, the photon pair in any event, its FM to me. And can ya expand on this "spin" state a bit, is it like a charge or a measurement of the proton's energy level, or perhaps like its polarization? tanx |
|
|
|
|
Dave W.
Info Junkie
USA
26031 Posts |
Posted - 05/14/2003 : 18:50:46 [Permalink]
|
Yeah, I'm saying "can't get there from here." Given the current state of physics knowledge, it simply can't be done (not "we dunno"). "It" being the transmission of information - quantum entanglement has already been shown, if I remember correctly, in an experiment done some five years ago or so in Europe. Shot an entangled pair of photons down many miles of two fiber-optic pathways, measured them, and out popped the answer predicted by the theory.
There is a really nifty web site which explains sub-atomic particles (and things like 'spin'), but I don't have it bookmarked here, and can't find it again on a quick search. I'll post a link to it tomorrow from my other machine. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
|
|
|
Dave W.
Info Junkie
USA
26031 Posts |
|
|
NubiWan
Skeptic Friend
USA
424 Posts |
Posted - 05/15/2003 : 10:57:37 [Permalink]
|
| OK, thanks for the link. Well, it's still early in the game IMO, will still hope for a breakthrough of some sort. :) |
|
|
|
|
Dr. Mabuse
Septic Fiend
Sweden
9696 Posts |
Posted - 05/20/2003 : 06:56:14 [Permalink]
|
quote:
Originally posted by NubiWan
With my daughter being in Iraq, and delighting in receiving a phone call from her on Mother's Day, bumped into the limitations of our current communication's net tech level. Even at near light speed, there was a noticeable delay, causing our conversation to stutter, with many false starts and overlaps. It made the experience a bit confusing, although the primary message, never actually spoken, came though loud and clear, she was alright.
Most of the lag time is not really due to the distance the signal has to travel, but delays in the electronic communication.
When you say something on your side, the audio has to be sampled, a number of samples are collected before a data packet gets assembled. Then the packet is compressed (like in GSM) to a lower bitrate. Then the packet is encrypted. Then it's split up in several parts that are mixed together (to ensure that if a packet is lost, enough information is still left to make sense). Then the package is distributed through several communication nodes, where each of the nodes has to keep track of the address: where it came from, and where it's going.
When the package finally arrives at it's destination it has to be de-interleaved, de-encrypted, de-packed and finally Digital-to-analogue converted.
Every stage requires time, and it sums up.
To demonstrate this effect, just borrow your friends cell phone, call it from yours, and you'll notice that there are up to a few tenths of a second delay, even though the signal only has to travel ten miles (to the cell phone base-station and back).
Edit: I did some checking up, and refreshed my memory about the geostationary orbit, since the call was probably routed through geostationary communication satellites. If the call was routed through satellites at "zenith" over Iraq and USA, the signal would have to travel a distance roughly 130 000 km which translates into a lag in the order of 0.4 to 0.5 seconds.
It would seem that I was a bit off when I assumed that the majority of the lag was from electronic equipment along the way. Now it seems like they have almost equal share, the speed of light adding slightly more lag than electronics.
|
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
| Edited by - Dr. Mabuse on 05/20/2003 15:47:37 |
|
|
|
NubiWan
Skeptic Friend
USA
424 Posts |
Posted - 05/29/2003 : 23:47:00 [Permalink]
|
Well, we've been making electrons jump thur hoops for over a century, now, and we've gotten pretty darn good at it. Photons are sort of a late comer to the game. Admit you are quite correct as to the current state of the art, today, Dave. Perhaps unrealistically, will still hold out hopes of solutions to the current road blocks. Like being able to contain and carry, one of an entangled pair of photons, it seems, is no longer such a problem.
Hau stops light cold:http://www.physics.harvard.edu/fac_staff/hau.html  |
|
|
|
|
 |
|
|
|
Topic Locked
