Posted this in r/askphysics, but if possible could do with a reply soon, to help me crack on with my work.
Got myself in a right conceptual mess before heading to bed last night, so have a few of questions. It's probably all really basic quantum theory, but having not done this sort of stuff in a couple of years, it's easy to confuse yourself.
1) Say i have a qubit in state a|0>+b|1> (normaliser implied). Now if 1 and 0 are energy levels, it wouldn't matter who I sent this qubit to, as long as we agreed on higher energy == |1>. But if it represents up/down of an electron (z axis), does it not matter what reference frame it is in? I.e If Bob's reference frame is rotated 180 deg in the Z axis from Alice's, he actually picks up the state a|1> + b|0>? If this is the case, do they need to share a full cartesian frame for the x,y,z directions to be able to agree on all possible measurements, or can they just share the z direction? (And I assume any answer applies for photon polarization)
2) Also a probably even stupider question on no-cloning/no-teleportation, which from what I can tell tells us about the lack of interchangeability between Qbits and Classical Bits(?) I.e you can't specify a quantum state with Cbits. But if I make in my lab a state in c|0> + d|1>, why can't I send a message saying "hey, make a state in c|0> + d|1>" ---> teleportation. Obviously wrong, but was wondering exactly why.
3). Most silly- Can you put singular photon into an energy superposition? How does this conserve energy?
Thanks for any clearing up on any of these questions, I may have more to follow if these are cleared up, but theyre the root of my current issues.
P.S I'm asking these for a project on information theory, where I'm trying to classify information. There's obviously classical Speakable information (so 1s and 0s), and classical unspeakable information (anything where you need a reference frame, so e.g. "left"), but I'm wondering how it goes into the quantum world, and trying to connect them all together into a single tree/table of information. I'm thinking spin is maybe quantum Unspeakable, and energy superpositions could be quantum Speakable. I'm also trying to find out out non-local information - i.e (just?) entanglement, where the information isn't contained in any local system.
Any thoughts or reading would be excellent, as most google searches end up with more applied stuff on Von-Neuman entropy etc, and no-one else on my course is doing anything like this project.
Submitted January 06, 2016 at 09:01AM by bistonut http://ift.tt/1kM8OaJ
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