3 ms·
Here's my writeup, this is a first-attempt so please offer constructive criticism if wrong: 2 labs (L1 and L2), these are like the box of shrodingers cat, they
by program_whiz 8y ago
Here's my writeup, this is a first-attempt so please offer constructive criticism if wrong:
2 labs (L1 and L2), these are like the box of shrodingers cat, they are in quantum uncertainty.
2 lab workers (Alice, Jane)
2 outside observers (Bob, Frank)
Time is denoted as T0, T1, ...
T0 Alice in Lab1 randomly selects heads / tails
T1 Alice uses heads / tails to setup a quantum particle S
T2 Jane in Lab2 reads the state of S, infers heads / tails and stores this information in a new particle Z
T3 Frank reads the state of Lab2 to infer Z, S, heads/tails and determines pass / fail (pass == was heads), lets call this variable W_frank
T4 Bob reads the state of Lab1 to infer S, heads / tails, and then makes his own pass / fail (pass == was heads) and that's variable W_bob
Since these are separate readings on untangled particles by Bob and Frank, they can get disparate readings W_frank != W_bob
This is a problem since we "collapsed" the state of W_frank -> Z -> S -> Coin, but this doesn't necessarily imply that we can known with certainty that W_bob will match (i.e. forward collapsed Coin -> S -> W_bob).
Basically its just that each lab is in a quantum uncertainty (Quantum Coin is heads/tails, S is in either state, Z is in either state until measured). And making the measurement should reveal this, but there's no guarantee both collapses will result in the same outcome (so in one case the coin was heads, and the other it was tails).
My conclusions:
1. There is no randomness, we just suck at measuring still
2. We are in the "many worlds" but impossible branches can't happen (reality stays consistent somehow) -- so it won't happen even though its theoretically possible
3. The forward collapse does happen, we just haven't done the experiment to verify it. In other words, the pass/fail result would change to keep things consistent (the whole system is entangled). Including the memories everyone would have about it. So maybe this is happening constantly but we just don't know it because it changes even our memories about it.
4. This experiment fractures reality, and we realize we all live in a simulation and that's where "white holes" come from :P
- program_whiz 8y agoSo to clarify one info flow is: Alice: Coin -> S, Jane: Z, Frank: Pass / Fail The other is: Alice: Coin -> S, Bob: Pass / Fail
- kgwgk 8y agoI think their problem is considering that the labs L1 and L2 are isolated quantum systems because there is obvious entanglement through the state S. In the sequence of events that they present at T1 the observer in L1 prepares S, transfers it to L2, and knowing the current state of L2 predicts what the observer outside L2 will measure later assuming that L2 is left unperturbed (the actions of the internal observer do not affect the system). But this prediction is invalid because the protocol specifies that before the last observer enters the scene at T4 the system L1/L2 will be perturbed by another external observer (the observer outside L1 when he does his thing at T3, as you said he's effectively measuring Z).
- kgwgk 8y agoLubos Motl’s take on the paper: https://motls.blogspot.com/2018/09/frauchiger-renner-qm-is-inconsistent.html https://motls.blogspot.com/2018/09/frauchiger-renner-qm-is-i... (Tl;dr: “People who still try to prove an inconsistency of quantum mechanics in 2018 are cretins.“)