6 ms·

"Many worlds" makes this "instantaneous" communication moot, which is why I'm surprised so many physicists are barking up the other tree. In "many worlds" what

"Many worlds" makes this "instantaneous" communication moot, which is why I'm surprised so many physicists are barking up the other tree. In "many worlds" what actually happens when a thing "decoheres" is that the experimenter gets pulled into its superposition. So now instead of a dead-alive cat and one scientist, you've got one dead cat, one alive cat, one sad scientist, one happy scientist. Or from another perspective, a dead-alive cat and a sad-happy scientist - the superposition still exists, but the number of things inside it has increased. So, "I flip a coin and whichever it comes up, heads or tails, the other entangled coin flipped at the same instant comes up the the opposite, with instantaneous communication" is the wrong view. Rather, the coins are entangled (in the past), and observing them pulls the observers into the entanglement one atom at a time as the informational contagion spreads, so now you have world A, where scientists saw "heads, tails" and world B where the same scientists saw "tails,heads". The scientists got slurped in, but they are simply observing an entanglement that existed and still exists and which was established in the past. Only now they are observing it from inside. Quantum spooky action "at a distance" is local in "many worlds" and never needs to be faster than light.

gibybo 13y ago
Many worlds is also my preferred interpretation, but it really puts the weirdness of super position into perspective. If we really are splitting entire universes all willy-nilly like, maybe some of the other possibilities aren't so weird in comparison. Is causality-breaking FTL travel really more improbable than the universe splitting into infinite pieces just from the act of observing particles?
- deleted 13y ago
  [deleted]
- JulianMorrison 13y ago
  It isn't so much splitting as getting involved in other particle's business.
snowwrestler 13y ago
So what ends the entanglement? Or is the idea that particles once entangled are forever entangled?
- JulianMorrison 13y ago
  From the "outside", it doesn't end. But consider world A and world B. They are pulled apart from interacting with each other, so they can't do anything to the A-B superposition like they used to. From inside world A, the entanglement seems to have ended because no matter what scientists(world A) do to coin_1(world A), it doesn't affect coin_2(world A). Likewise in world B.
kordless 13y ago
I know beans about this, but am intrigued and read as much as I can understand. For whatever reason this reminded me of the bitcoin protocol where they take measures to ensure a coin isn't duplicated in the system. From a personal perspective, I don't like the idea of more than one of me and would take steps to stop duplication of me if I could...
richardw 13y ago
What I don't like about many worlds is that it's spectacularly inefficient w.r.t. energy. A whole new universe is created for each option. That's very wasteful and doesn't gel with so much of what we see around us. Sure, you can say that energy is fixed within each universe but not in the whole system, but that sets off my internal Occam's Razor. You also don't just have two worlds, you have infinite. In the coin-flipping example, whenever a coin is flipped there are many other universe-splitting this-or-that events happening elsewhere in the universe at the same instant. So each instant there are infinite worlds created (or infinite x infinite to describe each combination), and again a split in each universe in the next instant for every next possibility. Mmm. Dodgy. My favourite: John Cramer's Transactional Interpretation. Doesn't require infinite universes' worth of energy, doesn't require an observer to collapse multiple possible waves. Does require you to accept backwards-in-time communication (breaks causality) but brings some very interesting what-if questions. http://en.wikipedia.org/wiki/Transactional_interpretation http://en.wikipedia.org/wiki/Transactional_interpretation http://en.wikipedia.org/wiki/Causality http://en.wikipedia.org/wiki/Causality
joe_the_user 13y ago
As I understand it, the "spooky action" is completely an artifact of the perception of randomness in the initial process. Take a black stone and a white stone, shake up in your hand, put one in one sealed container and one in a second sealed container. Take the two containers a hundred light year apart. Open one and "suddenly" you know the contents of another container light years away. I don't know how "spooky action" differs from this except in the way the process gets described. You could say "wow, until you know whether there's a black stone or a white stone in there, it's like the stone is half white and half black." You could but how does that help? I mean quantum seems to take a "because it absolutely can't be measured till, it absolutely doesn't happen till later" but that seems to just contradict ordinary understanding in gratuitously unnecessarily fashion.
- mike_esspe 13y ago
  You are explaining "hidden variable" theory. It is currently considered not compatible with experiments. https://en.wikipedia.org/wiki/Hidden_variable_theory https://en.wikipedia.org/wiki/Hidden_variable_theory
- warptera1 13y ago
  Your view was Einstein's view articulated in the 1935-1936 EPR Paradox paper. It proved that you need either local, real, hidden variables to account for quantum entanglement or FTL communication between particles was necessary--widely believed to be in violation of special relativity. Bell's inequality paper in 1964 proved that the predictions of a local reality system and a quantum entanglement system are in fact different for certain polarization experiments. Subsequent experimentation proved the two theories to be mutually exclusive and results back up FTL communication. An FTL mechanism has not been found experimentally, however we know that special relativity is not violated because quantum uncertainty prevents information from being transmitted via entanglement at FTL speeds.
- Morgawr 13y ago
  I remember years ago, back in highschool, when I studied quantum mechanics, our professor suggested this idea (he used a blue and a red ball in two briefcases) as a comparison to entanglement and then disproved it explaining that it's not quite the same. Unfortunately, too many years passed and I don't remember the counter-argument that explains why you can't apply that logic to entanglement but it involved Bell's theorem[1] and the EPR Paradox[2]. Actually I think Einstein himself made a counter-argument similar to that (just not with stones/balls but with actual particles) and was disproved later on. Sorry if I can't give more details, I'm not a physicist. [1] https://en.wikipedia.org/wiki/Bell%27s_theorem https://en.wikipedia.org/wiki/Bell%27s_theorem [2] https://en.wikipedia.org/wiki/EPR_paradox https://en.wikipedia.org/wiki/EPR_paradox
hrjet 13y ago
Interesting, but that still violates the principle of locality. Inside each world, the scientists are experiencing spooky action at a distance because information in their world is moving faster than light. edit: removed my question after reading joe_the_user's question.
Houshalter 13y ago
Many worlds terrifies me and I deeply hope that it is not true.

gibybo 13y ago

Many worlds is also my preferred interpretation, but it really puts the weirdness of super position into perspective. If we really are splitting entire universes all willy-nilly like, maybe some of the other possibilities aren't so weird in comparison. Is causality-breaking FTL travel really more improbable than the universe splitting into infinite pieces just from the act of observing particles?

deleted 13y ago
[deleted]
JulianMorrison 13y ago
It isn't so much splitting as getting involved in other particle's business.

snowwrestler 13y ago

So what ends the entanglement? Or is the idea that particles once entangled are forever entangled?

JulianMorrison 13y ago
From the "outside", it doesn't end. But consider world A and world B. They are pulled apart from interacting with each other, so they can't do anything to the A-B superposition like they used to. From inside world A, the entanglement seems to have ended because no matter what scientists(world A) do to coin_1(world A), it doesn't affect coin_2(world A). Likewise in world B.

kordless 13y ago

I know beans about this, but am intrigued and read as much as I can understand. For whatever reason this reminded me of the bitcoin protocol where they take measures to ensure a coin isn't duplicated in the system. From a personal perspective, I don't like the idea of more than one of me and would take steps to stop duplication of me if I could...

richardw 13y ago

What I don't like about many worlds is that it's spectacularly inefficient w.r.t. energy. A whole new universe is created for each option. That's very wasteful and doesn't gel with so much of what we see around us. Sure, you can say that energy is fixed within each universe but not in the whole system, but that sets off my internal Occam's Razor. You also don't just have two worlds, you have infinite. In the coin-flipping example, whenever a coin is flipped there are many other universe-splitting this-or-that events happening elsewhere in the universe at the same instant. So each instant there are infinite worlds created (or infinite x infinite to describe each combination), and again a split in each universe in the next instant for every next possibility. Mmm. Dodgy. My favourite: John Cramer's Transactional Interpretation. Doesn't require infinite universes' worth of energy, doesn't require an observer to collapse multiple possible waves. Does require you to accept backwards-in-time communication (breaks causality) but brings some very interesting what-if questions. http://en.wikipedia.org/wiki/Transactional_interpretation http://en.wikipedia.org/wiki/Transactional_interpretation http://en.wikipedia.org/wiki/Causality http://en.wikipedia.org/wiki/Causality

joe_the_user 13y ago

As I understand it, the "spooky action" is completely an artifact of the perception of randomness in the initial process. Take a black stone and a white stone, shake up in your hand, put one in one sealed container and one in a second sealed container. Take the two containers a hundred light year apart. Open one and "suddenly" you know the contents of another container light years away. I don't know how "spooky action" differs from this except in the way the process gets described. You could say "wow, until you know whether there's a black stone or a white stone in there, it's like the stone is half white and half black." You could but how does that help? I mean quantum seems to take a "because it absolutely can't be measured till, it absolutely doesn't happen till later" but that seems to just contradict ordinary understanding in gratuitously unnecessarily fashion.

mike_esspe 13y ago
You are explaining "hidden variable" theory. It is currently considered not compatible with experiments. https://en.wikipedia.org/wiki/Hidden_variable_theory https://en.wikipedia.org/wiki/Hidden_variable_theory
warptera1 13y ago
Your view was Einstein's view articulated in the 1935-1936 EPR Paradox paper. It proved that you need either local, real, hidden variables to account for quantum entanglement or FTL communication between particles was necessary--widely believed to be in violation of special relativity. Bell's inequality paper in 1964 proved that the predictions of a local reality system and a quantum entanglement system are in fact different for certain polarization experiments. Subsequent experimentation proved the two theories to be mutually exclusive and results back up FTL communication. An FTL mechanism has not been found experimentally, however we know that special relativity is not violated because quantum uncertainty prevents information from being transmitted via entanglement at FTL speeds.
Morgawr 13y ago
I remember years ago, back in highschool, when I studied quantum mechanics, our professor suggested this idea (he used a blue and a red ball in two briefcases) as a comparison to entanglement and then disproved it explaining that it's not quite the same. Unfortunately, too many years passed and I don't remember the counter-argument that explains why you can't apply that logic to entanglement but it involved Bell's theorem[1] and the EPR Paradox[2]. Actually I think Einstein himself made a counter-argument similar to that (just not with stones/balls but with actual particles) and was disproved later on. Sorry if I can't give more details, I'm not a physicist. [1] https://en.wikipedia.org/wiki/Bell%27s_theorem https://en.wikipedia.org/wiki/Bell%27s_theorem [2] https://en.wikipedia.org/wiki/EPR_paradox https://en.wikipedia.org/wiki/EPR_paradox

hrjet 13y ago

Interesting, but that still violates the principle of locality. Inside each world, the scientists are experiencing spooky action at a distance because information in their world is moving faster than light. edit: removed my question after reading joe_the_user's question.

Houshalter 13y ago

Many worlds terrifies me and I deeply hope that it is not true.