We experience a classical world. To explain this “away” would be bad. The broadest interpretation of the phrase “many worlds” is that there are many classical worlds equally real to the single world we experience. Surely you accept this. There are questions of how real is this classical world and where it comes from. The decoherence program tries to address this, though I understand it to be incomplete, or at least controversial.
What gets worse when you move to QFT? You seem concerned with what is ontologically fundamental. The classical states are not ontologically fundamental in ordinary QM. If that’s what you mean by MWI...well, you already admitted to being a troll.
I’m not so concerned about fundamental ontology, so I’m happy to talk about QFT as a bunch of ordinary QM systems, one for each reference frame. The decomposition into classical states is not the same in each frame (ie, is not relativistically covariant). Is this a problem? Isn’t the situation of ordinary QM already almost this bad? In ordinary QM, you can give states classical names, but they don’t actually evolve classically. The macroscale classical worlds that do evolve classically are pretty fuzzy.
[T]here are many classical worlds equally real to the single world we experience. Surely you accept this.
Surely? I don’t even know what it means. Words “real” and “experience” are close neighbours in my vocabulary, real unexperienced world sounds a lot like an oxymoron, at least if not based on a really strong argument.
What gets worse when you move to QFT?
Nothing. I have tried to (incompletely of course) explain the relation between the conventional and relativistic Hamiltonian formalism in case of mechanics, where it is slightly more intuitive and simpler. If you address my first remark, you have disinterpreted it. I don’t say that move to QFT isn’t justified, but that one conventional argument used to support this move isn’t good.
The classical states are not ontologically fundamental in ordinary QM. If that’s what you mean by MWI...
It isn’t. By MWI I mean probably the same thing as anybody else. Nothing particularly related to classical states. I have discussed classical states in order to give some background to my intuitions. My statement was that probably the quantum states are a redundant concept.
I’m happy to talk about QFT as a bunch of ordinary QM systems, one for each reference frame.
I would understand that QFT is a bunch of QM systems, one for each spacetime point. I don’t understand what reference frames do with it. In any fixed reference frame QFT has infinite number of degrees of freedom. Maybe you speak about momentum representation? I am confused.
We experience a classical world. To explain this “away” would be bad. The broadest interpretation of the phrase “many worlds” is that there are many classical worlds equally real to the single world we experience. Surely you accept this. There are questions of how real is this classical world and where it comes from. The decoherence program tries to address this, though I understand it to be incomplete, or at least controversial.
What gets worse when you move to QFT? You seem concerned with what is ontologically fundamental. The classical states are not ontologically fundamental in ordinary QM. If that’s what you mean by MWI...well, you already admitted to being a troll.
I’m not so concerned about fundamental ontology, so I’m happy to talk about QFT as a bunch of ordinary QM systems, one for each reference frame. The decomposition into classical states is not the same in each frame (ie, is not relativistically covariant). Is this a problem? Isn’t the situation of ordinary QM already almost this bad? In ordinary QM, you can give states classical names, but they don’t actually evolve classically. The macroscale classical worlds that do evolve classically are pretty fuzzy.
Surely? I don’t even know what it means. Words “real” and “experience” are close neighbours in my vocabulary, real unexperienced world sounds a lot like an oxymoron, at least if not based on a really strong argument.
Nothing. I have tried to (incompletely of course) explain the relation between the conventional and relativistic Hamiltonian formalism in case of mechanics, where it is slightly more intuitive and simpler. If you address my first remark, you have disinterpreted it. I don’t say that move to QFT isn’t justified, but that one conventional argument used to support this move isn’t good.
It isn’t. By MWI I mean probably the same thing as anybody else. Nothing particularly related to classical states. I have discussed classical states in order to give some background to my intuitions. My statement was that probably the quantum states are a redundant concept.
I would understand that QFT is a bunch of QM systems, one for each spacetime point. I don’t understand what reference frames do with it. In any fixed reference frame QFT has infinite number of degrees of freedom. Maybe you speak about momentum representation? I am confused.