On Sat, Mar 26, 2022 at 6:37 AM smitra <smi...@zonnet.nl> wrote: > On 24-03-2022 22:57, Bruce Kellett wrote: > > > > OK. I see now that your insistence that QM is local is based on dogma, > > rather than logic. Your claim is that the unitary time evolution in QM > > is local, therefore QM is a local theory, regardless of anything else. > > But that position relies on another hidden assumption. The unitary > > time evolution of QM depends on the Hamiltonian. The Hamiltonian is > > not given by the theory; it is constructed according to the details of > > the system one is attempting to model. Generally, one is modelling > > local systems, so one uses a local Hamiltonian and the time evolution > > is local. But this is by no means necessary. One could always use a > > non-local Hamiltonian, then the time evolution would not be local. > > > > One can indeed write down non-local effective Hamiltonians, but the > fundamental laws of physics are strictly local. >

God told you this, did he? If one needs non-local physics to describe certain experiments, then locality is not universal. > This is the situation with the entangled spinor case. The state vector > > is non-separable and does not specify any particular separation for > > the two entangled particles. If one wants to continue to treat this as > > a single system even when the particles are far apart, one must use a > > non-local Hamiltonian. > > The fundamental Hamiltonian that also describes how the entangled state > was created, is local. It's only when you put in the entangled spinor > state in by hand that you get an effective non-local Hamiltonian. > Where did you get the idea that the entangled spinor state was "put in by hand"? Sure, the entangled spinor state was created locally, but it is intrinsically non-local in that it refers to arbitrarily separated states in terms of a non-separable wave function. The entanglement is created at some point then particles move apart, but this separation preserves the entanglement, and if you are to understand the results of measurements on this entangled pair, you must consider it as a unified system, not as two separated and independent parts. That is, the system is intrinsically non-local, and you will never be able to understand a non-separable system in terms of independent parts. Do you not understand what "non-separable" means? Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLSCDnjPjy_xGjHhdPquXcnZmSzTz21kwMEfRkCAA_MwvA%40mail.gmail.com.