Interpretation miniatures

Most physicists do not have patience for reading long and obscure interpretation arguments and disputes. Hence, to attract attention of a wider physics community, in this paper various old and new aspects of quantum interpretations are explained in a concise and simple (almost trivial) form. About the “Copenhagen” interpretation, we note that there are several different versions of it and explain how to make sense of “local nonreality” interpretation. About the many-world interpretation (MWI), we explain that it is neither local nor nonlocal, that it cannot explain the Born rule, that it suffers from the preferred basis problem, and that quantum suicide cannot be used to test it. About the Bohmian interpretation, we explain that it is analogous to dark matter, use it to explain that there is no big difference between nonlocal correlation and nonlocal causation, and use some condensed-matter ideas to outline how nonrelativistic Bohmian theory could be a theory of everything. We also explain how different interpretations can be used to demystify the delayed choice experiment, to resolve the problem of time in quantum gravity, and to provide alternatives to quantum nonlocality. Finally, we explain why is life compatible with the second law.

Quantum interpretations of AWPP and APP

AWPP is a complexity class introduced by Fenner, Fortnow, Kurtz, and Li, which is defined using GapP functions. Although it is an important class as the best upperbound of BQP, its definition seems to be somehow artificial, and therefore it would be better if we have some “physical interpretation” of AWPP. Here we provide a quantum physical interpretation of AWPP: we show that AWPP is equal to the class of problems efficiently solved by a quantum computer with the ability of postselecting an event whose probability is close to an FP function. This result is applied to also obtain a quantum physical interpretation of APP. In addition, we consider a “classical physical analogue” of these results, and show that a restricted version of BPPpath contains UP ∩ coUP and is contained in WAPP.