SelfTesting of Physical Theories, or, Is Quantum Theory Optimal with Respect to Some InformationProcessing Task?
Abstract
Selftesting usually refers to the task of taking a given set of observed correlations that are assumed to arise via a process that is accurately described by quantum theory, and trying to infer the quantum state and measurements. In other words it is concerned with the question of whether we can tell what quantum blackbox devices are doing by looking only at their inputoutput behavior and is known to be possible in several cases. Here we introduce a more general question: is it possible to selftest a theory, and, in particular, quantum theory? More precisely, we ask whether within a particular causal structure there are tasks that can only be performed in theories that have the same correlations as quantum mechanics in any scenario. We present a candidate task for such a correlation selftest and analyze it in a range of generalized probabilistic theories (GPTs), showing that none of these perform better than quantum theory. A generalization of our results showing that all nonquantum GPTs are strictly inferior to quantum mechanics for this task would point to a new way to axiomatize quantum theory, and enable an experimental test that simultaneously rules out such GPTs.
 Publication:

Physical Review Letters
 Pub Date:
 August 2020
 DOI:
 10.1103/PhysRevLett.125.060406
 arXiv:
 arXiv:2003.00349
 Bibcode:
 2020PhRvL.125f0406W
 Keywords:

 Quantum Physics
 EPrint:
 6 pages