The operational reality of the quantum state and of its reduction
Year: 2020
Type: preprint
Abstract: Is the quantum state real? Does the reduction of the state of a quantum system by a measurement on another system, entangled with it and distant, constitute a real disturbance? As is well acknowledged, there is a lack of consensus among physicists over such ontological questions concerning quantum mechanics (QM). Here we argue that it is possible, surprisingly, to address such questions on the basis of only operational considerations. More generally, we show that the operational perspective itself provides an intrinsic interpretation of QM. The theory's syntax supplies its semantics, as it were. This interpretational framework, which we call ``signaling ontology'', builds on the simple insight that unconditional quantum state reduction, namely the state change of a measured quantum system due to a nonselective measurement, can be used for signaling locally, and that this signal provides a natural, operational criterion for the reality of the state reduction. This argument is formalized in the framework of generalized probability theories and extended to multipartite systems. Among other consequences of this approach, the two questions posed above at the beginning are testably answered in the affirmative. In particular, a steering inequality is proposed whose violation, together with a local signaling condition, provides an experimental test for the reality of the remote disturbance referenced in the second question. Accordingly, quantum correlations that meet this criterion are nonlocal in an operationally real sense. A further ramification of our work is an elucidation of the contrast between quantum no-signaling and relativistic signal locality.
Source: arXiv (Cornell University)
Author: R. Srikanth
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3048364604