Entanglement detection with bounded reference frames

Author(s): F. M. Costa, N. Harrigan, T. Rudolph, Č. Brukner

Journal: New Journal of Physics

Volume: 11

Page(s): 123007

Year: 2009

DOI Number: 10.1088/1367-2630/11/12/123007

Link: Link to publication

Abstract:

Abstract. Quantum experiments usually assume the existence of perfect,

classical reference frames (RFs), which allow for the specification of

measurement settings (e.g. orientation of the Stern-Gerlach magnet in spin

measurements) with arbitrary precision. If the RFs are ‘bounded’ (i.e. quantum

systems themselves, having a finite number of degrees of freedom), only limited

precision can be attained. Using spin coherent states as bounded RFs, we have

found the minimum size needed for them to violate local realism for entangled

spin systems. For composite systems of spin 1

2 particles, RFs of very small size are sufficient for the violation; however, to see this violation for macroscopic entangled spins, the size of the RF must be at least quadratically larger than that of the spins. The unavailability of such RFs gives a possible explanation for the non-observance of violation of local realism in everyday experience.

Note: http://arxiv.org/abs/0902.0935

File: Link to PDF

Ursin Group Ursin Group , Brukner Group