Entanglement detection with bounded reference frames

Abstract

Quantum experiments usually assume the existence of perfect, classical, reference frames, which allow for the specification of measurement settings (e.g. orientation of the Stern Gerlach magnet in spin measurements) with arbitrary precision. If the reference frames 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 reference frames we have found their minimal size needed to violate local realism for entangled spin systems. For composite systems of spin-1/2 particles reference frames of very small size are sufficient for the violation; however, to see this violation for macroscopic entangled spins, the size of the reference frame must be at least quadratically larger than that of the spins. Unavailability of such reference frames gives a possible explanation for the non-observance of violation of local realism in everyday experience.

7 pages, 1 figure. Published version

References in corpus (10)

• Beating the channel capacity limit for linear photonic superdense coding
• Reference frames, superselection rules, and quantum information
• Classical world arising out of quantum physics under the restriction of coarse-grained measurements
• Quantum communication without alignment using multiple-qubit single-photon states
• Degradation of a quantum reference frame
• Realistic clocks, universal decoherence and the black hole information paradox
• Relational physics with real rods and clocks and the measurement problem of quantum mechanics
• Optimal measurements for relative quantum information
• Observing quantum non-locality in the entanglement between modes of massive particles
• Detecting mode entanglement: The role of coherent states, superselection rules and particle statistics

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• Non-Inertial Frames in Minkowski Space-Time, Accelerated either Mathematical or Dynamical Observers and Comments on Non-Inertial Relativistic Quantum Mechanics
• Dynamics of a quantum reference frame undergoing selective measurements and coherent interactions
• Reference frames for Bell inequality violation in the presence of superselection rules
• On Relativistic Entanglement and Localization of Particles and on their Comparison with the Non-Relativistic Theory
• Searching for a physical description relative to a quantum system
• Are right angles special? The optimal primitive reference frame