arXiv:quant-ph/0302081 · Journal of Physics A Mathematical and General

Geometry of the three-qubit state, entanglement and division algebras

Bogdan Andrei Bernevig, Han-Dong Chen

Published Jul 17, 2003• 54 citations

Abstract

We present a generalization to three qubits of the standard Bloch sphere representation for a single qubit and of the seven-dimensional sphere representation for two qubits presented in Mosseri et al (Mosseri R and Dandoloff R 2001 J. Phys. A: Math. Gen. 34 10243). The Hilbert space of the three-qubit system is the 15-dimensional sphere S 15 , which allows for a natural (last) Hopf fibration with S 8 as base and S 7 as fibre. A striking feature is, as in the case of one and two qubits, that the map is entanglement sensitive, and the two distinct ways of un-entangling three qubits are naturally related to the Hopf map. We define a quantity that measures the degree of entanglement of the three-qubit state. Conjectures on the possibility of generalizing the construction for higher qubit states are also discussed.

DOI: 10.1088/0305-4470/36/30/309

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