# Quantum Entanglement and Projective Ring Geometry

Abstract : The paper explores the basic geometrical properties of the observables characterizing two-qubit systems by employing a novel projective ring geometric approach. After introducing the basic facts about quantum complementarity and maximal quantum entanglement in such systems, we demonstrate that the 15$\times$15 multiplication table of the associated four-dimensional matrices exhibits a so-far-unnoticed geometrical structure that can be regarded as three pencils of lines in the projective plane of order two. In one of the pencils, which we call the kernel, the observables on two lines share a base of Bell states. In the complement of the kernel, the eight vertices/observables are joined by twelve lines which form the edges of a cube. A substantial part of the paper is devoted to showing that the nature of this geometry has much to do with the structure of the projective lines defined over the rings that are the direct product of $n$ copies of the Galois field GF(2), with $n$ = 2, 3 and 4.
Document type :
Journal articles
Domain :

Cited literature [32 references]

https://hal.archives-ouvertes.fr/hal-00077093
Contributor : Michel Planat <>
Submitted on : Friday, August 18, 2006 - 1:41:00 PM
Last modification on : Thursday, November 12, 2020 - 9:42:11 AM
Long-term archiving on: : Friday, September 24, 2010 - 10:37:08 AM

### Citation

Michel Planat, Metod Saniga, Maurice Kibler. Quantum Entanglement and Projective Ring Geometry. SIGMA, 2006, 2, 066, 14 p. ⟨10.3842/SIGMA.2006.066⟩. ⟨hal-00077093v4⟩

Record views