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The mixed two qutrit system: local unitary invariants, entanglement monotones, and the SLOCC group SL(3,C)

Citation

Jarvis, PD, The mixed two qutrit system: local unitary invariants, entanglement monotones, and the SLOCC group SL(3,C), Journal of Physics A, 47, (21) Article 215302. ISSN 1751-8113 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 IOP Publishing Ltd

DOI: doi:10.1088/1751-8113/47/21/215302

Abstract

We consider local unitary invariants and entanglement monotones for the mixed two qutrit system. Character methods for the local SU(3) x SU(3) transformation group are used to establish the count of algebraically independent polynomial invariants up to degree 5 in the components of the density operator. These are identified up to quartic degree in the standard basis of Gell–Mann matrices, with the help of the calculus of f and d coefficients. Next, investigating local measurement operations, we study a SLOCC qutrit group, which plays the role of a 'relativistic' transformation group analogous to that of the Lorentz group SL(2, ℂ) ≃ SO(3, 1) for the qubit case. This is the group SL(3, ℂ), presented as a group of real 9 x 9 matrices acting linearly on the nine-dimensional space of projective coordinates for the qutrit density matrix. The counterpart, for qutrits, of the invariant 4 x 4 Minkowski metric of the qubit case, proves to be a certain 9 x 9 x 9 totally symmetric three-fold tensor generalizing the Gell–Mann d coefficient. Using this structure, we provide a count of the corresponding local special linear polynomial invariants using group character methods. Finally, we give an explicit construction of the lowest degree quantity (the cubic invariant) and its expansion in terms of SU(3) x SU(3) invariants, and we indicate how to construct higher degree analogues. These quantities are proven to yield entanglement monotones. This work generalizes and partly extends the paper of King et al (2007 J. Phys. A: Math. Theor. 40 10083) on the mixed two qubit system, which is reviewed in an appendix.

Item Details

Item Type:Refereed Article
Keywords:qutrit, entanglement, monotone, local unitary, polynomial invariant, SLOCC, SL(3, C)
Research Division:Mathematical Sciences
Research Group:Pure Mathematics
Research Field:Group Theory and Generalisations
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Mathematical Sciences
Author:Jarvis, PD (Dr Peter Jarvis)
ID Code:100387
Year Published:2014
Web of Science® Times Cited:3
Deposited By:Research Division
Deposited On:2015-05-14
Last Modified:2015-08-27
Downloads:0

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