Negentropically entangled objects are key entities in TGD inspired theory of consciousness and in the construction of tensor networks and the challenge is to understand how these could be constructed and what their properties could be. These states are diametrically opposite to unentangled eigenstates of single particle operators, usually elements of Cartan algebra of symmetry group. The entangled states should result as eigenstates of poly-local operators. Yangian algebras involve a hierarchy of poly-local operators, and twistorial considerations inspire the conjecture that Yangian counterparts of super-symplectic and other algebras made poly-local with respect to partonic 2-surfaces or end-points of boundaries of string world sheet at them are symmetries of quantum TGD. Could Yangians allow to understand maximal entanglement in terms of symmetries?
- In this respect the construction of maximally entangled states using bi-local operator Qz=Jx⊗ Jy - Jy⊗ Jx is highly interesting since entangled states would result by state function. Single particle operator like Jz would generate un-entangled states. The states obtained as eigenstates of this operator have permutation symmetries. The operator can be expressed as Qz=fzijJi⊗ Jj, where fABC are structure constants of SU(2) and could be interpreted as co-product associated with the Lie algebra generator Jz. Thus it would seem that unentangled states correspond to eigenstates of Jz and the maximally entangled state to eigenstates of co-generator Qz. Kind of duality would be in question.
- Could one generalize this construction to n-fold tensor products? What about other representations of SU(2)? Could one generalize from SU(2) to arbitrary Lie algebra by replacing Cartan generators with suitably defined co-generators and spin 1/2 representation with fundamental representation? The optimistic guess would be that the resulting states are maximally entangled and excellent candidates for states for which negentropic entanglement is maximized by NMP.
- Co-product is needed and there exists a rich spectrum of algebras with co-product (quantum groups, bialgebras, Hopf algebras, Yangian algebras). In particular, Yangians of Lie algebras are generated by ordinary Lie algebra generators and their co-generators subject to constraints. The outcome is an infinite-dimensional algebra analogous to one half of Kac-Moody algebra with the analog of conformal weight N counting the number of tensor factors. Witten gives a nice concrete explanation of Yangian for which co-generators of TA are given as QA= ∑i<j fABC TBi ⊗ TCj, where the summation is over discrete ordered points, which could now label partonic 2-surfaces or points of them or points of string like object. For a practically totally incomprehensible description of Yangian one can look at the Wikipedia article .
- This would suggest that the eigenstates of Cartan algebra co-generators of Yangian could define an eigen basis of Yangian algebra dual to the basis defined by the totally unentangled eigenstates of generators and that the quantum measurement of poly-local observables defined by co-generators creates entangled and perhaps even maximally entangled states. A duality between totally unentangled and completely entangled situations is suggestive and analogous to that encountered in twistor Grassmann approach where conformal symmetry and its dual are involved. A beautiful connection between generalization of Lie algebras, quantum measurement theory and quantum information theory would emerge.
For details see the chapter
From Principles to Diagrams or the article with the same title.