J. Sanchezruiz, STATES AND MINIMAL JOINT UNCERTAINTY FOR COMPLEMENTARY OBSERVABLES IN3-DIMENSIONAL HILBERT-SPACE, Journal of physics. A, mathematical and general, 27(21), 1994, pp. 120000843-120000846
The entropic uncertainty relation for sets of N + 1 complementary obse
rvables {A(r)} existing in N-dimensional Hilbert space, SIGMA(r) H(A(r
)) greater-than-or-equal-to (N + 1)ln((N + 1)/2), is shown to be optim
al in the case N = 3 by explicit construction of the states for which
equality holds. We prove that the lower bound cannot be attained when
N is even, and, on the basis of numerical calculations, this is conjec
tured to also be the case for odd N > 3.