arXiv subjects
Publications and source records attributed to Yoshiko Ogata.
We investigate local distinguishability of quantum states by use of the convex analysis about joint numerical range of operators on a Hilbert space. We show that any two orthogonal pure states are distinguishable by local operations and classical communications, even for infinite dimensional systems. An estimate of the local discrimination probability is also given for some family of more than two pure states.
We show that the non-equilibrium steady state (NESS) of the free lattice Fermion model far from equilibrium is macroscopically unstable. The problem is translated to that of the spectral analysis of {\it Liouville Operator}. We use the method of positive commutators to investigate it. We construct a positive commutator on the lattice Fermion system, whose dispersion relation is $ω(k)=\cos k-γ$.
We consider the decoherence free subalgebra which satisfies the minimal condition introduced by Alicki. We show the manifest form of it and relate the subalgebra with the Kraus representation. The arguments also provides a new proof for generalized Lüders theorem.
By the $C^*$-algebraic method, we investigate the magnetization profile in the intermediate time of diffusion. We observe a transition from monotone profile to non-monotone profile. This transition is purely thermal.