On the structure of positive maps between matrix algebras
A partial description of the structure of positive unital maps $ϕ: M_2(\bC) \to M_{n+1}(\bC)$ ($n\geq 2$) is given.
math.FA↗
arXiv subjects
Marcin Marciniak
Publications and source records attributed to Marcin Marciniak.
On quantum Lyapunov exponents
It was shown that quantum analysis constitutes the proper analytic basis for quantization of Lyapunov exponents in the Heisenberg picture. Differences among various quantizations of Lyapunov exponents are clarified.
quant-ph↗
Decomposability of extremal positive unital maps on $M_2$
A map $ϕ:M_m(\bC)\to M_n(\bC)$ is decomposable if it is of the form $ϕ=ϕ_1+ϕ_2$ where $ϕ_1$ is a CP map while $ϕ_2$ is a co-CP map. It is known that if $m=n=2$ then every positive map is decomposable. Given an extremal unital positive map $ϕ:M_2(\bC)\to M_2(\bC)$ we construct concrete maps (not necessarily unital) $ϕ_1$ and $ϕ_2$ which give a decomposition of $ϕ$. We also show that in most cases this decomposition is unique.
math.FA↗
On decomposability of positive maps between $M_2$ and $M_n$
A map $ϕ:M_m(\bC)\to M_n(\bC)$ is decomposable if it is of the form $ϕ=ϕ_1+ϕ_2$ where $ϕ_1$ is a CP map while $ϕ_2$ is a co-CP map. A partial characterization of decomposability for maps $ϕ: M_2(\bC) \to M_3(\bC)$ is given.
math.FA↗
$k$-decomposability of positive maps
The problem of classification of decomposable (in the sense of Stormer) positive maps between matrix algebras is presented. We propose the new notion of "finite" version of decomposability ($k$-decomposabilty). The characterisation of $k$-decomposability on the Hilbert space level is done. In the case of low dimensional algebras the notion of local decomposability and its applications for the description of decomposable maps are discussed.
quant-ph↗
On k-decomposability of positive maps
We extend the theory of decomposable maps by giving a detailed description of k-positive maps. A relation between transposition and modular theory is established. The structure of positive maps in terms of modular theory (the generalized Tomita-Takesaki scheme) is examined.
math-ph↗
Density matrix interpretation of solutions of Lie-Nambu equations
The spectrum of a density matrix $ρ(t)$ is conserved by a Lie-Nambu dynamics if $ρ(t)$ is a self-adjoint and Hilbert-Schmidt solution of a nonlinear triple-bracket equation. This generalizes to arbitrary separable (positive- and indefinite-metric) Hilbert spaces the previous result which was valid for finite-dimensional Hilbert spaces.
quant-ph↗