English

On a family of a linear maps from $M_{n}(\mathbb{C})$ to $M_{n^{2}}(\mathbb{C})$

Mathematical Physics 2019-02-27 v1 math.MP Quantum Physics

Abstract

Bhat characterizes the family of linear maps defined on B(H)B(\mathcal{H}) which preserve unitary conjugation. We generalize this idea and study the maps with a similar equivariance property on finite-dimensional matrix algebras. We show that the maps with equivariance property are significant to study kk-positivity of linear maps defined on finite-dimensional matrix algebras. Choi showed that nn-positivity is different from (n1)(n-1)-positivity for the linear maps defined on nn by nn matrix algebras. In this paper, we present a parametric family of linear maps Φα,β,n:Mn(C)Mn2(C)\Phi_{\alpha, \beta,n} : M_{n}(\mathbb{C}) \rightarrow M_{n^{2}}(\mathbb{C}) and study the properties of positivity, completely positivity, decomposability etc. We determine values of parameters α\alpha and β\beta for which the family of maps Φα,β,n\Phi_{\alpha, \beta,n} is positive for any natural number n3n \geq 3. We focus on the case of n=3,n=3, that is, Φα,β,3\Phi_{\alpha, \beta,3} and study the properties of 22-positivity, completely positivity and decomposability. In particular, we give values of parameters α\alpha and β\beta for which the family of maps Φα,β,3\Phi_{\alpha, \beta,3} is 22-positive and not completely positive.

Keywords

Cite

@article{arxiv.1802.07553,
  title  = {On a family of a linear maps from $M_{n}(\mathbb{C})$ to $M_{n^{2}}(\mathbb{C})$},
  author = {Benoit Collins and Hiroyuki Osaka and Gunjan Sapra},
  journal= {arXiv preprint arXiv:1802.07553},
  year   = {2019}
}

Comments

14 pages, 4 figures