23 citations · 33 across the 6 of their papers we have counts for
6 papers
Identification of community structure in networks with convex optimization
Roland Hildebrand
We reformulate the problem of modularity maximization over the set of partitions of a network as a conic optimization problem over the completely positive cone, converting it from…
Entangled states close to the maximally mixed state
Roland Hildebrand
We give improved upper bounds on the radius of the largest ball of separable states of an m-qubit system around the maximally mixed state. The ratio between the upper bound and the…
Semidefinite descriptions of separable matrix cones
Roland Hildebrand
Let K, K' be convex cones residing in finite-dimensional real vector spaces E, E'. An element in the tensor product E \otimes E' is K \otimes K'-separable if it can be represented…
Concurrence of Lorentz-positive maps
Roland Hildebrand
Let L_n be the n-dimensional Lorentz cone. A linear map M from R^m to R^n is called Lorentz-positive if M[L_m] is contained in L_n. We extend the notion of concurrence, which was i…
Combinatorial laplacians and positivity under partial transpose
Roland Hildebrand, Stefano Mancini, Simone Severini
Density matrices of graphs are combinatorial laplacians normalized to have trace one (Braunstein \emph{et al.} \emph{Phys. Rev. A,} \textbf{73}:1, 012320 (2006)). If the vertices o…
Separable balls around the maximally mixed state for a 3-qubit system
Roland Hildebrand
We obtain a new lower bound on the radius of the largest ball of separable unnormalized states around the identity matrix for a 3-qubit system. This also enables us to improve the…