97 citations · 467 across the 24 of their papers we have counts for
24 papers
Rigidly rotating gravitationally bound systems of point particles, compared to polytropes
Yngve Hopstad, Jan Myrheim
In order to simulate rigidly rotating polytropes we have simulated systems of point particles, with up to 1800. Two particles at a distance interact by an attractive po…
Nongeneric positive partial transpose states of rank five in dimensions
Leif Ove Hansen, Jan Myrheim
In dimensions, entangled mixed states that are positive under partial transposition (PPT states) must have rank at least four. They are well understood. We say that the…
Visualizing extremal positive maps in unital and trace preserving form
Leif Ove Hansen, Jan Myrheim
We define an entanglement witness in a composite quantum system as an observable having nonnegative expectation value in every separable state. Then a state is entangled if and onl…
Extremal entanglement witnesses
Leif Ove Hansen, Andreas Hauge, Jan Myrheim +1
We study extremal entanglement witnesses on a bipartite quantum system. We define the cone of witnesses as the dual of the set of separable density matrices, thus $\textrm{Tr}\,Ωρ\…
Extremal states of positive partial transpose in a system of three qubits
Øyvind Steensgaard Garberg, Børge Irgens, Jan Myrheim
We have studied mixed states in the system of three qubits with the property that all their partial transposes are positive, these are called PPT states. We classify a PPT state by…
Low rank positive partial transpose states and their relation to product vectors
Leif Ove Hansen, Andreas Hauge, Jan Myrheim +1
It is known that entangled mixed states that are positive under partial transposition (PPT states) must have rank at least four. In a previous paper we presented a classification o…