37 citations · 78 across the 9 of their papers we have counts for
4 papers · 1 filter
Restricted numerical shadow and geometry of quantum entanglement
Zbigniew Puchała, Jarosław Adam Miszczak, Piotr Gawron +3
The restricted numerical range of an operator acting on a -dimensional Hilbert space is defined as a set of all possible expectation values of this operator among p…
Numerical shadow and geometry of quantum states
Charles F. Dunkl, Piotr Gawron, John A. Holbrook +3
The totality of normalised density matrices of order N forms a convex set Q_N in R^(N^2-1). Working with the flat geometry induced by the Hilbert-Schmidt distance we consider image…
Higher-Rank Numerical Ranges of Unitary and Normal Matrices
Man-Duen Choi, John A. Holbrook, David W. Kribs +1
We verify a conjecture on the structure of higher-rank numerical ranges for a wide class of unitary and normal matrices. Using analytic and geometric techniques, we show precisely…
Noiseless subsystems and the structure of the commutant in quantum error correction
J. A. Holbrook, D. W. Kribs, R. Laflamme
The effect of noise on a quantum system can be described by a set of operators obtained from the interaction Hamiltonian. Recently it has been shown that generalized quantum error…