46 citations · 120 across the 4 of their papers we have counts for
4 papers
Effective criteria for entanglement witnesses in small dimensions
Łukasz Grzelka, Łukasz Skowronek, Karol Życzkowski
We present an effective set of necessary and sufficient criteria for block-positivity of matrices of order over . The approach is based on Sturm sequences and quart…
Three-by-three bound entanglement with general unextendible product bases
Łukasz Skowronek
We discuss the subject of Unextendible Product Bases with the orthogonality condition dropped and we prove that the lowest rank non-separable positive-partial-transpose states, i.e…
Product numerical range in a space with tensor product structure
Zbigniew Puchała, Piotr Gawron, Jarosław Adam Miszczak +3
We study operators acting on a tensor product Hilbert space and investigate their product numerical range, product numerical radius and separable numerical range. Concrete bounds f…
Restricted numerical range: a versatile tool in the theory of quantum information
Piotr Gawron, Zbigniew Puchała, Jarosław Adam Miszczak +2
Numerical range of a Hermitian operator X is defined as the set of all possible expectation values of this observable among a normalized quantum state. We analyze a modification of…