2014/10/31 by Mark Girard, Mark W. Girard, Gilad Gour · 5 citations
Computer Science · Physics and Astronomy · Psychology · #Algorithm #Computer science #Entanglement witness #Law #Negativity effect #Physics #Political science #Psychology #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #Qubit #Squashed entanglement #State (computer science) #Statistical physics #Theoretical physics #Witness #quant-ph
paper · pdf · doi:10.1088/1367-2630/17/9/093013
published in New Journal of Physics 17(9), 093013 (IOP Publishing) · 20 pages, 8 figures. Comments welcome. (Version 3: updated to published version) (Version 4: corrected minor error in eq. (4) on page 4)
openalex publication_date 2015/09/10 · arxiv created 2016/01/13 · arxiv updated 2016/01/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/08
The primary goal of entanglement theory is to determine convertibility conditions for two quantum states. Up until now, this has always been done with the use of entanglement monotones. With the exception of the negativity, such quantities tend to be rather uncomputable. We instead promote the idea of conversion witnesses in this paper. A conversion witness is a function on pairs of states and whose value determines whether a state can be converted into another. We construct a conversion witness that can be efficiently computed for arbitrary states in systems of any size. This conversion witness is always better than the negativity at detecting when two entangled states are not interconvertible. Furthermore, when considering states of two-qubit systems, this new conversion witness is sometimes better than the entanglement of formation. This shows that the study of conversion witness is in fact useful, and may have applications in resource theories beyond that of entanglement.