Pairwise concurrence dynamics: a four-qubit model
نویسندگان
چکیده
منابع مشابه
Lower bound of concurrence for qubit systems
We study the concurrence of four-qubit quantum states and provide analytical lower bounds of concurrence in terms of the monogamy inequality of concurrence for qubit systems. It is shown that these lower bounds are able to improve the existing bounds and detect entanglement better. The approach is generalized to arbitrary qubit systems.
متن کاملHidden two-qubit dynamics of a four-level Josephson circuit.
Multi-level control of quantum coherence exponentially reduces communication and computation resources required for a variety of applications of quantum information science. However, it also introduces complex dynamics to be understood and controlled. These dynamics can be simplified and made intuitive by employing group theory to visualize certain four-level dynamics in a 'Bell frame' comprisi...
متن کاملEntangled three-qubit states without concurrence and three-tangle.
We provide a complete analysis of mixed three-qubit states composed of a Greenberger-Horne-Zeilinger state and a W state orthogonal to the former. We present optimal decompositions and convex roofs for the three-tangle. Further, we provide an analytical method to decide whether or not an arbitrary rank-2 state of three qubits has vanishing three-tangle. These results highlight intriguing differ...
متن کاملConcurrence and Foliations Induced by Some 1-Qubit Channels
We start with a short introduction to the roof concept. An elementary discussion of phase-damping channels shows the role of anti-linear operators in representing their concurrences. A general expression for some concurrences is derived. We apply it to 1-qubit channels of length two, getting the induced foliations of the state space, the optimal decompositions, and the entropy of a state with r...
متن کاملCanonical Decompositions of n-qubit Quantum Computations and Concurrence
The two-qubit canonical decomposition SU(4) = [SU(2)⊗ SU(2)]∆[SU(2)⊗ SU(2)] writes any two-qubit quantum computation as a composition of a local unitary, a relative phasing of Bell states, and a second local unitary. Using Lie theory, we generalize this to an n-qubit decomposition, the concurrence canonical decomposition (C.C.D.) SU(2n) = KAK. The group K fixes a bilinear form related to the co...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Physics B: Atomic, Molecular and Optical Physics
سال: 2007
ISSN: 0953-4075,1361-6455
DOI: 10.1088/0953-4075/40/9/s02