Entanglement of Formation of an Arbitrary State of Two Qubits
William K. Wootters
Abstract
The entanglement of a pure state of a pair of quantum systems is defined as the entropy of either member of the pair. The entanglement of formation of a mixed state $\ensuremath{\rho}$ is the minimum average entanglement of an ensemble of pure states that represents \ensuremath{\rho}. An earlier paper conjectured an explicit formula for the entanglement of formation of a pair of binary quantum objects (qubits) as a function of their density matrix, and proved the formula for special states. The present paper extends the proof to arbitrary states of this system and shows how to construct entanglement-minimizing decompositions.
Topics & Concepts
Quantum entanglementW stateQuantum mechanicsPhysicsSquashed entanglementMultipartite entanglementQubitCluster stateDensity matrixState (computer science)Entanglement witnessEntropy (arrow of time)QuantumStatistical physicsMathematicsAlgorithmQuantum Mechanics and ApplicationsQuantum Information and CryptographyQuantum Computing Algorithms and Architecture