The interest on quantum entanglement has dramatically increased during the last two decades due to the emerging field of quantum information theory [1, 2]. It turns out that quantum entanglement may be used as basic resources in quantum information processing and communication. The prominent examples are quantum cryptography, quantum teleportation, quantum error correction codes and quantum com...

Quantum entanglement is the quantum information processing resource. Thus it is of importance to understand how much of entanglement particular quantum states have, and what kinds of laws entanglement and also transformation between entanglement states subject to. Therefore, it is essentialy important to use proper measures of entanglement which have nice properties. One of the major candidates...

Entanglement of two distant macroscopic objects is a key element for implementing large-scale quantum networks consisting of quantum channels and quantum nodes. Entanglement swapping can entangle two spatially separated quantum systems without direct interaction. Here we propose a scheme of deterministically entangling two remote atomic ensembles via continuous-variable entanglement swapping be...

Entanglement is closely related to some fundamental features of the dynamics of composite quantum systems: quantum entanglement enhances the “speed” of evolution of certain quantum states, as measured by the time required to reach an orthogonal state. The concept of “speed” of quantum evolution constitutes an important ingredient in any attempt to determine the fundamental limits that basic phy...

With any state of a multipartite quantum system its separability polytope is associated. This is an algebro-topological object (nontrivial only for mixed states) which captures the localisation of entanglement of the state. Particular examples of separabilty polytopes for 3-partite systems are explicitly provided. It turns out that this characterisation of entanglement is associated with simula...

Entanglement has played a key role in many quantum information processing, such as quantum computation [1], quantum teleportation [2], quantum dense coding [3], and entanglement-assisted quantum cryptography [4]. To function optimally these applications requires maximally entanglement. However, unwanted coupling to the environment causes the degradation of entanglement and entanglement concentr...

We show that for a particular class of quantum channels, which we call heralded channels, monogamy of squashed entanglement limits the superadditivity of Holevo capacity. Heralded channels provide a means to understand the quantum erasure channel composed with an arbitrary other quantum channel, as well as common situations in experimental quantum information that involve frequent loss of qubit...

We consider entanglement for quantum states defined in vector spaces over the real numbers. Such real entanglement is different from entanglement in standard quantum mechanics over the complex numbers. The differences provide insight into the nature of entanglement in standard quantum theory. Wootters [Phys. Rev. Lett. 80, 2245 (1998)] has given an explicit formula for the entanglement of forma...

We consider entanglement for quantum states defined in vector spaces over the real numbers. Such real entanglement is different from entanglement in standard quantum mechanics over the complex numbers. The differences provide insight into the nature of entanglement in standard quantum theory. Wootters [Phys. Rev. Lett. 80, 2245 (1998)] has given an explicit formula for the entanglement of forma...

One distinct property of quantum entanglement from other classical correlations is that multipartite entanglements cannot be freely shared among the parties: If two parties in a multi-party system share a maximally entangled state, then they cannot share any entanglement with the rest. This is known as monogamy of entanglement (MoE) [1], which is a key ingredient for secure quantum cryptography...