Optimal entanglement witnesses for continuous-variable systems

Recurrent construction of optimal entanglement witnesses for 2N-qubit systems

Entanglement and squeezingin continuous-variable systems

We introduce a multi-mode squeezing coefficient to characterize entanglement in N-partite continuous-variable systems. The coefficient relates to the squeezing of collective observables in the 2N-dimensional phase space and can be readily extracted from the covariance matrix. Simple extensions further permit to reveal entanglement within specific partitions of a multipartite system. Application...

Continuous-Variable Entanglement Swapping

We present a very brief overview of entanglement swapping as it relates to continuous-variable quantum information. The technical background required is discussed and the natural link to quantum teleportation is established before discussing the nature of Gaussian entanglement swapping. The limitations of Gaussian swapping are introduced, along with the general applications of swapping in the c...

Compact continuous-variable entanglement distillation.

We introduce a new scheme for continuous-variable entanglement distillation that requires only linear temporal and constant physical or spatial resources. Distillation is the process by which high-quality entanglement may be distributed between distant nodes of a network in the unavoidable presence of decoherence. The known versions of this protocol scale exponentially in space and doubly expon...

Entanglement Criteria for Continuous-Variable States

Entanglement is an amazing feature of quantum mechanics which is a nontrivial non-local correlation between states. It is studied and exploited greatly in the field of quantum information. Traditionally, most quantum systems of interest in quantum information is described by discrete variable states, e.g. spin of particles. Thus, entanglement is studied to a considerable extent in such state. N...