Distillability and Entanglement Purification for Gaussian States

Dagmar Bruß

Hiroki Takahashi, Jonas Schou Neergaard-Nielsen, Makoto Takeuchi +4 more

Jaromı́r Fiurášek

We propose an entanglement distillation and purification scheme for symmetric two-mode entangled Gaussian states that allows to asymptotically extract a pure entangled Gaussian state from any input entangled symmetric Gaussian state. The proposed scheme is a modified and extended version of the entanglement distillation protocol originally developed by Browne et al. [Phys. Rev. A 67, 062320 (2003)]. A key feature of the present protocol is that it utilizes a two-copy degaussification procedure that involves a Mach-Zehnder interferometer with single-mode non-Gaussian filters inserted in its two arms. The required non-Gaussian filtering operations can be implemented by coherently combining two sequences of single-photon addition and subtraction operations.

Vladimir I. Man’ko, Aleksandr A. Sergeevich

L.-M. Duan, G. Giedke, J. I. Cirac +1 more

Summary form only given. One of the key elements of quantum communication is the generation of maximally entangled states between distant nodes of a quantum network. We present an entanglement purification scheme which generates maximally entangled states in finite Hilbert spaces from the continuous two-mode squeezed states. With high probabilities, we get a more entangled stale, and the entanglement in the continuous partially entangled state is transferred to the maximally entangled states with high efficiency. Furthermore, in several practical cases this purification protocol can be readily extended to distill maximally entangled states from the mixed Gaussian continuous states.

Duan Duan, Giedke, Cirac +1 more