Quantum direct portation

Abstract

Quantum state that carries classical information, 0 or 1, can be safely and reliably transmitted using quantum secure direct communication. How to transmit an arbitrary quantum state is a wider issue and has important applications. One way is to use quantum teleportation, namely, first distribute a large number of Einstein-Podolsky-Rosen pairs, and then perform entanglement purification to obtain a near-perfect pair, and make quantum teleportation using the pair. In this article, we propose a method that directly port the quantum state with security and reliability using quantum secure direct communication. After sufficient number of copies of the same state have been directly ported, single-particle purification is performed to obtain a near perfect single particle state. This is important because it offers a new method for sending an arbitrary single particle state securely and reliably without using quantum teleportation. It is also an important extension of quantum secure direct communication to send an arbitrary quantum state. Quantum direct portation will have great potential in quantum internet.