Wan-Ying Wang

DOUBLING THE CAPACITY OF QUANTUM KEY DISTRIBUTION BY USING BOTH POLARIZATION AND DIFFERENTIAL PHASE SHIFT

Using differential phase shift and photon polarization, we propose two quantum key distribution schemes, i.e. a double-coding BB84 protocol and a double-coding BBM92 protocol. The information capacity of these protocols is twice of the original protocols and their security is ensured by the use of detection time slots, random choice of bases and quantum entanglement. These double-coding protocols are feasible with present technology.

Quantum key distribution using polarization and frequency hyperentangled photons

We propose a two-step quantum key distribution protocol using frequency and polarization hyperentangled photons. In this protocol, key information is encoded by unitary operations on the hyperentangled photons, and the hyperentangled photons are sent in two steps. We also designed a state measurement device and analyzed the security of the protocol.

Duality Quantum Information and Duality Quantum Communication

Quantum mechanical systems exhibit particle wave duality property. This duality property has been exploited for information processing. A duality quantum computer is a quantum computer on the move and passing through a multi‐slits. It offers quantum wave divider and quantum wave combiner operations in addition to those allowed in an ordinary quantum computer. It has been shown that all linear bounded operators can be realized in a duality quantum computer, and a duality quantum computer with n qubits and d‐slits can be realized in an ordinary quantum computer with n qubits and a qudit in the so‐called duality quantum computing mode. The quantum particle‐wave duality can be used in providing secure communication. In this paper, we will review duality quantum computing and duality quantum key distribution.

Quantum Direct Communication

Gui Lu Long1,2, Chuan Wang1,3, Fu-Guo Deng4, and Wan-Ying Wang1 1Key Laboratory of Atomic and Molecular Nanosciences and Department of Physics, Tsinghua University, Beijing 100084, 2Tsinghua National Laboratory for Information Science and Technology, Beijing 100084, 3School of Science and Key Laboratory of Optical Communication and Lightwave Technologies, Beijing University of Posts and Telecommunications, Beijing, 100876, 4Department of Physics, Beijing Normal University, Beijing 100875, Peoples Republic of China

From Quantum Key Distribution to Quantum Secure Direct Communication

In this talk, we review basic principles of quantum key distribution (QKD) and the quantum secure direct communication (QSDC) through concrete protocols. QSDC transmits secret messages directly without encoding them through a classical channel. QSDC places more strict security requirements. With advance in quantum technology, QSDC may find more applications.