The science of quantum information has arisen over the last two decades centered on the
manipulation of individual quanta of information, known as quantum bits or qubits. Quantum …

It is impossible to unambiguously distinguish the four Bell states in polarization, resorting to
linear optical elements only. Recently, the hyperentangled Bell state, the simultaneous …

We present an efficient multipartite entanglement purification protocol (MEPP) for N-photon
systems in a Greenberger-Horne-Zeilinger state with parity-check detectors. It contains two …

We present two complete maximally hyperentangled state analysis protocols for photons
entangled in the polarization and spatial-mode degrees of freedom. The first protocol is a …

We propose and experimentally demonstrate a near-optimal discrimination scheme for the
quadrature phase shift keying (QPSK) protocol. We show in theory that the performance of …

Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum
system, has attracted much attention as it can be used to increase both the channel capacity …

We experimentally demonstrate a quantum receiver based on the Kennedy scheme for
discrimination between two phase-modulated weak coherent states. The receiver is …

We propose quantum receivers with optical squeezing and photon-number-resolving
detectors (PNRDs) for the near-optimal discrimination of quaternary phase-shift-keyed …

We suggest and demonstrate a tomographic method to characterise homodyne detectors at
the quantum level. The positive operator measure associated with the detector is expanded …

Generalized quantum measurements identifying nonorthogonal states without ambiguity
often play an indispensable role in various quantum applications. For such an unambiguous …