Generation of continuous-variable high-dimensional entanglement with three degrees of freedom and multiplexing quantum dense coding

Abstract

High-dimensional entanglement is a critical foundation for the growing demand for information capacity to implement the high-capacity quantum task. Here, we report continuous-variable high-dimensional entanglement with three degrees of freedom (frequency, polarization, and orbital angular momentum) directly generated with a single type-II optical parametric oscillator (OPO) cavity. By compensating both for dispersion in frequency modes and astigmatism in higher-order transverse modes, the OPO is capable of oscillating simultaneously and outputting thousands of entanglement pairs. The three degrees of freedom high-dimensional entanglement are verified simultaneously possessing frequency comb, spin, and orbital angular momentum entanglement via 14 pairs of Hermite–Gaussian mode correlations measurement. Then, the “space-frequency” multiplexing quantum dense coding communication is also demonstrated by using the entanglement resource. It shows the great superiority of high-dimensional entanglement in implementing the high-capacity quantum task. Apart from an increased channel capacity, it is possible to conduct deterministic high-dimensional quantum protocols, quantum imaging, and especially quantum computing.

Entanglement Dynamics of Two V‐type Atoms with Dipole–Dipole Interaction in Dissipative Cavity

“…As a quantum communication scheme, the dense coding resources and protocols have been investigated by many physics and information scientists. [ 20–24 ]…”

“…As a quantum communication scheme, the dense coding resources and protocols have been investigated by many physics and information scientists. [20][21][22][23][24] For a closed system not to interact with its surroundings environment, quantum entanglement will not decay with time. However, for an open quantum system, decoherence [25] and dissipation always occur due to the unavoidable interaction with its surrounding environment, entanglement always undergoes either asymptotic degradation or sudden death processes.…”