Connecting heterogeneous quantum networks by hybrid entanglement swapping

Abstract

Recent advances in quantum technologies are rapidly stimulating the building of quantum networks. With the parallel development of multiple physical platforms and different types of encodings, a challenge for present and future networks is to uphold a heterogeneous structure for full functionality and therefore support modular systems that are not necessarily compatible with one another. Central to this endeavor is the capability to distribute and interconnect optical entangled states relying on different discrete and continuous quantum variables. Here, we report an entanglement swapping protocol connecting such entangled states. We generate single-photon entanglement and hybrid entanglement between particle- and wave-like optical qubits and then demonstrate the heralded creation of hybrid entanglement at a distance by using a specific Bell-state measurement. This ability opens up the prospect of connecting heterogeneous nodes of a network, with the promise of increased integration and novel functionalities.

Satellite‐based distribution of hybrid entanglement

“…Previous work has studied the scenario where both the state to be teleported and the teleportation channel are hybrid entangled states 11,25‐27 . However, the generation of a hybrid‐entangled teleportation resource channel is experimentally challenging—especially when the source is placed on board a satellite as in Figure 1(A).…”

Hybrid Entanglement between Optical Discrete Polarizations and Continuous Quadrature Variables

“…Recently, notable efforts [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] have been devoted to harnessing merits of both approaches to overcome the intrinsic individual limitations. Progress on integrating DV and CV technologies in unified hybrid architectures has manifested the capability of distributing and interconnecting optical DV and CV quantum states (or qubits).…”

“…Therefore, these hybrid techniques shed new light towards realizing scalable QIP and quantum communications. Although the endeavor of combining DV toolboxes with CV frameworks has started two decades ago in generating non-Gaussian states, it becomes only recently feasible to form hybrid optical entanglement between particle-and wave-like qubits in experiments [10][11][12][13][14][15][16]. The DV-CV hybridization turns out to enable potentially more powerful hybrid protocols.…”

“…The DV-CV hybridization turns out to enable potentially more powerful hybrid protocols. Among them include demonstrations of remote state preparation [14], quantum teleportation [12,13], entanglement swapping [16] and Einstein-Podolsky-Rosen (EPR) steering [15].…”

“…Rather, they both rely on homodyne detection, therefore resulting in an unavoidable crosstalk in measurement, especially in the presence of photon loss and vacuum noise. Furthermore, the generation of hybrid DV-CV entanglement in these studies [8][9][10][11][12][14][15][16][17][18][19][20][21][22] are highly sensitive to phase fluctuations of two indistinguishable optical pathways before the beam-splitter [17], which adversely make scalable QIP and quantum communications challenging.…”