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Physical Review Letters

Generating Honeycomb-Structured Entanglement with a Reconfigurable Spatially Structured Pump

Yu Guo, Xiaozhou Pan, Shengshuai Liu, Guanjun Zeng, Kai Zhang, Jietai Jing

Published Aug 11, 2026• 0 citations
Publisher

Abstract

Multipartite entanglement is a fundamental resource for quantum information processing. Various degrees of freedom of light, such as time, frequency, and space, have been widely exploited to create large-scale entangled quantum sources, enhancing information transmission capacity. Here, we demonstrate the generation of honeycomb-structured entanglement among 13 spatially separated beams with a reconfigurable pump field of a hexagonal structure, featuring the simultaneous multiplexing of 18 four-wave mixing processes within a single atomic ensemble. Such a reconfigurable spatially structured pump is constructed by loading a reprogrammable hologram onto a spatial light modulator. Additionally, we analyze 8190 possible steering bipartitions and examine the robustness of the quantum properties inherent in the system. Furthermore, by reconfiguring the pump fields with square, hexagonal, and eightfold quasicrystal structures, we can generate square-, hexagonal-, and octagonal-structured output fields. This enables the output mode number to be extended from 9 and 19 up to 21. These results provide a promising route to realizing spatially programmable multipartite entanglement, enabling reconfigurable multiuser quantum communication networks, and suggesting potential avenues toward exploring topological phenomena in continuous-variable quantum systems.

DOI
10.1103/pyq1-b4gj

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Multipartite entanglement is a fundamental resource for quantum information processing. Various degrees of freedom of light, such as time, frequency, and space, have been widely exploited to create large-scale entangled quantum sources, enhancing information transmission capacity. Here, we demonstrate the generation of honeycomb-structured entanglement among 13 spatially separated beams with a reconfigurable pump field of a hexagonal structure, featuring the simultaneous multiplexing of 18 four-wave mixing processes within a single atomic ensemble. Such a reconfigurable spatially structured pump is constructed by loading a reprogrammable hologram onto a spatial light modulator. Additionally, we analyze 8190 possible steering bipartitions and examine the robustness of the quantum properties inherent in the system. Furthermore, by reconfiguring the pump fields with square, hexagonal, and eightfold quasicrystal structures, we can generate square-, hexagonal-, and octagonal-structured output fields. This enables the output mode number to be extended from 9 and 19 up to 21. These results provide a promising route to realizing spatially programmable multipartite entanglement, enabling reconfigurable multiuser quantum communication networks, and suggesting potential avenues toward exploring topological phenomena in continuous-variable quantum systems.
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Multipartite entanglement (ME) is the fundamental ingredient for building quantum networks. The scale of ME determines its quantum information carrying and processing capability. Most of the current efforts for boosting the scale of ME focus on increasing the number of entangled nodes. However, the number of channels for broadcasting ME is also an important index for characterizing its scale. In this Letter, we experimentally exploit orbital angular momentum multiplexing and the spatial pump shaping technique to simultaneously and deterministically generate 11 channels of individually accessible and mutually orthogonal continuous variable (CV) spatially separated hexapartite entangled states over 66 optical modes in a single quantum system. These results suggest that our method can greatly expand the scale of ME and provide a new perspective and platform to construct a CV quantum network.
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Multipartite entanglement is used for quantum information applications, such as building multipartite quantum communications. Generally, generation of multipartite entanglement is based on a complex beam-splitter network. Here, based on the spatial freedom of light, we experimentally demonstrated spatial quadripartite continuous variable entanglement among first-order Hermite-Gaussian modes using a single type II optical parametric oscillator operating below threshold with an HG0245° pump beam. The entanglement can be scalable for larger numbers of spatial modes by changing the spatial profile of the pump beam. In addition, spatial multipartite entanglement will be useful for future spatial multichannel quantum information applications.
Multichannel vortex beams serve as an essential physical source for enabling multi-spot laser processing and high-dimensional spatial multiplexing communications. We demonstrate a compact, flexibly tunable multichannel vortex beam generator using spatially structured bidirectional two-color pump vortex four-wave mixing in a single 133Cs vapor cell. To enhance spatial multiplexing, both sides of the cell are utilized. By engineering the propagation directions and frequencies of five input beams, we establish a nonlinear interaction region that supports 16 concurrent phase-matching conditions, thereby enabling the parallel generation of up to eight vortex channels. The orbital angular momentum of the output beams follows deterministic algebraic rules, allowing for programmable control via tailored input orbital angular momentum combinations. Moreover, the channel count can be linearly tuned by selectively deactivating pumps—each switched-off pump reduces the number of output channels by two. This flexible control over orbital angular momentum states, together with channel count and spatial arrangement, establishes a highly integrated platform for on-demand vortex generation. This work highlights the potential of spatially bidirectional structured pumping in atomic vapor to expand optical dimensionality and enhance multiplexing capacity, paving the way toward multidimensional communications, quantum networks, and integrated photonics.