Continuous Quantum Aperture: Beamforming with a Single-Vapor-Cell Rydberg Receiver

TL;DR

This paper introduces a novel beamforming mechanism using a Rydberg-atom vapor cell as a continuous quantum aperture, enabling reconfigurable, multi-band, and multiuser electromagnetic reception within a single sensing volume.

Contribution

It establishes the theory of continuous quantum aperture and demonstrates reconfigurable beamforming using a single vapor cell, diverging from traditional array-based methods.

Findings

Experimental results match theoretical predictions across various aperture sizes and configurations.

Reconfigurable beam patterns include single-peak, multi-peak, and multiband modes.

The platform enables interference mitigation and multiuser access within a single vapor cell.

Abstract

Beamforming is conventionally understood as a collective property of many discrete antenna elements in both communication and radar fields, which links angular selectivity to array size, element spacing, and band-specific hardware. Here we uncover a fundamentally different beamforming mechanism achieved by a Rydberg atomic receiver: a Rydberg-atom vapor cell dressed by a local-oscillator field constitutes a continuous quantum aperture. In this regime, spatially-varying quantum coherence across the aperture provides continuous amplitude-phase control, allowing a directional beam pattern to emerge from one sensing volume rather than from an engineered array. We establish the theory of continuous quantum aperture and show that tailoring the local-oscillator field can directly program the aperture response. This enables reconfigurable single-peak, multipeak, and multiband beamforming within a single vapor cell. Experiments on a Rydberg atomic receiver prototype verify that practical beam patterns agree with theoretical predictions across aperture sizes, frequency bands, and local-oscillator configurations. Leveraging this new beamforming mechanism, we further demonstrate interference mitigation, multiuser access, and multiband multiuser access with the single-vapor-cell platform. Our results identify the continuous quantum aperture as a new operating principle of Rydberg atomic receivers and establish single-vapor-cell beamforming as an integrated and reconfigurable platform for spatially selective electromagnetic reception.