The characterisation of Quantum Channel Discrimination (QCD) offers critical insight for future quantum technologies in quantum metrology, sensing and communications. The task of multi-channel discrimination creates a scenario in which the discrimination of multiple quantum channels can be equated to the idea of pattern recognition, highly relevant to the tasks of quantum reading, illumination and more. Although the optimal quantum strategy for many scenarios is an entangled idler-assisted protocol, the extension to a multi-hypothesis setting invites the exploration of discrimination strategies based on unassisted, multipartite probe states. In this work, we expand the space of possible quantum-enhanced protocols by formulating general classes of unassisted multi-channel discrimination protocols which are not assisted by idler modes. Developing a general framework for idler-free protocols, we perform an explicit investigation in the bosonic setting, studying prominent Gaussian channel discrimination problems for real-world applications. Our findings uncover the existence of strongly quantum advantageous, idler-free protocols for the discrimination of bosonic loss and environmental noise. This circumvents the necessity for idler assistance to achieve quantum advantage in some of the most relevant discrimination settings, significantly loosening practical requirements for prominent quantum-sensing applications.

量子通道鉴别 (QCD) 的表征为未来量子计量、传感和通信领域的量子技术提供了重要见解。多通道识别任务创造了一个场景，其中多个量子通道的识别可以等同于模式识别的思想，与量子读取、照明等任务高度相关。尽管许多场景的最佳量子策略是纠缠的空闲辅助协议，但对多假设设置的扩展需要探索基于无辅助、多方探测状态的判别策略。在这项工作中，我们通过制定不受空闲模式辅助的无辅助多通道鉴别协议的一般类别来扩展可能的量子增强协议的空间。开发无空闲协议的通用框架，我们在玻色子环境中进行了明确的调查，研究了现实世界应用中突出的高斯通道鉴别问题。我们的研究结果揭示了存在强大的量子优势、无惰轮的协议，用于区分玻色子损失和环境噪声。这避免了在一些最相关的鉴别设置中需要空闲辅助来实现量子优势，显着放宽了突出的量子传感应用的实际要求。用于区分玻色损失和环境噪声的无空闲协议。这避免了在一些最相关的鉴别设置中需要空闲辅助来实现量子优势，显着放宽了突出的量子传感应用的实际要求。用于区分玻色损失和环境噪声的无空闲协议。这避免了在一些最相关的鉴别设置中需要空闲辅助来实现量子优势，显着放宽了突出的量子传感应用的实际要求。