Universal device for two-qubit entangled measurements via photonic quantum walks

التفاصيل البيبلوغرافية
العنوان: Universal device for two-qubit entangled measurements via photonic quantum walks
المؤلفون: Yan, Wen-Zhe, Hou, Zhibo, Tang, Jun-Feng, Xiang, Guo-Yong, Li, Chuan-Feng, Guo, Guang-Can, Renou, Marc-Olivier
سنة النشر: 2022
المجموعة: Quantum Physics
مصطلحات موضوعية: Quantum Physics
الوصف: Sophisticated quantum measurements are fundamental to obtain a quantum advantage in many informational problems. Here, we consider the task of guessing a direction encoded in a two-qubit pure state. We experimentally demonstrate that abstention can be used to recover optimal direction guessing (measured in terms of the fidelity and maximum likelihood scores) even from non ideal states. Our protocol uses nine-step photonic quantum walks to implement the optimal five-output two-qubit collective measurements with fidelities above 0.9850. Thanks to abstention, we obtain more than a 10-fold improvement of the direction guessing scores (in terms of deviation to the optimal guessing scores). Our work demonstrates the versatility of photonic quantum walks for implementing many-qubit sophisticated measurements.
Comment: Comments welcome! 5 pages + 12 pages appendix
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2204.11310
رقم الأكسشن: edsarx.2204.11310
قاعدة البيانات: arXiv