Quantum Distributed Sensing
Background
Distributed quantum sensing (DQS) could lead to novel applications and improvements in capabilities for space-based measurements, enabled by the potential for improved sensitivity and the inherent advantages of its distributed nature [1]. In lossless scenarios for phase quadrature sensing it is proven that the optimal probe is Gaussian. However, for lossy scenarios, this result no longer holds, and the optimal probe is not known. Nevertheless, there are indications that in such scenarios non-gaussian state (NGS) probes afford an improvement in sensitivity compared to the optimal Gaussian probe [2]. This project seeks to scope for the regime of NGS probes which demonstrates an advantage over the optimal Gaussian probe for sensing problems which involve loss (and thermal noise). To quantify this potential advantage, we initially consider the quantum Cramér-Rao bound (QCRB), whose analysis can instruct the optimal measurement scheme that saturates this bound [3,4]. In general, however, a measurement scheme that saturates the QCRB may be prohibitive for implementation, particularly in a space environment. Therefore, to constrain the search for advantageous NGS probes, we instead use the Fisher information as our metric: as this can include our assumption of a practical measurement scheme. Identifying advantageous NGS probes for both optimal and for practical measurement schemes could pave the way for DQS technologies in space. For instance, our results could inform the technological requirements for future space-based quantum sensors.
References
- Z. Zhang and Q. Zhuang, “Distributed quantum sensing”, Quantum Science and Technology 6, (2021), DOI: 10.1088/2058-9565/abd4c3
- Q. Zhuang, J. Preskill, and L. Jiang, “Distributed quantum sensing enhanced by continuous-variable error correction”, New Journal of Physics 22, (2020), DOI: 10.1088/1367-2630/ab7257
- M. Paris, “Quantum estimation for quantum technology”, International Journal of Quantum Information 7, (2009), DOI: 10.1142/S0219749909004839
- J. Yang et.al., “Optimal measurements for quantum multiparameter estimation with general states”, Physical Review A 100, (2019), DOI: 10.1103/PhysRevA.100.032104