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Related papers: Multiple phase estimation with photon-added multi-…

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Photon addition operations applied to squeezed states have been shown to significantly enhance phase sensitivity. In this study, we extend this approach by applying photon addition not only to coherent states but also within a Mach--Zehnder…

Quantum Physics · Physics 2025-10-21 Qisi Zhou , Qingqian Kang , Teng Zhao , Xin Su , Cunjin Liu , Liyun Hu

Quantification of coherence lies at the heart of quantum information processing and fundamental physics. Exact evaluation of coherence measures generally needs a full reconstruction of the density matrix, which becomes intractable for…

Quantum Physics · Physics 2021-06-28 Qi-Ming Ding , Xiao-Xu Fang , Xiao Yuan , Ting Zhang , He Lu

Multiparameter quantum estimation theory is crucial for many applications involving infinite-dimensional Gaussian quantum systems, since they can describe many physical platforms, e.g., quantum optical and optomechanical systems and atomic…

Quantum Physics · Physics 2025-04-28 Shoukang Chang , Marco G. Genoni , Francesco Albarelli

We present measurement schemes that do not rely on photon-number resolving detectors, but that are nevertheless optimal for estimating a differential phase shift in interferometry with either an entangled coherent state or a…

Quantum Physics · Physics 2024-09-12 Z. M. McIntyre , W. A. Coish

The accuracy of quantum measurements can be effectively improved by using both photon-added non-Gaussian operations and Kerr nonlinear phase shifters. Here, we employ coherent state mixed photon-added squeezed vacuum state as input into a…

Quantum Physics · Physics 2025-05-23 Zekun Zhao , Qingqian Kang , Shoukang Chang , Teng Zhao , Cunjin Liu , Xin Su , Liyun Hu

We propose a protocol for the second-order nonlinear phase estimation with a coherent state as input and balanced homodyne detection as measurement strategy. The sensitivity is sub-Heisenberg limit, which scales as $N^{-3/2}$ for $N$…

Quantum Physics · Physics 2019-06-24 Jian-Dong Zhang , Zi-Jing Zhang , Jun-Yan Hu , Long-Zhu Cen , Yi-Fei Sun , Chen-Fei Jin , Yuan Zhao

We investigate quantum measurement strategies capable of discriminating two coherent states probabilistically with significantly smaller error probabilities than can be obtained using non- probabilistic state discrimination. We apply a…

Quantum Physics · Physics 2010-10-12 Christoffer Wittmann , Ulrik L. Andersen , Masahiro Takeoka , Gerd Leuchs

Quantum metrology offers the potential to surpass its classical counterpart, pushing the boundaries of measurement precision toward the ultimate Heisenberg limit. This enhanced precision is normally attained by utilizing large squeezed…

We study the sensitivity of phase estimation in a lossy Mach-Zehnder interferometer (MZI) using two general, and practical, resources generated by a laser and a nonlinear optical medium with passive optimal elements, which are readily…

Quantum Physics · Physics 2017-12-07 Changhun Oh , Su-Yong Lee , Hyunchul Nha , Hyunseok Jeong

Quantum metrology is the state-of-the-art measurement technology. It uses quantum resources to enhance the sensitivity of phase estimation beyond what reachable within classical physics. While single parameter estimation theory has been…

We introduce a super-sensitive phase measurement technique that yields the Heisenberg limit without using either a squeezed state or a many-particle entangled state. Instead, we use a many-particle separable quantum state to probe the phase…

Quantum Physics · Physics 2020-05-20 Mayukh Lahiri , Manuel Erhard

Precise device characterization is a fundamental requirement for a large range of applications using photonic hardware, and constitutes a multi-parameter estimation problem. Estimates based on measurements using single photons or classical…

Quantum Physics · Physics 2023-08-24 Nana Liu , Hugo Cable

Achieving the ultimate quantum precision in the estimation of multiple physical parameters simultaneously is a challenge in quantum metrology due to fundamental limitations and experimental challenges in harnessing the necessary quantum…

Quantum Physics · Physics 2025-06-24 Atmadev Rai , Danilo Triggiani , Paolo Facchi , Vincenzo Tamma

Phase estimation is the most investigated protocol in quantum metrology, but its performance is affected by the presence of noise, also in the form of imperfect state preparation. Here we discuss how to address this scenario by using a…

A recently proposed phase-estimation protocol that is based on measuring the parity of a two-mode squeezed-vacuum state at the output of a Mach-Zehnder interferometer shows that Cram\'{e}r-Rao bound sensitivity can be obtained [P.\ M.\…

Quantum Physics · Physics 2013-09-10 Keith R. Motes , Petr M. Anisimov , Jonathan P. Dowling

We study the simultaneous estimation of multiple phases as a discretised model for the imaging of a phase object. We identify quantum probe states that provide an enhancement compared to the best quantum scheme for the estimation of each…

Quantum Physics · Physics 2013-09-10 Peter C. Humphreys , Marco Barbieri , Animesh Datta , Ian A. Walmsley

The Cram\'er-Rao bound captures completely the performance of single-parameter quantum sensors. On the other hand, its extension to multiple parameters demands more caution. Different aspects need to be captured at once, including,…

Quantum Physics · Physics 2026-01-14 Jayanth Jayakumar , Marco Barbieri , Magdalena Stobińska

We propose a Bell measurement scheme by employing a logical qubit in Greenberger-Horne-Zeilinger (GHZ) entanglement with an arbitrary number of photons. Remarkably, the success probability of the Bell measurement as well as teleportation of…

Quantum Physics · Physics 2015-03-20 Seung-Woo Lee , Kimin Park , Timothy C. Ralph , Hyunseok Jeong

Entangled many-body states enable high-precision quantum sensing beyond the standard quantum limit. We develop interferometric sensing protocols based on quantum critical wavefunctions and compare their performance with…

Quantum Physics · Physics 2026-01-09 Yinan Chen , Sara Murciano , Pablo Sala , Jason Alicea

The simultaneous multi-parameter estimation problem using a class of multi-mode entangled states is investigated in this paper. Specifically, the problem of optical phase imaging is considered and the quantum probe is taken to be a balanced…

Quantum Physics · Physics 2017-03-29 Lu Zhang , Kam Wai Clifford Chan