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We study the measurement-induced non-Gaussian operation on the single- and two-mode \textit{Gaussian} squeezed vacuum states with beam splitters and on-off type photon detectors, with which \textit{mixed non-Gaussian} states are generally…

Quantum Physics · Physics 2009-11-11 Akira Kitagawa , Masahiro Takeoka , Kentaro Wakui , Masahide Sasaki

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

Optomechanical systems have been exploited in ultrasensitive measurements of force, acceleration, and magnetic fields. The fundamental limits for optomechanical sensing have been extensively studied and now well understood -- the intrinsic…

In open quantum systems, the precision of metrology inevitably suffers from the noise. {In Markovian open quantum dynamics, the precision can not be improved by using entangled probes although the measurement time is effectively shortened.}…

Fast and precise characterization of Gaussian states is crucial for their effective use in quantum technologies. In this work, we apply a multi-parameter moment-based estimation method that enables rapid and accurate determination of…

We measured the covariance matrix of the fields generated in an integrated third-order optical parametric oscillator operating above threshold. We observed up to $(2.3 \pm 0.3)$ dB of squeezing in amplitude difference, inferred $(4.9 \pm…

We present an experimental analysis of quadrature entanglement produced from a pair of amplitude squeezed beams. The correlation matrix of the state is characterized within a set of reasonable assumptions, and the strength of the…

Quantum Physics · Physics 2009-11-10 W. P. Bowen , R. Schnabel , P. K. Lam , T. C. Ralph

Precise measurements are the key to advances in all fields of science. Quantum entanglement shows higher sensitivity than achievable by classical methods. Most physical quantities including position, displacement, distance, angle, and…

Quantum Physics · Physics 2017-07-05 Zhi-Yuan Zhou , Shi-Long Liu , Shi-Kai Liu , Yin-Hai Li , Dong-Sheng Ding , Guang-Can Guo , Bao-Sen Shi

Quantum entanglement and squeezing associated with the motions of massive mechanical oscillators play an essential role in both fundamental science and emerging quantum technologies, yet realizing such macroscopic nonclassical states…

We study the application of squeezed states in a quantum optical scheme for direct sampling of the phase space by photon counting. We prove that the detection setup with a squeezed coherent probe field is equivalent to the probing of the…

Optics · Physics 2015-06-26 Konrad Banaszek , Krzysztof Wodkiewicz

Recent developments in quantum technologies have enabled significant improvements in the precision of optical sensing systems. This work explores the integration of distributed quantum sensing (DQS) with optical gyroscopes to improve the…

Quantum Physics · Physics 2025-11-11 Priyanka M. Kannath , Girish S. Agarwal , Ashok Kumar

Entanglement is recognized as a key resource for quantum computation and quantum cryptography. For quantum metrology, the use of entangled states has been discussed and demonstrated as a means of improving the signal-to-noise ratio. In…

Quantum Physics · Physics 2007-05-23 C. F. Roos , M. Chwalla , K. Kim , M. Riebe , R. Blatt

Optimal phase estimation of a phase-squeezed quantum state of light has been recently shown to beat the coherent-state limit. Here, the estimation is made robust to uncertainties in underlying parameters using a robust fixed-interval…

Quantum Physics · Physics 2015-09-14 Shibdas Roy , Ian R. Petersen , Elanor H. Huntington

Balancing high sensitivity with a broad dynamic range is a fundamental challenge in measurement science, as improving one often compromises the other. While traditional quantum metrology has prioritized enhancing local sensitivity, a large…

Quantum Physics · Physics 2025-07-25 Qi Liu , Ming Xue , Matthew Radzihovsky , Xinwei Li , Denis V. Vasilyev , Ling-Na Wu , Vladan Vuletić

We present two results which combined enable one to reliably detect multimode, multipartite entanglement in the presence of measurement errors. The first result leads to a method to compute the best (approximated) physical covariance matrix…

Quantum Physics · Physics 2016-10-05 E. Shchukin , P. van Loock

Quantum estimation of parameters defining open-system dynamics may be enhanced by using ancillas that are entangled with the probe but are not submitted to the dynamics. Here we consider the important problem of estimation of transmission…

Quantum Physics · Physics 2024-03-04 Jiaxuan Wang , Ruynet. L. de Matos Filho , Girish S. Agarwal , Luiz Davidovich

We study the generation of planar quantum squeezed (PQS) states by quantum non-demolition (QND) measurement of a cold ensemble of $^{87}$Rb atoms. Precise calibration of the QND measurement allows us to infer the conditional covariance…

Quantum Physics · Physics 2017-06-14 G. Colangelo , F. Martin Ciurana , G. Puentes , M. W. Mitchell , R. J. Sewell

We derive a phase-entanglement criterion for two bosonic modes which is immune to number fluc- tuations, using the generalized Moore-Penrose inverse to normalize the phase-quadrature operator. We also obtain a phase-squeezing criterion that…

Quantum Physics · Physics 2014-05-09 Q. Y. He , T. G. Vaughan , P. D. Drummond , M. D. Reid

We predict that the phase-dependent error distribution of locally unentangled quantum states directly affects quantum parameter estimation accuracy. Therefore, we employ the displaced squeezed vacuum (DSV) state as a probe state and…

Quantum Physics · Physics 2021-05-04 Zhiwei Tao , Yichong Ren , Azezigul Abdukirim , Shiwei Liu , Ruizhong Rao

Graph states are an important class of multipartite entangled states. Previous experimental generation of graph states and in particular the Greenberger-Horne-Zeilinger (GHZ) states in linear optics quantum information schemes is subjected…

Quantum Physics · Physics 2022-03-01 Sheng Zhang , Yu-Kai Wu , Chang Li , Nan Jiang , Yun-Fei Pu , Lu-Ming Duan