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The out-of-time-ordered correlator (OTOC) is a powerful tool for probing quantum information scrambling, a fundamental process by which local information spreads irreversibly throughout a quantum many-body system. Experimentally measuring…

Quantum Physics · Physics 2026-03-18 Haruki Emori , Hiroyasu Tajima

We investigate the ultimate precision achievable in Gaussian quantum metrology. We derive general analytical expressions for the quantum Fisher information matrix and for the measurement compatibility condition, ensuring asymptotic…

Quantum Physics · Physics 2018-07-18 Rosanna Nichols , Pietro Liuzzo-Scorpo , Paul A. Knott , Gerardo Adesso

We propose an approach to quantum phase estimation that can attain precision near the Heisenberg limit without requiring single-particle-resolved state detection. We show that the "one-axis twisting" interaction, well known for generating…

Quantum Physics · Physics 2016-02-03 Emily Davis , Gregory Bentsen , Monika Schleier-Smith

Quantum entanglement is a powerful quantum resource for enhancing measurement precision beyond classical limit. % Here we propose an entanglement-enhanced symmetry-protected destructive many-body Ramsey interferometry for precise parameter…

Quantum Physics · Physics 2025-09-11 Sijie Chen , Jiahao Huang , Min Zhuang , Chaohong Lee

Orthogonal time-frequency space (OTFS) is a potential waveform for integrated sensing and communications (ISAC) systems because it can manage communication and sensing metrics in one unified domain, and has better performance in high…

Signal Processing · Electrical Eng. & Systems 2025-04-08 Zhenyu Zhang , Qianli Wang , Gang Liu , FeiFei Gao , Pingzhi Fan

Spin squeezing (SS) is a recognized resource for realizing measurement precision beyond the standard quantum limit $\propto 1/\sqrt{N}$. The rudimentary one-axis twisting (OAT) interaction can facilitate SS and has been realized in diverse…

Quantum Gases · Physics 2019-10-16 Feng Chen , Jun-Jie Chen , Ling-Na Wu , Yong-Chun Liu , Li You

The Fisher information $F$ gives a limit to the ultimate precision achievable in a phase estimation protocol. It has been shown recently that the Fisher information for a linear two-mode interferometer cannot exceed the number of particles…

We investigate a probe state preparation protocol based on two non-selective generalized quantum measurements to enhance parameter estimation in single-qubit systems. By fine-tuning the measurement strengths, we demonstrate the ability to…

Quantum Physics · Physics 2026-05-13 Jonas F. G. Santos , Shanhe Su , Moises Rojas

We introduce a new spin-squeezing technique that is a hybrid of two well established spin-squeezing techniques, quantum nondemolition measurement (QND) and one-axis twisting (OAT). This hybrid method aims to improve spin-squeezing over what…

Quantum Physics · Physics 2023-10-26 Liam Fuderer , Joseph J Hope , Simon A Haine

Shearing interferometry is a common-path quantitative phase imaging technique in which an object beam interferes with a laterally shifted replica of itself, providing high temporal stability, reduced sensitivity to environmental noise,…

Recent experiments have demonstrated the generation of entanglement by quasi-adiabatically driving through quantum phase transitions of a ferromagnetic spin-1 Bose-Einstein condensate in the presence of a tunable quadratic Zeeman shift. We…

Quantum Physics · Physics 2018-04-04 P. Feldmann , M. Gessner , M. Gabbrielli , C. Klempt , L. Santos , L. Pezzè , A. Smerzi

Adaptive measurements were recently shown to significantly improve the performance of quantum state tomography. Utilizing information about the system for the on-line choice of optimal measurements allows to reach the ultimate bounds of…

Interference between multiple distinct paths is a defining property of quantum physics, where "paths" may involve actual physical trajectories, as in interferometry, or transitions between different internal (e.g. spin) states, or both. A…

Estimating multiple parameters simultaneously is of great importance to measurement science and application. For a single parameter, atomic Ramsey interferometry (or equivalently optical Mach-Zehnder interferometry) is capable of providing…

Quantum Physics · Physics 2020-04-09 Xinwei Li , Jia-Hao Cao , Qi Liu , Meng Khoon Tey , Li You

Quantum state estimation is an important task of many quantum information protocols. We consider two families of unitary evolution operators, one with a one-parameter and the other with a two-parameter, which enable the estimation of a…

Quantum Physics · Physics 2023-01-27 Cristian A. Galvis Florez , J. Martínez-Cifuentes , K. M. Fonseca-Romero

One-axis twisting (OAT) interaction is a pivotal resource for manipulating quantum states of atomic ensembles, enabling spin squeezing, atomic-cat-state generation, and weak-phase amplification. Current implementations of OAT dynamics…

Quantum Physics · Physics 2026-03-13 Jinfeng Liu , Yan Mu , Lili Song , Gang Liu , Mingfeng Wang

We develop a variational principle to determine the quantum controls and initial state which optimizes the quantum Fisher information, the quantity characterizing the precision in quantum metrology. When the set of available controls is…

Quantum Physics · Physics 2022-04-27 Jing Yang , Shengshi Pang , Zekai Chen , Andrew N. Jordan , Adolfo del Campo

We investigate the ultimate quantum limits to the achievable uncertainty in the estimation of the transition frequency between two atomic levels. We focus on Rabi, Ramsey, and coherent population trapping (CPT) techniques, which are widely…

Quantum Physics · Physics 2026-05-15 Stefano Olivares , Salvatore Micalizio , Matteo G. A. Paris

When an optimal treatment regime (OTR) is considered, we need to evaluate the OTR in a valid and efficient way. The classical inference applied to the mean outcome under OTR, assuming the OTR is the same as the estimated OTR, might be…

Methodology · Statistics 2026-04-21 Shuoxun Xu , Xinzhou Guo

We present a simple and effective method to create highly entangled spin states on a faster timescale than that of the commonly employed one-axis twisting (OAT) model. We demonstrate that by periodically driving the Dicke Hamiltonian at a…