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Simultaneous estimation of multiple parameters in quantum metrological models is complicated by factors relating to the (i) existence of a single probe state allowing for optimal sensitivity for all parameters of interest, (ii) existence of…

Quantum Physics · Physics 2019-02-01 Sammy Ragy , Marcin Jarzyna , Rafal Demkowicz-Dobrzanski

Quantum metrology has been shown to surpass classical limits of correlation, resolution, and sensitivity. It has been introduced to interferometric Radar schemes, with intriguing preliminary results. Even quantum-inspired detection of…

Quantum Physics · Physics 2024-01-11 Leonid Vidro , Liran Shirizly , Naftali Kirsh , Nadav Katz , Hagai S. Eisenberg

We derive rates of convergence for limit theorems that reveal the intricate structure of the phase transitions in a mean-field version of the Blume-Emery-Griffith model. The theorems consist of scaling limits for the total spin. The model…

Probability · Mathematics 2015-06-15 Peter Eichelsbacher , Bastian Martschink

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

Entanglement often increases quantum measurement schemes' sensitivity. However, we find that in precision measurements with zero-mean Gaussian states, such as squeezed states, entanglement between different paths degrades measurement…

Quantum Physics · Physics 2025-04-28 Benjamin Lou , Hudson A. Loughlin , Nergis Mavalvala

Quantum phase transitions encompass a variety of phenomena that occur in quantum systems exhibiting several possible symmetries. Traditionally, these transitions are explored by continuously varying a control parameter that connects two…

Quantum Physics · Physics 2024-06-12 Á. Sáiz , J. Khalouf-Rivera , J. M. Arias , P. Pérez-Fernández , J. Casado-Pascual

We consider the situation when the signal propagating through each arm of an interferometer has a complicated multi-mode structure. We find the relation between the particle-entanglement and the possibility to surpass the shot-noise limit…

Quantum Physics · Physics 2017-09-20 J. Chwedenczuk

We study pretty good quantum state transfer (i.e., state transfer that becomes arbitrarily close to perfect) between vertices of graphs with an involution in the presence of an energy potential. In particular, we show that if a graph has an…

Combinatorics · Mathematics 2017-02-24 Mark Kempton , Gabor Lippner , Shing-Tung Yau

We identify optimal measurement strategies for phase estimation in different scenarios. For pure states of a single qubit, we show that optimal measurements form a broad set parametrized with a continuous variable. When the state is mixed…

Quantum Physics · Physics 2013-10-11 T. Wasak , J. Chwedenczuk , L. Pezze , A. Smerzi

Graph states provide a powerful framework for describing multipartite entanglement in quantum information science. In their standard formulation, graph states are generated by controlled-$Z$ interactions and naturally encode symmetric…

Quantum Physics · Physics 2026-05-05 Matheus R. de Jesus , Eduardo O. C. Hoefel , Renato M. Angelo

The author studies the Cramer-Rao type bound by a linear programming approach. By this approach, he found a necessary and sufficient condition that the Cramer-Rao type bound is attained by a random measurement. In a spin 1/2 system, this…

Quantum Physics · Physics 2007-05-23 Masahito Hayashi

We address the problem of optimal estimation of the relative phase for two-dimensional quantum systems in mixed states. In particular, we derive the optimal measurement procedures for an arbitrary number of qubits prepared in the same mixed…

Quantum Physics · Physics 2007-05-23 Giacomo Mauro D'Ariano , Chiara Macchiavello , Paolo Perinotti

We analytically investigate the sensitivity of Kerr nonlinear phase estimation in a Mach-Zehnder interferometer with two-mode squeezed vacuum states. We find that such a metrological scheme could access a sensitivity scaling over the Boixo…

Quantum Physics · Physics 2022-03-23 Yun-Feng Guo , Wei Zhong , Lan Zhou , Yu-Bo Sheng

The interferometric power of a bipartite quantum state quantifies the precision, measured by quantum Fisher information, that such a state enables for the estimation of a parameter embedded in a unitary dynamics applied to one subsystem…

Quantum Physics · Physics 2014-08-25 Gerardo Adesso

In presence of dissipation, quantal states may acquire complex-valued phase effects. We suggest a notion of dissipative interferometry that accommodates this complex-valued structure and that may serve as a tool for analyzing the effect of…

Quantum Physics · Physics 2016-08-16 Erik Sjöqvist

We consider various configuration of quantum-enhanced interferometers, both linear (SU(2)) and non-linear (SU(1,1)) ones, as well as hybrid SU(2)/SU(1,1) schemes. Using the unified modular approach, based on the Quantum Cramer-Rao bound, we…

Quantum Physics · Physics 2022-12-16 Dariya Salykina , Farid Ya. Khalili

Relative phase is treated as a physical quantity for two mode systems in quantum atom optics, adapting the Pegg-Barnett treatment of quantum optical phase to define a linear Hermitian relative phase operator via first introducing a complete…

Quantum Gases · Physics 2011-08-24 B J Dalton

In this article we show that, in a two-arm interferometer, pure quantum states of perfect path distinguishability (particles) are geometrically equidistant from all states with constant path distinguishability D. This property is not shared…

Quantum Physics · Physics 2020-01-07 Miguel Orszag , Sergio Carrasco

Phase measurement using a lossless Mach-Zehnder interferometer with certain entangled $N$-photon states can lead to a phase sensitivity of the order of 1/N, the Heisenberg limit. However, previously considered output measurement schemes are…

Quantum Physics · Physics 2009-11-13 Yang Gao , Hwang Lee

We study Fock state interferometry, consisting of a Mach-Zehnder Interferometer with two Fock state inputs and photon-number-resolved detection at the two outputs. We show that it allows discrimination of a discrete number of apriori-known…

Quantum Physics · Physics 2021-02-16 Reihaneh Shahrokhshahi , Saikat Guha , Olivier Pfister