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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

The generation of high-performance nonclassical light remains a cornerstone of quantum technologies, yet faces a fundamental trade-off between emission purity and brightness. Here, we demonstrate that cavity-mediated many-body spin-exchange…

Quantum Physics · Physics 2026-04-20 Tang Jing , Yuangang Deng

Multi-photon states are widely applied in quantum information technology. By the methods presented in this paper, the structure of a multi-photon state in the form of multiple single photon qubit product can be mapped to a single photon…

Quantum Physics · Physics 2009-10-16 Qing Lin , Bing He , János A. Bergou , Yuhang Ren

Understanding the fundamental limits on the precision to which an optical phase can be estimated is of key interest for many investigative techniques utilized across science and technology. We study the estimation of a fixed optical phase…

Quantum Physics · Physics 2017-12-13 Patrick M. Birchall , Jeremy L. O'Brien , Jonathan C. F. Matthews , Hugo Cable

An exploratory approach to the possibility of analyzing nonorthogonality as a quantifiable property is presented. Three different measures for the nonorthogonality of pure states are introduced, and one of these measures is extended to…

Quantum Physics · Physics 2009-10-31 Oliver Cohen

Developments in the foundations of quantum mechanics have identified several attributes and tests associated with the "quantumness" of systems, including entanglement, nonlocality, quantum erasure, Bell test, etc. Here we introduce and…

Quantum Physics · Physics 2016-05-03 Torsten Scholak , Paul Brumer

A possible two-qubit gate for optical quantum computing is the parity gate based on the weak Kerr effect. Two photonic qubits modulate the phase of a coherent state, and a quadrature measurement of the coherent state reveals the parity of…

Quantum Physics · Physics 2010-03-26 Pieter Kok

The state vector evolution in the interaction of initial measured pure state with collective quantum system or the field with a very large number of degrees of freedom N is analysed in a nonperturbative QED formalism. As the example the…

Quantum Physics · Physics 2007-05-23 S. N. Mayburov

Quantum state tomography is a technique in quantum information science used to reconstruct the density matrix of an unknown quantum state, providing complete information about the quantum state. It is of significant importance in fields…

Quantum Physics · Physics 2025-07-23 Wenlong Zhao , Da Zhang , Huili Zhang , Haifeng Yu , Zhang-qi Yin

The algebraic quantification of nonclassicality, which naturally arises from the quantum superposition principle, is related to properties of regular nonclassicality quasiprobabilities. The latter are obtained by non-Gaussian filtering of…

Quantum Physics · Physics 2018-05-21 B. Kühn , W. Vogel

In quantum optics, nonclassicality of quantum states is commonly associated with negativities of phase-space quasiprobability distributions. We argue that the impossibility of any classical simulations with phase-space functions is a…

Quantum Physics · Physics 2022-01-03 A. A. Semenov , A. B. Klimov

We derive the stochastic master equations, that is to say, quantum filters, and master equations for an arbitrary quantum system probed by a continuous-mode bosonic input field in two types of non-classical states. Specifically, we consider…

Quantum Physics · Physics 2012-10-17 J. E. Gough , M. R. James , H. I. Nurdin , Joshua Combes

In this work we investigate the thermodynamical properties and modified dynamics of black hole solutions in the semiclassical regime of affine coherent state quantization. Using the weak correspondence principle we build a semiclassical…

High Energy Physics - Theory · Physics 2014-09-26 Simone Zonetti

A new theorem on the non-classicality depth of states has been proved. We show that if $W_{\hat \rho} (\alpha_m,s_m)=0$ exist for some value of the ordering parameter $s$ at some phase-space point $\alpha_m$, and if $W_{\hat \rho}…

Quantum Physics · Physics 2012-06-08 F. Shähandeh , M. R. Bazrafkan

Assessing whether a quantum state $\hat \rho$ is nonclassical ($\textit{i.e.}$, incompatible with a mixture of coherent states) is a ubiquitous question in quantum optics, yet a nontrivial experimental task because many nonclassicality…

Quantum Physics · Physics 2023-09-01 Célia Griffet , Matthieu Arnhem , Stephan De Bièvre , Nicolas J. Cerf

Non-classical states that are characterized by their non-positive quasi-probabilities in phase space are known to be the basis for various quantum effects. In this work, we investigate the interrelation between the non-classicality and…

Quantum Physics · Physics 2010-10-12 Kisik Kim , Jaewan Kim , Joonwoo Bae

Quantum enhanced sensing is a powerful technique in which nonclassical states are used to improve the sensitivity of a measurement. For enhanced mechanical displacement sensing, squeezed states of light have been shown to reduce the photon…

Quantum Physics · Physics 2016-07-05 Jeremy B. Clark , Florent Lecocq , Raymond W. Simmonds , José Aumentado , John D. Teufel

Polymer quantization is a non-standard representation of the quantum mechanics that inspired by loop quantum gravity. To study the associated statistical mechanics, one needs to find microstates' energies which are eigenvalues of the…

General Relativity and Quantum Cosmology · Physics 2015-06-18 M. A. Gorji , Kourosh Nozari , B. Vakili

Multi-photon quantum interference is the underlying principle for optical quantum information processing protocols. Indistinguishability is the key to quantum interference. Therefore, the success of many protocols in optical quantum…

Quantum Physics · Physics 2020-09-23 Liang Cui , Jie Su , Jiamin Li , Yuhong Liu , Xiaoying Li , Z. Y. Ou

Processing quantum information on continuous variables requires a highly nonlinear element in order to attain universality. Noise reduction in processing such quantum information involves the use of a nonlinear phase state as a non-Gaussian…

Quantum Physics · Physics 2019-11-27 Darren W. Moore , Andrey A. Rakhubovsky , Radim Filip