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Measurement interaction between a measured object and a measuring instrument, if both are initially in a pure state, produces a (final) bipartite entangled state vector. The quasi-classical part of the correlations in it is connected with…

Quantum Physics · Physics 2007-05-23 Fedor Herbut

We establish a novel approach to probing spatially resolved multi-time correlation functions of interacting many-body systems, with scalable experimental overhead. Specifically, designing nonlinear measurement protocols for multidimensional…

Quantum Physics · Physics 2014-10-07 M. Gessner , F. Schlawin , H. Haeffner , S. Mukamel , A. Buchleitner

Quantum entanglement is usually revealed via a well aligned, carefully chosen set of measurements. Yet, under a number of experimental conditions, for example in communication within multiparty quantum networks, noise along the channels or…

Given a bipartite quantum state rho with subsystems A and B of arbitrary dimensions, we study the entanglement detecting capabilities of locally noneffective, or cyclic, unitary operations [L. B. Fu, Europhys. Lett., vol. 75, pp. 1-7,…

Quantum Physics · Physics 2009-12-21 Sevag Gharibian , Hermann Kampermann , Dagmar Bruss

The nonrelativistic limit of nonlocal modifications to the Klein Gordon operator is studied, and the experimental possibilities of casting stringent constraints on the nonlocality scale via planned and/or current optomechanical experiments…

General Relativity and Quantum Cosmology · Physics 2017-02-01 Alessio Belenchia , Dionigi M. T. Benincasa , Stefano Liberati , Francesco Marin , Francesco Marino , Antonello Ortolan

We introduce a general model for a network of quantum sensors, and we use this model to consider the question: When can entanglement between the sensors, and/or global measurements, enhance the precision with which the network can measure a…

Quantum Physics · Physics 2018-02-28 Timothy J. Proctor , Paul A. Knott , Jacob A. Dunningham

We develop a theory of indirect measurements where a probe is able to read, in short interaction times, the quantum state of a remote system through an incoherent wall. The probe and the system can interact with an ancilla in an incoherent…

Quantum Physics · Physics 2015-05-14 J. Casanova , G. Romero , I. Lizuain , J. C. Retamal , C. F. Roos , J. G. Muga , E. Solano

We develop a theory of quadratic quantum measurements by a mesoscopic detector. It is shown that quadratic measurements should have non-trivial quantum information properties, providing, for instance, a simple way of entangling two…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Wenjin Mao , Dmitri V. Averin , Rusko Ruskov , Alexander N. Korotkov

We derive an analytical approximate solution of the time-dependent state vector in terms of material Bell states and coherent states of the field for a generalized two-atom Tavis-Cummings model with nonlinear intensity dependent…

Quantum Physics · Physics 2021-12-02 Rocío Gómez-Rosas , Carlos A. González-Gutiérrez , Juan Mauricio Torres

Synchronization of coupled harmonic oscillators is investigated. Coupling considered here is pairwise, unidirectional, and described by a nonlinear function (whose graph resides in the first and third quadrants) of some projection of the…

Dynamical Systems · Mathematics 2009-08-04 S. Emre Tuna

Typical optomechanical systems involving optical cavities and mechanical oscillators rely on a coupling that varies linearly with the oscillator displacement. However, recently a coupling varying instead as the square of the mechanical…

Quantum Physics · Physics 2015-06-15 H. Shi , M. Bhattacharya

Entanglement is one of the fundamental properties of a quantum state and is a crucial differentiator between classical and quantum computation. There are many ways to define entanglement and its measure, depending on the problem or…

Quantum Physics · Physics 2025-01-07 Andrii Semenov , Niall Murphy , Simone Patscheider , Alessandra Bernardi , Elena Blokhina

Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and has become a highly successful method for experiments in chemical physics. Current quantum optical experiments…

Quantum Physics · Physics 2016-10-19 Frank Schlawin , Manuel Gessner , Shaul Mukamel , Andreas Buchleitner

Quantum entanglement lies at the heart of quantum mechanics in both fundamental and practical aspects. The entanglement of quantum states has been studied widely, however, the entanglement of operators has not been studied much in spite of…

We present the experimental results of measurements of the overlap of both pure and mixed polarization states of photons. The fidelity and purity of mixed states were also measured. The experimental apparatus exploits the fact that a beam…

Quantum Physics · Physics 2009-11-07 Martin Hendrych , Miloslav Dusek , Radim Filip , Jaromir Fiurasek

This article investigates entanglement of the motional states of massive coupled oscillators. The specific realization of an idealized diatomic molecule in one-dimension is considered, but the techniques developed apply to any massive…

Quantum Physics · Physics 2015-03-13 N. L. Harshman , W. F. Flynn

The quantum nature of the state of a bosonic quantum field manifests itself in its entanglement, coherence, or optical nonclassicality which are each known to be resources for quantum computing or metrology. We provide quantitative and…

Quantum Physics · Physics 2020-09-25 Anaelle Hertz , Nicolas J. Cerf , Stephan De Bièvre

We address the quantification of nonlinearity for quantum oscillators and introduce two measures based on the properties of the ground state rather than on the form of the potential itself. The first measure is a fidelity-based one, and…

Quantum Physics · Physics 2015-01-22 Matteo G. A. Paris , Marco G. Genoni , Nathan Shammah , Berihu Teklu

Entanglement is a key resource for quantum computing, sensing, and communication, however it is highly susceptible to decoherence. To address this, quantum optics has explored filtering techniques like photon ancillas and Rydberg atom…

Measurements with randomly chosen settings determine many important properties of quantum states without the need for a shared reference frame or calibration. They naturally emerge in the context of quantum communication and quantum…