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In [J. C. Howell and J. A. Yeazell, Phys. Rev. A 62, 012102 (2000)], a proposal is made to generate entangled macroscopically distinguishable states of two spatially separated traveling optical modes. We model the decoherence due to light…

Quantum Physics · Physics 2016-04-26 J. Clausen , L. Knoell , D. -G. Welsch

We present schemes for the generation and evaluation of continuous variable entanglement of bright optical beams and give a brief overview of the variety of optical techniques and quantum communication applications on this basis. A new…

Quantum Physics · Physics 2009-11-07 N. Korolkova , Ch. Silberhorn , O. Gloeckl , S. Lorenz , Ch. Marquardt , G. Leuchs

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 investigate the entanglement and non-locality between specific spectral components of continuous variable two-mode squeezed mixed states, identifying their limits. These spectral components are selected from output modes using filters…

Quantum Physics · Physics 2025-04-23 Souvik Agasti

We propose a robust deterministic scheme to generate entanglement at high fidelity without the need of photodetectors even for quantum bits, qubits, with extremely poor optically active states. Our protocol employs stimulated Raman…

Quantum Physics · Physics 2013-05-29 Yuichiro Matsuzaki , Paolo Solinas , Mikko Möttönen

Frequency-entangled photons can be readily produced using parametric down-conversion. We have recently shown how such entanglement could be manipulated and measured using electro-optic phase modulators and narrow-band frequency filters,…

We explore the possibility of entanglement detection in continuous variable systems by entanglement witnesses based on covariance matrices, constructible from random homodyne measurements. We propose new linear constraints characterizing…

Quantum Physics · Physics 2021-01-20 Tatiana Mihaescu , Hermann Kampermann , Giulio Gianfelici , Aurelian Isar , Dagmar Bruss

We demonstrate experimentally and theoretically that a coherent image of a pure phase object may be obtained by use of a spatially incoherent illumination beam. This is accomplished by employing a two-beam source of entangled photons…

Optical parametric oscillators (OPOs) are widely utilized in photonics as classical and quantum light sources. Conventional OPOs produce co-propagating signal and idler waves that can be either degenerately or non-degenerately…

Optics · Physics 2025-05-05 Fengyan Yang , Jiacheng Xie , Yiyu Zhou , Yubo Wang , Chengxing He , Yu Guo , Hong X. Tang

A detailed study of the effects of phase fluctuation and dephasing on the dynamics of the entanglement generated from a coherently pumped correlated emission laser is presented. It is found that the time evolution of the entanglement is…

Quantum Physics · Physics 2015-05-27 Sintayehu tesfa

Einstein-Podolsky-Rosen (EPR) entanglement is a criterion that is more demanding than just certifying entanglement. We theoretically and experimentally analyze the low resource generation of bi-partite continuous variable entanglement, as…

We investigate the dynamics for a two level atomic system entangled to coherent states using the recently developed mode invisibility technique. Using a quantum 2-level probe, we demonstrate a way to non-destructively measure a number of…

Quantum Physics · Physics 2017-10-04 Paulina Corona-Ugalde , Marvellous Onuma-Kalu , Robert B. Mann

We describe a scheme for entangling mechanical resonators which is efficient also beyond the resolved sideband regime. It employs the radiation pressure force of the squeezed light produced by a degenerate optical parametric oscillator,…

Quantum Physics · Physics 2016-06-15 Muhammad Asjad , Stefano Zippilli , David Vitali

We present novel experimental results demonstrating the coherence properties of the nonlinear emission from semiconductor microcavities in the strong coupling regime, recently interpreted by parametric polariton four-wave mixing. We use a…

We show that non-classical intensity correlations and quadrature entanglement can be generated by frequency doubling in a resonator with two output ports. We predict twin-beam intensity correlations 6 dB below the coherent state limit, and…

Quantum Physics · Physics 2012-02-01 Oo-Kaw Lim , Mark Saffman

We suggest an entanglement purification scheme for mixed entangled coherent states using 50-50 beam splitters and photodetectors. This scheme is directly applicable for mixed entangled coherent states of the Werner type, and can be useful…

Quantum Physics · Physics 2007-05-23 H. Jeong , M. S. Kim

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

In recent years, the presence of local potentials has significantly enriched and diversified the entanglement patterns in monitored free fermion systems. In our approach, we employ the stochastic Schr\"odinger equation to simulate a…

Quantum Physics · Physics 2026-02-09 Yu-Jun Zhao , Xuyang Huang , Yi-Rui Zhang , Han-Ze Li , Jian-Xin Zhong

Quantum metrology exploits entangled states of particles to improve sensing precision beyond the limit achievable with uncorrelated particles. All previous methods required detection noise levels below this standard quantum limit to realize…

Quantum Physics · Physics 2020-12-09 O. Hosten , R. Krishnakumar , N. J. Engelsen , M. A. Kasevich

Optical parametric amplification/oscillation provide a powerful tool for coherent light generation in spectral regions inaccessible to lasers. Parametric gain is based on a frequency {\it down-conversion} process, and thus it can not be…

Optics · Physics 2016-05-04 Stefano Longhi