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We study experimentally the spatial distribution of quantum noise in the twin beams produced by a type II Optical Parametric Oscillator operating in a confocal cavity above threshold. The measured intensity correlations are at the same time…

Quantum Physics · Physics 2009-11-07 Marcello Martinelli , Nicolas Treps , Sara Ducci , Sylvain Gigan , Agnes Maitre , Claude Fabre

We study the light generated by spontaneous emission into a mode of a cavity QED system under weak excitation of the orthogonally polarized mode. Operating in the intermediate regime of cavity QED with comparable coherent and decoherent…

Quantum Physics · Physics 2009-11-13 M. L. Terraciano , R. Olson Knell , D. L. Freimund , L. A. Orozco , J. P. Clemens , P. R. Rice

Quantum fluctuations of a cavity field coupled into the motion of ultracold bosons can be strongly amplified by a mechanism analogous to the Petermann excess noise factor in lasers with unstable cavities. For a Bose-Einstein condensate in a…

Quantum Physics · Physics 2009-02-26 G. Szirmai , D. Nagy , P. Domokos

The interaction of a quantized field with three-level atoms in $\Lambda$ configuration inside a two-mode cavity is analyzed in the small noise approximation. The atoms are in a two-photon detuning with respect to the carriers of the field.…

Quantum Physics · Physics 2008-01-24 Pablo Barberis-Blostein

We use the quantum correlations of twin-beams of light to probe the added noise when one of the beams propagates through a medium with anomalous dispersion. The experiment is based on two successive four-wave mixing processes in rubidium…

In this paper we study photon pairs generated in a nonlinear cavity, composed of a nonlinear crystal surrounded by mirrors, by the process of spontaneous parametric downconversion. We analyze two different regimes: singly-resonant cavities…

Quantum Physics · Physics 2010-06-02 Yasser Jeronimo-Moreno , Saul Rodriguez-Benavides , Alfred B. U'Ren

We investigate spontaneous photon emission processes of two-level atoms in parabolic and ellipsoidal cavities thereby taking into account the full multimode scenario. In particular, we calculate the excitation probabilities of the atoms and…

Quantum Physics · Physics 2014-12-05 Gernot Alber , Nils Trautmann

Noise affects the coherence of qubits and thereby places a bound on the performance of quantum computers. We theoretically study a generic two-level system with fluctuating control parameters in a photonic cavity and find that basic…

Mesoscale and Nanoscale Physics · Physics 2022-06-22 Philipp M. Mutter , Guido Burkard

We discuss the generation of entangled states of two two-level atoms inside an optical cavity. The cavity mode is supposed to be coupled to a white noise with adjustable intensity. We describe how the entanglement between the atoms inside…

Quantum Physics · Physics 2009-11-10 X. X. Yi , C. S. Yu , L. Zhou , H. S. Song

The influence of outside quantum noises on the amplification of weak measurements is investigated. Three typical quantum noises are discussed. The maximum values of the pointer's shifts decrease sharply with the strength of the depolarizing…

Quantum Physics · Physics 2015-05-11 Xuanmin Zhu , Yu-Xiang Zhang

The rate of spontaneous emission is known to depend on the environment of a light source, and the enhancement of one-photon emission in a resonant cavity is known as the Purcell effect. Here we develop a theory of spontaneous two-photon…

Mesoscale and Nanoscale Physics · Physics 2014-05-21 Alexander N. Poddubny , Pavel Ginzburg , Pavel A. Belov , Anatoly V. Zayats , Yuri S. Kivshar

By invoking the quantum theory of optical coherence, we theoretically show that the quantum noise in conventional optical heterodyne devices, which were previously identified as usual phase-insensitive amplifiers with additional quantum…

Quantum Physics · Physics 2014-11-03 Dechao He , Boya Xie , Yu Xiao , Sheng Feng

We investigate the influence of environmental noise on polarization entangled light generated by parametric emission in a cavity. By adopting a recently developed separability criterion, we show that: i) self-stimulation may suppress the…

Quantum Physics · Physics 2016-08-16 S. Portolan , O. Di Stefano , S. Savasta , F. Rossi , R. Girlanda

In this paper, we develop a simple model describing inherent photon-number noise in Rarity-Tapster type interferometers. This noise is caused by generating photon pairs in the process of spontaneous parametric down-conversion and adding a…

Quantum Physics · Physics 2017-08-30 Vojtěch Trávníček , Karol Bartkiewicz , Antonín Černoch , Karel Lemr

We develop a theory for non-degenerate parametric resonance in a tunable superconducting cavity. We focus on nonlinear effects that are caused by nonlinear Josephson elements connected to the cavity. We analyze parametric amplification in a…

Quantum Physics · Physics 2017-08-31 Waltraut Wustmann , Vitaly Shumeiko

PT-symmetric optical resonators combine absorbing regions with active, amplifying regions. The latter are the source of radiation generated via spontaneous and stimulated emission, which embodies quantum noise and can result in lasing. We…

Optics · Physics 2012-02-29 Gwangsu Yoo , H. -S. Sim , Henning Schomerus

We study the quantum noise in the harmonic mode of a singly resonant frequency doubler simultaneously driven in both modes. This simple extension of the frequency doubler greatly improves its performance as a bright squeezed light source.…

Quantum Physics · Physics 2016-09-08 C. Cabrillo , J. L. Roldan , P. Garcia-Fernandez

Overparametrization is one of the most surprising and notorious phenomena in machine learning. Recently, there have been several efforts to study if, and how, Quantum Neural Networks (QNNs) acting in the absence of hardware noise can be…

Quantum Physics · Physics 2024-03-19 Diego García-Martín , Martin Larocca , M. Cerezo

We introduce a second quantization scheme based on quasinormal modes, which are the dissipative modes of leaky optical cavities and plasmonic resonators with complex eigenfrequencies. The theory enables the construction of…

The expressive capacity of quantum systems for machine learning is limited by quantum sampling noise incurred during measurement. Although it is generally believed that noise limits the resolvable capacity of quantum systems, the precise…

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