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By using parametric down-conversion process with a strong signal field injection, we demonstrate coherent frequency down-conversion from a pump photon to an idler photon. Contrary to a common misunderstanding, we show that the process can…

Quantum Physics · Physics 2016-04-13 Yu Ding , Z. Y. Ou

The distribution of entanglement across distant qubits is a central challenge for the operation of scalable quantum computers and large-scale quantum networks. Existing approaches rely on deterministic state transfer schemes or…

Quantum Physics · Physics 2025-10-09 A. Andrés-Juanes , J. Agustí , R. Sett , E. S. Redchenko , L. Kapoor , S. Hawaldar , P. Rabl , J. M. Fink

Entanglement is the quintessential quantum mechanical phenomenon understood to lie at the heart of future quantum technologies and the subject of fundamental scientific investigations. Mixture, resulting from noise, is often an unwanted…

The unconditional entanglement swapping for continuous variables is experimentally demonstrated. Two initial entangled states are produced from two nondegenerate optical parametric amplifiers operating at deamplification. Through…

Quantum Physics · Physics 2009-11-10 Xiaojun Jia , Xiaolong Su , Qing Pan , Jiangrui Gao , Changde Xie , Kunchi Peng

By making use of the spatial shape of paired photons, parametric down-conversion allows the generation of two-photon entanglement in a multidimensional Hilbert space. How much entanglement can be generated in this way? In principle, the…

Quantum Physics · Physics 2012-11-19 Jiří Svozilík , Jan Peřina , Juan P. Torres

In this work we demonstrate the use of stimulated emission tomography to characterize a hyper-entangled state generated by spontaneous parametric down-conversion in a CW-pumped source. In particular, we consider the generation of…

Spontaneous parametric down conversion has been largely exploited as a tool for absolute calibration of photon counting detectors, photomultiplier tubes or avalanche photodiodes working in Geiger regime. In this work we investigate the…

Quantum Physics · Physics 2009-11-13 G. Brida , M. Chekhova , M. Genovese , M. L. Rastello , I. Ruo-Berchera

This article is a theoretical and quantitative exploration of the limit regarding the pump intensity between the two regimes of spontaneous-parametric down-conversion (SPDC) as well as of four-wave-mixing (FWM) in the framework of a…

Quantum Physics · Physics 2026-02-04 Benoît Boulanger , Gaspar Mougin-Trichon , Véronique Boutou

Sources of entangled photon pairs using two parametric down-converters are capable of generating interchangeable entanglement in two different degrees of freedom. The connection between these two degrees of freedom allows the control of the…

Quantum Physics · Physics 2009-11-07 D. P. Caetano , P. H. Souto Ribeiro

In this work, we demonstrate the effect of self-splitting spatial quantum correlations induced by Gouy phase engineering. In the process of spontaneous parametric down conversion the pump beam is structured with a mode superposition that…

We investigate the dynamical behavior of the atom-photon entanglement in a V-type three-level quantum system using the atomic reduced entropy. It is shown that an atom and photons are entangled at the steady-state; however disentanglement…

Quantum Physics · Physics 2012-10-16 Mohammad Abazari , Ali Mortezapour , Mohammad Mahmoudi , Mostafa Sahrai

We consider pulsed-pump spontaneous parametric downconversion (SPDC) as well as pulsed single- and dual-pump spontaneous four-wave mixing processes in waveguides within a unified Hamiltonian theoretical framework. Working with linear…

Quantum Physics · Physics 2021-03-08 L. G. Helt , N. Quesada

We present an integrated source of counterpropagating entangled states based on a coupled resonator optical waveguide that is pumped by a classical pulsed source incident from above the waveguide. We investigate theoretically the generation…

Optics · Physics 2019-10-15 Hossein Seifoory , L. G. Helt , J. E. Sipe , Marc M. Dignam

As a tutorial to the spatial aspects of Spontaneous Parametric Downconversion (SPDC), we present a detailed first-principles derivation of the transverse correlation width of photon pairs in degenerate collinear SPDC. This width defines the…

Quantum Physics · Physics 2018-03-01 James Schneeloch , John C. Howell

Continuous variables multipartite entanglement is a key resource for quantum technologies. This works considers the multipartite entanglement generated in separated spatial modes of the same light beam by three different parametric sources:…

Quantum Physics · Physics 2021-12-08 Alessandra Gatti

The creation of high-quality cluster states in superconducting microwave circuits is a relevant ingredient in continuous-variable quantum computing. Although large-scale cluster states have been established in optical systems, dissipation…

We present a scheme to conditionally engineer an optical quantum system via continuous-variable measurements. This scheme yields high-fidelity squeezed single photon and superposition of coherent states, from input single and two photon…

Continuous-variable encoding of quantum information in the optical domain has recently yielded large temporal and spectral entangled states instrumental for quantum computing and quantum communication. We introduce a protocol for the…

Quantum Physics · Physics 2021-01-20 D. Barral , K. Bencheikh , J. A. Levenson , N. Belabas

In this Letter, we demonstrate the generation of multimode entangled states of propagating microwaves. The entangled states are generated by parametrically pumping a multimode superconducting cavity. By combining different pump frequencies,…

A workflow for evaluation of entanglement source quality is proposed. Based on quantum state density matrices obtained from theoretical models and experimental data, we make an estimate of a potential performance of a quantum entanglement…

Quantum Physics · Physics 2021-04-27 Radim Hošák , Ivo Straka , Ana Predojević , Radim Filip , Miroslav Ježek