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We consider novel method for implementation of hybrid entanglement between microscopic and macroscopic states on output of spontaneous parametric down converter through the depletion of the pump wave. The generated signal, idler and pumping…

Quantum Physics · Physics 2017-08-23 Sergey A. Podoshvedov

A genuine feature of projective quantum measurements is that they inevitably alter the mean energy of the observed system if the measured quantity does not commute with the Hamiltonian. Compared to the classical case, Jacobs proved that…

Statistical Mechanics · Physics 2015-06-10 Kay Brandner , Michael Bauer , Michael T. Schmid , Udo Seifert

We report the observation of symmetry protected two-photon coherence time of biphotons generated from backward spontaneous four-wave mixing in laser-cooled $^{87}$Rb atoms. When biphotons are nondegenerate, non-symmetric photonic absorption…

Quantum Physics · Physics 2024-06-21 Xuanying Lai , Christopher Li , Alan Zanders , Yefeng Mei , Shengwang Du

We study the physics of four-photon states generated in spontaneous parametric down-conversion with a pulsed pump field. In the limit where the coherence time of the photons t_c is much shorter than the duration of the pump pulse Delta t,…

We study how entanglement in photoionization is transferred from an electron-ion pair to an electron-photon pair by fluorescence. Time-resolved von Neumann entropies are used to establish how information is shared between the particles.…

Quantum Physics · Physics 2025-08-18 Axel Stenquist , Jakob Nicolai Bruhnke , Felipe Zapata , Jan Marcus Dahlström

Coherence is intrinsically related to projective measurement. When the fixed projective measurement involves higher-rank projectors, the coherence resource is referred to as block coherence, which comes from the superposition of orthogonal…

Quantum Physics · Physics 2024-07-29 Yu-Hui Wang , Li-Hang Ren , Ming-Liang Hu , Yan-Kui Bai

We demonstrate experimentally the tunable control of the joint spectrum, i.e. waveform and degree of frequency correlations, of paired photons generated in spontaneous parametric downconversion. This control is mediated by the spatial shape…

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 report on an experiment demonstrating entanglement swapping of time-frequency entangled photons. We perform a frequency-resolved Bell-state measurement on the idler photons from two independent entangled photon pairs, which projects the…

Quantum Physics · Physics 2019-10-16 Sofiane Merkouche , Valérian Thiel , Alex O. C. Davis , Brian J. Smith

We provide a theoretical framework to describe the nonequilibrium temporal dynamics of correlated electron systems for realistic system parameters and the consequent, often exponentially long time scales. It is based on an entirely…

Strongly Correlated Electrons · Physics 2026-05-29 Francisco Meirinhos , Michael Turaev , Michael Kajan , Tim Bode , Johann Kroha

We investigate the emergence of quantum coherence and quantum correlations in a two-particle system with deformed symmetries arising from the quantum nature of spacetime. We demonstrate that the deformation of energy-momentum composition…

Quantum Physics · Physics 2025-11-18 Iarley P. Lobo , Gislaine Varão , Giulia Gubitosi , Moises Rojas , Valdir B. Bezerra

We calculate the bi-photon state generated by spontaneous parametric down conversion in a thin crystal and under collinear phase matching conditions using a pump consisting of any superposition of Laguerre-Gauss modes. The result has no…

Quantum Physics · Physics 2011-05-26 Alison M. Yao

The quantum interference of entangled photons forms a key phenomenon underlying various quantum-optical technologies. It is known that the quantum interference patterns of entangled photon pairs can be reconstructed classically by the…

Quantum Physics · Physics 2018-02-21 Kazuhisa Ogawa , Hirokazu Kobayashi , Akihisa Tomita

We demonstrate sub-shot-noise photon-number correlations in a (temporal) multimode mesoscopic ($\sim 10^3$ detected photons) twin-beam produced by ps-pulsed spontaneous non-degenerate parametric downconversion. We have separately detected…

Quantum Physics · Physics 2009-11-13 Maria Bondani , Alessia Allevi , Guido Zambra , Matteo G. A. Paris , Alessandra Andreoni

A pulsed source of entangled photons is desirable for some applications. Yet, such a source has intrinsic problems arising from the simultaneous arrival of the signal and noise photons to the detectors. These problems are analyzed and…

Optics · Physics 2015-06-18 Mónica B. Agüero , Alejandro A. Hnilo , Marcelo G. Kovalsky

We report an experimental study of group-velocity dispersion effect on an entangled two-photon wavepacket, generated via spontaneous parametric down-conversion and propagating through a dispersive medium. Even in the case of using CW laser…

Quantum Physics · Physics 2016-09-08 Alejandra Valencia , Maria V. Chekhova , Alexei Trifonov , Yanhua Shih

We study the onset of a classical order parameter after a second-order phase transition in quantum field theory. We consider a quantum scalar field theory in which the system-field (long-wavelength modes), interacts with its environment,…

High Energy Physics - Phenomenology · Physics 2015-06-25 F. C. Lombardo , F. D. Mazzitelli , R. J. Rivers

Coherence can be induced or stimulated in parametric down-conversion using two or three crystals when, for example, the idler modes of the crystals are aligned. Previous experiments with induced coherence [Phys. Rev. Lett. 114, 053601…

Quantum Physics · Physics 2015-09-23 A. Heuer , R. Menzel , P. W. Milonni

We report on the observation of an unusual type of parametric down-conversion. In the regime where collinear degenerate emission is in the anomalous range of group-velocity dispersion, its spectrum is restricted in both angle and…

Quantum Physics · Physics 2016-06-29 Kirill Spasibko , Denis Kopylov , Tatiana Murzina , Gerd Leuchs , Maria Chekhova

The first direct measurement of photon bunching (g2 correlation function) in one output arm of a spontaneous-parametric-down-conversion source operated with a continuous pump laser in the single-photon regime is demonstrated. The result is…