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Discussions about quantum interference, indistinguishability and superpostion between quantum states goes back to the beginning of quantum mechanics, but the theoretical problem concerning quantitative measures for quantum coherence was…

Optics · Physics 2020-06-24 P. Machado , S. Pádua

Controlling the photon statistics of light is paramount for quantum science and technologies. Recently, we demonstrated that transmitting resonant laser light past an ensemble of two-level emitters can result in a stream of single photons…

Quantum Physics · Physics 2022-12-20 Martin Cordier , Max Schemmer , Philipp Schneeweiss , Jürgen Volz , Arno Rauschenbeutel

In a recent letter [Phys. Rev. Lett. 94, 100501 (2005)], we presented a scheme for generating pure entangled states of spatial qudits ($D$-dimensional quantum systems) by using the momentum transverse correlation of the parametric…

Quantum Physics · Physics 2008-08-14 G. Lima , F. A. Torres-Ruiz , L. Neves , A. Delgado , C. Saavedra , S. Padua

The study of how to generate high-dimensional quantum states (qudits) is justified by the advantages that they can bring for the field of quantum information. However, to have some real practical potential for quantum communication, these…

Quantum Physics · Physics 2015-05-13 G. Lima , A. Vargas , L. Neves , R. Guzmán , C. Saavedra

Dispersively coupled distant qubits in a shared cavity can become entangled through virtual photon exchange with energy-conserving phase evolution of their quantum states. This interaction can potentially be accelerated by operating on…

Other Condensed Matter · Physics 2026-03-16 Andrei Nikitchenko , Guido Burkard

Entangling gates for electron spins in semiconductor quantum dots are generally based on exchange, a short-ranged interaction that requires wavefunction overlap. Coherent spin-photon coupling raises the prospect of using photons as…

Mesoscale and Nanoscale Physics · Physics 2020-03-04 F. Borjans , X. G. Croot , X. Mi , M. J. Gullans , J. R. Petta

We report a quantum eraser experiment which actually uses a Young double-slit to create interference. The experiment can be considered an optical analogy of an experiment proposed by Scully, Englert and Walther. One photon of an entangled…

Quantum Physics · Physics 2009-11-07 S. P. Walborn , M. O. Terra Cunha , S. Padua , C. H. Monken

Geometrical and topological phases play a fundamental role in quantum theory. Geometric phases have been proposed as a tool for implementing unitary gates for quantum computation. A fractional topological phase has been recently discovered…

Pure entangled states of two spatial qudits have been produced by using the momentum transverse correlation of the parametric down-converted photons [Phys. Rev. Lett. \textbf{94} 100501]. Here we show a generalization of this process to…

Quantum Physics · Physics 2009-11-13 G. Lima , F. A. Torres-Ruiz , L. Neves , A. Delgado , C. Saavedra , S. Pádua

We study and experimentally implement a double-slit quantum eraser in the presence of a controlled decoherence mechanism. A two-photon state, produced in a spontaneous parametric down conversion process, is prepared in a maximally entangled…

Quantum Physics · Physics 2015-05-14 F. A. Torres-Ruiz , G. Lima , A. Delgado , S. Pádua , C. Saavedra

Quantum correlation and its measurement are essential in exploring fundamental quantum physics problems and developing quantum enhanced technologies. Quantum correlation may be generated and manipulated in different spaces, which demands…

A double-slit experiment with entangled photons is theoretically analyzed. It is shown that, under suitable conditions, two entangled photons of wavelength $\lambda$ can behave like a \emph{biphoton} of wavelength $\lambda/2$. The…

Quantum Physics · Physics 2018-02-23 Ananya Paul , Tabish Qureshi

We present one- and two-photon diffraction and interference experiments involving parametric down-converted photon pairs. By controlling the divergence of the pump beam in parametric down-conversion, the diffraction-interference pattern…

Quantum Physics · Physics 2009-11-13 Ryosuke Shimizu , Keiichi Edamatsu , Tadashi Itoh

We report an experiment to generate maximally entangled states of D-dimensional quantum systems, qudits, by using transverse spatial correlations of two parametric down-converted photons. Apertures with D-slits in the arms of the twin…

Quantum Physics · Physics 2009-11-10 Leonardo Neves , G. Lima , J. G. Aguirre Gómez , C. H. Monken , C. Saavedra , S. Pádua

High-dimensional entanglement in the form of transverse spatial correlation between a pair of photons generated via spontaneous parametric downconversion is not only a valuable resource in many academic and real-life applications but also…

Quantum Physics · Physics 2025-08-18 Rounak Chatterjee , Vikas S Bhat , Kiran Bajar , Sushil Mujumdar

The realization of strong photon-photon interactions has presented an enduring challenge across photonics, particularly in quantum computing, where two-photon gates form essential components for scalable quantum information processing…

Spatially entangled photon pairs (biphotons) generated by spontaneous parametric down-conversion offer unique opportunities for quantum imaging, but image-plane biphoton correlations are difficult to observe with camera-based detectors.…

Quantum Physics · Physics 2026-01-01 David McFadden , Rainer Heintzmann

The spatial structure of single photons is becoming an extensively explored resource used for facilitating the free-space quantum key distribution and quantum computation as well as for benchmarking the limits of quantum entanglement…

Quantum Physics · Physics 2016-11-08 Radosław Chrapkiewicz , Michał Jachura , Konrad Banaszek , Wojciech Wasilewski

We propose an experimental method to measure the entanglement of coupled spins, each in a separate quantum dot, by means of multiphoton interference patterns generated through the scattering of two laser beams off the quantum dots. We…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Michael N. Leuenberger , Michael E. Flatte , D. D. Awschalom

With Rydberg dipole interactions, a mesoscopic atomic ensemble may behave like a two-level single atom, resulting in the so-called picture of superatom. It is in potential a strong candidate as a qubit in quantum information science,…

Quantum Physics · Physics 2021-06-22 Chao-Wei Yang , Jun Li , Ming-Ti Zhou , Xiao Jiang , Xiao-Hui Bao , Jian-Wei Pan