English
Related papers

Related papers: Four Photon Entanglement from Down Conversion

200 papers

We propose a simple and realizable method using a two-particle interferometer for the experimental measurement of pairwise entanglement, assuming some prior knowledge about the quantum state. The basic idea is that the properties of the…

Quantum Physics · Physics 2007-05-23 Jian-Ming Cai , Zheng-Wei Zhou , Guang-Can Guo

Tremendous progress has been realized in quantum optics for engineering and detecting the quantum properties of light. Today, photon pairs are routinely created in entangled states. Entanglement is revealed using single-photon detectors in…

Quantum Physics · Physics 2016-05-16 Valentina Caprara Vivoli , Pavel Sekatski , Nicolas Sangouard

This manuscript presents a method to convert position correlation of photon-pairs into polarization entanglement. This is achieved by individually manipulating the polarization state of photons generated in different parts of a non-linear…

Quantum Physics · Physics 2020-07-15 Chithrabhanu Perumangatt , Alexander Lohrmann , Alexander Ling

Entanglement and spontaneous emission are fundamental quantum phenomena that drive many applications of quantum physics. During the spontaneous emission of light from an excited two-level atom, the atom briefly becomes entangled with the…

We explore possibilities of entangling two distant material qubits with the help of an optical radiation field in the regime of strong quantum electrodynamical coupling with almost resonant interaction. For this purpose the optimum…

Quantum Physics · Physics 2025-10-10 J. Z. Bernád , G. Alber

Tomographic analysis demonstrates that the polarization state of pairs of photons emitted from a biexciton decay cascade becomes entangled when spectral filtering is applied. The measured density matrix of the photon pair satisfies the…

Quantum Physics · Physics 2009-11-11 N. Akopian , N. H. Lindner , E. Poem , Y. Berlatzky , J. Avron , D. Gershoni , B. D. Gerardot , P. M. Petroff

An entangled photon experiment has been performed with a large variation of the temperature of the non-linear crystal generating the entangled pair by spontaneous downconversion. The photon pairs are separated by a nonpolarizing…

Quantum Physics · Physics 2019-09-04 Joakim Bergli , Guillaume Adenier , Andreas P. Thörn , Arnt Inge Vistnes

The heralded generation of entangled states is a long-standing goal in quantum information processing, because it is indispensable for a number of quantum protocols. Polarization entangled photon pairs are usually generated through…

Biphoton systems exhibiting entanglement in position-momentum variables, known as spatial entanglement, are among the most intriguing and well-studied phenomena in quantum optics. A notable subset of these are phase entangled states, where…

Quantum Physics · Physics 2025-08-26 Rounak Chatterjee , Mayuresh Kanagal , Vikas S Bhat , Kiran Bajar , Sushil Mujumdar

We classify different classes of entangled states arise in a two-qubit system. Some of these classes are of Bell's state types, while others are of the Werner's state types. The degree of entanglement is quantified for different values of…

Quantum Physics · Physics 2011-05-05 F. N. M. Al-Showaikh , N. Metwally , M. Abdel-Aty

We report an experimental demonstration of entanglement swapping over two quantum stages. By successful realizations of two cascaded photonic entanglement swapping processes, entanglement is generated and distributed between two photons,…

We theoretically model the electronic dynamics of a coupled quantum dot pair in a static electric field. We then investigate the possibility of polarization-entangled photon emission from the radiative cascade of the molecular biexciton…

Mesoscale and Nanoscale Physics · Physics 2016-03-23 Cameron Jennings , Michael Scheibner

Using the process of spontaneous parametric down conversion in a novel two-crystal geometry, one can generate a source of polarization-entangled photon pairs which is orders of magnitude brighter than previous sources. We have measured a…

Quantum Physics · Physics 2009-10-31 Paul G. Kwiat , Edo Waks , Andrew G. White , Ian Appelbaum , Philippe H. Eberhard

A quantum system composed of two or more subsystems can be in an entangled state, i.e. a state in which the properties of the global system are well defined but the properties of each subsystem are not. Entanglement is at the heart of…

The emission of entangled light from planar semiconductor microcavities is studied and the entanglement properties are analyzed and quantified. Phase-matching of the intra-cavity scattering dynamics for multiple pump beams or pulses,…

Quantum Physics · Physics 2015-06-05 D. Pagel , H. Fehske , J. Sperling , W. Vogel

We present a detailed theoretical analysis for the distillation of one copy of a mixed two-mode continuous-variable entangled state using beamsplitters and coherent photon-detection techniques, including conventional on-off detectors and…

Quantum Physics · Physics 2013-05-29 ShengLi Zhang , Peter van Loock

We investigate the quantum state generated by optical parametric down-conversion in a $\chi^{(2) } $ medium driven by two noncollinear light modes. The analysis shows the emergence of multipartite, namely 3- or 4-partite, entangled states…

Quantum Physics · Physics 2021-05-05 Alessandra Gatti , Enrico Brambilla , Ottavia Jedrkiewicz

We image with cameras entangled photon light transmitted through a random medium. Near-field and far-field spatial quantum correlations show that entangled photon pairs (bi-photons) generated by spontaneous optical parametric…

Quantum Physics · Physics 2019-07-09 Soro Gnatiessoro , Alexis Mosset , Eric Lantz , Fabrice Devaux

An experimental scheme for concentrating entanglement in partially entangled photon pairs is proposed. In this scheme, two separated parties obtain one maximally entangled photon pair from previously shared two partially entangled photon…

Quantum Physics · Physics 2009-11-07 Takashi Yamamoto , Masato Koashi , Nobuyuki Imoto

In this theoretical study we demonstrate that entangled states are able to significantly extend the functionality of Hong-Ou-Mandel (HOM) interferometers. By generating a coherent superposition of parametric-down-conversion photons and…

Quantum Physics · Physics 2018-02-07 P. R. Sharapova , K. H. Luo , H. Herrmann , M. Reichelt , C. Silberhorn , T. Meier