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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

Bell nonlocality plays a fundamental role in quantum theory. Numerous tests of the Bell inequality have been reported since the ground-breaking discovery of the Bell theorem.Up to now, however, most discussions of the Bell scenario have…

Quantum Physics · Physics 2018-11-08 Meng-Jun Hu , Zhi-Yuan Zhou , Xiao-Min Hu , Chuan-Feng Li , Guang-Can Guo , Yong-Sheng Zhang

We report a nonlocal interferometer capable of detecting entanglement and identifying Bell states statistically. This is possible due to the interferometer's unique correlation dependence on the anti-diagonal elements of the density matrix,…

Quantum Physics · Physics 2016-06-09 Brian P. Williams , Travis S. Humble , Warren P. Grice

We study the frequency-angular lineshape for a phase-matched nonlinear process producing entangled states and show that there is a continuous variety of maximally-entangled states generated for different mismatch values within the natural…

Quantum Physics · Physics 2015-05-13 G. Brida , M. V. Chekhova , M. Genovese , L. A. Krivitsky

Nonlocality is a fascinating and counterintuitive aspect of Nature, revealed by the violation of a Bell inequality. The standard and easiest configuration in which Bell inequalities can be measured has been proposed by…

Quantum Physics · Physics 2015-03-17 Enrico Pomarico , Jean-Daniel Bancal , Bruno Sanguinetti , Anas Rochdi , Nicolas Gisin

Entanglement is an intrinsic property of quantum mechanics and is predicted to be exhibited in the particles produced at the Large Hadron Collider. A measurement of the extent of entanglement in top quark-antiquark ($\mathrm{t\bar{t}}$)…

High Energy Physics - Experiment · Physics 2024-10-30 CMS Collaboration

A method is proposed for generating and discriminating Bell states of high fidelity from consecutive single-photons generated in a semiconductor quantum dot. The use of a non-symmetric beam splitter is found to be essential and sufficient,…

Quantum Physics · Physics 2012-09-17 Partha Ghose

Quantum entanglement is a fundamental property of quantum mechanics. Recently, studies have explored entanglement in the $t\bar{t}$ system at the Large Hadron Collider (LHC) when both the top quark and anti-top quark decay leptonically.…

High Energy Physics - Phenomenology · Physics 2023-10-30 Tao Han , Matthew Low , Tong Arthur Wu

Quantum entangled states of light are essential for quantum technologies and fundamental tests of physics. While quantum information science has relied on systems with entanglement in 2D degrees of freedom, e.g. quantum bits with…

Optics · Physics 2017-10-06 Matthew Reichert , Hugo Defienne , Jason W. Fleischer

Transferring entangled states between photon pairs is essential for quantum communication technologies. Semiconductor quantum dots are the most promising candidate for generating polarization-entangled photons deterministically. Recent…

Quantum Physics · Physics 2019-10-23 Michael Zopf , Robert Keil , Yan Chen , Jingzhong Yang , Disheng Chen , Fei Ding , Oliver G. Schmidt

The generation of entangled photon pairs by parametric down--conversion from solid state CW lasers with small coherence time is theoretically and experimentally analyzed. We consider a compact and low-cost setup based on a two-crystal…

Quantum Physics · Physics 2009-04-16 Simone Cialdi , Fabrizio Castelli , Matteo G. A. Paris

Entanglement does not always require one particle per party. It was predicted some thirty years ago that a single photon traversing a beam splitter could violate a Bell inequality. Although initially debated, single-photon nonlocality was…

Quantum Physics · Physics 2026-04-16 Daniel Kun , Teodor Strömberg , Borivoje Dakić , Philip Walther , Lee A. Rozema

We implement experimentally a deterministic method to prepare and measure so called single-photon two-qubit entangled states or single-photon Bell-states, in which the polarization and the spatial modes of a single-photon each represent a…

Quantum Physics · Physics 2009-11-10 Yoon-Ho Kim

Quantum entanglement represents an ideal resource to guarantee the security of random numbers employed in many scientific and cryptographic applications. However, entanglement-based certified random number generators are particularly…

Quantum Physics · Physics 2022-03-07 Nicolò Leone , Stefano Azzini , Sonia Mazzucchi , Valter Moretti , Lorenzo Pavesi

It is well known that the violation of Bell's inequality in the form given by Clauser, Horne, Shimony, and Holt (CHSH) in two-qubit systems requires entanglement, but not vice versa, i.e., there are entangled states which do not violate the…

Quantum Physics · Physics 2013-11-20 Karol Bartkiewicz , Bohdan Horst , Karel Lemr , Adam Miranowicz

Entangled measurement is a crucial tool in quantum technology. We propose a new entanglement measure of multi-mode detection, which estimates the amount of entanglement that can be created in a measurement. To illustrate the proposed…

We have applied an entanglement purification protocol to produce a single entangled pair of photons capable of violating a CHSH Bell inequality from two pairs that individually could not. The initial poorly-entangled photons were created by…

Quantum Physics · Physics 2009-11-11 P. Walther , K. J. Resch , C. Brukner , A. M. Steinberg , J. -W. Pan , A. Zeilinger

The relation between the violation of the Bell-CHSH inequalities and entanglement properties of quantum states is not clear so one may consider the mixedness of the system to understand the entanglement properties better than the Bell-CHSH…

Quantum Physics · Physics 2009-06-11 Satyabrata Adhikari

Nonlocality, evidenced by the violation of Bell inequalities, not only signifies entanglement but also highlights measurement incompatibility in quantum systems. Utilizing the generalized Clauser-Horne-Shimony-Holt (CHSH) Bell inequality,…

Using a spontaneous-downconversion photon source, we produce true non-maximally entangled states, i.e., without the need for post-selection. The degree and phase of entanglement are readily tunable, and are characterized both by a standard…

Quantum Physics · Physics 2009-10-31 Andrew G. White , Daniel F. V. James , Philippe H. Eberhard , Paul G. Kwiat