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We consider a system of two spin-1/2 particles, initially in an entangled Bell state. If one of the particles is interacting with an environment (e.g. a collection of N independent spins), the two-particle system undergoes decoherence.…

Quantum Physics · Physics 2009-12-27 Fedor Levkovich-Maslyuk

A Greenberger Horne Zeilinger (GHZ) entangled state with a phase is crucial for realizing desired multipartite quantum states for practical applications. Here, we report violations of the general Bell inequality (GBI) introduced in [1]…

Quantum Physics · Physics 2023-03-16 Jiho Park , Junghee Ryu , Heonoh Kim , Han Seb Moon

Witnessing continuous-variable Bell nonlocality is a challenging endeavor, but Bell himself showed how one might demonstrate this nonlocality. Though Bell nearly showed a violation using the CHSH inequality with sign-binned…

Quantum Physics · Physics 2016-01-20 James Schneeloch , Samuel H. Knarr , Daniel J. Lum , John C. Howell

Violations of Bell inequalities in classical optics have been demonstrated in terms of field mean intensities and correlations, however, the quantum meaning of violations point to statistics and probabilities. We present a violation of Bell…

Quantum Physics · Physics 2023-01-31 Laura Ares , Alfredo Luis

Many solid-state quantum platforms do not permit sharp, projective measurements but instead yield continuous voltage or field traces under weak, non-demolition readout. In such systems, standard Bell tests based on dichotomic projective…

Quantum Physics · Physics 2025-12-30 Shalender Singh , Santosh Kumar

We find that Bell's inequality can be significantly violated (up to Tsirelson's bound) with two-mode entangled coherent states using only homodyne measurements. This requires Kerr nonlinear interactions for local operations on the entangled…

Quantum Physics · Physics 2007-06-13 Magdalena Stobińska , Hyunseok Jeong , Timothy C. Ralph

The Rayleigh criterion is a widely known limit in the resolution of incoherent sources with classical measurements in the spatial domain. Unsurprisingly the estimation of the time delay between two weak incoherent signals is afflicted by an…

Quantum Physics · Physics 2026-02-12 Salvatore Muratore , Vincenzo Tamma

In an endeavour to better define the distinction between classical macroscopic and quantum microscopic regimes, the Leggett-Garg inequalities were established as a test of macroscopic-realistic theories, which are commonly thought to be a…

Quantum Physics · Physics 2021-04-14 Hadrien Chevalier , A. J. Paige , Hyukjoon Kwon , M. S. Kim

We develop a green light source with low spatial coherence via intracavity frequency doubling of a solid-state degenerate laser. The second harmonic emission supports many more transverse modes than the fundamental emission, and exhibit…

The nature of quantum correlations in networks featuring independent sources of entanglement remains poorly understood. Here, focusing on the simplest network of entanglement swapping, we start a systematic characterization of the set of…

Quantum Physics · Physics 2021-04-21 Nicolas Gisin , Quanxin Mei , Armin Tavakoli , Marc-Olivier Renou , Nicolas Brunner

We study an asymmetric form of two-mode entangled coherent state (ECS), where the two local amplitudes have different values, for testing the Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) inequality. We find that the asymmetric ECSs have…

Quantum Physics · Physics 2015-05-20 Chae-Yeun Park , Hyunseok Jeong

We propose a whole family of physical states that yield a violation of the Bell CHSH inequality arbitrarily close to its maximum value, when using quadrature phase homodyne detection. This result is based on a new binning process called…

The second-order temporal interference between two independent single-mode continuous-wave lasers is discussed by employing two-photon interference in Feynman's path integral theory. It is concluded that whether the second-order temporal…

Optics · Physics 2016-03-18 Jianbin Liu , Dong Wei , Hui Chen , Yu Zhou , Huaibin Zheng , Hong Gao , Fu-li Li , Zhuo Xu

We present a Bell-type polarization experiment using two independent sources of polarized optical photons, and detecting the temporal coincidence of pairs of uncorrelated photons which have never been entangled in the apparatus. Very…

Quantum Physics · Physics 2020-02-10 M. Iannuzzi , R. Francini , R. Messi , D. Moricciani

For the case of two spin-1/2 particles in the singlet state, we provide a GHZ-type proof of Bell's theorem by using the idea of postselected measurements. Furthermore, we show that in spite of the low efficiency of the detectors one can…

Quantum Physics · Physics 2007-05-23 Afshin Shafiee , Mehdi Golshani

We investigate how accidental counts, the detection events not originating from genuine entangled photon pairs, impact the observed violation of Bell inequalities in photonic experiments. These false coincidences become increasingly…

Quantum Physics · Physics 2025-07-29 Piotr Mironowicz , Mohamed Bourennane

We computationally investigate the complete polytope of Bell inequalities for 2 particles with small numbers of possible measurements and outcomes. Our approach is limited by Pitowsky's connection of this problem to the computationally hard…

Quantum Physics · Physics 2023-03-23 Daniel Collins , Nicolas Gisin

We analyze the light scattered by a single InAs quantum dot interacting with a resonant continuous-wave laser. High resolution spectra reveal clear distinctions between coherent and incoherent scattering, with the laser intensity spanning…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 K. Konthasinghe , J. Walker , M. Peiris , C. K. Shih , Y. Yu , M. F. Li , J. F. He , L. J. Wang , H. Q. Ni , Z. C. Niu , A. Muller

We study Bell inequality tests with entanglement between a coherent-state field in a cavity and a two-level atom. In order to detect the cavity field for such a test, photon on/off measurements and photon number parity measurements,…

Quantum Physics · Physics 2015-03-19 Jinwoo Park , Mark Saunders , Yong-il Shin , Kyungwon An , Hyunseok Jeong

We experimentally demonstrate that violations of Bell's inequalities for two-photon polarization-entangled states with colored noise are extremely robust, whereas this is not the case for states with white noise. Controlling the amount of…

Quantum Physics · Physics 2009-07-28 Fabio A. Bovino , Giuseppe Castagnoli , Adan Cabello , Antia Lamas-Linares