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This paper examines a quantitative and optimal lower bound on the detector efficiency in a (2,2,2) Bell experiment within a fully device-independent framework, whereby the detectors used in the experiment are uncharacterized. We provide a…

Quantum Physics · Physics 2025-11-25 Arkaprabha Ghosal , Soumyadip Patra , Peter Bierhorst

Recent experiments to test Bell's inequality using entangled photons and ions aimed at tests of basic quantum mechanical principles. Interesting results have been obtained and many loopholes could be closed. In this paper we want to point…

Quantum Physics · Physics 2015-06-26 Dimitris G. Angelakis , Almut Beige , Peter L. Knight , William J. Munro , Ben Tregenna

Evaluating an expectation value of an arbitrary observable $A\in{\mathbb C}^{2^n\times 2^n}$ through na\"ive Pauli measurements requires a large number of terms to be evaluated. We approach this issue using a method based on Bell…

Quantum Physics · Physics 2022-04-20 Ruho Kondo , Yuki Sato , Satoshi Koide , Seiji Kajita , Hideki Takamatsu

A family of local models containing two angles as hidden variables is defined for experiments measuring polarization correlation of optical photons. Searching for the best model of the family, that is giving predictions most close to…

Quantum Physics · Physics 2021-06-16 Emilio Santos

Photonic systems based on energy-time entanglement have been proposed to test local realism using the Bell inequality. A violation of this inequality normally also certifies security of device-independent quantum key distribution, so that…

We have developed a scheme to generate, control, transmit and measure entangled photonic qutrits (two photons each of dimension d = 3). A Bell test of this source has previously been reported elsewhere [1], therefore, here we focus on how…

Quantum Physics · Physics 2009-11-10 R. T. Thew , S. Tanzilli , A. Acin , H. Zbinden , N. Gisin

Bell's inequality sets a strict threshold for how strongly correlated the outcomes of measurements on two or more particles can be, if the outcomes of each measurement are independent of actions undertaken at arbitrarily distant locations.…

Quantum Physics · Physics 2022-05-24 David I. Kaiser

A classical model is presented for the features of parametric down-conversion and homodyne detection relevant to recent proposed ``loophole-free'' Bell tests. The Bell tests themselves are uncontroversial: there are no obvious loopholes…

Quantum Physics · Physics 2007-05-23 Caroline H Thompson

Entanglement, describing the inseparability of a quantum multiparty system, is one of the most intriguing features of quantum mechanics. Violation of Bell inequality, for ruling out the possibility of local hidden variable theories, is…

Quantum Physics · Physics 2017-04-21 Xianxin Guo , Yefeng Mei , Shengwang Du

Euclidean volume ratios between quantum states with positive partial transpose and all quantum states in bipartite systems are investigated. These ratios allow a quantitative exploration of the typicality of entanglement and of its…

Quantum Physics · Physics 2022-07-07 A. Sauer , J. Z. Bernád , H. J. Moreno , G. Alber

The use of higher-dimensional photonic encodings (qudits) instead of two-dimensional encodings (qubits) can improve the loss tolerance and reduce the computational resources of photonic-based quantum information processing. To harness this…

Quantum Physics · Physics 2025-04-23 Niv Bharos , Liubov Markovich , Johannes Borregaard

Proposals for Bell inequality tests on systems restricted by superselection rules often require operations that are difficult to implement in practice. In this paper, we derive a new Bell inequality, where pairs of states are used to…

Quantum Physics · Physics 2015-05-19 Libby Heaney , Seung-Woo Lee , Dieter Jaksch

We propose a Bell measurement scheme by employing a logical qubit in Greenberger-Horne-Zeilinger (GHZ) entanglement with an arbitrary number of photons. Remarkably, the success probability of the Bell measurement as well as teleportation of…

Quantum Physics · Physics 2015-03-20 Seung-Woo Lee , Kimin Park , Timothy C. Ralph , Hyunseok Jeong

Recent proposed ``loophole-free'' Bell tests are discussed in the light of classical models for the relevant features of optical parametric amplification and homodyne detection. The Bell tests themselves are uncontroversial: there are no…

Quantum Physics · Physics 2007-05-23 Caroline H Thompson

We derive a Bell inequality based on a generalized quasiprobability function which is parameterized by one non-positive real value. Two types of known Bell inequalities formulated in terms of the Wigner and Q functions are included as…

Quantum Physics · Physics 2009-08-06 Seung-Woo Lee , Hyunseok Jeong , Dieter Jaksch

Recently, V\'{e}rtesi and Bene [Phys. Rev. A. {\bf 82}, 062115 (2010)] derived a two-qubit Bell inequality, $I_{CH3}$, which they show to be maximally violated only when more general positive operator valued measures (POVMs) are used…

Quantum Physics · Physics 2015-06-05 J. F. Barra , E. S. Gómez , G. Cañas , W. A. T. Nogueira , L. Neves , G. Lima

We apply a distance-based Bell-test analysis method [E. Knill et al., Phys. Rev. A. 91, 032105 (2015)] to three experimental data sets where conventional analyses failed or required additional assumptions. The first is produced from a new…

Quantum Physics · Physics 2015-10-28 B. G. Christensen , A. Hill , P. G. Kwiat , E. Knill , S. W. Nam , K. Coakley , S. Glancy , L. K. Shalm , Y. Zhang

A primary requirement for a robust and unconditionally secure quantum network is the establishment of quantum nonlocal correlations over a realistic channel. While loophole-free tests of Bell nonlocality allow for entanglement certification…

We study local-realistic inequalities, Bell-type inequalities, for bipartite pure states of finite dimensional quantum systems -- qudits. There are a number of proposed Bell-type inequalities for such systems. Our interest is in relating…

Quantum Physics · Physics 2017-04-19 Chandan Datta , Pankaj Agrawal , Sujit K. Choudhary

We have determined the maximum quantum violation of 241 tight bipartite Bell inequalities with up to five two-outcome measurement settings per party by constructing the appropriate measurement operators in up to six-dimensional complex and…

Quantum Physics · Physics 2014-03-04 K. F. Pál , T. Vértesi