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Entangled photons are a crucial resource for quantum communication and linear optical quantum computation. Unfortunately, the applicability of many photon-based schemes is limited due to the stochastic character of the photon sources.…

Quantum Physics · Physics 2012-02-07 Stefanie Barz , Gunther Cronenberg , Anton Zeilinger , Philip Walther

Topological pumping and duality transformations are paradigmatic concepts in condensed matter and statistical mechanics. In this paper, we extend the concept of topological pumping of particles to topological pumping of quantum…

Quantum Physics · Physics 2020-02-12 T. Haug , L. Amico , L. -C. Kwek , W. J. Munro , V. M. Bastidas

In most configurations aimed at generating entangled photons based on spontaneous parametric down conversion (SPDC), the generated pairs of photons are required to be entangled in only one degree of freedom. Any distinguishing information…

Quantum Physics · Physics 2009-11-13 Clara I. Osorio , Alejandra Valencia , Juan P. Torres

We present an experiment where two photonic systems of arbitrary dimensions can be entangled. The method is based on spontaneous parametric down conversion with trains of d pump pulses with a fixed phase relation, generated by a mode-locked…

Quantum computation (QC) and simulation rely on long-lived qubits with controllable interactions. Early work in quantum computing made use of molecules because of their readily available intramolecular nuclear spin coupling and chemical…

Three entanglement concentration protocols (ECPs) are proposed. The first ECP and a modified version of that are shown to be useful for the creation of maximally entangled cat and GHZ-like states from their non-maximally entangled…

Quantum Physics · Physics 2022-06-07 Chitra Shukla , Anindita Banerjee , Anirban Pathak

The wave-particle duality demonstrates a competition relation between wave and particle behavior for a particle going through an interferometer. This duality can be formulated as an inequality, which upper bounds the sum of interference…

Quantum Physics · Physics 2018-01-31 Kaifeng Bu , Lu Li , Junde Wu , Shao-Ming Fei

Quantification of quantum entanglement plays a crucial role in the study of quantum information tasks. We present analytical lower bounds for both concurrence and 2-concurrence based on the correlation matrices of bipartite quantum states.…

Quantum Physics · Physics 2025-03-21 Zhi-Bo Chen , Shao-Ming Fei

Pulsed parametric downconversion (PDC) processes generate photon pairs with a rich spectral-temporal structure, which offer an attractive potential for quantum information and communication applications. In this paper, we investigate the…

Quantum Physics · Physics 2013-06-21 Benjamin Brecht , Christine Silberhorn

Polarization-entangled photons are key resources for a wide range of protocols in quantum computation and quantum key distribution. Achieving a near-unity degree of polarization entanglement is essential for minimizing qubit error rates in…

Quantum Physics · Physics 2026-01-27 Urmimala Dewan , Parvendra Kumar , Amarendra K. Sarma

Entanglement distillation has many applications in quantum information processing and is an important tool for improving the quality and efficiency of quantum communication, cryptography, computing, and simulation. We propose an…

Quantum Physics · Physics 2023-08-23 Dan Xu , Changjia Chen , Brian T. Kirby , Li Qian

Entanglement is an extraordinary feature of quantum mechanics. Sources of entangled optical photons were essential to test the foundations of quantum physics through violations of Bell's inequalities. More recently, entangled many-body…

We construct a linear optics measurement process to determine the entanglement measure, named \emph{I-concurrence}, of a set of $4 \times 4$ dimensional two-photon entangled pure states produced in the optical parametric down conversion…

Quantum Physics · Physics 2007-11-20 F. W. Sun , J. M. Cai , J. S. Xu , G. Chen , B. H. Liu , C. F. Li , Z. W. Zhou , G. C. Guo

Entanglement distribution is at the heart of most quantum communication protocols. Inevitable loss of photons along quantum channels is a major obstacle for distributing entangled photons over long distances, as the no-cloning theorem…

We present the convergence study of a recurrence entanglement purification protocol using arbitrary two-qubit initial states. The protocol is based on a rank two projector in the Bell basis which serves as a two-qubit operation replacing…

Quantum Physics · Physics 2016-11-23 Juan Mauricio Torres , József Zsolt Bernád

We investigate entanglement transfer from a system of two spin-entangled electron-hole pairs, each placed in a separate single mode cavity, to the photons emitted during their recombination process. Dipole selection rules and a splitting…

Mesoscale and Nanoscale Physics · Physics 2010-06-24 Jan C. Budich , Bjoern Trauzettel

We present an entanglement criterion for two mode squeezed states which relies on particle counting only. The proposed inequality is optimal for the state under consideration and robust against particle losses up to 2/3. As it does not…

Quantum Physics · Physics 2008-09-16 Christine A. Muschik , Eugene S. Polzik , J. Ignacio Cirac

Quantum entanglement and its paradoxical properties hold the key to an information processing revolution. Much attention has focused recently on the challenging problem of characterizing entanglement. Entanglement for a two qubit system is…

Quantum Physics · Physics 2009-11-07 Vivien M Kendon , Kae Nemoto , William J Munro

Deterministic sources of high-fidelity entangled qubit pairs encoded in the dual-rail photonic basis, i.e., presence of a single photon in one of two orthogonal modes, are a key enabling technology of many applications of quantum…

Quantum Physics · Physics 2022-03-31 Prajit Dhara , Spencer J. Johnson , Christos N. Gagatsos , Paul G. Kwiat , Saikat Guha

Multiparticle entanglement leads to richer correlations than two-particle entanglement and gives rise to striking contradictions with local realism, inequivalent classes of entanglement, and applications such as one-way or topological…

Quantum Physics · Physics 2010-12-03 J. T. Barreiro , P. Schindler , O. Gühne , T. Monz , M. Chwalla , C. F. Roos , M. Hennrich , R. Blatt