Erratum: Bell's theorem with and without inequalities for the three-qubit Greenberger-Horne-Zeilinger and W states [Phys. Rev. A 65, 032108 (2002)]
Adan Cabello
Abstract not available. [Phys. Rev. A 85, 029903 ] published .
Realizing the Multiparticle Hanbury BrownTwiss Interferometer Using Nitrogen-Vacancy Centers in Diamond Crystals
Li Dai and L. C. Kwek
We demonstrate that the multiparticle Hanbury BrownTwiss interferometer can be realized in a network of nitrogen-vacancy centers: for an N-particle system, the interference effect is manifested only in the Nth-order intensity correlation function. The interference effect can be enhanced through a po ... [Phys. Rev. Lett. 108, 066803 ] published .
Complete Set of Operational Measures for the Characterization of Three-Qubit Entanglement
J. I. de Vicente, T. Carle, C. Streitberger, and B. Kraus
We characterize the entanglement contained in a pure three-qubit state via operational entanglement measures. To this end, we derive a new decomposition for arbitrary three-qubit states which is characterized by five parameters (up to local unitary operations). We show that these parameters are uniq ... [Phys. Rev. Lett. 108, 060501 ] published .
Correlations in optically controlled quantum emitters
Cristian E. Susa and John H. Reina
We address the problem of optically controlling and quantifying the dissipative dynamics of quantum and classical correlations in a setup of individual quantum emitters under external laser excitation. We show that both types of correlations, the former measured by the quantum discord, are present i ... [Phys. Rev. A 85, 022111 ] published .
NMR implementation of a quantum delayed-choice experiment
Soumya Singha Roy, Abhishek Shukla, and T. S. Mahesh
We report an experimental demonstration of a quantum delayed-choice experiment via nuclear magnetic resonance techniques. Two spin-1/2 nuclei from each molecule of a liquid ensemble are used as target and ancilla qubits. The circuit corresponding to the recently proposed quantum delayed-choice setup ... [Phys. Rev. A 85, 022109 ] published .
Local-channel-induced rise of quantum correlations in continuous-variable systems
Francesco Ciccarello and Vittorio Giovannetti
It was recently discovered that the quantum correlations of a pair of disentangled qubits, as measured by the quantum discord, can increase solely because of their interaction with a local dissipative bath. Here, we show that a similar phenomenon can occur in continuous-variable bipartite systems. W ... [Phys. Rev. A 85, 022108 ] published .
Observers can always generate nonlocal correlations without aligning measurements by covering all their bases
Joel J. Wallman and Stephen D. Bartlett
Quantum theory allows for correlations between the outcomes of distant measurements that are inconsistent with any locally causal model, as demonstrated by the violation of a Bell inequality. Typical demonstrations of these correlations require careful alignment between the measurements, which requi ... [Phys. Rev. A 85, 024101 ] published .
Low-rank positive-partial-transpose states and their relation to product vectors
Leif Ove Hansen, Andreas Hauge, Jan Myrheim, and Per Oyvind Sollid
Deciding whether a mixed quantum state is separable or entangled is a difficult problem in general. Separable states are positive under partial transposition [they are positive-partial-transpose (PPT) states], but this simple test does not exclude all entangled states. In order to understand the ent ... [Phys. Rev. A 85, 022309 ] published .
Amplitude control of quantum interference
W. J. Mullin and F. Laloe
Usually, the oscillations of interference effects are controlled by relative phases. We show that varying the amplitudes of quantum waves, for instance by changing the reflectivity of beam splitters, can also lead to quantum oscillations and even to Bell violations of local realism. We first study t ... [Phys. Rev. A 85, 023602 ] published .
Nonlocality with less complementarity
Tobias Fritz
In quantum mechanics, nonlocality (a violation of a Bell inequality) is intimately linked to complementarity, by which we mean that consistently assigning values to different observables at the same time is not possible. Nonlocality can only occur when some of the relevant observables do not commute ... [Phys. Rev. A 85, 022102 ] published .
Optimal teleportation with a noisy source
B. G. Taketani, F. de Melo, and R. L. de Matos Filho
We establish the optimal quantum teleportation protocol for the realistic scenario where both the input state and quantum channel are afflicted by noise. By taking these effects into account, higher fidelities are achieved. The optimality of the proposed protocol prevails even when restricted to a r ... [Phys. Rev. A 85, 020301 ] published .
Local Unitary Classification of Arbitrary Dimensional Multipartite Pure States
Bin Liu, Jun-Li Li, Xikun Li, and Cong-Feng Qiao
We propose a practical entanglement classification scheme for general multipartite pure states in arbitrary dimensions under local unitary equivalence by exploiting the high order singular value decomposition technique and local symmetries of the states. By virtue of this scheme, the method of deter ... [Phys. Rev. Lett. 108, 050501 ] published .
Quantum discord and noncontextual hidden-variable models
Kazuo Fujikawa
It is shown that theoretically viable noncontextual hidden-variable models in d=2 lead to conflicting dispersion-free expressions in the analysis of the conditional measurement of two non-orthogonal projectors. No satisfactory criterion of the quantum discord, which relies on the analysis of conditi ... [Phys. Rev. A 85, 012114 ] published .
Engineering two-mode continuous-variable entangled states of distant atomic spin ensembles with superconducting quantum circuits
Peng-Bo Li, Shao-Yan Gao, and Fu-Li Li
We present an experimental feasible scheme to generate two-mode entangled states of two spatially separated atomic spin ensembles, using superconducting quantum circuits consisting of two coplanar waveguide resonators and a charge qubit. We show that, with the charge qubit as a tunable coupler and t ... [Phys. Rev. A 85, 014303 ] published .
Creating quantum correlations through local nonunitary memoryless channels
Francesco Ciccarello and Vittorio Giovannetti
We show that two qubits, initially in a fully classical state, can develop significant quantum correlations as measured by the quantum discord (QD) under the action of a local memoryless noise (specifically we consider the case of a Markovian amplitude-damping channel). This is analytically proven a ... [Phys. Rev. A 85, 010102 ] published .
Indistinguishable Entangled Photons Generated by a Light-Emitting Diode
R. M. Stevenson, C. L. Salter, J. Nilsson, A. J. Bennett, M. B. Ward et al.
A linear optical quantum computer relies on interference between photonic qubits for logic, and entanglement for near-deterministic operation. Here we measure the interference and entanglement properties of photons emitted by a quantum dot embedded within a light-emitting diode. We show that pairs o ... [Phys. Rev. Lett. 108, 040503 ] published .
Quantum privacy witness
Konrad Banaszek, Karol Horodecki, and Pawel Horodecki
While it is usually known that the mean value of a single observable is enough to detect entanglement or its distillability, the counterpart of such an approach in the case of quantum privacy has been missing. Here we develop the concept of a privacy witness, i.e., a single observable that may detec ... [Phys. Rev. A 85, 012330 ] published .
Local phase damping of single qubits sets an upper bound on the phase damping rate of entangled states
Stephan Durr
I derive an inequality in which the phase damping rates of single qubits set an upper bound for the phase damping rate of entangled states of many qubits. The derivation is based on two assumptions: first, that the phase damping can be described by a dissipator in Lindblad form and, second, that the ... [Phys. Rev. A 85, 012110 ] published .
Nonlocality Tests Enhanced by a Third Observer
Daniel Cavalcanti, Rafael Rabelo, and Valerio Scarani
We consider Bell tests involving bipartite states shared between three parties. We show that the simple inclusion of a third part may greatly simplify the measurement scenario (in terms of the number of measurement settings per part) and allows the identification of previously unknown nonlocal resou ... [Phys. Rev. Lett. 108, 040402 ] published .
Efficient Entanglement Criteria beyond Gaussian Limits Using Gaussian Measurements
Hyunchul Nha, Su-Yong Lee, Se-Wan Ji, and M. S. Kim
We present a formalism to derive entanglement criteria beyond the Gaussian regime that can be readily tested by only homodyne detection. The measured observable is the Einstein-Podolsky-Rosen (EPR) correlation. Its arbitrary functional form enables us to detect non-Gaussian entanglement even when an ... [Phys. Rev. Lett. 108, 030503 ] published .
Quantum Nonlocality Does Not Imply Entanglement Distillability
Tamas Vertesi and Nicolas Brunner
Entanglement and nonlocality are both fundamental aspects of quantum theory, and play a prominent role in quantum information science. The exact relation between entanglement and nonlocality is, however, still poorly understood. Here we make progress in this direction by showing that, contrary to wh ... [Phys. Rev. Lett. 108, 030403 ] published .