Quantum discord provides a measure for quantifying quantum correlations beyond entanglement and is very hard to compute even two-qubit states because of the minimization over all possible measurements. Recently simple algorithm evaluate X-states proposed by Ali, Rau Alber [Phys. Rev. A 81, 042105 (2010)] with taken only few cases. Here we shall at first identify class X-states, whose can be evaluated analytically without any minimization, which their valid, also family fails. And then...

Quantum contextuality, as proved by Kochen and Specker, also Bell, should manifest itself in any state system with more than two distinguishable states recently has been experimentally verified. However, for the simplest capable of exhibiting a qutrit, quantum contextuality is verified only dependently experiment because too many (at least 31) observables are involved all known state-independent tests. Here we report an testable inequality involving 13 that satisfied noncontextual realistic...

A kinematic approach to the geometric phase for mixed quantal states in nonunitary evolution is proposed. This manifestly gauge invariant and can be experimentally tested interferometry. It leads well-known results when unitary.

Both cavity quantum electrodynamics and photons are promising candidates for information processing. We consider a combination of both with single photon going through spatially separate cavities to entangle the atomic qubits, based on input-output process cavities. present general expression regarding low-$Q$ confining atom, which works in wide range parameters. Focusing case, we propose some schemes processing Faraday rotation using photons, is much different from high-$Q$ strong-coupling cases.

Realizing Majorana modes (MMs) in condensed-matter systems is of vast experimental and theoretical interests, some signatures MMs have been measured already. To facilitate future observations to explore further applications MMs, generating many at ease an experimentally accessible manner has become one important issue. This task achieved here a one-dimensional $p$-wave superconductor system with the nearest- next-nearest-neighbor interactions. In particular, periodic modulation parameters...

We study the entanglement preservation of two qubits locally interacting with their reservoirs. show that existence a bound state qubit and its reservoir non-Markovian effect are essential ingredients interplay plays crucial role in preserving steady state. When is neglected, sudden death (ESD) reproduced. On other hand, when significantly strong but absent, phenomenon ESD revival recovered. Our formulation presents unified picture about provides clear clue on how to preserve quantum...

We propose an experimental scheme to simulate and detect the properties of time-reversal invariant topological insulators, using cold atoms trapped in one-dimensional bichromatic optical lattices. This system is described by a Aubry-Andre model with additional SU(2) gauge structure, which captures essential two-dimensional ${Z}_{2}$ insulator. demonstrate that topologically protected edge states, opposite spin orientations, can be pumped across lattice sweeping laser phase adiabatically....

Examples of geometric phases abound in many areas physics. They offer both fundamental insights into physical phenomena and lead to interesting practical implementations. One them, as indicated recently, might be an inherently fault-tolerant quantum computation. This, however, requires one deal with the presence noise interactions between different subsystems. Despite wealth literature on subject very little is known about this important case. Here we report first experimental study for...

The novel experimental realization of three-level optical quantum systems is presented. We use the polarization state biphotons to generate a specific sequence states that are used in extended version BB84 protocol. experimentally verify orthogonality basis and demonstrate ability easily switch between them. tomography procedure employed reconstruct density matrices generated states.

A different way to realize nonadiabatic geometric quantum computation is proposed by varying parameters in the Hamiltonian for nuclear-magnetic resonance, where dynamical and phases are implemented separately without usual operational process. Therefore phase accumulated gate a pure any input state. In comparison with conventional gates rotating operations, our approach simplifies experimental implementations making them robust certain errors. contrast unconventional gates, distinguishes...

We propose an optical means to realize the spin-Hall effect (SHE) in a neutral atomic system by coupling internal spin states of atoms radiation. The interaction between external fields and creates effective magnetic that act opposite directions on "electrically" with polarizations. This leads Landau level structure for each orientation direct analogy familiar SHE semiconductors. conservation topological properties current, creation pure current are discussed.

Identifying non-Markovianity with non-divisibility, we propose a measure for non-Markovinity of quantum process. Three examples are presented to illustrate the non-Markovianity, is calculated and discussed. Comparison other measures made. Our has merit that no optimization procedure required it finite any process, which greatly enhances practical relevance proposed measure.

We examine the quantitative condition which has been widely used as a criterion for adiabatic approximation but was recently found insufficient. Our results indicate that usual is sufficient special class of quantum mechanical systems. For general systems, it may not be sufficient, along with additional conditions sufficient. The and constitute validity approximation, applicable to all $N-$dimensional Moreover, we illustrate use in some physical models.

We show that a single Bell's inequality with two dichotomic observables for each observer, which originates from Hardy's nonlocality proof without inequalities, is violated by all entangled pure states of given number particles, may have different energy levels. Thus Gisin's theorem proved in its most general form it follows and quantum entanglement are equivalent.

Fragile quantum features such as entanglement are employed to improve the precision of parameter estimation and a consequence gain becomes vulnerable noise. As an established tool subdue noise, error correction is unfortunately overprotective because enhancement can still be achieved even if states irrecoverably affected, provided that Fisher information, which sets ultimate limit metrological schemes, preserved attained. Here, we develop theory robust schemes preserve information instead...

For general bipartite quantum systems, many sets of locally indistinguishable orthogonal product states have been constructed so far. Here, we first present a method to construct multipartite in ${d}_{1}\ensuremath{\bigotimes}{d}_{2}\ensuremath{\bigotimes}\ensuremath{\cdots}\ensuremath{\bigotimes}{d}_{n}({d}_{1,2,\ensuremath{\cdots},n}\ensuremath{\ge}3,n\ensuremath{\ge}4)$ by using some states. And prove that these cannot be distinguished local operations and classical communication....

We show a new Bell-Clauser-Horne inequality for two entangled three-dimensional quantum systems (so-called qutrits). This is not violated by maximally state of qutrits observed through symmetric three-input- and three-output-port beam splitter only if the amount noise in system greater than $(11\ensuremath{-}6\sqrt{3})/2\ensuremath{\approx}0.308.$ result perfect agreement with previous numerical calculations presented Kaszlikowski et al. [Phys. Rev. Lett. 85, 4418 (2000)]. Moreover, we prove...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExtraordinarily potent antimalarial compounds: new, structurally simple, easily synthesized, tricyclic 1,2,4-trioxanes.Gary H. Posner, Chang Ho Oh, Lucia Gerena, and Wilbur K. MilhousCite this: J. Med. Chem. 1992, 35, 13, 2459–2467Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://pubs.acs.org/doi/10.1021/jm00091a014https://doi.org/10.1021/jm00091a014research-articleACS...

We present a scheme to drive finite-dimensional quantum system into the decoherence-free subspaces(DFS) by Lyapunov control. Control fields are established function. This proposal works well for both closed and open systems, with replacing DFS desired subspaces systems. An example which consists of four-level three degenerate states driven lasers is presented gain further insight scheme, numerical simulations dynamics performed results good.

We derive a single inequality as the sufficient and necessary condition for two unsharp observables of two-level system to be jointly measurable in apparatus construct explicitly joint observables. By introducing generalized distinguishability measure unsharpness an measurement, we complementarity inequality, which generalizes Englert's duality from measurement orthogonal

We investigate dynamics of a laser-driven and dissipative system consisting two nitrogen-vacancy (N-$V$) centers embedded in spatially separated single-mode nanocavities planar photonic crystal (PC). Spontaneous emission from the excited states N-$V$ can be effectively suppressed by virtue Raman transition dispersive regime. The displays series damped oscillations under various experimental situations, where we solve time-dependent Schr\"odinger equation analytically for arbitrary values...

We present a scheme for remotely preparing an arbitrary two-qubit pure state by using two bipartite partially entangled states as the quantum channel, is then generalized to three-qubit case. For cases of remote preparation, we construct different efficient projective measurement bases at sender's side and calculate corresponding success probabilities. It shown that preparation or can be probabilistically achieved with unity fidelity. Moreover, some special ensembles initial states, find...

We extend the recent result of a bipartite Bell singlet [A. W. Carr and M. Saffman, Phys. Rev. Lett. 111, 033607 (2013)] to stationary three-dimensional entanglement between two-individual neutral Rydberg atoms. This proposal makes full use coherent dynamics provided by Rydberg-mediated interaction dissipative factor originating from spontaneous emission state. The numerical simulation master equation reveals that both target state negativity $\mathcal{N}({\stackrel{\ifmmode \hat{}\else...

We investigate the non-Markovian dynamics of quantum correlation between two initially entangled nitrogen-vacancy centers (NVC) embedded in photonic crystal cavities (PCC). find that a finite is preserved even asymptotically when transition frequency NVC within band gap PCC, which quantitatively different from result approaching zero under Born-Markovian approximation. In addition, once far beyond prepared will be fully transferred to reservoirs long-time limit. Our reveals interplay effect...