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Sample records for nonlocal pancharatnam phase

  1. Transition of Bery Phase and Pancharatnam Phase and Phase Change

    NASA Astrophysics Data System (ADS)

    Fu, Guolan; Pan, Hui; Wang, Zisheng

    2016-07-01

    Berry Phase and time-dependent Pancharatnam phase are investigated for nuclear spin polarization in a liquid by a rotation magnetic field, where two-state mixture effect is exactly included in the geometric phases. We find that when the system of nuclear spin polarization is in the unpolarized state, the transitive phenomena of both Berry phase and Pancharatnam phase are taken place. For the polarized system, in contrast, such a transition is not taken place. It is obvious that the transitions of geometric phase correspond to the phase change of physical system.

  2. Nonlinearity of Pancharatnam's geometric phase in polarizing interferometers.

    PubMed

    Hils, B; Dultz, W; Martienssen, W

    1999-08-01

    Earlier investigations show a time-variable nonlinear shift of the fringe pattern in a polarizing interferometer while rotating a polarizer at the exit. This effect was identified as Pancharatnam's geometrical phase and proposed for applications in interferometry and fast optical switching devices. A heterodyne analysis attributes moving fringes to a frequency difference between the interfering beams; thus changing fringe velocities point to a dynamic frequency development within the period of the uniformly rotating analyzer. This explanation offends the intuition and we undertake an experimental and theoretical investigation of the effect to solve the paradox. We determine, e.g., the complete frequency and mode spectrum of an arbitrary state of polarization P0 behind a rotating linear analyzer and behind a rotating arbitrary linear birefringent plate. We find that, in spite of a fast changing phase in the interferometer, no other (higher) frequency components appear in the spectral distribution of the intensity at the exit than the double of the rotary frequency of the analyzer: phase nonlinearities are compensated for by intensity changes. Only a phase-sensitive detector like an array of photodetectors is able to observe the nonlinearity of Pancharatnam's geometrical phase. A single detector only finds a sinusoidal intensity variation. Our insight into these relations leads us to two new applications of Pancharatnam's phase: supersensitivity of a polarizing double beam interferometer with a video camera acting as a phase detector and external tuning of a Fizeau interferometer. PMID:11970029

  3. Pancharatnam Phase and Quantum Correlation for Two-qubit System in Correlated Dephasing Environment

    NASA Astrophysics Data System (ADS)

    Xie, Bing; Zeng, G. R.; Pan, Hui; Wang, Zisheng

    2016-03-01

    The time-dependent Pancharatnam phase and the quantum correlations are studied for the two-qubit system in correlated dephasing environment. We find that in both X-state and Y-state, the rapid changes of the time-dependent Pancharatnam phase are intrinsic in the died and alive phenomena of quantum entanglement described by the concurrence under the exactly same parameters, while the slow changes of the time-dependent Pancharatnam phase correspond to the sudden death of entanglement. The results show that the time-dependent Pancharatnam phase includes the information of quantum correlations.

  4. Measurement of Pancharatnam's phase by robust interferometric and polarimetric methods

    SciTech Connect

    Loredo, J. C.; Ortiz, O.; De Zela, F.; Weingaertner, R.

    2009-07-15

    We report on theoretical calculations and experimental observations of Pancharatnam's phase originating from arbitrary SU(2) transformations applied to polarization states of light. We have implemented polarimetric and interferometric methods, which allow us to cover the full Poincare sphere. As a distinctive feature, our interferometric array is robust against mechanical and thermal disturbances, showing that the polarimetric method is not inherently superior over the interferometric one, as previously assumed. Our strategy effectively amounts to feeding an interferometer with two copropagating beams that are orthogonally polarized with respect to each other. It can be applied to different types of standard arrays, such as a Michelson, a Sagnac, or a Mach-Zehnder interferometer. We exhibit the versatility of our arrangement by performing measurements of Pancharatnam's phases and fringe visibilities that closely fit the theoretical predictions. Our approach can be easily extended to deal with mixed states and to study decoherence effects.

  5. The Pancharatnam-Berry phase in polarization singular beams

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay; Viswanathan, Nirmal K.

    2013-04-01

    Space-variant inhomogeneously polarized field formed due to superposition of orthogonally polarized Gaussian (LG00) and Laguerre-Gaussian (LG01) beams results in polarization singular beams with different morphology structures such as lemon, star and dipole patterns around the C-point in the beam cross-section. The Pancharatnam-Berry phase plays a critical role in the formation and characteristics of these spatially inhomogeneous fields. We present our experimental results wherein we measure the variable geometric phase by tracking the trajectory of the component vortices in the beam cross-section, by interfering with selective polarization states and by tracking different latitudes on the Poincaré sphere without the effect of a dynamic phase.

  6. Tunable graphene metasurfaces by discontinuous Pancharatnam-Berry phase shift

    NASA Astrophysics Data System (ADS)

    Hu, Xin; Wen, Long; Song, Shichao; Chen, Qin

    2015-12-01

    Metal-dielectric-graphene three-layer structures are proposed to improve the interaction of graphene micro- and nanostructures with incident waves, as the upper graphene cut-wire layer introduces a discontinuous Pancharatnam-Berry phase profile. A semi-analytical method based on the Jones calculus is conducted to investigate the conversion efficiency of cross-polarized light on this graphene metasurface for circularly polarized wave incidence, which predicts that the physical constraint (25%) of cross-coupling conversion efficiency for individual graphene layers can be overcome. Numerical simulations confirm the conclusion and demonstrate an efficiency as high as 60%. Based on this mechanism, high-efficiency anomalous reflection surfaces and flat focal mirrors are designed with the tunability of reflection angles and one order of magnitude improved focusing intensity. This method paves the way to engineering high-efficiency graphene metasurfaces for tunable electromagnetic wave manipulation.

  7. Tunable graphene metasurfaces by discontinuous Pancharatnam-Berry phase shift.

    PubMed

    Hu, Xin; Wen, Long; Song, Shichao; Chen, Qin

    2015-12-18

    Metal-dielectric-graphene three-layer structures are proposed to improve the interaction of graphene micro- and nanostructures with incident waves, as the upper graphene cut-wire layer introduces a discontinuous Pancharatnam-Berry phase profile. A semi-analytical method based on the Jones calculus is conducted to investigate the conversion efficiency of cross-polarized light on this graphene metasurface for circularly polarized wave incidence, which predicts that the physical constraint (25%) of cross-coupling conversion efficiency for individual graphene layers can be overcome. Numerical simulations confirm the conclusion and demonstrate an efficiency as high as 60%. Based on this mechanism, high-efficiency anomalous reflection surfaces and flat focal mirrors are designed with the tunability of reflection angles and one order of magnitude improved focusing intensity. This method paves the way to engineering high-efficiency graphene metasurfaces for tunable electromagnetic wave manipulation. PMID:26585113

  8. Optical integration of Pancharatnam-Berry phase lens and dynamical phase lens

    NASA Astrophysics Data System (ADS)

    Ke, Yougang; Liu, Yachao; Zhou, Junxiao; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-03-01

    In the optical system, most elements such as lens, prism, and optical fiber are made of silica glass. Therefore, integrating Pancharatnam-Berry phase elements into silica glass has potential applications in the optical system. In this paper, we take a lens, for example, which integrates a Pancharatnam-Berry phase lens into a conventional plano-convex lens. The spin states and positions of focal points can be modulated by controlling the polarization states of the incident beam. The proposed lens has a high transmission efficiency, and thereby acts as a simple and powerful tool to manipulate spin photons. Furthermore, the method can be conveniently extended to the optical fiber and laser cavity, and may provide a route to the design of the spin-photonic devices.

  9. A Tunable Dispersion-Free Terahertz Metadevice with Pancharatnam-Berry-Phase-Enabled Modulation and Polarization Control.

    PubMed

    Cong, Longqing; Xu, Ningning; Han, Jiaguang; Zhang, Weili; Singh, Ranjan

    2015-11-01

    It is extremely challenging to control the phase of light at will in free space. Here, Pancharatnam-Berry-phase-enabled, tunable phase control of free-space light is experimentally demonstrated in an ultrathin flexible dispersion-free metadevice. This metadevice enables the broadband conversion of linearly polarized light into any desired output polarization. PMID:26421902

  10. Realization of tunable photonic spin Hall effect by tailoring the Pancharatnam-berry phase.

    PubMed

    Ling, Xiaohui; Zhou, Xinxing; Shu, Weixing; Luo, Hailu; Wen, Shuangchun

    2014-01-01

    Recent developments in the field of photonic spin Hall effect (SHE) offer new opportunities for advantageous measurement of the optical parameters (refractive index, thickness, etc.) of nanostructures and enable spin-based photonics applications in the future. However, it remains a challenge to develop a tunable photonic SHE with any desired spin-dependent splitting for generation and manipulation of spin-polarized photons. Here, we demonstrate experimentally a scheme to realize the photonic SHE tunably by tailoring the space-variant Pancharatnam-Berry phase (PBP). It is shown that light beams whose polarization with a tunable spatial inhomogeneity can contribute to steering the space-variant PBP which creates a spin-dependent geometric phase gradient, thereby possibly realizing a tunable photonic SHE with any desired spin-dependent splitting. Our scheme provides a convenient method to manipulate the spin photon. The results can be extrapolated to other physical system with similar topological origins. PMID:24990359

  11. Realization of Tunable Photonic Spin Hall Effect by Tailoring the Pancharatnam-Berry Phase

    PubMed Central

    Ling, Xiaohui; Zhou, Xinxing; Shu, Weixing; Luo, Hailu; Wen, Shuangchun

    2014-01-01

    Recent developments in the field of photonic spin Hall effect (SHE) offer new opportunities for advantageous measurement of the optical parameters (refractive index, thickness, etc.) of nanostructures and enable spin-based photonics applications in the future. However, it remains a challenge to develop a tunable photonic SHE with any desired spin-dependent splitting for generation and manipulation of spin-polarized photons. Here, we demonstrate experimentally a scheme to realize the photonic SHE tunably by tailoring the space-variant Pancharatnam-Berry phase (PBP). It is shown that light beams whose polarization with a tunable spatial inhomogeneity can contribute to steering the space-variant PBP which creates a spin-dependent geometric phase gradient, thereby possibly realizing a tunable photonic SHE with any desired spin-dependent splitting. Our scheme provides a convenient method to manipulate the spin photon. The results can be extrapolated to other physical system with similar topological origins. PMID:24990359

  12. Switchable liquid-crystal phase-shift mask for super-resolution photolithography based on Pancharatnam-Berry phase

    NASA Astrophysics Data System (ADS)

    Glazar, Nikolaus; Culbreath, Christopher; Li, Yannian; Yokoyama, Hiroshi

    2015-11-01

    We present a novel liquid-crystal-based phase-shift mask that utilizes the Pancharatnam-Berry phase for super-resolution photolithography. Using an automated maskless photoalignment technique, we pattern an azobenzene alignment layer in a nematic liquid-crystal cell to fabricate the mask. Since the image is formed by phase cancellation, the minimum feature size is not restricted by the diffraction limit; here, we obtain submicron features. The liquid-crystal properties of the cell allow the mask to be switched on and off by applying a voltage. The cost effectiveness and flexibility of this technique make it a promising new technology for photolithography.

  13. Identifying Orbital Angular Momentum of Vectorial Vortices with Pancharatnam Phase and Stokes Parameters

    PubMed Central

    Zhang, Dengke; Feng, Xue; Cui, Kaiyu; Liu, Fang; Huang, Yidong

    2015-01-01

    In this work, an explicit formula is deduced for identifying the orbital angular moment (OAM) of vectorial vortex with space-variant state of polarization (SOP). Different to scalar vortex, the OAM of vectorial vortex can be attributed to two parts: 1. the azimuthal gradient of Pancharatnam phase; 2. the product between the azimuthal gradient of orientation angle of SOP and relevant solid angle on the Poincaré sphere. With our formula, a geometrical description for OAM of light beams can be achieved under the framework of the traditional Poincaré sphere. Numerical simulations for two types of vectorial vortices have been carried on to confirm our presented formula as well as demonstrate the geometrical description of OAM. Furthermore, this work would pave the way for precise characterization of OAM charge of vectorial vortices. PMID:26160007

  14. Polarization-controlled evolution of light transverse modes and associated Pancharatnam geometric phase in orbital angular momentum

    SciTech Connect

    Karimi, Ebrahim; Marrucci, Lorenzo; Slussarenko, Sergei; Piccirillo, Bruno; Santamato, Enrico

    2010-05-15

    We present an easy, efficient, and fast method to generate arbitrary linear combinations of light orbital angular-momentum eigenstates l={+-}2 starting from a linearly polarized TEM{sub 00} laser beam. The method exploits the spin-to-orbital angular-momentum conversion capability of a liquid-crystal-based q plate and a Dove prism inserted into a Sagnac polarizing interferometer. The nominal generation efficiency is 100%, being limited only by reflection and scattering losses in the optical components. When closed paths are followed on the polarization Poincare sphere of the input beam, the associated Pancharatnam geometric phase is transferred unchanged to the orbital angular momentum state of the output beam.

  15. Analysis of a dual-twist Pancharatnam phase device with ultrahigh-efficiency large-angle optical beam steering.

    PubMed

    Cheng, HsienHui; Bhowmik, Achintya K; Bos, Philip J

    2015-12-01

    It has been previously shown that a Pancharatnam phase device with a dual-twist structure can deflect light up to 60° with nearly perfect efficiency. This was beyond the limits previously assumed for these types of devices, which were considered to be optically similar to Raman-Nath gratings. In this paper we first consider the range of parameters that will allow for high efficiency and show the results for a structure that demonstrates 80° deflection. We then explore the light propagation through these devices to point out interesting intensity variations in the deflected mode of light as it traverses the deflecting layer. Finally, we explain the key to understanding the efficiency of these devices, which is not the typical parameters that are important for traditional diffractive devices, but rather the control of the polarization state of light. We provide a simple design approach for optimizing the twist angle and retardation for high efficiency. PMID:26836657

  16. Nonlocal nonlinear refraction in Hibiscus sabdariffa with large phase shifts.

    PubMed

    Ramírez-Martínez, D; Alvarado-Méndez, E; Trejo-Durán, M; Vázquez-Guevara, M A

    2014-10-20

    In this work we present a study of nonlinear optical properties in organic materials (hibiscus sabdariffa). Our results demonstrate that the medium exhibits a highly nonlocal nonlinear response. We show preliminary numerical results of the transmittance as nonlocal response by considering, simultaneously, the nonlinear absorption and refraction in media. Numerical results are accord to measurement obtained by Z- scan technique where we observe large phase shifts. We also analyze the far field diffraction ring patterns of the sample. PMID:25401548

  17. Persistent chimera states in nonlocally coupled phase oscillators

    NASA Astrophysics Data System (ADS)

    Suda, Yusuke; Okuda, Koji

    2015-12-01

    Chimera states in the systems of nonlocally coupled phase oscillators are considered stable in the continuous limit of spatially distributed oscillators. However, it is reported that in the numerical simulations without taking such limit, chimera states are chaotic transient and finally collapse into the completely synchronous solution. In this Rapid Communication, we numerically study chimera states by using the coupling function different from the previous studies and obtain the result that chimera states can be stable even without taking the continuous limit, which we call the persistent chimera state.

  18. Frustrated quantum phase diffusion and increased coherence of solitons due to nonlocality

    SciTech Connect

    Batz, Sascha; Peschel, Ulf

    2011-03-15

    We investigate the quantum properties of solitons with nonlocal self-interaction. We find significant changes when compared to the local interaction. Quantum phase diffusion of nonlocal solitons is always reduced with respect to the local interaction and vanishes in the strongly nonlocal limit. Thus, coherence is increased in the nonlocal case. Furthermore, we compare the intrinsic quantum wave packet spreading to the recently discussed classical Gordon-Haus effect for nonlocal solitons [V. Folli and C. Conti, Phys. Rev. Lett. 104, 193901 (2010)].

  19. Phase-flip chimera induced by environmental nonlocal coupling.

    PubMed

    Chandrasekar, V K; Gopal, R; Senthilkumar, D V; Lakshmanan, M

    2016-07-01

    We report the emergence of a collective dynamical state, namely, the phase-flip chimera, from an ensemble of identical nonlinear oscillators that are coupled indirectly via the dynamical variables from a common environment, which in turn are nonlocally coupled. The phase-flip chimera is characterized by the coexistence of two adjacent out-of-phase synchronized coherent domains interspersed by an incoherent domain, in which the nearby oscillators are in out-of-phase synchronized states. Attractors of the coherent domains are either from the same or from different basins of attractions, depending on whether they are periodic or chaotic. The conventional chimera precedes the phase-flip chimera in general. Further, the phase-flip chimera emerges after the completely synchronized evolution of the ensemble, in contrast to conventional chimeras, which emerge as an intermediate state between completely incoherent and coherent states. We have also characterized the observed dynamical transitions using the strength of incoherence, probability distribution of the correlation coefficient, and framework of the master stability function. PMID:27575124

  20. Phase-flip chimera induced by environmental nonlocal coupling

    NASA Astrophysics Data System (ADS)

    Chandrasekar, V. K.; Gopal, R.; Senthilkumar, D. V.; Lakshmanan, M.

    2016-07-01

    We report the emergence of a collective dynamical state, namely, the phase-flip chimera, from an ensemble of identical nonlinear oscillators that are coupled indirectly via the dynamical variables from a common environment, which in turn are nonlocally coupled. The phase-flip chimera is characterized by the coexistence of two adjacent out-of-phase synchronized coherent domains interspersed by an incoherent domain, in which the nearby oscillators are in out-of-phase synchronized states. Attractors of the coherent domains are either from the same or from different basins of attractions, depending on whether they are periodic or chaotic. The conventional chimera precedes the phase-flip chimera in general. Further, the phase-flip chimera emerges after the completely synchronized evolution of the ensemble, in contrast to conventional chimeras, which emerge as an intermediate state between completely incoherent and coherent states. We have also characterized the observed dynamical transitions using the strength of incoherence, probability distribution of the correlation coefficient, and framework of the master stability function.

  1. Meson phenomenology and phase transitions in nonlocal chiral quark models

    NASA Astrophysics Data System (ADS)

    Carlomagno, J. P.; Gomez Dumm, D.; Pagura, V.; Scoccola, N. N.

    2015-07-01

    We study the features of nonlocal chiral quark models that include wave function renormalization. Model parameters are determined from meson phenomenology, considering different nonlocal form factor shapes. In this context we analyze the characteristics of the deconfinement and chiral restoration transitions at finite temperature and chemical potential, introducing the couplings of fermions to the Polyakov loop for different Polyakov potentials. The results for various thermodynamical quantities are compared with data obtained from lattice QCD calculations.

  2. Detecting Majorana fermions in quasi-one-dimensional topological phases using nonlocal order parameters

    NASA Astrophysics Data System (ADS)

    Bahri, Yasaman; Vishwanath, Ashvin

    2014-04-01

    Topological phases which host Majorana fermions can not be identified via local order parameters. We give simple nonlocal order parameters to distinguish quasi-one-dimensional (1D) topological superconductors of spinless fermions, for any interacting model in the absence of time reversal symmetry. These string or "brane" order parameters are natural for measurements in cold atom systems using quantum gas microscopy. We propose them as a way to identify symmetry-protected topological phases of Majorana fermions in cold atom experiments via bulk rather than edge degrees of freedom. Subsequently, we study two-dimensional (2D) topological superconductors via the quasi-1D limit of coupling N identical chains on the cylinder. We classify the symmetric, interacting topological phases protected by the additional ZN translation symmetry. The phases include quasi-1D analogs of (i) the p +ip chiral topological superconductor, which can be distinguished up to the 2D Chern number mod 2, and (ii) the 2D weak topological superconductor. We devise general rules for constructing nonlocal order parameters which distinguish the phases. These rules encode the signature of the fermionic topological phase in the symmetry properties of the terminating operators of the nonlocal string or brane. The nonlocal order parameters for some of these phases simply involve a product of the string order parameters for the individual chains. Finally, we give a physical picture of one of the topological phases as a condensate of certain defects, which motivates the form of the nonlocal order parameter and is reminiscent of higher dimensional constructions of topological phases.

  3. Phase diagram and critical end point in nonlocal PNJL models with wavefunction renormalization

    SciTech Connect

    Contrera, Gustavo A.; Orsaria, Milva G.; Scoccola, Norberto N.

    2010-11-12

    We study the chiral phase transition at finite temperature and chemical potential considering a non-local chiral quark model which includes wave-function renormalization and coupling to the Polyakov loop. In particular, we determine the position of the Critical End Point as well as the value of the associated critical exponents for different model parameterizations.

  4. Controllable soliton propagation based on phase-front curvature in asymmetrical nonlocal media

    NASA Astrophysics Data System (ADS)

    Zhang, Huafeng; Lü, Hua; Luo, Jianghua; Sun, Lihui

    2016-08-01

    The influence of phase-front curvature on the dynamical behavior of the fundamental mode soliton during its transmission in asymmetrical nonlocal media is studied in detail and the phase-front curvature can be imposed on the fundamental mode soliton by reshaping or phase imprinting technologies. By changing the phase-front curvature or its imposed position, controllable soliton propagation in asymmetrical nonlocal media can be achieved. Project supported by the National Natural Science Foundation of China (Grants Nos. 11547007 and 11304024), the Innovation Personnel Training Plan for Excellent Youth of Guangdong University Project (Grant No. 2013LYM_0023), and the Yangtze Fund for Youth Teams of Science and Technology Innovation (Grant No. 2015cqt03).

  5. Three phases in the three-dimensional Abelian-Higgs model with nonlocal gauge interactions

    SciTech Connect

    Takashima, Shunsuke; Ichinose, Ikuo; Matsui, Tetsuo; Sakakibara, Kazuhiko

    2006-08-15

    We study the phase structure of the three-dimensional (3D) nonlocal compact U(1) lattice gauge theory coupled with a Higgs field by Monte Carlo simulations. The nonlocal interactions among gauge variables are along the temporal direction and mimic the effect of local coupling to massless particles. In contrast to the 3D local Abelian-Higgs model having only the confinement phase, the present model exhibits the confinement, Higgs, and Coulomb phases separated by three second-order transition lines emanating from a triple point. This result is relevant not only to the 3D massless QED coupled with a Higgs field but also to electron fractionalization phenomena in strongly correlated electron systems like the high-T{sub c} superconductors and the fractional quantum Hall effect.

  6. Generalized Ginzburg-Landau approach to inhomogeneous phases in nonlocal chiral quark models

    NASA Astrophysics Data System (ADS)

    Carlomagno, J. P.; Gómez Dumm, D.; Scoccola, N. N.

    2015-05-01

    We analyze the presence of inhomogeneous phases in the QCD phase diagram within the framework of nonlocal chiral quark models. We concentrate in particular in the positions of the tricritical (TCP) and Lifshitz (LP) points, which are studied in a general context using a generalized Ginzburg-Landau approach. We find that for all the phenomenologically acceptable model parametrizations considered the TCP is located at a higher temperature and a lower chemical potential in comparison with the LP. Consequently, these models seem to favor a scenario in which the onset of the first order transition between homogeneous phases is not covered by an inhomogeneous, energetically favored phase.

  7. Deconfinement Phase Transition in a 3D Nonlocal U(1) Lattice Gauge Theory

    SciTech Connect

    Arakawa, Gaku; Ichinose, Ikuo; Matsui, Tetsuo; Sakakibara, Kazuhiko

    2005-06-03

    We introduce a 3D compact U(1) lattice gauge theory having nonlocal interactions in the temporal direction, and study its phase structure. The model is relevant for the compact QED{sub 3} and strongly correlated electron systems like the t-J model of cuprates. For a power-law decaying long-range interaction, which simulates the effect of gapless matter fields, a second-order phase transition takes place separating the confinement and deconfinement phases. For an exponentially decaying interaction simulating matter fields with gaps, the system exhibits no signals of a second-order transition.

  8. Phase diagram of neutral quark matter in nonlocal chiral quark models

    NASA Astrophysics Data System (ADS)

    Gómez Dumm, D.; Blaschke, D. B.; Grunfeld, A. G.; Scoccola, N. N.

    2006-06-01

    We consider the phase diagram of two-flavor quark matter under neutron star constraints for two nonlocal, covariant quark models within the mean-field approximation. In the first case (Model I) the nonlocality arises from the regularization procedure, motivated by the instanton liquid model, whereas in the second one (Model II) a separable approximation of the one-gluon exchange interaction is applied. We find that Model II predicts a larger quark mass gap and a chiral symmetry breaking (CSB) phase transition line which extends 15 20% further into the phase diagram spanned by temperature (T) and chemical potential (μ). The corresponding critical temperature at μ=0, Tc(0)≃140MeV, is in better accordance to recent lattice QCD results than the prediction of the standard local NJL model, which exceeds 200 MeV. For both Model I and Model II we have considered various coupling strengths in the scalar diquark channel, showing that different low-temperature quark matter phases can occur at intermediate densities: a normal quark matter (NQM) phase, a two-flavor superconducting (2SC) quark matter phase and a mixed 2SC-NQM phase. Although in most cases there is also a gapless 2SC phase, this occurs in general in a small region at nonzero temperatures, thus its effect should be negligible for compact star applications.

  9. Hierarchy, factorization law of two measurement-induced nonlocalities and their performances in quantum phase transition

    NASA Astrophysics Data System (ADS)

    Qiu, Liang; Liu, Zhi

    2016-05-01

    There are two measurement-induced nonlocalities, which are, respectively, defined via the trace norm (MIN-1) and Hilbert-Schmidt norm (MIN-2). We investigate the hierarchy relation and factorization law of them. Their performances in quantum phase transition have also been explored. For X-shape states, a rigorous hierarchy relation is established between two MINs. When two qubits, which are initially prepared in an X-shape state, interact independently with the corresponding multimode vacuum reservoirs, the evolutions of two MINs satisfy the factorization law. With quantum renormalization group method, it is found that two MINs can signify the criticality of the spin system while the position where the derivative of MIN-1 takes the minimum value is always larger than that where the derivative of MIN-2 takes the minimum value. Therefore, MIN-1 is more suitable to identify the critical point of quantum phase transition.

  10. Chimera states in systems of nonlocal nonidentical phase-coupled oscillators

    NASA Astrophysics Data System (ADS)

    Xie, Jianbo; Kao, Hsien-Ching; Knobloch, Edgar

    2015-03-01

    Chimera states consisting of domains of coherently and incoherently oscillating nonlocally coupled phase oscillators in systems with spatial inhomogeneity are studied. The inhomogeneity is introduced through the dependence of the oscillator frequency on its location. Two types of spatial inhomogeneity, localized and spatially periodic, are considered and their effects on the existence and properties of multicluster and traveling chimera states are explored. The inhomogeneity is found to break up splay states, to pin the chimera states to specific locations, and to trap traveling chimeras. Many of these states can be studied by constructing an evolution equation for a complex order parameter. Solutions of this equation are in good agreement with the results of numerical simulations.

  11. Geometric phases and quantum correlations of superconducting two-qubit system with dissipative effect

    NASA Astrophysics Data System (ADS)

    Xue, Liyuan; Yu, Yanxia; Cai, Xiaoya; Pan, Hui; Wang, Zisheng

    2016-01-01

    We investigate time-dependent Pancharatnam phases and the relations between such geometric phases and quantum correlations, i.e., quantum discord and concurrence, of superconducting two-qubit coupling system in dissipative environment with the mixture effects of four different eigenstates of density matrix. We find that the time-dependent Pancharatnam phases not only keep the motion memory of such a two-qubit system, but also include the information of quantum correlations. We show that the sudden died and alive phenomena of quantum entanglement are intrinsic in the transition of Pancharatnam phase in the X-state and the complex oscillations of Pancharatnam phase in the Y-state. The faster the Pancharatnam phases change, the slower the quantum correlations decay. In particular, we find that a subspace of quantum entanglement can exist in the Y-state by choosing suitable coupling parameters between two-qubit system and its environment, or initial conditions.

  12. On an Inviscid Model for Incompressible Two-Phase Flows with Nonlocal Interaction

    NASA Astrophysics Data System (ADS)

    Gal, Ciprian G.

    2016-03-01

    We consider a diffuse interface model which describes the motion of an ideal incompressible mixture of two immiscible fluids with nonlocal interaction in two-dimensional bounded domains. This model consists of the Euler equation coupled with a convective nonlocal Cahn-Hilliard equation. We establish the existence of globally defined weak solutions as well as well-posedness results for strong/classical solutions.

  13. Morphological evolution and migration of void in bi-piezoelectric interface based on nonlocal phase field method

    NASA Astrophysics Data System (ADS)

    Li, H. B.; Wang, X.

    2016-05-01

    This paper reports the result of investigation into the morphological evolution and migration of void in bi-piezoelectric material interface by utilizing nonlocal phase field model and finite element method (FEM), where the small scale effect containing the long-range forces among atoms is considered. The nonlocal elastic strain energy and the nonlocal electric energy around the void are firstly calculated by the finite element method. Then based on the finite difference method (FDM), the thermodynamic equilibrium equation containing the surface energy and anisotropic diffusivity is solved to simulate the morphological evolution and migration of elliptical void in bi-piezoelectric films interface. Results show that the way of load condition plays a significant role in the evolution process, and the boundary of void's long axis gradually collapses toward the center of ellipse. In addition, the evolutionary speed of left boundary gradually decreases with scale effect coefficient growth. This work can provide references for the safety evaluation of piezoelectric materials in micro electro mechanical system.

  14. Aspects of the strongly interacting matter phase diagram within non-local quark models

    SciTech Connect

    Pagura, V.; Dumm, D. G.; Scoccola, N. N.

    2013-03-25

    We study a nonlocal extension of the so-called Polyakov Nambu-Jona-Lasinio model at finite temperature and chemical potential, considering the impact of the presence of dynamical quarks on the scale parameter appearing in the Polyakov potential. Both real and imaginary chemical potentials are considered. The effect of varying the current quark mass is also investigated.

  15. Pancharatnam-Berry optical element sorter of full angular momentum eigenstate.

    PubMed

    Walsh, Gary F

    2016-03-21

    We propose and numerically demonstrate a Pancharatnam-Berry optical element (PBOE) device that simultaneously sorts spin (SAM) and orbital (OAM) angular momentum. This device exploits the circular polarization selective properties of PBOEs to modulate independently the orthogonal SAM eigenstates within a geometric optical transformation that sorts OAM, enabling single measurement characterization of the full angular momentum eigenstate. This expands the available state space for OAM communication and enables characterization of the eigenmode composition of structured polarization beams. We define the two-dimensional orientation patterns of the transversely varying half-waveplate PBOEs that implement the angular momentum sorter. We show that the device discriminates the OAM and SAM eigenstates of optical beams including laser cavity modes such as Laguerre-Gaussian OAM eigenmodes, Hermite-Gaussian modes, and hybrid modes with complex structured polarization. We also demonstrate that it can determine the m parameter of higher order LGml Laguerre-Gaussian modes. The ability of this device to decode information from spatially structured optical phase has potential for applications in communication, encryption, modal characterization, and scientific measurements. PMID:27136857

  16. Nonlocality Without Nonlocality

    NASA Astrophysics Data System (ADS)

    Weinstein, Steven

    2009-08-01

    Bell’s theorem is purported to demonstrate the impossibility of a local “hidden variable” theory underpinning quantum mechanics. It relies on the well-known assumption of ‘locality’, and also on a little-examined assumption called ‘statistical independence’ ( SI). Violations of this assumption have variously been thought to suggest “backward causation”, a “conspiracy” on the part of nature, or the denial of “free will”. It will be shown here that these are spurious worries, and that denial of SI simply implies nonlocal correlation between spacelike degrees of freedom. Lorentz-invariant theories in which SI does not hold are easily constructed: two are exhibited here. It is conjectured, on this basis, that quantum-mechanical phenomena may be modeled by a local theory after all.

  17. Rate-Independent Dynamics and Kramers-Type Phase Transitions in Nonlocal Fokker-Planck Equations with Dynamical Control

    NASA Astrophysics Data System (ADS)

    Herrmann, Michael; Niethammer, Barbara; Velázquez, Juan J. L.

    2014-08-01

    The hysteretic behavior of many-particle systems with non-convex free energy can be modeled by nonlocal Fokker-Planck equations that involve two small parameters and are driven by a time-dependent constraint. In this paper we consider the fast reaction regime related to Kramers-type phase transitions and show that the dynamics in the small-parameter limit can be described by a rate-independent evolution equation with hysteresis. For the proof we first derive mass-dissipation estimates by means of Muckenhoupt constants, formulate conditional stability estimates, and characterize the mass flux between the different phases in terms of moment estimates that encode large deviation results. Afterwards we combine all these partial results and establish the dynamical stability of localized peaks as well as sufficiently strong compactness results for the basic macroscopic quantities.

  18. On the connection between quantum nonlocality and phase sensitivity of two-mode entangled Fock state superpositions

    NASA Astrophysics Data System (ADS)

    Seshadreesan, Kaushik P.; Wildfeuer, Christoph F.; Kim, Moochan B.; Lee, Hwang; Dowling, Jonathan P.

    2016-03-01

    In two-mode interferometry, for a given total photon number N, entangled Fock state superpositions of the form (|N-mrangle _a|mrangle _b+e^{i (N-2m)φ }|mrangle _a|N-mrangle _b)/sqrt{2} have been considered for phase estimation. Indeed all such states are maximally mode-entangled and violate a Clauser-Horne-Shimony-Holt (CHSH) inequality. However, they differ in their optimal phase estimation capabilities as given by their quantum Fisher informations. The quantum Fisher information is the largest for the N00 N state (|Nrangle _a|0rangle _b+e^{i Nφ }|0rangle _a|Nrangle _b)/sqrt{2} and decreases for the other states with decreasing photon number difference between the two modes. We ask the question whether for any particular Clauser-Horne (CH) (or CHSH) inequality, the maximal values of the CH (or the CHSH) functional for the states of the above type follow the same trend as their quantum Fisher informations, while also violating the classical bound whenever the states are capable of sub-shot-noise phase estimation, so that the violation can be used to quantify sub-shot-noise sensitivity. We explore CH and CHSH inequalities in a homodyne setup. Our results show that the amount of violation in those nonlocality tests may not be used to quantify sub-shot-noise sensitivity of the above states.

  19. Correlation and nonlocality measures as indicators of quantum phase transitions in several critical systems

    SciTech Connect

    Altintas, Ferdi Eryigit, Resul

    2012-12-15

    We have investigated the quantum phase transitions in the ground states of several critical systems, including transverse field Ising and XY models as well as XY with multiple spin interactions, XXZ and the collective system Lipkin-Meshkov-Glick models, by using different quantumness measures, such as entanglement of formation, quantum discord, as well as its classical counterpart, measurement-induced disturbance and the Clauser-Horne-Shimony-Holt-Bell function. Measurement-induced disturbance is found to detect the first and second order phase transitions present in these critical systems, while, surprisingly, it is found to fail to signal the infinite-order phase transition present in the XXZ model. Remarkably, the Clauser-Horne-Shimony-Holt-Bell function is found to detect all the phase transitions, even when quantum and classical correlations are zero for the relevant ground state. - Highlights: Black-Right-Pointing-Pointer The ability of correlation measures to detect quantum phase transitions has been studied. Black-Right-Pointing-Pointer Measurement induced disturbance fails to detect the infinite order phase transition. Black-Right-Pointing-Pointer CHSH-Bell function detects all phase transitions even when the bipartite density matrix is uncorrelated.

  20. Hybrid nonlocality distillation

    NASA Astrophysics Data System (ADS)

    Wu, Keng-Shuo; Hsu, Li-Yi

    2013-08-01

    In this Letter, we introduce the notion of hybrid nonlocality distillation, in which different nonlocal boxes are exploited for nonlocality distillation. Here, we quantify the nonlocality using the violation degree of either the Clauser-Horne-Shimony-Holt inequality or the I3322 inequality. Our study shows that hybrid nonlocality distillation can outperform nonlocality distillation using copies of single nonlocal boxes. In particular, more nonlocality of undistillable boxes can be activated with the assistance of distillable boxes. Equivalently, distillable boxes can achieve more nonlocality with the assistance of undistillable boxes.

  1. Phase conjugation used as a test of the local and nonlocal characteristics of optical nonlinearities in microemulsions.

    PubMed

    Freysz, E; Laffon, E; Ducasse, A

    1991-11-01

    We report what are to our knowledge the first degenerate four-wave mixing experiments in microemulsions using a cw argon laser. The static and dynamic behavior of the reflectivity of both induced gratings is quantitatively analyzed. The conjugated signal dependence on the angle between the pump and probe waves is used to separate the local electrostrictive and the nonlocal thermodiffusive nonlinear processes, which are both efficient in the studied microemulsion. PMID:19784095

  2. Some geometric properties of quantum phases and calculation of phase formulas

    NASA Astrophysics Data System (ADS)

    Bracken, Paul

    An introduction to several geometrical ideas which are of use to quantum mechanics is presented. The Aharonov-Anandan phase is introduced and without reference to any dynamical equation, this phase is formulated by defining an appropriate connection on a specific fiber bundle. The holonomy element gives the phase. By introducing another connection, the Pancharatnam phase formula is derived following a different procedure.

  3. Non-locality Sudden Death in Tripartite Systems

    SciTech Connect

    Jaeger, Gregg; Ann, Kevin

    2009-03-10

    Bell non-locality sudden death is the disappearance of non-local properties in finite times under local phase noise, which decoheres states only in the infinite-time limit. We consider the relationship between decoherence, disentanglement, and Bell non-locality sudden death in bipartite and tripartite systems in specific large classes of state preparation.

  4. Observation of photonic spin Hall effect with phase singularity at dielectric metasurfaces.

    PubMed

    Li, Ying; Liu, Yachao; Ling, Xiaohui; Yi, Xunong; Zhou, Xinxing; Ke, Yougang; Luo, Hailu; Wen, Shuangchun; Fan, Dianyuan

    2015-01-26

    Observation of photonic spin Hall effect (SHE) near the phase singularity at dielectric metasurfaces is presented. The structured metasurface works as a space-variant Pancharatnam-Berry phase element and produces a vortex beam with phase singularity. The dynamical vortex phase is introduced to eliminate or enhance the phase singularity, thus realizing the manipulation of spin-dependent Pancharatnam-Berry phase. The spin-orbit coupling near the singularity of the Pancharatnam-Berry phase leads to the observation of the photonic SHE which manifests itself as spin-dependent splitting. The underlying mechanism is significantly different from previously reported cases. It thereby provides an alternative way to manipulate the spin states of photons. PMID:25835932

  5. Temporal Non-locality

    NASA Astrophysics Data System (ADS)

    Filk, Thomas

    2013-04-01

    In this article I investigate several possibilities to define the concept of "temporal non-locality" within the standard framework of quantum theory. In particular, I analyze the notions of "temporally non-local states", "temporally non-local events" and "temporally non-local observables". The idea of temporally non-local events is already inherent in the standard formalism of quantum mechanics, and Basil Hiley recently defined an operator in order to measure the degree of such a temporal non-locality. The concept of temporally non-local states enters as soon as "clock-representing states" are introduced in the context of special and general relativity. It is discussed in which way temporally non-local measurements may find an interesting application for experiments which test temporal versions of Bell inequalities.

  6. Stability of Planar Fronts for a Non-Local Phase Kinetics Equation with a Conservation Law in D ≤ 3

    NASA Astrophysics Data System (ADS)

    Carlen, Eric A.; Orlandi, Enza

    2012-05-01

    We consider, in a D-dimensional cylinder, a non-local evolution equation that describes the evolution of the local magnetization in a continuum limit of an Ising spin system with Kawasaki dynamics and Kac potentials. We consider sub-critical temperatures, for which there are two local spatially homogeneous equilibria, and show a local nonlinear stability result for the minimum free energy profiles for the magnetization at the interface between regions of these two different local equilibrium; i.e. the planar fronts: We show that an initial perturbation of a front that is sufficiently small in L2 norm, and sufficiently localized yields a solution that relaxes to another front, selected by a conservation law, in the L1 norm at an algebraic rate that we explicitly estimate. We also obtain rates for the relaxation in the L2 norm and the rate of decrease of the excess free energy.

  7. Light steering in a strongly nonlocal nonlinear medium

    SciTech Connect

    Ouyang Shigen; Hu Wei; Guo Qi

    2007-11-15

    With a strongly nonlocal model, we present an analytical solution of the coherent interaction of two Gaussian beams with an arbitrary phase difference and arbitrary incident angles. Numerical simulations show that the analytical solution can describe the interaction of two Gaussian beams very well in the strongly nonlocal case. It is theoretically shown that one can steer lights in strongly nonlocal media by tuning the incident conditions of coherently interacting beams like the phase difference between beams and their relative amplitude.

  8. Nonlocality with ultracold atoms in a lattice

    NASA Astrophysics Data System (ADS)

    Pelisson, Sophie; Pezzè, Luca; Smerzi, Augusto

    2016-02-01

    We study the creation of nonlocal states with ultracold atoms trapped in an optical lattice. We show that these states violate Bell inequality by measuring one- and two-body correlations. Our scheme only requires beam-splitting operations and global phase shifts, and can be realized within the current technology, employing single-site addressing. This proposal paves the way to study multipartite nonlocality and entanglement in ultracold-atomic systems.

  9. Nonlocal magnetorotational instability

    SciTech Connect

    Mikhailovskii, A. B.; Erokhin, N. N.; Lominadze, J. G.; Galvao, R. M. O.; Churikov, A. P.; Kharshiladze, O. A.; Amador, C. H. S.

    2008-05-15

    An analytical theory of the nonlocal magnetorotational instability (MRI) is developed for the simplest astrophysical plasma model. It is assumed that the rotation frequency profile has a steplike character, so that there are two regions in which it has constant different values, separated by a narrow transition layer. The surface wave approach is employed to investigate the MRI in this configuration. It is shown that the main regularities of the nonlocal MRI are similar to those of the local instability and that driving the nonaxisymmetric MRI is less effective than the axisymmetric one, also for the case of the nonlocal instability. The existence of nonlocal instabilities in nonmagnetized plasma is predicted.

  10. Nonlocal General Relativity

    NASA Astrophysics Data System (ADS)

    Mashhoon, Bahram

    2014-12-01

    A brief account of the present status of the recent nonlocal generalization of Einstein's theory of gravitation is presented. The main physical assumptions that underlie this theory are described. We clarify the physical meaning and significance of Weitzenbock's torsion and emphasize its intimate relationship with the gravitational field, characterized by the Riemannian curvature of spacetime. In this theory, nonlocality can simulate dark matter; in fact, in the Newtonian regime, we recover the phenomenological Tohline-Kuhn approach to modified gravity. To account for the observational data regarding dark matter, nonlocality is associated with a characteristic length scale of order 1 kpc. The confrontation of nonlocal gravity with observation is briefly discussed.

  11. Can EPR non-locality be geometrical?

    SciTech Connect

    Ne`eman, Y. |; Botero, A.

    1995-10-01

    The presence in Quantum Mechanics of non-local correlations is one of the two fundamentally non-intuitive features of that theory. The non-local correlations themselves fall into two classes: EPR and Geometrical. The non-local characteristics of the geometrical type are well-understood and are not suspected of possibly generating acausal features, such as faster-than-light propagation of information. This has especially become true since the emergence of a geometrical treatment for the relevant gauge theories, i.e. Fiber Bundle geometry, in which the quantum non-localities are seen to correspond to pure homotopy considerations. This aspect is reviewed in section 2. Contrary-wise, from its very conception, the EPR situation was felt to be paradoxical. It has been suggested that the non-local features of EPR might also derive from geometrical considerations, like all other non-local characteristics of QM. In[7], one of the authors was able to point out several plausibility arguments for this thesis, emphasizing in particular similarities between the non-local correlations provided by any gauge field theory and those required by the preservation of the quantum numbers of the original EPR state-vector, throughout its spatially-extended mode. The derivation was, however, somewhat incomplete, especially because of the apparent difference between, on the one hand, the closed spatial loops arising in the analysis of the geometrical non-localities, from Aharonov-Bohm and Berry phases to magnetic monopoles and instantons, and on the other hand, in the EPR case, the open line drawn by the positions of the two moving decay products of the disintegrating particle. In what follows, the authors endeavor to remove this obstacle and show that as in all other QM non-localities, EPR is somehow related to closed loops, almost involving homotopy considerations. They develop this view in section 3.

  12. Prediction of negative dispersion by a nonlocal poroelastic theory.

    PubMed

    Chakraborty, Abir

    2008-01-01

    The objective of this work is to show that the negative dispersion of ultrasonic waves propagating in cancellous bone can be explained by a nonlocal version of Biot's theory of poroelasticity. The nonlocal poroelastic formulation is presented in this work and the exact solutions for one- and two-dimensional systems are obtained by the method of Fourier transform. The nonlocal phase speeds for solid- and fluid-borne waves show the desired negative dispersion where the magnitude of dispersion is strongly dependent on the nonlocal parameters and porosity. Dependence of the phase speed and attenuation is studied for both porosity and frequency variation. It is shown that the nonlocal parameter can be easily estimated by comparing the theoretical dispersion rate with experimental observations. It is also shown that the modes of Lamb waves show similar negative dispersion when predicted by the nonlocal poroelastic theory. PMID:18177138

  13. Multipartite nonlocality distillation

    SciTech Connect

    Hsu, Li-Yi; Wu, Keng-Shuo

    2010-11-15

    The stronger nonlocality than that allowed in quantum theory can provide an advantage in information processing and computation. Since quantum entanglement is distillable, can nonlocality be distilled in the nonsignalling condition? The answer is positive in the bipartite case. In this article the distillability of the multipartite nonlocality is investigated. We propose a distillation protocol solely exploiting xor operations on output bits. The probability-distribution vectors and matrix are introduced to tackle the correlators. It is shown that only the correlators with extreme values can survive the distillation process. As the main result, the amplified nonlocality cannot maximally violate any Bell-type inequality. Accordingly, a distillability criterion in the postquantum region is proposed.

  14. Making space for nonlocality

    NASA Astrophysics Data System (ADS)

    Millen, James

    2016-04-01

    George Musser's book Spooky Action at a Distance focuses on one of quantum physics' more challenging concepts, nonlocality, and its multitude of implications, particularly its assault on space itself.

  15. Spiraling multivortex solitons in nonlocal nonlinear media.

    PubMed

    Buccoliero, Daniel; Desyatnikov, Anton S; Krolikowski, Wieslaw; Kivshar, Yuri S

    2008-01-15

    We demonstrate the existence of a broad class of higher-order rotating spatial solitons in nonlocal nonlinear media. We employ the generalized Hermite-Laguerre-Gaussian ansatz for constructing multivortex soliton solutions and study numerically their dynamics and stability. We discuss in detail the tripole soliton carrying two spiraling phase dislocations, or self-trapped optical vortices. PMID:18197238

  16. A generalized nonlocal vector calculus

    NASA Astrophysics Data System (ADS)

    Alali, Bacim; Liu, Kuo; Gunzburger, Max

    2015-10-01

    A nonlocal vector calculus was introduced in Du et al. (Math Model Meth Appl Sci 23:493-540, 2013) that has proved useful for the analysis of the peridynamics model of nonlocal mechanics and nonlocal diffusion models. A formulation is developed that provides a more general setting for the nonlocal vector calculus that is independent of particular nonlocal models. It is shown that general nonlocal calculus operators are integral operators with specific integral kernels. General nonlocal calculus properties are developed, including nonlocal integration by parts formula and Green's identities. The nonlocal vector calculus introduced in Du et al. (Math Model Meth Appl Sci 23:493-540, 2013) is shown to be recoverable from the general formulation as a special example. This special nonlocal vector calculus is used to reformulate the peridynamics equation of motion in terms of the nonlocal gradient operator and its adjoint. A new example of nonlocal vector calculus operators is introduced, which shows the potential use of the general formulation for general nonlocal models.

  17. Quantum networks reveal quantum nonlocality.

    PubMed

    Cavalcanti, Daniel; Almeida, Mafalda L; Scarani, Valerio; Acín, Antonio

    2011-01-01

    The results of local measurements on some composite quantum systems cannot be reproduced classically. This impossibility, known as quantum nonlocality, represents a milestone in the foundations of quantum theory. Quantum nonlocality is also a valuable resource for information-processing tasks, for example, quantum communication, quantum key distribution, quantum state estimation or randomness extraction. Still, deciding whether a quantum state is nonlocal remains a challenging problem. Here, we introduce a novel approach to this question: we study the nonlocal properties of quantum states when distributed and measured in networks. We show, using our framework, how any one-way entanglement distillable state leads to nonlocal correlations and prove that quantum nonlocality is a non-additive resource, which can be activated. There exist states, local at the single-copy level, that become nonlocal when taking several copies of them. Our results imply that the nonlocality of quantum states strongly depends on the measurement context. PMID:21304513

  18. Unstable nonlocal interface dynamics.

    PubMed

    Nicoli, Matteo; Cuerno, Rodolfo; Castro, Mario

    2009-06-26

    Nonlocal effects occur in many nonequilibrium interfaces, due to diverse physical mechanisms like diffusive, ballistic, or anomalous transport, with examples from flame fronts to thin films. While dimensional analysis describes stable nonlocal interfaces, we show the morphologically unstable condition to be nontrivial. This is the case for a family of stochastic equations of experimental relevance, paradigmatically including the Michelson-Sivashinsky system. For a whole parameter range, the asymptotic dynamics is scale invariant with dimension-independent exponents reflecting a hidden Galilean symmetry. The usual Kardar-Parisi-Zhang nonlinearity, albeit irrelevant in that parameter range, plays a key role in this behavior. PMID:19659099

  19. Non-local equilibrium two-phase flow model with phase change in porous media and its application to reflooding of a severely damaged reactor core

    NASA Astrophysics Data System (ADS)

    Bachrata, A.; Fichot, F.; Quintard, M.; Repetto, G.; Fleurot, J.

    2012-05-01

    A generalized non local-equilibrium, three-equation model was developed for the macroscopic description of two-phase flow heat and mass transfer in porous media subjected to phase change. Six pore-scale closure problems were proposed to determine all the effective transport coefficients for representative unit cells. An improved model is presented in this paper with the perspective of application to intense boiling phenomena. The objective of this paper is to present application of this model to the simulation of reflooding of severely damaged nuclear reactor cores. In case of accident at a nuclear power plant, water sources may not be available for a long period of time and the core heats up due to the residual power. Any attempt to inject water during core degradation can lead to quenching and further fragmentation of the core material. The fragmentation of fuel rods and melting of reactor core materials may result in the formation of a "debris bed". The typical particle size in a debris bed might reach few millimeters (characteristic length-scale: 1 to 5 mm), which corresponds to a high permeability porous medium. The proposed two-phase flow model is implemented in the ICARECATHARE code, developed by IRSN to study severe accident scenarios in pressurized water reactors. Currently, the French IRSN has set up two experimental facilities to study debris bed reflooding, PEARL and PRELUDE, with the objective to validate safety models. The PRELUDE program studies the complex two phase flow of water and steam in a porous medium (diameter 180 mm, height 200 mm), initially heated to a high temperature (400°C or 700°C). The series of PRELUDE experiments achieved in 2010 constitute a significant complement to the database of high temperature bottom reflood experimental data. They provide relevant data to understand the progression of the quench front and the intensity of heat transfer. Modeling accurately these experiments required improvements to the reflooding model

  20. Non-local equilibrium two-phase flow model with phase change in porous media and its application to reflooding of a severely damaged reactor core

    SciTech Connect

    Bachrata, A.; Fichot, F.; Quintard, M.; Repetto, G.; Fleurot, J.

    2012-05-15

    A generalized non local-equilibrium, three-equation model was developed for the macroscopic description of two-phase flow heat and mass transfer in porous media subjected to phase change. Six pore-scale closure problems were proposed to determine all the effective transport coefficients for representative unit cells. An improved model is presented in this paper with the perspective of application to intense boiling phenomena. The objective of this paper is to present application of this model to the simulation of reflooding of severely damaged nuclear reactor cores. In case of accident at a nuclear power plant, water sources may not be available for a long period of time and the core heats up due to the residual power. Any attempt to inject water during core degradation can lead to quenching and further fragmentation of the core material. The fragmentation of fuel rods and melting of reactor core materials may result in the formation of a {sup d}ebris bed{sup .} The typical particle size in a debris bed might reach few millimeters (characteristic length-scale: 1 to 5 mm), which corresponds to a high permeability porous medium. The proposed two-phase flow model is implemented in the ICARECATHARE code, developed by IRSN to study severe accident scenarios in pressurized water reactors. Currently, the French IRSN has set up two experimental facilities to study debris bed reflooding, PEARL and PRELUDE, with the objective to validate safety models. The PRELUDE program studies the complex two phase flow of water and steam in a porous medium (diameter 180 mm, height 200 mm), initially heated to a high temperature (400 deg. C or 700 deg. C). The series of PRELUDE experiments achieved in 2010 constitute a significant complement to the database of high temperature bottom reflood experimental data. They provide relevant data to understand the progression of the quench front and the intensity of heat transfer. Modeling accurately these experiments required improvements to the

  1. Teaching Quantum Nonlocality

    ERIC Educational Resources Information Center

    Hobson, Art

    2012-01-01

    Nonlocality arises from the unified "all or nothing" interactions of a spatially extended field quantum such as a photon or an electron. In the double-slit experiment with light, for example, each photon comes through both slits and arrives at the viewing screen as an extended but unified energy bundle or "field quantum." When the photon interacts…

  2. Geometric phase in p -n junctions of helical edge states

    NASA Astrophysics Data System (ADS)

    Wadhawan, Disha; Mehta, Poonam; Das, Sourin

    2016-02-01

    The quantum spin Hall effect is endowed with topologically protected edge modes with a gapless Dirac spectrum. Applying a magnetic field locally along the edge leads to a gapped edge spectrum with the opposite parity for winding of spin texture for conduction and valence bands. Using Pancharatnam's prescription for the geometric phase it is shown that mismatch of this parity across a p -n junction, which could be engineered into the edge by electrical gate induced doping, leads to a phase dependence in the two-terminal conductance which is quantized to either zero or π . It is further shown that application of a nonuniform magnetic field across the junction could lead to a nonquantized value of this geometric phase which is tunable between zero and π . A current asymmetry measurement which is shown to be robust against electron-electron interactions is proposed to infer the appearance of this Pancharatnam's geometric phase in transport across such junctions.

  3. Uncertainty-induced quantum nonlocality

    NASA Astrophysics Data System (ADS)

    Wu, Shao-xiong; Zhang, Jun; Yu, Chang-shui; Song, He-shan

    2014-01-01

    Based on the skew information, we present a quantity, uncertainty-induced quantum nonlocality (UIN) to measure the quantum correlation. It can be considered as the updated version of the original measurement-induced nonlocality (MIN) preserving the good computability but eliminating the non-contractivity problem. For 2×d-dimensional state, it is shown that UIN can be given by a closed form. In addition, we also investigate the maximal uncertainty-induced nonlocality.

  4. Solitons shedding from Airy beams and bound states of breathing Airy solitons in nonlocal nonlinear media

    PubMed Central

    Shen, Ming; Gao, Jinsong; Ge, Lijuan

    2015-01-01

    We investigate the spatially optical solitons shedding from Airy beams and anomalous interactions of Airy beams in nonlocal nonlinear media by means of direct numerical simulations. Numerical results show that nonlocality has profound effects on the propagation dynamics of the solitons shedding from the Airy beam. It is also shown that the strong nonlocality can support periodic intensity distribution of Airy beams with opposite bending directions. Nonlocality also provides a long-range attractive force between Airy beams, leading to the formation of stable bound states of both in-phase and out-of-phase breathing Airy solitons which always repel in local media. PMID:25900878

  5. Nonlocal and quasilocal field theories

    NASA Astrophysics Data System (ADS)

    Tomboulis, E. T.

    2015-12-01

    We investigate nonlocal field theories, a subject that has attracted some renewed interest in connection with nonlocal gravity models. We study, in particular, scalar theories of interacting delocalized fields, the delocalization being specified by nonlocal integral kernels. We distinguish between strictly nonlocal and quasilocal (compact support) kernels and impose conditions on them to insure UV finiteness and unitarity of amplitudes. We study the classical initial value problem for the partial integro-differential equations of motion in detail. We give rigorous proofs of the existence but accompanying loss of uniqueness of solutions due to the presence of future, as well as past, "delays," a manifestation of acausality. In the quantum theory we derive a generalization of the Bogoliubov causality condition equation for amplitudes, which explicitly exhibits the corrections due to nonlocality. One finds that, remarkably, for quasilocal kernels all acausal effects are confined within the compact support regions. We briefly discuss the extension to other types of fields and prospects of such theories.

  6. Algebraic Rate of Decay for the Excess Free Energy and Stability of Fronts for a Nonlocal Phase Kinetics Equation with a Conservation Law. I

    NASA Astrophysics Data System (ADS)

    Carlen, E. A.; Carvalho, M. C.; Orlandi, E.

    1999-06-01

    This is the first of two papers devoted to the study of a nonlocal evolution equation that describes the evolution of the local magnetization in a continuum limit of an Ising spin system with Kawasaki dynamics and Kac potentials. We consider subcritical temperatures, for which there are two local equilibria, and begin the proof of a local nonlinear stability result for the minimum free energy profiles for the magnetization at the interface between regions of these two different local equilibria; i.e., the fronts. We shall show in the second paper that an initial perturbation v 0 of a front that is sufficiently small in L 2 norm, and sufficiently localized that ∫ x 2 v 0( x)2 dx<∞, yields a solution that relaxes to another front, selected by a conservation law, in the L 1 norm at an algebraic rate that we explicitly estimate. There we also obtain rates for the relaxation in the L 2 norm and the rate of decrease of the excess free energy. Here we prove a number of estimates essential for this result. Moreover, the estimates proved here suffice to establish the main result in an important special case.

  7. Two flavor superconductivity in non-local models

    SciTech Connect

    Duhau, R.; Grunfeld, A.G.; Scoccola, N.N.

    2004-12-02

    In the present work we study a relativistic quark model at finite temperature and density with non-local quark-antiquark and quark-quark interactions with SU(2) flavour and SU(3) color symmetries. After proper bosonization, we analyze the structure of the corresponding phase diagram and discuss the competition between the chiral and 2SC phases.

  8. (1+2)-dimensional strongly nonlocal solitons

    SciTech Connect

    Ouyang Shigen; Guo Qi

    2007-11-15

    Approximate solutions of (1+2)-dimensional strongly nonlocal solitons (SNSs) are presented. It is shown that the power of a SNS in a nematic liquid crystal is in direct proportion to the second power of the degree of nonlocality, the power of a SNS in a nonlocal medium with a logarithmic nonlocal response is in inverse proportion to the second power of its beamwidth, and the power of a SNS in a nonlocal medium with an sth-power decay nonlocal response is in direct proportion to the (s+2)th power of the degree of nonlocality.

  9. Turbulence transport with nonlocal interactions

    SciTech Connect

    Linn, R.R.; Clark, T.T.; Harlow, F.H.; Turner, L.

    1998-03-01

    This preliminary report describes a variety of issues in turbulence transport analysis with particular emphasis on closure procedures that are nonlocal in wave-number and/or physical space. Anomalous behavior of the transport equations for large scale parts of the turbulence spectrum are resolved by including the physical space nonlocal interactions. Direct and reverse cascade processes in wave-number space are given a much richer potential for realistic description by the nonlocal formulations. The discussion also describes issues, many still not resolved, regarding new classes of self-similar form functions.

  10. Nonlocal gravity: Conformally flat spacetimes

    NASA Astrophysics Data System (ADS)

    Bini, Donato; Mashhoon, Bahram

    2016-04-01

    The field equations of the recent nonlocal generalization of Einstein’s theory of gravitation are presented in a form that is reminiscent of general relativity. The implications of the nonlocal field equations are studied in the case of conformally flat spacetimes. Even in this simple case, the field equations are intractable. Therefore, to gain insight into the nature of these equations, we investigate the structure of nonlocal gravity (NLG) in 2D spacetimes. While any smooth 2D spacetime is conformally flat and satisfies Einstein’s field equations, only a subset containing either a Killing vector or a homothetic Killing vector can satisfy the field equations of NLG.

  11. Bounds for nonlocality distillation protocols

    SciTech Connect

    Forster, Manuel

    2011-06-15

    Nonlocality can be quantified by the violation of a Bell inequality. Since this violation may be amplified by local operations, an alternative measure has been proposed--distillable nonlocality. The alternative measure is difficult to calculate exactly due to the double exponential growth of the parameter space. In this paper, we give a way to bound the distillable nonlocality of a resource by the solutions to a related optimization problem. Our upper bounds are exponentially easier to compute than the exact value and are shown to be meaningful in general and tight in some cases.

  12. Nonlocal anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Zhang, Shulei; Vignale, Giovanni

    Anomalous Hall effect (AHE) is a distinctive transport property of ferromagnetic metals arising from spin orbit coupling (SOC) in concert with spontaneous spin polarization. Nonetheless, recent experiments have shown that the effect also appears in a nonmagnetic metal in contact with a magnetic insulator. The main puzzle lies in the apparent absence of spin polarized electrons in the non-magnetic metal. Here, we theoretically demonstrate that the scattering of electrons from a rough metal-insulator interface is generally spin-dependent, which results in mutual conversion between spin and charge currents flowing in the plane of the layer. It is the current-carrying spin polarized electrons and the spin Hall effect in the bulk of the metal layer that conspire to generate the AH current. This novel AHE differs from the conventional one only in the spatial separation of the SOC and the magnetization, so we name it as nonlocal AHE. In contrast to other previously proposed mechanisms (e.g., spin Hall AHE and magnetic proximity effect (MPE)), the nonlocal AHE appears on the first order of spin Hall angle and does not rely on the induced moments in the metal layer, which make it experimentally detectable by contrasting the AH current directions of two layered structures such as Pt/Cu/YIG and β -Ta/Cu/YIG (with a thin inserted Cu layer to eliminate the MPE). We predict that the directions of the AH currents in these two trilayers would be opposite since the spin Hall angles of Pt and β -Ta are of opposite signs. Work supported by NSF Grants DMR-1406568.

  13. Lattice Gas Model with Nonlocal Interactions

    NASA Astrophysics Data System (ADS)

    Das, Shankar P.

    We analyze the nature of the hydrodynamic modes in a Lattice Gas Automata (LGA) model defined on a hexagonal lattice and having nonlocal interactions of attractive and repulsive type simultaneously. The model is similar in spirit to the liquid gas model of Appert and Zaleski [Phys. Rev. Lett. 64, 1 (1990)]. The phase diagram for the model is computed using the kinetic pressure. The dynamics is studied with a mean field type approach in the Boltzmann approximation ignoring effects of correlated collisions. We compute the transport coefficients and the speed of sound propagation. The presence of attractive interactions show increase in the transport coefficients at intermediate densities.

  14. Nonlocal Anomalous Hall Effect

    NASA Astrophysics Data System (ADS)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  15. Nonlocal Intracranial Cavity Extraction

    PubMed Central

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  16. Bipartite units of nonlocality

    SciTech Connect

    Forster, Manuel; Wolf, Stefan

    2011-10-15

    Imagine a task in which a group of separated players aim to simulate a statistic that violates a Bell inequality. Given measurement choices the players shall announce an output based solely on the results of local operations--which they can discuss before the separation--on shared random data and shared copies of a so-called unit correlation. In the first part of this paper we show that in such a setting the simulation of any bipartite correlation, not containing the possibility of signaling, can be made arbitrarily accurate by increasing the number of shared Popescu-Rohrlich (PR) boxes. This establishes the PR box as a simple asymptotic unit of bipartite nonlocality. In the second part we study whether this property extends to the multipartite case. More generally, we ask if it is possible for separated players to asymptotically reproduce any nonsignaling statistic by local operations on bipartite unit correlations. We find that nonadaptive strategies are limited by a constant accuracy and that arbitrary strategies on n resource correlations make a mistake with a probability greater or equal to c/n, for some constant c.

  17. Fast separable nonlocal means

    NASA Astrophysics Data System (ADS)

    Ghosh, Sanjay; Chaudhury, Kunal N.

    2016-03-01

    We propose a simple and fast algorithm called PatchLift for computing distances between patches (contiguous block of samples) extracted from a given one-dimensional signal. PatchLift is based on the observation that the patch distances can be efficiently computed from a matrix that is derived from the one-dimensional signal using lifting; importantly, the number of operations required to compute the patch distances using this approach does not scale with the patch length. We next demonstrate how PatchLift can be used for patch-based denoising of images corrupted with Gaussian noise. In particular, we propose a separable formulation of the classical nonlocal means (NLM) algorithm that can be implemented using PatchLift. We demonstrate that the PatchLift-based implementation of separable NLM is a few orders faster than standard NLM and is competitive with existing fast implementations of NLM. Moreover, its denoising performance is shown to be consistently superior to that of NLM and some of its variants, both in terms of peak signal-to-noise ratio/structural similarity index and visual quality.

  18. Nonlocal optical response in metallic nanostructures.

    PubMed

    Raza, Søren; Bozhevolnyi, Sergey I; Wubs, Martijn; Asger Mortensen, N

    2015-05-13

    This review provides a broad overview of the studies and effects of nonlocal response in metallic nanostructures. In particular, we thoroughly present the nonlocal hydrodynamic model and the recently introduced generalized nonlocal optical response (GNOR) model. The influence of nonlocal response on plasmonic excitations is studied in key metallic geometries, such as spheres and dimers, and we derive new consequences due to the GNOR model. Finally, we propose several trajectories for future work on nonlocal response, including experimental setups that may unveil further effects of nonlocal response. PMID:25893883

  19. Towards LHC physics with nonlocal Standard Model

    NASA Astrophysics Data System (ADS)

    Biswas, Tirthabir; Okada, Nobuchika

    2015-09-01

    We take a few steps towards constructing a string-inspired nonlocal extension of the Standard Model. We start by illustrating how quantum loop calculations can be performed in nonlocal scalar field theory. In particular, we show the potential to address the hierarchy problem in the nonlocal framework. Next, we construct a nonlocal abelian gauge model and derive modifications of the gauge interaction vertex and field propagators. We apply the modifications to a toy version of the nonlocal Standard Model and investigate collider phenomenology. We find the lower bound on the scale of nonlocality from the 8 TeV LHC data to be 2.5-3 TeV.

  20. Two-dimensional multipole solitons in nonlocal nonlinear media.

    PubMed

    Rotschild, Carmel; Segev, Mordechai; Xu, Zhiyong; Kartashov, Yaroslav V; Torner, Lluis; Cohen, Oren

    2006-11-15

    We present the experimental observation of scalar multipole solitons in highly nonlocal nonlinear media, including dipole, tripole, quadrupole, and necklace-type solitons, organized as arrays of out-of-phase bright spots. These complex solitons are metastable, but with a large parameters range where the instability is weak, permitting their experimental observation. PMID:17072407

  1. Nonlocal quartic interactions and universality classes in perovskite manganites.

    PubMed

    Singh, Rohit; Dutta, Kishore; Nandy, Malay K

    2015-07-01

    A modified Ginzburg-Landau model with a screened nonlocal interaction in the quartic term is treated via Wilson's renormalization-group scheme at one-loop order to explore the critical behavior of the paramagnetic-to-ferromagnetic phase transition in perovskite manganites. We find the Fisher exponent η to be O(ε) and the correlation exponent to be ν=1/2+O(ε) through epsilon expansion in the parameter ε=d(c)-d, where d is the space dimension, d(c)=4+2σ is the upper critical dimension, and σ is a parameter coming from the nonlocal interaction in the model Hamiltonian. The ensuing critical exponents in three dimensions for different values of σ compare well with various existing experimental estimates for perovskite manganites with various doping levels. This suggests that the nonlocal model Hamiltonian contains a wide variety of such universality classes. PMID:26274140

  2. Nonlocal Measurements via Quantum Erasure

    NASA Astrophysics Data System (ADS)

    Brodutch, Aharon; Cohen, Eliahu

    2016-02-01

    Nonlocal observables play an important role in quantum theory, from Bell inequalities and various postselection paradoxes to quantum error correction codes. Instantaneous measurement of these observables is known to be a difficult problem, especially when the measurements are projective. The standard von Neumann Hamiltonian used to model projective measurements cannot be implemented directly in a nonlocal scenario and can, in some cases, violate causality. We present a scheme for effectively generating the von Neumann Hamiltonian for nonlocal observables without the need to communicate and adapt. The protocol can be used to perform weak and strong (projective) measurements, as well as measurements at any intermediate strength. It can also be used in practical situations beyond nonlocal measurements. We show how the protocol can be used to probe a version of Hardy's paradox with both weak and strong measurements. The outcomes of these measurements provide a nonintuitive picture of the pre- and postselected system. Our results shed new light on the interplay between quantum measurements, uncertainty, nonlocality, causality, and determinism.

  3. Nonlocal Measurements via Quantum Erasure.

    PubMed

    Brodutch, Aharon; Cohen, Eliahu

    2016-02-19

    Nonlocal observables play an important role in quantum theory, from Bell inequalities and various postselection paradoxes to quantum error correction codes. Instantaneous measurement of these observables is known to be a difficult problem, especially when the measurements are projective. The standard von Neumann Hamiltonian used to model projective measurements cannot be implemented directly in a nonlocal scenario and can, in some cases, violate causality. We present a scheme for effectively generating the von Neumann Hamiltonian for nonlocal observables without the need to communicate and adapt. The protocol can be used to perform weak and strong (projective) measurements, as well as measurements at any intermediate strength. It can also be used in practical situations beyond nonlocal measurements. We show how the protocol can be used to probe a version of Hardy's paradox with both weak and strong measurements. The outcomes of these measurements provide a nonintuitive picture of the pre- and postselected system. Our results shed new light on the interplay between quantum measurements, uncertainty, nonlocality, causality, and determinism. PMID:26943514

  4. Pancharatnam-Berry phase optical elements for generation and control of complex light: generalized superelliptical q-plates

    NASA Astrophysics Data System (ADS)

    Piccirillo, Bruno; Kumar, Vijay; Marrucci, Lorenzo; Santamato, E.

    2015-03-01

    We present newly conceived liquid-crystal-based retardation waveplates in which the optic axis distribution has a "superelliptically" symmetric azimuthal structure with a topological charge q superimposed. Such devices, named superelliptical q-plates, act as polarization-to-spatial modes converters that can be used to produce optical beams having peculiar spiral spectra. These spectra reflect the topological charge of the optic axis distribution as well as the symmetry properties of the underlying superellipse. The peculiar capability of q-plates of producing optical modes entangled with respect to spin and orbital angular momentum is here extended to superelliptical q-plates in order to create more complex optical modes structurally inseparable with respect to polarization and spatial degrees of freedom. Such superelliptical modes can play a crucial role in studying polarization singularities or to develop polarization metrology.

  5. Dynamics of polarized vortex solitons in nonlocal media with Bessel optical lattices.

    PubMed

    Zhang, Bingzhi; Chen, Zhifeng

    2015-09-21

    We investigate the formation of polarized vortex solitons in nonlocal media with Bessel optical lattices and show the various dynamics of these solitons. Particularly, the stable high-order polarized vortex solitons, which are not found in local media with Bessel optical lattices, are found in nonlocal media. It is found that the nonlocal nonlinearity plays an important role in the stability of these solitons which is similar to that of phase vortex solitons. However, we show that the dynamics of these polarized vortex solitons are quite different from the phase vortex solitons. PMID:26406632

  6. (1 + 2)-Dimensional sub-strongly nonlocal spatial optical solitons: Perturbation method

    NASA Astrophysics Data System (ADS)

    Ren, Hongyan; Ouyang, Shigen; Guo, Qi; Wu, Lijun

    2007-07-01

    By extending the (1 + 1)-dimensional [(1 + 1)-D] perturbation method suggested by Ouyang et al. [S. Ouyang, Q. Guo, W. Hu, Phys. Rev. E. 74 (2006) 036622] to the (1 + 2)-D case, we obtain a fundamental soliton solution to the (1 + 2)-D nonlocal nonlinear Schrödinger equation (NNLSE) with a Gaussian-type response function for the sub-strongly nonlocal case. Numerical simulations show that the soliton solution obtained in this paper can describe the soliton states in both the sub-strongly nonlocal case and the strongly nonlocal case. It is found that the phase constant and the power of the (1 + 2)-D strongly nonlocal spatial optical soliton with a Gaussian-type response function are both in inverse proportion to the 4th power of its beam width.

  7. Aspects of nonlocality in quantum field theory, quantum gravity and cosmology

    NASA Astrophysics Data System (ADS)

    Barvinsky, A. O.

    2015-01-01

    This paper contains a collection of essays on nonlocal phenomena in quantum field theory, gravity and cosmology. Mechanisms of nonlocal contributions to the quantum effective action are discussed within the covariant perturbation expansion in field strengths and spacetime curvatures. Euclidean version of the Schwinger-Keldysh technique for quantum expectation values is presented as a special rule of obtaining the nonlocal effective equations of motion for the mean quantum field from the Euclidean effective action. This rule is applied to a new model of ghost free nonlocal cosmology which can generate the de Sitter (dS) cosmological evolution at an arbitrary value of Λ — a model of dark energy with the dynamical scale selected by a kind of a scaling symmetry breaking mechanism. This model is shown to interpolate between the superhorizon phase of a scalar mediated gravity and the short distance general relativistic limit in a special metric frame related by a nonlocal conformal transformation to the original metric.

  8. Closed sets of nonlocal correlations

    SciTech Connect

    Allcock, Jonathan; Linden, Noah; Brunner, Nicolas; Popescu, Sandu; Skrzypczyk, Paul; Vertesi, Tamas

    2009-12-15

    We present a fundamental concept - closed sets of correlations - for studying nonlocal correlations. We argue that sets of correlations corresponding to information-theoretic principles, or more generally to consistent physical theories, must be closed under a natural set of operations. Hence, studying the closure of sets of correlations gives insight into which information-theoretic principles are genuinely different, and which are ultimately equivalent. This concept also has implications for understanding why quantum nonlocality is limited, and for finding constraints on physical theories beyond quantum mechanics.

  9. Nonlocal Transport in the Reversed Field Pinch

    SciTech Connect

    Spizzo, G.; White, R. B.; Cappello, S.; Marrelli, L.

    2009-09-21

    Several heuristic models for nonlocal transport in plasmas have been developed, but they have had a limited possibility of detailed comparision with experimental data. Nonlocal aspects introduced by the existence of a known spectrum of relatively stable saturated tearing modes in a low current reversed field pinch offers a unique possibility for such a study. A numerical modelling of the magnetic structure and associated particle transport is carried out for the reversed-field pinch experiment at the Consorzio RFX, Padova, Italy. A reproduction of the tearing mode spectrum with a guiding center code1 reliably reproduces the observed soft X-ray tomography. Following particle trajectories in the stochastic magnetic field shows the transport across the unperturbed flux surfaces to be due to a spectrum of Levy flights, with the details of the spectrum position dependent. The resulting transport is subdiffusive, and cannot be described by Rechester-Rosenbluth diffusion, which depends on a random phase approximation. If one attempts to fit the local transport phenomenologically, the subdiffusion can be fit with a combination of diffusion and inward pinch2. It is found that whereas passing particles explore the stochastic field and hence participate in Levy flights, the trapped particles experience normal neoclassical diffusion. A two fluid nonlocal Montroll equation is used to model this transport, with a Levy flight defined as the motion of an ion during the period that the pitch has one sign. The necessary input to the Montroll equation consists of a time distribution for the Levy flights, given by the pitch angle scattering operator, and a distribution of the flight distances, determined numerically using a guiding center code. Results are compared to experiment. The relation of this formulation to fractional kinetics is also described.

  10. Effect of Non-local Thermodynamic Equilibrium Model Atmospheres on Photometric Amplitudes and Phases of Early B-type Pulsating Stars

    NASA Astrophysics Data System (ADS)

    Daszyńska-Daszkiewicz, J.; Szewczuk, W.

    2011-02-01

    Amplitudes and phases of the light variation of a pulsating star in various photometric passbands contain information about the geometry of observed modes. Because oscillation spectra of early B-type main-sequence stars do not exhibit regular patterns, these observables are very often the only ones from which mode identification can be derived. Moreover, these data can yield valuable constraints on mean stellar parameters, subphotospheric convection, microphysics, and atmospheres. We study all possible sources of inaccuracy in theoretical values of the photometric observables, i.e., amplitude ratios and phase differences, of early B-type main-sequence pulsators. Here, we discuss the effects of parameters coming from both model atmospheres and linear nonadiabatic theory of stellar pulsation. In particular, we evaluate for the first time the effect of the departure from the local thermodynamic equilibrium (LTE) approximation. To this end, for non-LTE model atmospheres, we compute tables with the passband fluxes, flux derivatives over effective temperature and gravity, as well as the nonlinear limb-darkening coefficients in 12 passbands most often used. We make these tables publicly available at the Wrocław HELAS Web site.

  11. Plastic failure of nonlocal beams.

    PubMed

    Challamel, Noël; Lanos, Christophe; Casandjian, Charles

    2008-08-01

    This paper questions the mode of collapse of some simple softening nonlocal structural systems comprising the classical cantilever beam. Nanobeams can be concerned by such an elementary model. The homogeneous cantilever beam loaded by a concentrated force at its extremity is first considered as a structural paradigm. A nonlocal plasticity model is developed in order to control the localization process induced by microcracking phenomena. An implicit gradient plasticity model equivalent to a nonlocal integral plasticity model is used in this paper. It is shown that the regularized problem is well posed. Closed-form solutions of the elastoplastic deflection are finally derived. The length of the plastic zone grows during the softening process until an asymptotic limited value, which depends on the characteristic length of the material. Scale effects are clearly obtained for these static bending tests. Other structural cases are also presented, including the simply supported beam under uniform transverse loading. It is concluded that the mode of collapse is firmly a nonlocal phenomenon. PMID:18850959

  12. Nonlocal Equations with Measure Data

    NASA Astrophysics Data System (ADS)

    Kuusi, Tuomo; Mingione, Giuseppe; Sire, Yannick

    2015-08-01

    We develop an existence, regularity and potential theory for nonlinear integrodifferential equations involving measure data. The nonlocal elliptic operators considered are possibly degenerate and cover the case of the fractional p-Laplacean operator with measurable coefficients. We introduce a natural function class where we solve the Dirichlet problem, and prove basic and optimal nonlinear Wolff potential estimates for solutions. These are the exact analogs of the results valid in the case of local quasilinear degenerate equations established by Boccardo and Gallouët (J Funct Anal 87:149-169, 1989, Partial Differ Equ 17:641-655, 1992) and Kilpeläinen and Malý (Ann Scuola Norm Sup Pisa Cl Sci (IV) 19:591-613, 1992, Acta Math 172:137-161, 1994). As a consequence, we establish a number of results that can be considered as basic building blocks for a nonlocal, nonlinear potential theory: fine properties of solutions, Calderón-Zygmund estimates, continuity and boundedness criteria are established via Wolff potentials. A main tool is the introduction of a global excess functional that allows us to prove a nonlocal analog of the classical theory due to Campanato (Ann Mat Pura Appl (IV) 69:321-381, 1965). Our results cover the case of linear nonlocal equations with measurable coefficients, and the one of the fractional Laplacean, and are new already in such cases.

  13. Quantum nonlocality does not exist.

    PubMed

    Tipler, Frank J

    2014-08-01

    Quantum nonlocality is shown to be an artifact of the Copenhagen interpretation, in which each observed quantity has exactly one value at any instant. In reality, all physical systems obey quantum mechanics, which obeys no such rule. Locality is restored if observed and observer are both assumed to obey quantum mechanics, as in the many-worlds interpretation (MWI). Using the MWI, I show that the quantum side of Bell's inequality, generally believed nonlocal, is really due to a series of three measurements (not two as in the standard, oversimplified analysis), all three of which have only local effects. Thus, experiments confirming "nonlocality" are actually confirming the MWI. The mistaken interpretation of nonlocality experiments depends crucially on a question-begging version of the Born interpretation, which makes sense only in "collapse" versions of quantum theory, about the meaning of the modulus of the wave function, so I use the interpretation based on the MWI, namely that the wave function is a world density amplitude, not a probability amplitude. This view allows the Born interpretation to be derived directly from the Schrödinger equation, by applying the Schrödinger equation to both the observed and the observer. PMID:25015084

  14. On nonlocal electron heat conduction

    SciTech Connect

    Krasheninnikov, S.I. )

    1993-01-01

    An improvement of the Albritton nonlocal electron heat transport model is proposed for high-[ital Z] plasmas. The thermal decay of the temperature perturbation in a uniform plasma as calculated by this model is compared with that obtained by Fokker--Planck simulations. Complete agreement is found up to values [ital k][lambda][sub [ital e

  15. Learning Non-Local Dependencies

    ERIC Educational Resources Information Center

    Kuhn, Gustav; Dienes, Zoltan

    2008-01-01

    This paper addresses the nature of the temporary storage buffer used in implicit or statistical learning. Kuhn and Dienes [Kuhn, G., & Dienes, Z. (2005). Implicit learning of nonlocal musical rules: implicitly learning more than chunks. "Journal of Experimental Psychology-Learning Memory and Cognition," 31(6) 1417-1432] showed that people could…

  16. Serendipitous discoveries in nonlocal gravity theory

    NASA Astrophysics Data System (ADS)

    Barvinsky, A. O.

    2012-05-01

    We present a class of generally covariant nonlocal gravity models which have a flat-space general relativistic limit and also possess a stable de Sitter or anti-de Sitter (AdS) background with an arbitrary value of its cosmological constant. The nonlocal action of the theory is formulated in the Euclidean signature spacetime and is understood as an approximation to the quantum effective action (generating functional of one-particle irreducible diagrams) originating from fundamental quantum gravity theory. Using the known relation between the Schwinger-Keldysh technique for quantum expectation values and the Euclidean quantum field theory we derive from this action the causal effective equations of motion for mean value of the metric field in the physical Lorentzian-signature spacetime. Thus we show that the (A)dS background of the theory carries as free propagating modes massless gravitons having two polarizations identical to those of the Einstein theory with a cosmological term. The on-shell action of the theory is vanishing both for the flat-space and (A)dS backgrounds which play the role of stable vacua underlying, respectively, the ultraviolet and infrared phases of the theory. We also obtain linearized gravitational potentials of compact matter sources and show that in the infrared (A)dS phase their effective gravitational coupling Geff can be essentially different from the Newton gravitational constant GN of the short-distance general relativistic phase. When Geff≫GN the (A)dS phase can be regarded as a strongly coupled infrared modification of Einstein theory not only describing the dark energy mechanism of cosmic acceleration but also simulating the dark matter phenomenon by enhanced gravitational attraction at long distances.

  17. Light steering of Air-Gaussian beam in Nonlocal Nonlinear Medium

    NASA Astrophysics Data System (ADS)

    Chen, Ran; Zhang, Xiaping

    2016-07-01

    With a nonlocal model, we investigate the propagation dynamics of a single Airy-Gaussian (AiG) beam and their interaction in one-dimensional condition by means of direct numerical simulations. With the split-step Fourier method, numerical results show that nonlocality can support periodic intensity distribution of AiG beams leading to the formation of stable bound states. Espesically, by tuning the phase difference between the two beams, we can steer the centre of the bound AiG beams in nonlocal nonlinear media.

  18. Bound states of breathing Airy-Gaussian beams in nonlocal nonlinear medium

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaping

    2016-05-01

    With a nonlocal model, we investigate the propagation dynamics of a single Airy-Gaussian (AiG) beam and their interaction in one-dimensional condition by means of direct numerical simulations. With the split-step Fourier method, numerical results shows that nonlocality can support periodic intensity distribution of AiG beams leading to the formation of stable bound states. Especially, by tuning the phase difference between the two beams, we can steer the center of the bound AiG beams in nonlocal nonlinear media.

  19. Nonlocality and conflicting interest games.

    PubMed

    Pappa, Anna; Kumar, Niraj; Lawson, Thomas; Santha, Miklos; Zhang, Shengyu; Diamanti, Eleni; Kerenidis, Iordanis

    2015-01-16

    Nonlocality enables two parties to win specific games with probabilities strictly higher than allowed by any classical theory. Nevertheless, all known such examples consider games where the two parties have a common interest, since they jointly win or lose the game. The main question we ask here is whether the nonlocal feature of quantum mechanics can offer an advantage in a scenario where the two parties have conflicting interests. We answer this in the affirmative by presenting a simple conflicting interest game, where quantum strategies outperform classical ones. Moreover, we show that our game has a fair quantum equilibrium with higher payoffs for both players than in any fair classical equilibrium. Finally, we play the game using a commercial entangled photon source and demonstrate experimentally the quantum advantage. PMID:25635538

  20. Optimal protocols for nonlocality distillation

    SciTech Connect

    Hoeyer, Peter; Rashid, Jibran

    2010-10-15

    Forster et al. recently showed that weak nonlocality can be amplified by giving the first protocol that distills a class of nonlocal boxes (NLBs) [Phys. Rev. Lett. 102, 120401 (2009)] We first show that their protocol is optimal among all nonadaptive protocols. We next consider adaptive protocols. We show that the depth-2 protocol of Allcock et al. [Phys. Rev. A 80, 062107 (2009)] performs better than previously known adaptive depth-2 protocols for all symmetric NLBs. We present a depth-3 protocol that extends the known region of distillable NLBs. We give examples of NLBs for which each of the Forster et al., the Allcock et al., and our protocols perform best. The understanding we develop is that there is no single optimal protocol for NLB distillation. The choice of which protocol to use depends on the noise parameters for the NLB.

  1. Randomness versus nonlocality and entanglement.

    PubMed

    Acín, Antonio; Massar, Serge; Pironio, Stefano

    2012-03-01

    The outcomes obtained in Bell tests involving two-outcome measurements on two subsystems can, in principle, generate up to 2 bits of randomness. However, the maximal violation of the Clauser-Horne-Shimony-Holt inequality guarantees the generation of only 1.23 bits of randomness. We prove here that quantum correlations with arbitrarily little nonlocality and states with arbitrarily little entanglement can be used to certify that close to the maximum of 2 bits of randomness are produced. Our results show that nonlocality, entanglement, and randomness are inequivalent quantities. They also imply that device-independent quantum key distribution with an optimal key generation rate is possible by using almost-local correlations and that device-independent randomness generation with an optimal rate is possible with almost-local correlations and with almost-unentangled states. PMID:22463395

  2. Certifying nonlocality from separable marginals

    NASA Astrophysics Data System (ADS)

    Vértesi, Tamás; Laskowski, Wiesław; Pál, Károly F.

    2014-01-01

    Imagine three parties, Alice, Bob, and Charlie, who share a state of three qubits such that all two-party reduced states A-B, A-C, and B-C are separable. Suppose that they have information only about these marginals but not about the global state. According to recent results, there exists an example for a set of three separable two-party reduced states that is only compatible with an entangled global state. In this paper, we show a stronger result by exhibiting separable two-party reduced states A-B, A-C, and B-C, such that any global state compatible with these marginals is nonlocal. Hence, we obtain that nonlocality of multipartite states can be certified from information only about separable marginals.

  3. Activation of nonlocal quantum resources.

    PubMed

    Navascués, Miguel; Vértesi, Tamás

    2011-02-11

    We find two two-qubit bipartite states ρ1, ρ2 such that arbitrarily many copies of one or the other cannot exhibit nonlocal correlations in a two-setting-two-outcome Bell scenario. However, the bipartite state ρ1 ⊗ ρ2 violates the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality [J. F. Clauser, M. A. Horne, A. Shimony, and R. A. Holt, Phys. Rev. Lett. 23, 880 (1969).] by an amount of 2.023. We also identify a CHSH-local state ρ such that ρ⊗2 is CHSH inequality-violating. The tools employed can be easily adapted to find instances of nonlocality activation in arbitrary Bell scenarios. PMID:21405447

  4. Nonlocality of high-dimensional two-photon orbital angular momentum states

    SciTech Connect

    Aiello, A.; Oemrawsingh, S. S. R.; Eliel, E. R.; Woerdman, J. P.

    2005-11-15

    We propose an interferometric method to investigate the nonlocality of high-dimensional two-photon orbital angular momentum states generated by spontaneous parametric down conversion. We incorporate two half-integer spiral phase plates and a variable-reflectivity output beam splitter into a Mach-Zehnder interferometer to build an orbital angular momentum analyzer. This setup enables testing the nonlocality of high-dimensional two-photon states by repeated use of the Clauser-Horne-Shimony-Holt inequality.

  5. Temporal nonlocality in bistable perception

    NASA Astrophysics Data System (ADS)

    Atmanspacher, Harald; Filk, Thomas

    2012-12-01

    A novel conceptual framework for theoretical psychology is presented and illustrated for the example of bistable perception. A basic formal feature of this framework is the non-commutativity of operations acting on mental states. A corresponding model for the bistable perception of ambiguous stimuli, the Necker-Zeno model, is sketched and some empirical evidence for it so far is described. It is discussed how a temporal nonlocality of mental states, predicted by the model, can be understood and tested.

  6. Quantum nonlocality does not exist

    PubMed Central

    Tipler, Frank J.

    2014-01-01

    Quantum nonlocality is shown to be an artifact of the Copenhagen interpretation, in which each observed quantity has exactly one value at any instant. In reality, all physical systems obey quantum mechanics, which obeys no such rule. Locality is restored if observed and observer are both assumed to obey quantum mechanics, as in the many-worlds interpretation (MWI). Using the MWI, I show that the quantum side of Bell’s inequality, generally believed nonlocal, is really due to a series of three measurements (not two as in the standard, oversimplified analysis), all three of which have only local effects. Thus, experiments confirming “nonlocality” are actually confirming the MWI. The mistaken interpretation of nonlocality experiments depends crucially on a question-begging version of the Born interpretation, which makes sense only in “collapse” versions of quantum theory, about the meaning of the modulus of the wave function, so I use the interpretation based on the MWI, namely that the wave function is a world density amplitude, not a probability amplitude. This view allows the Born interpretation to be derived directly from the Schrödinger equation, by applying the Schrödinger equation to both the observed and the observer. PMID:25015084

  7. Frustrated Brownian Motion of Nonlocal Solitary Waves

    SciTech Connect

    Folli, V.; Conti, C.

    2010-05-14

    We investigate the evolution of solitary waves in a nonlocal medium in the presence of disorder. By using a perturbational approach, we show that an increasing degree of nonlocality may largely hamper the Brownian motion of self-trapped wave packets. The result is valid for any kind of nonlocality and in the presence of nonparaxial effects. Analytical predictions are compared with numerical simulations based on stochastic partial differential equations.

  8. Origin of Dynamical Quantum Non-locality

    NASA Astrophysics Data System (ADS)

    Pachon, Cesar E.; Pachon, Leonardo A.

    2014-03-01

    Non-locality is one of the hallmarks of quantum mechanics and is responsible for paradigmatic features such as entanglement and the Aharonov-Bohm effect. Non-locality comes in two ``flavours'': a kinematic non-locality- arising from the structure of the Hilbert space- and a dynamical non-locality- arising from the quantum equations of motion-. Kinematic non-locality is unable to induce any change in the probability distributions, so that the ``action-at-a-distance'' cannot manifest. Conversely, dynamical non-locality does create explicit changes in probability, though in a ``causality-preserving'' manner. The origin of non-locality of quantum measurements and its relations to the fundamental postulates of quantum mechanics, such as the uncertainty principle, have been only recently elucidated. Here we trace the origin of dynamical non-locality to the superposition principle. This relation allows us to establish and identify how the uncertainty and the superposition principles determine the non-local character of the outcome of a quantum measurement. Being based on group theoretical and path integral formulations, our formulation admits immediate generalizations and extensions to to, e.g., quantum field theory. This work was supported by the Departamento Administrativo de Ciencia, Tecnologia e Innovacion -COLCIENCIAS- of Colombia under the grant number 111556934912.

  9. Unified criteria for multipartite quantum nonlocality

    SciTech Connect

    Cavalcanti, E. G.; He, Q. Y.; Reid, M. D.; Wiseman, H. M.

    2011-09-15

    Wiseman and co-workers [H. M. Wiseman, S. J. Jones, and A. C. Doherty, Phys. Rev. Lett. 98, 140402, (2007)] proposed a distinction among the nonlocality classes of Bell's nonlocality, Einstein-Podolsky-Rosen (EPR) paradox or steering, and entanglement based on whether or not an overseer trusts each party in a bipartite scenario where they are asked to demonstrate entanglement. Here we extend that concept to the multipartite case and derive inequalities that progressively test for those classes of nonlocality, with different thresholds for each level. This framework includes the three classes of nonlocality above in special cases and introduces a family of others.

  10. Robustness of multiparty nonlocality to local decoherence

    NASA Astrophysics Data System (ADS)

    Jang, Sung Soon; Cheong, Yong Wook; Kim, Jaewan; Lee, Hai-Woong

    2006-12-01

    We investigate the robustness of multiparty nonlocality under local decoherence, acting independently and equally on each subsystem. To be specific, we consider an N -qubit Greenberger-Horne-Zeilinger (GHZ) state under a depolarization, dephasing, or dissipation channel, and examine nonlocality by testing violation of the Mermin-Klyshko inequality, which is one of Bell’s inequalities for multiqubit systems. The results show that the robustness of nonlocality increases with the number of qubits, and that the nonlocality of an N -qubit GHZ state with even N is extremely persistent against dephasing.

  11. More nonlocality with less entanglement

    SciTech Connect

    Vidick, Thomas; Wehner, Stephanie

    2011-05-15

    Recent numerical investigations [K. Pal and T. Vertesi, Phys. Rev. A 82, 022116 (2010)] suggest that the I3322 inequality, arguably the simplest extremal Bell inequality after the CHSH inequality, has a very rich structure in terms of the entangled states and measurements that maximally violate it. Here we show that for this inequality the maximally entangled state of any dimension achieves the same violation than just a single EPR pair. In contrast, stronger violations can be achieved using higher dimensional states which are less entangled. This shows that the maximally entangled state is not the most nonlocal resource, even when one restricts attention to the most simple extremal Bell inequalities.

  12. Cosmological perturbations in non-local higher-derivative gravity

    SciTech Connect

    Craps, Ben; Jonckheere, Tim De; Koshelev, Alexey S. E-mail: Tim.De.Jonckheere@vub.ac.be

    2014-11-01

    We study cosmological perturbations in a non-local higher-derivative model of gravity introduced by Biswas, Mazumdar and Siegel. We extend previous work, which had focused on classical scalar perturbations around a cosine hyperbolic bounce solution, in three ways. First, we point out the existence of a Starobinsky solution in this model, which is more attractive from a phenomenological point of view (even though it has no bounce). Second, we study classical vector and tensor pertuxsxrbations. Third, we show how to quantize scalar and tensor perturbations in a de Sitter phase (for choices of parameters such that the model is ghost-free). Our results show that the model is well-behaved at this level, and are very similar to corresponding results in local f(R) models. In particular, for the Starobinsky solution of non-local higher-derivative gravity, we find the same tensor-to-scalar ratio as for the conventional Starobinsky model.

  13. Hyperbolic metamaterial lens with hydrodynamic nonlocal response.

    PubMed

    Yan, Wei; Mortensen, N Asger; Wubs, Martijn

    2013-06-17

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves of the free-electron plasma in the metal constituents. We derive the nonlocal corrections to the effective material parameters analytically, and illustrate the noticeable nonlocal effects on the dispersion curves numerically. As an application, we find that the focusing characteristics of a HMM lens in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we propose to measure the near-field distribution of a hyperbolic metamaterial lens. PMID:23787690

  14. A dispersive wave equation using nonlocal elasticity

    NASA Astrophysics Data System (ADS)

    Challamel, Noël; Rakotomanana, Lalaonirina; Le Marrec, Loïc

    2009-08-01

    Nonlocal continuum mechanics allows one to account for the small length scale effect that becomes significant when dealing with micro- or nano-structures. This Note investigates a model of wave propagation in a nonlocal elastic material. We show that a dispersive wave equation is obtained from a nonlocal elastic constitutive law, based on a mixture of a local and a nonlocal strain. This model comprises both the classical gradient model and the Eringen's integral model. The dynamic properties of the model are discussed, and corroborate well some recent theoretical studies published to unify both static and dynamics gradient elasticity theories. Moreover, an excellent matching of the dispersive curve of the Born-Kármán model of lattice dynamics is obtained with such nonlocal model. To cite this article: N. Challamel et al., C. R. Mecanique 337 (2009).

  15. Virial Theorem in Nonlocal Newtonian Gravity

    NASA Astrophysics Data System (ADS)

    Mashhoon, Bahram

    2016-05-01

    Nonlocal gravity is the recent classical nonlocal generalization of Einstein's theory of gravitation in which the past history of the gravitational field is taken into account. In this theory, nonlocality appears to simulate dark matter. The virial theorem for the Newtonian regime of nonlocal gravity theory is derived and its consequences for "isolated" astronomical systems in virial equilibrium at the present epoch are investigated. In particular, for a sufficiently isolated nearby galaxy in virial equilibrium, the galaxy's baryonic diameter---namely, the diameter of the smallest sphere that completely surrounds the baryonic system at the present time---is predicted to be larger than the effective dark matter fraction times a universal length that is the basic nonlocality length scale of about 3 kpc.

  16. Thermodynamics of a three-flavor nonlocal Polyakov-Nambu-Jona-Lasinio model

    SciTech Connect

    Hell, T.; Roessner, S.; Cristoforetti, M.; Weise, W.

    2010-04-01

    The present work generalizes a nonlocal version of the Polyakov-loop-extended Nambu and Jona-Lasinio (PNJL) model to the case of three active quark flavors, with inclusion of the axial U(1) anomaly. Gluon dynamics is incorporated through a gluonic background field, expressed in terms of the Polyakov loop. The thermodynamics of the nonlocal PNJL model accounts for both chiral and deconfinement transitions. Our results obtained in mean-field approximation are compared to lattice QCD results for N{sub f}=2+1 quark flavors. Additional pionic and kaonic contributions to the pressure are calculated in random phase approximation. Finally, this nonlocal three-flavor PNJL model is applied to the finite density region of the QCD phase diagram. It is confirmed that the existence and location of a critical point in this phase diagram depend sensitively on the strength of the axial U(1) breaking interaction.

  17. Global multipartite nonlocality and Bell-type inequalities in infinite-size quantum spin chains

    NASA Astrophysics Data System (ADS)

    Sun, Zhao-Yu; Guo, Bin; Huang, Hai-Lin

    2015-08-01

    In this paper, we characterize the global multipartite nonlocality in one-dimensional infinite-size spin-1/2 chains. For this purpose, we calculate the multipartite nonlocality of n -site subchains, and take the large-n limit. As n increases from 2 to 100, we find that the average revenue and the marginal revenue of nonlocality converge gradually, thus they can be used to characterize the global multipartite nonlocality in infinite-size chains. Furthermore, in the vicinity of the quantum phase transition (QPT) points of the transverse-field Ising model and the XXZ model, in the large-n limit, multipartite nonlocality becomes extremely sensitive to external perturbation, that is, arbitrarily small perturbation away from the QPT points would lead to a drastic change in the global nonlocality. This signal of QPTs is easily distinguishable, and can be used to detect QPTs. We also draw a vivid physical picture of multipartite correlations and QPTs by analogy with magnetic domains in ferromagnets.

  18. Hierarchy in loss of nonlocal correlations of two-qubit states in noisy environments

    NASA Astrophysics Data System (ADS)

    Paulson, K. G.; Satyanarayana, S. V. M.

    2016-04-01

    Composite quantum systems exhibit nonlocal correlations. These counterintuitive correlations form a resource for quantum information processing and quantum computation. In our previous work on two-qubit maximally entangled mixed states, we observed that entangled states, states that can be used for quantum teleportation, states that violate Bell-CHSH inequality, and states that do not admit local hidden variable description is the hierarchy in terms of the order of nonlocal correlations. In order to establish this hierarchy, in the present work, we investigate the effect of noise on two-qubit states that exhibit higher-order nonlocal correlations. We find that loss of nonlocal correlations in the presence of noise follows the same hierarchy, that is, higher-order nonlocal correlation disappears for small strength of noise, whereas lower-order nonlocal correlations survive strong noisy environment. We show this results for decoherence due to amplitude damping channel on various quantum states. However, we observe that same hierarchy is followed by states undergoing decoherence due to phase damping as well as depolarizing channels.

  19. On the nonlocal properties of relativistic ponderomotive force

    SciTech Connect

    Iwata, Natsumi; Kishimoto, Yasuaki

    2013-08-15

    A theory of relativistic ponderomotive force of transversely localized laser fields is presented by taking into account the nonlocal effects that correspond to higher order terms of the expansion parameter ε≡l/L, i.e., the ratio between particle excursion length and scale length of the field amplitude gradient, while the existing local theory is the first order of ε. As a method for preserving the Hamiltonian structure up to higher orders, we employ the variational principle in noncanonical phase space coordinates incorporated with the Lie transformation. By finding noncanonical coordinates and gauges, we obtain a new formula for the ponderomotive force that involves new terms in the third order represented by the second and third spatial derivatives. The force then depends not only on the local field gradient but also on the curvature and its variation which represent the effects of higher-order nonlocal particle motion. The higher-order terms are found to be subject to the symmetry of the field structure. The obtained formula is accessible to the regime in which the higher derivatives of the field amplitude regulate the interaction. We have applied the formula to laser fields exhibiting flat-top super Gaussian and concave hollow transverse structures which are effective in maintaining the long time scale interaction. The associated nonlocal effects are found to play a key role in determining the interactions. Comparison with the direct integration of the particle orbit demonstrates the validity of the derived formula.

  20. Experimental test of nonlocal causality.

    PubMed

    Ringbauer, Martin; Giarmatzi, Christina; Chaves, Rafael; Costa, Fabio; White, Andrew G; Fedrizzi, Alessandro

    2016-08-01

    Explaining observations in terms of causes and effects is central to empirical science. However, correlations between entangled quantum particles seem to defy such an explanation. This implies that some of the fundamental assumptions of causal explanations have to give way. We consider a relaxation of one of these assumptions, Bell's local causality, by allowing outcome dependence: a direct causal influence between the outcomes of measurements of remote parties. We use interventional data from a photonic experiment to bound the strength of this causal influence in a two-party Bell scenario, and observational data from a Bell-type inequality test for the considered models. Our results demonstrate the incompatibility of quantum mechanics with a broad class of nonlocal causal models, which includes Bell-local models as a special case. Recovering a classical causal picture of quantum correlations thus requires an even more radical modification of our classical notion of cause and effect. PMID:27532045

  1. Experimental test of nonlocal causality

    PubMed Central

    Ringbauer, Martin; Giarmatzi, Christina; Chaves, Rafael; Costa, Fabio; White, Andrew G.; Fedrizzi, Alessandro

    2016-01-01

    Explaining observations in terms of causes and effects is central to empirical science. However, correlations between entangled quantum particles seem to defy such an explanation. This implies that some of the fundamental assumptions of causal explanations have to give way. We consider a relaxation of one of these assumptions, Bell’s local causality, by allowing outcome dependence: a direct causal influence between the outcomes of measurements of remote parties. We use interventional data from a photonic experiment to bound the strength of this causal influence in a two-party Bell scenario, and observational data from a Bell-type inequality test for the considered models. Our results demonstrate the incompatibility of quantum mechanics with a broad class of nonlocal causal models, which includes Bell-local models as a special case. Recovering a classical causal picture of quantum correlations thus requires an even more radical modification of our classical notion of cause and effect. PMID:27532045

  2. Nonlocality of the Aharonov-Bohm effect

    NASA Astrophysics Data System (ADS)

    Aharonov, Yakir; Cohen, Eliahu; Rohrlich, Daniel

    2016-04-01

    Although the Aharonov-Bohm and related effects are familiar in solid-state and high-energy physics, the nonlocality of these effects has been questioned. Here we show that the Aharonov-Bohm effect has two very different aspects. One aspect is instantaneous and nonlocal; the other aspect, which depends on entanglement, unfolds continuously over time. While local, gauge-invariant variables may occasionally suffice for explaining the continuous aspect, we argue that they cannot explain the instantaneous aspect. Thus the Aharonov-Bohm effect is, in general, nonlocal.

  3. All entangled quantum states are nonlocal.

    PubMed

    Buscemi, Francesco

    2012-05-18

    Departing from the usual paradigm of local operations and classical communication adopted in entanglement theory, we study here the interconversion of quantum states by means of local operations and shared randomness. A set of necessary and sufficient conditions for the existence of such a transformation between two given quantum states is given in terms of the payoff they yield in a suitable class of nonlocal games. It is shown that, as a consequence of our result, such a class of nonlocal games is able to witness quantum entanglement, however weak, and reveal nonlocality in any entangled quantum state. An example illustrating this fact is provided. PMID:23003127

  4. Nonlocal magnetic configuration controlling realized in a triple-quantum-dot Josephson junction

    NASA Astrophysics Data System (ADS)

    Yi, Guang-Yu; Wang, Xiao-Qi; Wu, Hai-Na; Gong, Wei-Jiang

    2016-07-01

    We investigate the Josephson effect in a superconductor/triple-quantum-dot/superconductor junction in which the central dot is coupled to the superconductors. It is found that the supercurrent exhibits rich 0-π phase translations due to the interplay between interdot spin and electron correlations. Moreover, when the side dots are half-occupied, the nonlocal spin correlation between them, i.e., ferromagnetic or antiferromagnetic, coincides well with the supercurrent phase. We thus consider such a system to be a promising candidate for controlling the nonlocal magnetic configuration based on the Josephson effect.

  5. Nonlocal ordinary magnetoresistance in indium arsenide

    NASA Astrophysics Data System (ADS)

    Liu, Pan.; Yuan, Zhonghui.; Wu, Hao.; Ali, S. S.; Wan, Caihua.; Ban, Shiliang.

    2015-07-01

    Deflection of carriers by Lorentz force results in an ordinary magnetoresistance (OMR) of (μB)2 at low field. Here we demonstrate that the OMR in high mobility semiconductor InAs could be enhanced by measurement geometry where two probes of voltmeter were both placed on one outer side of two probes of current source. The nonlocal OMR was 3.6 times as large as the local one, reaching 1.8×104% at 5 T. The slope of the linear field dependence of the nonlocal OMR was improved from 12.6 T-1 to 45.3 T-1. The improvement was ascribed to polarity-conserved charges accumulating on boundaries in nonlocal region due to Hall effect. This InAs device with nonlocal geometry could be competitive in B-sensors due to its high OMR ratio, linear field dependence and simple structure.

  6. Nonsmooth feedback controls of nonlocal dispersal models

    NASA Astrophysics Data System (ADS)

    Malaguti, Luisa; Rubbioni, Paola

    2016-03-01

    The paper deals with a nonlocal diffusion equation which is a model for biological invasion and disease spread. A nonsmooth feedback control term is included and the existence of controlled dynamics is proved, satisfying different kinds of nonlocal condition. Jump discontinuities appear in the process. The existence of optimal control strategies is also shown, under suitably regular control functionals. The investigation makes use of techniques of multivalued analysis and is based on the degree theory for condensing operators in Hilbert spaces.

  7. Structure of quantum and broadcasting nonlocal correlations

    NASA Astrophysics Data System (ADS)

    Saha, Debashis; Pawłowski, Marcin

    2015-12-01

    The multipartite setting offers much more complexity of nonlocality than the bipartite one. We analyze the structure of tripartite nonlocal correlations by proposing inequalities satisfied by each of type bilocal, broadcasting, and quantum but violated by the other two. One of the inequalities satisfied by broadcasting correlations is generalized for multipartite systems. The study of its quantum mechanical violation reveals that Greenberger-Horne-Zeilinger-like states exhibit new, powerful correlations.

  8. Symmetric states: Their nonlocality and entanglement

    SciTech Connect

    Wang, Zizhu; Markham, Damian

    2014-12-04

    The nonlocality of permutation symmetric states of qubits is shown via an extension of the Hardy paradox and the extension of the associated inequality. This is achieved by using the Majorana representation, which is also a powerful tool in the study of entanglement properties of symmetric states. Through the Majorana representation, different nonlocal properties can be linked to different entanglement properties of a state, which is useful in determining the usefulness of different states in different quantum information processing tasks.

  9. Chaotic Orbits for Systems of Nonlocal Equations

    NASA Astrophysics Data System (ADS)

    Dipierro, Serena; Patrizi, Stefania; Valdinoci, Enrico

    2016-07-01

    We consider a system of nonlocal equations driven by a perturbed periodic potential. We construct multibump solutions that connect one integer point to another one in a prescribed way. In particular, heteroclinic, homoclinic and chaotic trajectories are constructed. This is the first attempt to consider a nonlocal version of this type of dynamical systems in a variational setting and the first result regarding symbolic dynamics in a fractional framework.

  10. Effects of nonlocality on transfer reactions

    NASA Astrophysics Data System (ADS)

    Titus, Luke

    Nuclear reactions play a key role in the study of nuclei away from stability. Single-nucleon transfer reactions involving deuterons provide an exceptional tool to study the single-particle structure of nuclei. Theoretically, these reactions are attractive as they can be cast into a three-body problem composed of a neutron, proton, and the target nucleus. Optical potentials are a common ingredient in reactions studies. Traditionally, nucleon-nucleus optical potentials are made local for convenience. The effects of nonlocal potentials have historically been included approximately by applying a correction factor to the solution of the corresponding equation for the local equivalent interaction. This is usually referred to as the Perey correction factor. In this thesis, we have systematically investigated the effects of nonlocality on (p,d) and (d,p) transfer reactions, and the validity of the Perey correction factor. We implemented a method to solve the single channel nonlocal equation for both bound and scattering states. We also developed an improved formalism for nonlocal interactions that includes deuteron breakup in transfer reactions. This new formalism, the nonlocal adiabatic distorted wave approximation, was used to study the effects of including nonlocality consistently in ( d,p) transfer reactions. For the (p,d) transfer reactions, we solved the nonlocal scattering and bound state equations using the Perey-Buck type interaction, and compared to local equivalent calculations. Using the distorted wave Born approximation we construct the T-matrix for (p,d) transfer on 17O, 41Ca, 49Ca, 127 Sn, 133Sn, and 209Pb at 20 and 50 MeV. Additionally we studied (p,d) reactions on 40Ca using the the nonlocal dispersive optical model. We have also included nonlocality consistently into the adiabatic distorted wave approximation and have investigated the effects of nonlocality on on (d,p) transfer reactions for deuterons impinged on 16O, 40Ca, 48Ca, 126Sn, 132Sn, 208Pb at 10

  11. Quantum Overloading Cryptography Using Single-Photon Nonlocality

    NASA Astrophysics Data System (ADS)

    Tan, Yong-Gang; Cai, Qing-Yu; Shi, Ting-Yun

    2007-08-01

    Using the single-photon nonlocality, we propose a quantum novel overloading cryptography scheme, in which a single photon carries two bits information in one-way quantum channel. Two commutative modes of the single photon, the polarization mode and the spatial mode, are used to encode secret information. Strict time windows are set to detect the impersonation attack. The spatial mode which denotes the existence of photons is noncommutative with the phase of the photon, so that our scheme is secure against photon-number-splitting attack. Our protocol may be secure against individual attack.

  12. Dark matter from spacetime nonlocality

    NASA Astrophysics Data System (ADS)

    Saravani, Mehdi; Aslanbeigi, Siavash

    2015-11-01

    We propose that dark matter is not yet another new particle in nature, but that it is a remnant of quantum gravitational effects on known fields. We arrive at this possibility in an indirect and surprising manner: by considering retarded, nonlocal, and Lorentzian evolution for quantum fields. This is inspired by recent developments in causal set theory, where such an evolution shows up as the continuum limit of scalar field propagation on a background causal set. Concretely, we study the quantum theory of a massless scalar field whose evolution is given not by the the d'Alembertian □, but by an operator □˜ which is Lorentz invariant, reduces to □ at low energies, and defines an explicitly retarded evolution: (□˜ϕ )(x ) only depends on ϕ (y ), where y is in the causal past of x . This modification results in the existence of a continuum of massive particles, in addition to the usual massless ones, in the free theory. When interactions are introduced, these massive or off-shell quanta can be produced by the scattering of massless particles, but once produced, they no longer interact, which makes them a natural candidate for dark matter.

  13. Nonlocality in deuteron stripping reactions.

    PubMed

    Timofeyuk, N K; Johnson, R C

    2013-03-15

    We propose a new method for the analysis of deuteron stripping reactions, A(d,p)B, in which the nonlocality of nucleon-nucleus interactions and three-body degrees of freedom are accounted for in a consistent way. The model deals with equivalent local nucleon potentials taken at an energy shifted by ∼40  MeV from the "E(d)/2" value frequently used in the analysis of experimental data, where E(d) is the incident deuteron energy. The "E(d)/2" rule lies at the heart of all three-body analyses of (d, p) reactions performed so far with the aim of obtaining nuclear structure properties such as spectroscopic factors and asymptotic normalization coefficients that are crucial for our understanding of nuclear shell evolution in neutron- and proton-rich regions of the nuclear periodic table and for predicting the cross sections of stellar reactions. The large predicted shift arises from the large relative kinetic energy of the neutron and proton in the incident deuteron in those components of the n+p+A wave function that dominate the (d, p) reaction amplitude. The large shift reduces the effective d-A potentials and leads to a change in predicted (d, p) cross sections, thus affecting the interpretation of these reactions in terms of nuclear structure. PMID:25166525

  14. Nonlocality of orthogonal product states

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Chao; Gao, Fei; Qin, Su-Juan; Yang, Ying-Hui; Wen, Qiao-Yan

    2015-07-01

    In this paper, we mainly study the local indistinguishability of mutually orthogonal product basis quantum states in d ⊗d . In 3 ⊗3 , Bennett et al. [ Phys. Rev. A 59, 1070 (1999), 10.1103/PhysRevA.59.1070] presented nine orthogonal product basis quantum states which cannot be distinguished by local operations and classical communication (LOCC). In the work by Zhang et al. [Z.-C. Zhang et al., Phys. Rev. A 90, 022313 (2014), 10.1103/PhysRevA.90.022313], this result was generalized in d ⊗d , where d is odd. In this paper, we aim to construct locally indistinguishable orthogonal product basis quantum states in d ⊗d . For the general d ⊗d (d >2 ) quantum system, we first construct 4 d -4 orthogonal product states, and prove these states are locally indistinguishable using a very simple but quite effective method. Then, based on these states, we construct some classes of locally indistinguishable orthogonal product basis quantum states (OPBS) in d ⊗d (d >2 ) . Finally, we construct some LOCC indistinguishable OPBS in multipartite quantum systems. All of the above results demonstrate the phenomenon of nonlocality without entanglement.

  15. Small and Medium-Sized Information Technology Firms: Assessment of Non-Local Partnership Facilitators

    ERIC Educational Resources Information Center

    Findikoglu, Melike Nur

    2012-01-01

    A two-phased qualitative study was conducted to explore the facilitators of non-local (i.e. domestic or international) partnerships formed by small- and medium-sized firms (SME). Rooted in trust, proximity and dynamic capabilities lenses, the study focused on behaviors of SMEs performing in dynamic, competitive and highly interlinked industry, the…

  16. Batalin-Fradkin-Vilkovisky approach for a nonlocal symmetry of QED

    NASA Astrophysics Data System (ADS)

    Rabello, Silvio J.; Gaete, Patricio

    1995-12-01

    In this paper we use the Batalin-Fradkin-Vilkovisky (BFV) formalism to study a recently proposed nonlocal symmetry of QED. In the BFV extended phase space we show that this symmetry stems from a canonical transformation in the ghost sector.

  17. Relativistic Inverse Scattering Problem for a Superposition of a Nonlocal Separable and a Local Quasipotential

    SciTech Connect

    Chernichenko, Yu.D.

    2005-01-01

    Within the relativistic quasipotential approach to quantum field theory, the relativistic inverse scattering problem is solved for the case where the total quasipotential describing the interaction of two relativistic spinless particles having different masses is a superposition of a nonlocal separable and a local quasipotential. It is assumed that the local component of the total quasipotential is known and that there exist bound states in this local component. It is shown that the nonlocal separable component of the total interaction can be reconstructed provided that the local component, an increment of the phase shift, and the energies of bound states are known.

  18. Extensions and further applications of the nonlocal Polyakov-Nambu-Jona-Lasinio model

    SciTech Connect

    Hell, T.; Weise, W.; Kashiwa, K.

    2011-06-01

    The nonlocal Polyakov-loop-extended Nambu-Jona-Lasinio model is further improved by including momentum-dependent wave-function renormalization in the quark quasiparticle propagator. Both two- and three-flavor versions of this improved Polyakov-loop-extended Nambu-Jona-Lasinio model are discussed, the latter with inclusion of the (nonlocal) 't Hooft-Kobayashi-Maskawa determinant interaction in order to account for the axial U(1) anomaly. Thermodynamics and phases are investigated and compared with recent lattice-QCD results.

  19. Maximally nonlocal theories cannot be maximally random.

    PubMed

    de la Torre, Gonzalo; Hoban, Matty J; Dhara, Chirag; Prettico, Giuseppe; Acín, Antonio

    2015-04-24

    Correlations that violate a Bell inequality are said to be nonlocal; i.e., they do not admit a local and deterministic explanation. Great effort has been devoted to study how the amount of nonlocality (as measured by a Bell inequality violation) serves to quantify the amount of randomness present in observed correlations. In this work we reverse this research program and ask what do the randomness certification capabilities of a theory tell us about the nonlocality of that theory. We find that, contrary to initial intuition, maximal randomness certification cannot occur in maximally nonlocal theories. We go on and show that quantum theory, in contrast, permits certification of maximal randomness in all dichotomic scenarios. We hence pose the question of whether quantum theory is optimal for randomness; i.e., is it the most nonlocal theory that allows maximal randomness certification? We answer this question in the negative by identifying a larger-than-quantum set of correlations capable of this feat. Not only are these results relevant to understanding quantum mechanics' fundamental features, but also put fundamental restrictions on device-independent protocols based on the no-signaling principle. PMID:25955039

  20. Different kinds of chimera death states in nonlocally coupled oscillators.

    PubMed

    Premalatha, K; Chandrasekar, V K; Senthilvelan, M; Lakshmanan, M

    2016-05-01

    We investigate the significance of nonisochronicity parameter in a network of nonlocally coupled Stuart-Landau oscillators with symmetry breaking form. We observe that the presence of nonisochronicity parameter leads to structural changes in the chimera death region while varying the strength of the interaction. This gives rise to the existence of different types of chimera death states such as multichimera death state, type I periodic chimera death (PCD) state, and type II periodic chimera death state. We also find that the number of periodic domains in both types of PCD states decreases exponentially with an increase of coupling range and obeys a power law under nonlocal coupling. Additionally, we also analyze the structural changes of chimera death states by reducing the system of dynamical equations to a phase model through the phase reduction. We also briefly study the role of nonisochronicity parameter on chimera states, where the existence of a multichimera state with respect to the coupling range is pointed out. Moreover, we also analyze the robustness of the chimera death state to perturbations in the natural frequencies of the oscillators. PMID:27300886

  1. Different kinds of chimera death states in nonlocally coupled oscillators

    NASA Astrophysics Data System (ADS)

    Premalatha, K.; Chandrasekar, V. K.; Senthilvelan, M.; Lakshmanan, M.

    2016-05-01

    We investigate the significance of nonisochronicity parameter in a network of nonlocally coupled Stuart-Landau oscillators with symmetry breaking form. We observe that the presence of nonisochronicity parameter leads to structural changes in the chimera death region while varying the strength of the interaction. This gives rise to the existence of different types of chimera death states such as multichimera death state, type I periodic chimera death (PCD) state, and type II periodic chimera death state. We also find that the number of periodic domains in both types of PCD states decreases exponentially with an increase of coupling range and obeys a power law under nonlocal coupling. Additionally, we also analyze the structural changes of chimera death states by reducing the system of dynamical equations to a phase model through the phase reduction. We also briefly study the role of nonisochronicity parameter on chimera states, where the existence of a multichimera state with respect to the coupling range is pointed out. Moreover, we also analyze the robustness of the chimera death state to perturbations in the natural frequencies of the oscillators.

  2. Effectively nonlocal metric-affine gravity

    NASA Astrophysics Data System (ADS)

    Golovnev, Alexey; Koivisto, Tomi; Sandstad, Marit

    2016-03-01

    In metric-affine theories of gravity such as the C-theories, the spacetime connection is associated to a metric that is nontrivially related to the physical metric. In this article, such theories are rewritten in terms of a single metric, and it is shown that they can be recast as effectively nonlocal gravity. With some assumptions, known ghost-free theories with nonsingular and cosmologically interesting properties may be recovered. Relations between different formulations are analyzed at both perturbative and nonperturbative levels, taking carefully into account subtleties with boundary conditions in the presence of integral operators in the action, and equivalences between theories related by nonlocal redefinitions of the fields are verified at the level of equations of motion. This suggests a possible geometrical interpretation of nonlocal gravity as an emergent property of non-Riemannian spacetime structure.

  3. Nonlocal spectroscopy of Andreev bound states

    NASA Astrophysics Data System (ADS)

    Schindele, J.; Baumgartner, A.; Maurand, R.; Weiss, M.; Schönenberger, C.

    2014-01-01

    We experimentally investigate Andreev bound states (ABSs) in a carbon nanotube quantum dot (QD) connected to a superconducting Nb lead (S). A weakly coupled normal metal contact acts as a tunnel probe that measures the energy dispersion of the ABSs. Moreover, we study the response of the ABS to nonlocal transport processes, namely, Cooper pair splitting and elastic co-tunnelling, which are enabled by a second QD fabricated on the same nanotube on the opposite side of S. We find an appreciable nonlocal conductance with a rich structure, including a sign reversal at the ground-state transition from the ABS singlet to a degenerate magnetic doublet. We describe our device by a simple rate equation model that captures the key features of our observations and demonstrates that the sign of the nonlocal conductance is a measure for the charge distribution of the ABS, given by the respective Bogoliubov-de Gennes amplitudes u and v.

  4. Nonlocal Markovian models for image denoising

    NASA Astrophysics Data System (ADS)

    Salvadeo, Denis H. P.; Mascarenhas, Nelson D. A.; Levada, Alexandre L. M.

    2016-01-01

    Currently, the state-of-the art methods for image denoising are patch-based approaches. Redundant information present in nonlocal regions (patches) of the image is considered for better image modeling, resulting in an improved quality of filtering. In this respect, nonlocal Markov random field (MRF) models are proposed by redefining the energy functions of classical MRF models to adopt a nonlocal approach. With the new energy functions, the pairwise pixel interaction is weighted according to the similarities between the patches corresponding to each pair. Also, a maximum pseudolikelihood estimation of the spatial dependency parameter (β) for these models is presented here. For evaluating this proposal, these models are used as an a priori model in a maximum a posteriori estimation to denoise additive white Gaussian noise in images. Finally, results display a notable improvement in both quantitative and qualitative terms in comparison with the local MRFs.

  5. Hardy's criterion of nonlocality for mixed states

    SciTech Connect

    Ghirardi, GianCarlo; Marinatto, Luca

    2006-03-15

    We generalize Hardy's proof of nonlocality to the case of bipartite mixed statistical operators, and we exhibit a necessary condition which has to be satisfied by any given mixed state {sigma} in order that a local and realistic hidden variable model exists which accounts for the quantum mechanical predictions implied by {sigma}. Failure of this condition will imply both the impossibility of any local explanation of certain joint probability distributions in terms of hidden variables and the nonseparability of the considered mixed statistical operator. Our result can be also used to determine the maximum amount of noise, arising from imperfect experimental implementations of the original Hardy's proof of nonlocality, in presence of which it is still possible to put into evidence the nonlocal features of certain mixed states.

  6. Nonlocal formulation of spin Coulomb drag

    NASA Astrophysics Data System (ADS)

    D'Amico, I.; Ullrich, C. A.

    2013-10-01

    The spin Coulomb drag (SCD) effect occurs in materials and devices where charged carriers with different spins exchange momentum via Coulomb scattering. This causes frictional forces between spin-dependent currents that lead to intrinsic dissipation, which may limit spintronics applications. A nonlocal formulation of SCD is developed which is valid for strongly inhomogeneous systems such as nanoscale spintronics devices. This nonlocal formulation of SCD is successfully applied to linewidths of intersubband spin plasmons in semiconductor quantum wells, where experiments have shown that the local approximation fails.

  7. Reversed rainbow with a nonlocal metamaterial

    NASA Astrophysics Data System (ADS)

    Morgado, Tiago A.; Marcos, João S.; Costa, João T.; Costa, Jorge R.; Fernandes, Carlos A.; Silveirinha, Mário G.

    2014-12-01

    One of the intriguing potentials of metamaterials is the possibility to realize a nonlocal electromagnetic reaction, such that the effective medium response at a given point is fundamentally entangled with the macroscopic field distribution at long distances. Here, it is experimentally and numerically verified that a microwave nonlocal metamaterial formed by crossed metallic wires enables a low-loss broadband anomalous material response such that the refractive index decreases with frequency. Notably, it is shown that an electromagnetic beam refracted by our metamaterial prism creates a reversed microwave rainbow.

  8. Experimental nonlocal and surreal Bohmian trajectories.

    PubMed

    Mahler, Dylan H; Rozema, Lee; Fisher, Kent; Vermeyden, Lydia; Resch, Kevin J; Wiseman, Howard M; Steinberg, Aephraim

    2016-02-01

    Weak measurement allows one to empirically determine a set of average trajectories for an ensemble of quantum particles. However, when two particles are entangled, the trajectories of the first particle can depend nonlocally on the position of the second particle. Moreover, the theory describing these trajectories, called Bohmian mechanics, predicts trajectories that were at first deemed "surreal" when the second particle is used to probe the position of the first particle. We entangle two photons and determine a set of Bohmian trajectories for one of them using weak measurements and postselection. We show that the trajectories seem surreal only if one ignores their manifest nonlocality. PMID:26989784

  9. Reversed rainbow with a nonlocal metamaterial

    SciTech Connect

    Morgado, Tiago A. Marcos, João S.; Silveirinha, Mário G.; Costa, João T.; Costa, Jorge R.; Fernandes, Carlos A.

    2014-12-29

    One of the intriguing potentials of metamaterials is the possibility to realize a nonlocal electromagnetic reaction, such that the effective medium response at a given point is fundamentally entangled with the macroscopic field distribution at long distances. Here, it is experimentally and numerically verified that a microwave nonlocal metamaterial formed by crossed metallic wires enables a low-loss broadband anomalous material response such that the refractive index decreases with frequency. Notably, it is shown that an electromagnetic beam refracted by our metamaterial prism creates a reversed microwave rainbow.

  10. Observational viability and stability of nonlocal cosmology

    SciTech Connect

    Deser, S.; Woodard, R.P. E-mail: woodard@phys.ufl.edu

    2013-11-01

    We show that the nonlocal gravity models, proposed to explain current cosmic acceleration without dark energy, pass two essential tests: first, they can be defined so as not to alter the, observationally correct, general relativity predictions for gravitationally bound systems. Second, they are stable, ghost-free, with no additional excitations beyond those of general relativity. In this they differ from their, ghostful, localized versions. The systems' initial value constraints are the same as in general relativity, and our nonlocal modifications never convert the original gravitons into ghosts.

  11. Compressive Sensing via Nonlocal Smoothed Rank Function.

    PubMed

    Fan, Ya-Ru; Huang, Ting-Zhu; Liu, Jun; Zhao, Xi-Le

    2016-01-01

    Compressive sensing (CS) theory asserts that we can reconstruct signals and images with only a small number of samples or measurements. Recent works exploiting the nonlocal similarity have led to better results in various CS studies. To better exploit the nonlocal similarity, in this paper, we propose a non-convex smoothed rank function based model for CS image reconstruction. We also propose an efficient alternating minimization method to solve the proposed model, which reduces a difficult and coupled problem to two tractable subproblems. Experimental results have shown that the proposed method performs better than several existing state-of-the-art CS methods for image reconstruction. PMID:27583683

  12. Experimental nonlocal and surreal Bohmian trajectories

    PubMed Central

    Mahler, Dylan H.; Rozema, Lee; Fisher, Kent; Vermeyden, Lydia; Resch, Kevin J.; Wiseman, Howard M.; Steinberg, Aephraim

    2016-01-01

    Weak measurement allows one to empirically determine a set of average trajectories for an ensemble of quantum particles. However, when two particles are entangled, the trajectories of the first particle can depend nonlocally on the position of the second particle. Moreover, the theory describing these trajectories, called Bohmian mechanics, predicts trajectories that were at first deemed “surreal” when the second particle is used to probe the position of the first particle. We entangle two photons and determine a set of Bohmian trajectories for one of them using weak measurements and postselection. We show that the trajectories seem surreal only if one ignores their manifest nonlocality. PMID:26989784

  13. Wavefunction Collapse via a Nonlocal Relativistic Variational Principle

    SciTech Connect

    Harrison, Alan K.

    2012-06-18

    Since the origin of quantum theory in the 1920's, some of its practitioners (and founders) have been troubled by some of its features, including indeterminacy, nonlocality and entanglement. The 'collapse' process described in the Copenhagen Interpretation is suspect for several reasons, and the act of 'measurement,' which is supposed to delimit its regime of validity, has never been unambiguously defined. In recent decades, nonlocality and entanglement have been studied energetically, both theoretically and experimentally, and the theory has been reinterpreted in imaginative ways, but many mysteries remain. We propose that it is necessary to replace the theory by one that is explicitly nonlinear and nonlocal, and does not distinguish between measurement and non-measurement regimes. We have constructed such a theory, for which the phase of the wavefunction plays the role of a hidden variable via the process of zitterbewegung. To capture this effect, the theory must be relativistic, even when describing nonrelativistic phenomena. It is formulated as a variational principle, in which Nature attempts to minimize the sum of two spacetime integrals. The first integral tends to drive the solution toward a solution of the standard quantum mechanical wave equation, and also enforces the Born rule of outcome probabilities. The second integral drives the collapse process. We demonstrate that the new theory correctly predicts the possible outcomes of the electron two-slit experiment, including the infamous 'delayed-choice' variant. We observe that it appears to resolve some long-standing mysteries, but introduces new ones, including possible retrocausality (a cause later than its effect). It is not clear whether the new theory is deterministic.

  14. Modeling of Carbon Nanotube Composites Based on Nonlocal Elasticity Approach

    NASA Astrophysics Data System (ADS)

    Alavinasab, Ali; Jha, Ratneshwar; Ahmadi, G.

    2014-01-01

    Nonlocal continuum theory is studied for modeling stress distributions in nanocomposites. The second-order approximation in nonlocal theory is considered since the first-order approximation leads to an unacceptable solution. A representative volume element (RVE) of CNT composite is utilized to derive unknown constants in the nonlocal theory model. Stress distributions in RVE using nonlocal theory, classical elasticity, and finite element method are obtained. All three approaches yield the same force, but classical elasticity gives an incorrect value of first moment. Wave propagation studies show that the dispersion curve obtained by nonlocal theory is quite close to the atomic Born-von Karman model.

  15. Nonlocality and entanglement via the Unruh effect

    SciTech Connect

    Tian, Zehua; Wang, Jieci; Jing, Jiliang

    2013-05-15

    Modeling the qubit by a two-level semiclassical detector coupled to a massless scalar field, we investigate how the Unruh effect affects the nonlocality and entanglement of two-qubit and three-qubit states when one of the entangled qubits is accelerated. Two distinct differences with the results of free field model in non-inertial frames are (i) for the two-qubit state, the CHSH inequality cannot be violated for sufficiently large but finite acceleration, furthermore, the concurrence will experience “sudden death”; and (ii) for the three-qubit state, not only does the entanglement vanish in the infinite acceleration limit, but also the Svetlichny inequality cannot be violated in the case of large acceleration. -- Highlights: ► We compare entanglement and nonlocality of two-level detector model with that of free field model in noninertial frame. ► Two-qubit state entanglement experiences “sudden death”. ► Three-qubit state entanglement vanishes in the infinite acceleration limit. ► Bipartite nonlocal correlations vanish for finite values of the acceleration. ► Tripartite nonlocal correlations vanish for finite values of the acceleration as well.

  16. Resonant and nonlocal properties of phononic metasolids

    NASA Astrophysics Data System (ADS)

    Torrent, Daniel; Pennec, Yan; Djafari-Rouhani, Bahram

    2015-11-01

    We derive a general theory of effective properties in metasolids based on phononic crystals with low frequency resonances. We demonstrate that in general these structures need to be described by means of a frequency-dependent and nonlocal anisotropic mass density, stiffness tensor and a third-rank coupling tensor, which shows that they behave like a nonlocal Willis medium. The effect of nonlocality and coupling tensor manifest themselves for some particular resonances, whereas they become negligible for other resonances. Considering the example of a two-dimensional phononic crystal, consisting of triangular arrangements of cylindrical shells in an elastic matrix, we show that its mass density tensor is strongly resonant and anisotropic presenting both positive and negative divergent values, while becoming scalar in the quasistatic limit. Moreover, it is found that the negative value of transverse component of the mass density is induced by a dipolar resonance, while that of the vertical component is induced by a monopolar one. Finally, the dispersion relation obtained by the effective parameters of the crystal is compared with the band structure, showing good agreement for the low-wave-number region, although the nonlocal effects are important given the existence of some resonant values of the wave number.

  17. 29 CFR 780.320 - Nonlocal minors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... That Is Exempted From the Minimum Wage and Overtime Pay Requirements Under Section 13(a)(6) Statutory... 29 Labor 3 2010-07-01 2010-07-01 false Nonlocal minors. 780.320 Section 780.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  18. 29 CFR 780.320 - Nonlocal minors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... That Is Exempted From the Minimum Wage and Overtime Pay Requirements Under Section 13(a)(6) Statutory... 29 Labor 3 2014-07-01 2014-07-01 false Nonlocal minors. 780.320 Section 780.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  19. 29 CFR 780.320 - Nonlocal minors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... That Is Exempted From the Minimum Wage and Overtime Pay Requirements Under Section 13(a)(6) Statutory... 29 Labor 3 2011-07-01 2011-07-01 false Nonlocal minors. 780.320 Section 780.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  20. 29 CFR 780.320 - Nonlocal minors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... That Is Exempted From the Minimum Wage and Overtime Pay Requirements Under Section 13(a)(6) Statutory... 29 Labor 3 2013-07-01 2013-07-01 false Nonlocal minors. 780.320 Section 780.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  1. 29 CFR 780.320 - Nonlocal minors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... That Is Exempted From the Minimum Wage and Overtime Pay Requirements Under Section 13(a)(6) Statutory... 29 Labor 3 2012-07-01 2012-07-01 false Nonlocal minors. 780.320 Section 780.320 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY...

  2. Nonlocal edge state transport in topological insulators

    NASA Astrophysics Data System (ADS)

    Protogenov, Alexander P.; Verbus, Valery A.; Chulkov, Evgueni V.

    2013-11-01

    We use the N-terminal scheme for studying the edge-state transport in two-dimensional topological insulators. We find the universal nonlocal response in the ballistic transport approach. This macroscopic exhibition of the topological order offers different areas for applications.

  3. Measuring non-local Lagrangian peak bias

    NASA Astrophysics Data System (ADS)

    Biagetti, Matteo; Chan, Kwan Chuen; Desjacques, Vincent; Paranjape, Aseem

    2014-06-01

    We investigate non-local Lagrangian bias contributions involving gradients of the linear density field, for which we have predictions from the excursion set peak formalism. We begin by writing down a bias expansion which includes all the bias terms, including the non-local ones. Having checked that the model furnishes a reasonable fit to the halo mass function, we develop a one-point cross-correlation technique to measure bias factors associated with χ2-distributed quantities. We validate the method with numerical realizations of peaks of Gaussian random fields before we apply it to N-body simulations. We focus on the lowest (quadratic) order non-local contributions -2χ _{10}(k_1\\cdot k_2) and χ _{01}[3(k_1\\cdot k_2)^2-k_1^2 k_2^2], where k_1, k_2 are wave modes. We can reproduce our measurement of χ10 if we allow for an offset between the Lagrangian halo centre-of-mass and the peak position. The sign and magnitude of χ10 is consistent with Lagrangian haloes sitting near linear density maxima. The resulting contribution to the halo bias can safely be ignored for M = 1013 M⊙ h-1, but could become relevant at larger halo masses. For the second non-local bias χ01 however, we measure a much larger magnitude than predicted by our model. We speculate that some of this discrepancy might originate from non-local Lagrangian contributions induced by non-spherical collapse.

  4. Nonlocal thermoelectric effects and nonlocal Onsager relations in a three-terminal superconducter/ferromagnet proximity system

    NASA Astrophysics Data System (ADS)

    Eschrig, Matthias; Machon, Peter; Belzig, Wolfgang

    2013-03-01

    Heterostructures of ferromagnets and superconductors are presently subject of intense study since they show interesting phenomena based on the singlet-triplet conversion of pairing amplitudes at the interfaces, and the resulting spin-dependent proximity effect. Spectacular examples are long-range triplet Josephson currents due to inhomogeneous magnetic order, or due to the spin-dependence of the interface reflection and transmission amplitudes, which were confirmed in a set of pivotal experiments in 2010. Here, we study thermal and charge transport in a three-terminal setup consisting of a superconducting and two ferromagnetic contacts. We predict that the simultaneous presence of spin-filtering and of spin-dependent scattering phase shifts at each of the two interfaces will lead to giant non-local thermoelectric effects both in clean and in disordered systems. The symmetries of thermal and electric transport coefficients are related to fundamental thermodynamic principles by the Onsager reciprocity. Our results show that a non-local version of the Onsager relations for thermoelectric currents holds in a three terminal quantum coherent ferromagnet-superconductor heterostructure including spin-dependent crossed Andreev reflection and coherent electron transfer processes. WB and PM acknowledge financial support from the DFG and the Baden-Württemberg-Stiftung. ME acknowledges support from the EPSRC under grant reference EP/J010618/1.

  5. Unification of the family of Garrison-Wright's phases

    PubMed Central

    Cui, Xiao-Dong; Zheng, Yujun

    2014-01-01

    Inspired by Garrison and Wight's seminal work on complex-valued geometric phases, we generalize the concept of Pancharatnam's “in-phase” in interferometry and further develop a theoretical framework for unification of the abelian geometric phases for a biorthogonal quantum system modeled by a parameterized or time-dependent nonhermitian hamiltonian with a finite and nondegenerate instantaneous spectrum, that is, the family of Garrison-Wright's phases, which will no longer be confined in the adiabatic and nonadiabatic cyclic cases. Besides, we employ a typical example, Bethe-Lamb model, to illustrate how to apply our theory to obtain an explicit result for the Garrison-Wright's noncyclic geometric phase, and also to present its potential applications in quantum computation and information. PMID:25056412

  6. Hidden variables and nonlocality in quantum mechanics

    NASA Astrophysics Data System (ADS)

    Hemmick, Douglas Lloyd

    1997-05-01

    Most physicists hold a skeptical attitude toward a 'hidden variables' interpretation of quantum theory, despite David Bohm's successful construction of such a theory and John S. Bell's strong arguments in favor of the idea. The first reason for doubt concerns certain mathematical theorems (von Neumann's, Gleason's, Kochen and Specker's, and Bell's) which can be applied to the hidden variables issue. These theorems are often credited with proving that hidden variables are indeed 'impossible', in the sense that they cannot replicate the predictions of quantum mechanics. Many who do not draw such a strong conclusion nevertheless accept that hidden variables have been shown to exhibit prohibitively complicated features. The second concern is that the most sophisticated example of a hidden variables theory-that of David Bohm-exhibits non-locality, i.e., consequences of events at one place can propagate to other places instantaneously. However, neither the mathematical theorems in question nor the attribute of nonlocality detract from the importance of a hidden variables interpretation of quantum theory. Nonlocality is present in quantum mechanics itself, and is a required characteristic of any theory that agrees with the quantum mechanical predictions. We first discuss the earliest analysis of hidden variables-that of von Neumann's theorem-and review John S. Bell's refutation of von Neumann's 'impossibility proof'. We recall and elaborate on Bell's arguments regarding the theorems of Gleason, and Kochen and Specker. According to Bell, these latter theorems do not imply that hidden variables interpretations are untenable, but instead that such theories must exhibit contextuality, i.e., they must allow for the dependence of measurement results on the characteristics of both measured system and measuring apparatus. We demonstrate a new way to understand the implications of both Gleason's theorem and Kochen and Specker's theorem by noting that they prove a result we call

  7. Rician noise reduction in magnetic resonance images using adaptive non-local mean and guided image filtering

    NASA Astrophysics Data System (ADS)

    Mahmood, Muhammad Tariq; Chu, Yeon-Ho; Choi, Young-Kyu

    2016-05-01

    This paper proposes a Rician noise reduction method for magnetic resonance (MR) images. The proposed method is based on adaptive non-local mean and guided image filtering techniques. In the first phase, a guidance image is obtained from the noisy image through an adaptive non-local mean filter. Sobel operators are applied to compute the strength of edges which is further used to control the spread of the kernel in non-local mean filtering. In the second phase, the noisy and the guidance images are provided to the guided image filter as input to restore the noise-free image. The improved performance of the proposed method is investigated using the simulated and real data sets of MR images. Its performance is also compared with the previously proposed state-of-the art methods. Comparative analysis demonstrates the superiority of the proposed scheme over the existing approaches.

  8. Rician noise reduction in magnetic resonance images using adaptive non-local mean and guided image filtering

    NASA Astrophysics Data System (ADS)

    Mahmood, Muhammad Tariq; Chu, Yeon-Ho; Choi, Young-Kyu

    2016-06-01

    This paper proposes a Rician noise reduction method for magnetic resonance (MR) images. The proposed method is based on adaptive non-local mean and guided image filtering techniques. In the first phase, a guidance image is obtained from the noisy image through an adaptive non-local mean filter. Sobel operators are applied to compute the strength of edges which is further used to control the spread of the kernel in non-local mean filtering. In the second phase, the noisy and the guidance images are provided to the guided image filter as input to restore the noise-free image. The improved performance of the proposed method is investigated using the simulated and real data sets of MR images. Its performance is also compared with the previously proposed state-of-the art methods. Comparative analysis demonstrates the superiority of the proposed scheme over the existing approaches.

  9. Classification of scalar and dyadic nonlocal optical response models.

    PubMed

    Wubs, M

    2015-11-30

    Nonlocal optical response is one of the emerging effects on the nanoscale for particles made of metals or doped semiconductors. Here we classify and compare both scalar and tensorial nonlocal response models. In the latter case the nonlocality can stem from either the longitudinal response, the transverse response, or both. In phenomenological scalar models the nonlocal response is described as a smearing out of the commonly assumed infinitely localized response, as characterized by a distribution with a finite width. Here we calculate explicitly whether and how tensorial models, such as the hydrodynamic Drude model and generalized nonlocal optical response theory, follow this phenomenological description. We find considerable differences, for example that nonlocal response functions, in contrast to simple distributions, assume negative and complex values. Moreover, nonlocal response regularizes some but not all diverging optical near fields. We identify the scalar model that comes closest to the hydrodynamic model. Interestingly, for the hydrodynamic Drude model we find that actually only one third (1/3) of the free-electron response is smeared out nonlocally. In that sense, nonlocal response is stronger for transverse and scalar nonlocal response models, where the smeared-out fractions are 2/3 and 3/3, respectively. The latter two models seem to predict novel plasmonic resonances also below the plasma frequency, in contrast to the hydrodynamic model that predicts standing pressure waves only above the plasma frequency. PMID:26698757

  10. Molecular decay rate near nonlocal plasmonic particles.

    PubMed

    Girard, Christian; Cuche, Aurélien; Dujardin, Erik; Arbouet, Arnaud; Mlayah, Adnen

    2015-05-01

    When the size of metal nanoparticles is smaller than typically 10 nm, their optical response becomes sensitive to both spatial dispersion and quantum size effects associated with the confinement of the conduction electrons inside the particle. In this Letter, we propose a nonlocal scheme to compute molecular decay rates near spherical nanoparticles which includes the electron-electron interactions through a simple model of electronic polarizabilities. The plasmonic particle is schematized by a dynamic dipolar polarizability α(NL)(ω), and the quantum system is characterized by a two-level system. In this scheme, the light matter interaction is described in terms of classical field susceptibilities. This theoretical framework could be extended to address the influence of nonlocality on the dynamics of quantum systems placed in the vicinity of nano-objects of arbitrary morphologies. PMID:25927799

  11. Nonlocal polarization interferometer for entanglement detection

    SciTech Connect

    Williams, Brian P.; Humble, Travis S.; Grice, Warren P.

    2014-10-30

    We report a nonlocal interferometer capable of detecting entanglement and identifying Bell states statistically. This is possible due to the interferometer's unique correlation dependence on the antidiagonal elements of the density matrix, which have distinct bounds for separable states and unique values for the four Bell states. The interferometer consists of two spatially separated balanced Mach-Zehnder or Sagnac interferometers that share a polarization-entangled source. Correlations between these interferometers exhibit nonlocal interference, while single-photon interference is suppressed. This interferometer also allows for a unique version of the Clauser-Horne-Shimony-Holt Bell test where the local reality is the photon polarization. In conclusion, we present the relevant theory and experimental results.

  12. Nonlocal polarization interferometer for entanglement detection

    NASA Astrophysics Data System (ADS)

    Williams, Brian P.; Humble, Travis S.; Grice, Warren P.

    2014-10-01

    We report a nonlocal interferometer capable of detecting entanglement and identifying Bell states statistically. This is possible due to the interferometer's unique correlation dependence on the antidiagonal elements of the density matrix, which have distinct bounds for separable states and unique values for the four Bell states. The interferometer consists of two spatially separated balanced Mach-Zehnder or Sagnac interferometers that share a polarization-entangled source. Correlations between these interferometers exhibit nonlocal interference, while single-photon interference is suppressed. This interferometer also allows for a unique version of the Clauser-Horne-Shimony-Holt-Bell test where the local reality is the photon polarization. We present the relevant theory and experimental results.

  13. Nonlocality of orthogonal product basis quantum states

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Chao; Gao, Fei; Tian, Guo-Jing; Cao, Tian-Qing; Wen, Qiao-Yan

    2014-08-01

    In this paper, we mainly study the local indistinguishability of mutually orthogonal product basis quantum states in the high-dimensional quantum systems. In the Hilbert space of 3⊗3, Walgate and Hardy [Phys. Rev. Lett. 89, 147901 (2002), 10.1103/PhysRevLett.89.147901] presented a very simple proof for nonlocality of nine orthogonal product basis quantum states which are given by Bennett et al. [Phys. Rev. A 59, 1070 (1999), 10.1103/PhysRevA.59.1070]. In the quantum system of d⊗d, where d is odd, we construct d2 orthogonal product basis quantum states and prove these states are locally indistinguishable. Then we are able to construct some locally indistinguishable product basis quantum states in the multipartite systems. All these results reveal the phenomenon of "nonlocality without entanglement."

  14. Sampling Quantum Nonlocal Correlations with High Probability

    NASA Astrophysics Data System (ADS)

    González-Guillén, C. E.; Jiménez, C. H.; Palazuelos, C.; Villanueva, I.

    2016-05-01

    It is well known that quantum correlations for bipartite dichotomic measurements are those of the form {γ=(< u_i,v_jrangle)_{i,j=1}^n}, where the vectors u i and v j are in the unit ball of a real Hilbert space. In this work we study the probability of the nonlocal nature of these correlations as a function of {α=m/n}, where the previous vectors are sampled according to the Haar measure in the unit sphere of {R^m}. In particular, we prove the existence of an {α_0 > 0} such that if {α≤ α_0}, {γ} is nonlocal with probability tending to 1 as {n→ ∞}, while for {α > 2}, {γ} is local with probability tending to 1 as {n→ ∞}.

  15. Absolute nonlocality via distributed computing without communication

    NASA Astrophysics Data System (ADS)

    Czekaj, Ł.; Pawłowski, M.; Vértesi, T.; Grudka, A.; Horodecki, M.; Horodecki, R.

    2015-09-01

    Understanding the role that quantum entanglement plays as a resource in various information processing tasks is one of the crucial goals of quantum information theory. Here we propose an alternative perspective for studying quantum entanglement: distributed computation of functions without communication between nodes. To formalize this approach, we propose identity games. Surprisingly, despite no signaling, we obtain that nonlocal quantum strategies beat classical ones in terms of winning probability for identity games originating from certain bipartite and multipartite functions. Moreover we show that, for a majority of functions, access to general nonsignaling resources boosts success probability two times in comparison to classical ones for a number of large enough outputs. Because there are no constraints on the inputs and no processing of the outputs in the identity games, they detect very strong types of correlations: absolute nonlocality.

  16. Nonlocal polarization interferometer for entanglement detection

    DOE PAGESBeta

    Williams, Brian P.; Humble, Travis S.; Grice, Warren P.

    2014-10-30

    We report a nonlocal interferometer capable of detecting entanglement and identifying Bell states statistically. This is possible due to the interferometer's unique correlation dependence on the antidiagonal elements of the density matrix, which have distinct bounds for separable states and unique values for the four Bell states. The interferometer consists of two spatially separated balanced Mach-Zehnder or Sagnac interferometers that share a polarization-entangled source. Correlations between these interferometers exhibit nonlocal interference, while single-photon interference is suppressed. This interferometer also allows for a unique version of the Clauser-Horne-Shimony-Holt Bell test where the local reality is the photon polarization. In conclusion, wemore » present the relevant theory and experimental results.« less

  17. Inverse scattering for a specific resonating group model nonlocality

    SciTech Connect

    Pantis, G.; Sofianos, S.A.

    1996-10-01

    An inverse scattering method of Lipperheide and Fiedeldey [Z. Phys. A {bold 286}, 45 (1978); {bold 301}, 81 (1981)] has been used to construct an energy-dependent potential from the elastic-scattering phase shifts of the recently developed {ital K} model of Kaneko, LeMere, and Tang [Phys. Rev. C {bold 44}, 1588 (1991); {bold 46}, 298 (1992)] for the {ital n}{minus}{alpha} and {ital n}{minus}{sup 40}Ca systems. The local momentum of the inversion potential is subsequently used to recover the Wigner transforms of the {ital K} model. The results obtained indicate that it is possible to find, via inversion, an {ital l}-independent Wigner transform, which, when calculated at all energies, can provide us with the full nonlocality. {copyright} {ital 1996 The American Physical Society.}

  18. Inverse scattering for a specific resonating group model nonlocality

    NASA Astrophysics Data System (ADS)

    Pantis, G.; Sofianos, S. A.

    1996-10-01

    An inverse scattering method of Lipperheide and Fiedeldey [Z. Phys. A 286, 45 (1978); 301, 81 (1981)] has been used to construct an energy-dependent potential from the elastic-scattering phase shifts of the recently developed K model of Kaneko, LeMere, and Tang [Phys. Rev. C 44, 1588 (1991); 46, 298 (1992)] for the n-α and n-40Ca systems. The local momentum of the inversion potential is subsequently used to recover the Wigner transforms of the K model. The results obtained indicate that it is possible to find, via inversion, an l-independent Wigner transform, which, when calculated at all energies, can provide us with the full nonlocality.

  19. Nonlocal soliton scattering in random potentials

    NASA Astrophysics Data System (ADS)

    Piccardi, Armando; Residori, Stefania; Assanto, Gaetano

    2016-07-01

    We experimentally investigate the transport behaviour of nonlocal spatial optical solitons when launched in and interacting with propagation-invariant random potentials. The solitons are generated in nematic liquid crystals; the randomness is created by suitably engineered illumination of planar voltage-biased cells equipped with a photosensitive wall. We find that the fluctuations follow a super-diffusive trend, with the mean square displacement lowering for decreasing spatial correlation of the noise.

  20. EPR paradox, quantum nonlocality and physical reality

    NASA Astrophysics Data System (ADS)

    Kupczynski, M.

    2016-03-01

    Eighty years ago Einstein, Podolsky and Rosen demonstrated that instantaneous reduction of wave function, believed to describe completely a pair of entangled physical systems, led to EPR paradox. The paradox disappears in statistical interpretation of quantum mechanics (QM) according to which a wave function describes only an ensemble of identically prepared physical systems. QM predicts strong correlations between outcomes of measurements performed on different members of EPR pairs in far-away locations. Searching for an intuitive explanation of these correlations John Bell analysed so called local realistic hidden variable models and proved that correlations consistent with these models satisfy Bell inequalities which are violated by some predictions of QM and by experimental data. Several different local models were constructed and inequalities proven. Some eminent physicists concluded that Nature is definitely nonlocal and that it is acting according to a law of nonlocal randomness. According to these law perfectly random, but strongly correlated events, can be produced at the same time in far away locations and a local and causal explanation of their occurrence cannot be given. We strongly disagree with this conclusion and we prove the contrary by analysing in detail some influential finite sample proofs of Bell and CHSH inequalities and so called Quantum Randi Challenges. We also show how one can win so called Bell's game without violating locality of Nature. Nonlocal randomness is inconsistent with local quantum field theory, with standard model in elementary particle physics and with causal laws and adaptive dynamics prevailing in the surrounding us world. The experimental violation of Bell-type inequalities does not prove the nonlocality of Nature but it only confirms a contextual character of quantum observables and gives a strong argument against counterfactual definiteness and against a point of view according to which experimental outcomes are produced

  1. Nonlocal dynamics of p-adic strings

    NASA Astrophysics Data System (ADS)

    Dragovich, B. G.

    2010-09-01

    We consider the construction of Lagrangians that might be suitable for describing the entire p-adic sector of an adelic open scalar string. These Lagrangians are constructed using the Lagrangian for p-adic strings with an arbitrary prime number p. They contain space-time nonlocality because of the d’Alembertian in the argument of the Riemann zeta function. We present a brief review and some new results.

  2. Nonlocality of cluster states of qubits

    SciTech Connect

    Scarani, Valerio; Acin, Antonio; Schenck, Emmanuel; Aspelmeyer, Markus

    2005-04-01

    We investigate cluster states of qubits with respect to their nonlocal properties. We demonstrate that a Greenberger-Horne-Zeilinger (GHZ) argument holds for any cluster state: more precisely, it holds for any partial, thence mixed, state of a small number of connected qubits (five, in the case of one-dimensional lattices). In addition, we derive a Bell inequality that is maximally violated by the four-qubit cluster state and is not violated by the four-qubit GHZ state.

  3. Switching non-local vector median filter

    NASA Astrophysics Data System (ADS)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2016-04-01

    This paper describes a novel image filtering method that removes random-valued impulse noise superimposed on a natural color image. In impulse noise removal, it is essential to employ a switching-type filtering method, as used in the well-known switching median filter, to preserve the detail of an original image with good quality. In color image filtering, it is generally preferable to deal with the red (R), green (G), and blue (B) components of each pixel of a color image as elements of a vectorized signal, as in the well-known vector median filter, rather than as component-wise signals to prevent a color shift after filtering. By taking these fundamentals into consideration, we propose a switching-type vector median filter with non-local processing that mainly consists of a noise detector and a noise removal filter. Concretely, we propose a noise detector that proactively detects noise-corrupted pixels by focusing attention on the isolation tendencies of pixels of interest not in an input image but in difference images between RGB components. Furthermore, as the noise removal filter, we propose an extended version of the non-local median filter, we proposed previously for grayscale image processing, named the non-local vector median filter, which is designed for color image processing. The proposed method realizes a superior balance between the preservation of detail and impulse noise removal by proactive noise detection and non-local switching vector median filtering, respectively. The effectiveness and validity of the proposed method are verified in a series of experiments using natural color images.

  4. Kummer solitons in strongly nonlocal nonlinear media

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Ping; Belić, Milivoj

    2009-01-01

    We solve the three-dimensional (3D) time-dependent strongly nonlocal nonlinear Schrödinger equation (NNSE) in spherical coordinates, with the help of Kummer's functions. We obtain analytical solitary solutions, which we term the Kummer solitons. We compare analytical solutions with the numerical solutions of NNSE. We discuss higher-order Kummer spatial solitons, which can exist in various forms, such as the 3D vortex solitons and the multipole solitons.

  5. Delayed-choice Measurement and Temporal Nonlocality

    NASA Astrophysics Data System (ADS)

    Kim, Ilki; Mahler, Günter

    2001-02-01

    We study for a composite quantum system with a quantum Turing architecture the temporal non-locality of quantum mechanics by using the temporal Bell inequality, which will be derived for a discretized network dynamics by identifying the subsystem indices with (discrete) parameter time. However, the direct "observation" of the quantum system will lead to no violation of the temporal Bell inequality and to consistent histories of any subsystem. Its violation can be demonstrated, though, for a delayedchoice measurement

  6. Exploring the renormalization of quantum discord and Bell non-locality in the one-dimensional transverse Ising model

    NASA Astrophysics Data System (ADS)

    Liu, Cheng-cheng; Shi, Jia-dong; Ding, Zhi-yong; Ye, Liu

    2016-08-01

    In this paper, the effect of external magnet field g on the relationship among the quantum discord, Bell non-locality and quantum phase transition by employing quantum renormalization-group (QRG) method in the one-dimensional transverse Ising model is investigated. In our model, external magnet field g can influence the phase diagrams. The results have shown that both the two quantum correlation measures can develop two saturated values, which are associated with two distinct phases: long-ranged ordered Ising phase and the paramagnetic phase with the number of QRG iterations increasing. Additionally, quantum non-locality always existent in the long-ranged ordered Ising phase no matter whatever the value of g is and what times QRG steps are carried out and we conclude that the quantum non-locality always exists not only suitable for the two sites of block, but for nearest-neighbor blocks in the long-ranged ordered Ising phase. However, the block-block correlation in the paramagnetic phase is not strong enough to violate the Bell-CHSH inequality as the size of system becomes large. Furthermore, when the system violates the CHSH inequality, i.e., satisfies quantum non-locality, it needs to be entangled. On the other way, if the system obeys the CHSH inequality, it may be entangled or not. To gain further insight, the non-analytic and scaling behavior of QD and Bell non-locality have also been analyzed in detail and this phenomenon indicates that the behavior of the correlation can perfectly help one to observe the quantum critical properties of the model.

  7. Nonlocal modeling of granular flows down inclines.

    PubMed

    Kamrin, Ken; Henann, David L

    2015-01-01

    Flows of granular media down a rough inclined plane demonstrate a number of nonlocal phenomena. We apply the recently proposed nonlocal granular fluidity model to this geometry and find that the model captures many of these effects. Utilizing the model's dynamical form, we obtain a formula for the critical stopping height of a layer of grains on an inclined surface. Using an existing parameter calibration for glass beads, the theoretical result compares quantitatively to existing experimental data for glass beads. This provides a stringent test of the model, whose previous validations focused on driven steady-flow problems. For layers thicker than the stopping height, the theoretical flow profiles display a thickness-dependent shape whose features are in agreement with previous discrete particle simulations. We also address the issue of the Froude number of the flows, which has been shown experimentally to collapse as a function of the ratio of layer thickness to stopping height. While the collapse is not obvious, two explanations emerge leading to a revisiting of the history of inertial rheology, which the nonlocal model references for its homogeneous flow response. PMID:25376561

  8. Quantum nonlocality of multipartite orthogonal product states

    NASA Astrophysics Data System (ADS)

    Xu, Guang-Bao; Wen, Qiao-Yan; Qin, Su-Juan; Yang, Ying-Hui; Gao, Fei

    2016-03-01

    Local distinguishability of orthogonal quantum states is an area of active research in quantum information theory. However, most of the relevant results are about local distinguishability in bipartite Hilbert space and very little is known about the multipartite case. In this paper we present a generic method to construct a completable n -partite (n ≥3 ) product basis with only 2 n members, which exhibits nonlocality without entanglement with n parties, each holding a system of any finite dimension. We give an effective proof of the nonlocality of the completable multipartite product basis. In addition, we construct another incomplete multipartite product basis with a smaller number of members that cannot be distinguished by local operations and classical communication in a d1⊗d2⊗⋯⊗dn quantum system, where n ≥3 and di≥2 for i =1 ,2 ,...,n . The results can lead to a better understanding of the phenomenon of nonlocality without entanglement in any multipartite quantum system.

  9. A nonlocal Fourier's law and its application to the heat conduction of one-dimensional and two-dimensional thermal lattices

    NASA Astrophysics Data System (ADS)

    Challamel, Noël; Grazide, Cécile; Picandet, Vincent; Perrot, Arnaud; Zhang, Yingyan

    2016-06-01

    This study focuses on heat conduction in unidimensional lattices also known as microstructured rods. The lattice thermal properties can be representative of concentrated thermal interface phases in one-dimensional segmented rods. The exact solution of the linear time-dependent spatial difference equation associated with the lattice problem is presented for some given initial and boundary conditions. This exact solution is compared to the quasicontinuum approximation built by continualization of the lattice equations. A rational-based asymptotic expansion of the pseudo-differential problem leads to an equivalent nonlocal-type Fourier's law. The differential nonlocal Fourier's law is analysed with respect to thermodynamic models available in the literature, such as the Guyer-Krumhansl-type equation. The length scale of the nonlocal heat law is calibrated with respect to the lattice spacing. An error analysis is conducted for quantifying the efficiency of the nonlocal model to capture the lattice evolution problem, as compared to the local model. The propagation of error with the nonlocal model is much slower than that in its local counterpart. A two-dimensional thermal lattice is also considered and approximated by a two-dimensional nonlocal heat problem. It is shown that nonlocal and continualized heat equations both approximate efficiently the two-dimensional thermal lattice response. These extended continuous heat models are shown to be good candidates for approximating the heat transfer behaviour of microstructured rods or membranes.

  10. Connection between Bell nonlocality and Bayesian game theory.

    PubMed

    Brunner, Nicolas; Linden, Noah

    2013-01-01

    In 1964, Bell discovered that quantum mechanics is a nonlocal theory. Three years later, in a seemingly unconnected development, Harsanyi introduced the concept of Bayesian games. Here we show that, in fact, there is a deep connection between Bell nonlocality and Bayesian games, and that the same concepts appear in both fields. This link offers interesting possibilities for Bayesian games, namely of allowing the players to receive advice in the form of nonlocal correlations, for instance using entangled quantum particles or more general no-signalling boxes. This will lead to novel joint strategies, impossible to achieve classically. We characterize games for which nonlocal resources offer a genuine advantage over classical ones. Moreover, some of these strategies represent equilibrium points, leading to the notion of quantum/no-signalling Nash equilibrium. Finally, we describe new types of question in the study of nonlocality, namely the consideration of nonlocal advantage given a set of Bell expressions. PMID:23820748

  11. Imaging nonlocal transport in graphene using scanning gate microscopy

    NASA Astrophysics Data System (ADS)

    Connolly, Malcolm; Dou, Ziwei; Morikawa, Sei; Wang, Shu-Wei; Smith, Charles; Watanabe, Kenji; Taniguchi, Takashi; Masubuchi, Satoru; Machida, Tomoki

    Nonlocal transport measurements are designed to detect when charge injected by a current probe induces voltages far from the classical current path. While a range of exotic forces can induce nonlocal transport of Dirac fermions in graphene such as bandstructure topology, Zeeman spin Hall, and many-body interactions, it is important to understand the role of density fluctuations around the Dirac point where nonlocality can be most pronounced. We use scanning gate microscopy to image current flow and nonlocal signals directly in high-mobility graphene encapsulated by hexagonal boron nitride. Despite being located several mean-free paths from the current injector, Hall voltage probes parallel with current path display an order of magnitude larger nonlocal signal than expected around the Dirac point. SGM images captured at different carrier density are consistent with current spreading due to percolation. Such long range charge transport should be considered when designing devices and calculating the relaxation length of nonlocal currents. Supported by EPSRC.

  12. Nonlocal transport in dual-gated bilayer graphene

    NASA Astrophysics Data System (ADS)

    Shimazaki, Yuya; Yamamoto, Michihisa; Watanabe, Kenji; Taniguchi, Takashi; Tarucha, Seigo

    2014-03-01

    We report nonlocal transport measurement of biased bilayer graphene. Dual gated bilayer graphene Hall bars sandwiched between two h-BN insulating layers were prepared using the transfer technique with PMMA thin flims. We measured both local and non-local transport at temperatures between 1.5 K and 200 K. We found enhancement of the nonlocal resistance near the charge neutrality point when we increase the perpendicular electric field. Observed nonlocal resistance at 70K is much larger than what is expected as the Ohmic contribution from van der Pauw formula with measured local resistivity. This observation indicates additional contribution to the nonlocal transport in biased bilayer graphene. We present temperature and displacement field dependence of the nonlocal resistance and discuss its origin in terms of valley Hall effect and transport through disordered edge states.

  13. Gap solitons under competing local and nonlocal nonlinearities

    SciTech Connect

    Kuo, Kuan-Hsien; Lin Yuanyao; Lee, Ray-Kuang; Malomed, Boris A.

    2011-05-15

    We analyze the existence, bifurcations, and shape transformations of one-dimensional gap solitons (GSs) in the first finite band gap induced by a periodic potential built into materials with local self-focusing and nonlocal self-defocusing nonlinearities. Originally stable on-site GS modes become unstable near the upper edge of the band gap with the introduction of the nonlocal self-defocusing nonlinearity with a small nonlocality radius. Unstable off-site GSs bifurcate into a new branch featuring single-humped, double-humped, and flat-top modes due to the competition between local and nonlocal nonlinearities. The mechanism underlying the complex bifurcation pattern and cutoff effects (termination of some bifurcation branches) is illustrated in terms of the shape transformation under the action of the varying degree of the nonlocality. The results of this work suggest a possibility of optical-signal processing by means of the competing nonlocal and local nonlinearities.

  14. Origins of Nonlocality Near the Neutrality Point in Graphene

    NASA Astrophysics Data System (ADS)

    Folk, Joshua

    Nonlocal measurements are an effective experimental tool for probing non-charge characteristics of carriers using a (charge) transport measurement. For example, nonlocal signals in a Hall bar geometry can indicate spin currents, or valley currents, or heat currents flowing through a sample without an accompanying charge current. We present an experimental study of nonlocal electrical signals near the Dirac point in graphene, with the goal of disentangling the various types of current that might give rise to nonlocality. The in-plane magnetic field dependence of the nonlocal signal confirms the role of spin in this effect, as expected from predictions of the Zeeman spin Hall effect in graphene, but our experiments show that thermo-magneto-electric effects also contribute to nonlocality, and the effect is sometimes stronger than that due to spin.

  15. Monogamy of Measurement-Induced Nonlocality Based on Relative Entropy

    NASA Astrophysics Data System (ADS)

    Luo, Yu; Xi, Zheng-Jun; Li, Yong-Ming

    2014-11-01

    In this paper, using relative entropy, we study monogamous properties of measurement-induced nonlocality based on relative entropy. Depending on different measurement sides, we provide necessary and sufficient conditions for two types of monogamy inequalities. By the concept of nonlocality monogamy score, we find a necessary condition of the vanished nonlocality monogamy score for arbitrary three-party states. In addition, two types of necessary and sufficient conditions of the vanished nonlocality monogamy scores are obtained for any pure states. As an application, we show that measurement-induced nonlocality based on relative entropy can be viewed as a “nonlocality witness” to distinguish generalized GHZ states from the generalized W states.

  16. Nonlocal Polyakov-Nambu-Jona-Lasinio model and imaginary chemical potential

    NASA Astrophysics Data System (ADS)

    Kashiwa, Kouji; Hell, Thomas; Weise, Wolfram

    2011-09-01

    With the aim of setting constraints for the modeling of the QCD phase diagram, the phase structure of the two-flavor Polyakov-loop-extended Nambu and Jona-Lasinio (PNJL) model is investigated in the range of imaginary chemical potentials (μI) and compared with available Nf=2 lattice QCD results. The calculations are performed using the advanced nonlocal version of the PNJL model with the inclusion of vector-type quasiparticle interactions between quarks, and with wave-function-renormalization corrections. It is demonstrated that the nonlocal PNJL model reproduces important features of QCD at finite μI, such as the Roberge-Weiss (RW) periodicity and the RW transition. Chiral and deconfinement transition temperatures for Nf=2 turn out to coincide both at zero chemical potential and at finite μI. Detailed studies are performed concerning the RW endpoint and its neighborhood where a first-order transition occurs.

  17. Exact solutions for a coupled nonlocal model of nanobeams

    SciTech Connect

    Marotti de Sciarra, Francesco E-mail: raffaele.barretta@unina.it; Barretta, Raffaele E-mail: raffaele.barretta@unina.it

    2014-10-06

    BERNOULLI-EULER nanobeams under concentrated forces/couples with the nonlocal constitutive behavior proposed by ERINGEN do not exhibit small-scale effects. A new model obtained by coupling the ERINGEN and gradient models is formulated in the present note. A variational treatment is developed by imposing suitable thermodynamic restrictions for nonlocal models and the ensuing differential and boundary conditions of elastic equilibrium are provided. The nonlocal elastostatic problem is solved in a closed-form for nanocantilever and clamped nanobeams.

  18. Nonlocal heat transport in a stochastic magnetic field

    SciTech Connect

    Rax, J.M.; White, R.B.

    1991-12-01

    Heat transport in a stochastic magnetic field configuration is shown to be nonlocal. Collisional transport processes, in such a disordered media, cannot always be reduced to a standard diffusion process, and the concept of a diffusion coefficient is meaningless for a wide range of typical tokamak parameters. In the nonlocal regime the relaxation of a gradient is described by an integral equation, involving a nonlocal propagator. This propagator is calculated, and the relation to previous results is elucidated. 15 refs.

  19. Gravity and large-scale nonlocal bias

    NASA Astrophysics Data System (ADS)

    Chan, Kwan Chuen; Scoccimarro, Román; Sheth, Ravi K.

    2012-04-01

    For Gaussian primordial fluctuations the relationship between galaxy and matter overdensities, bias, is most often assumed to be local at the time of observation in the large-scale limit. This hypothesis is however unstable under time evolution, we provide proofs under several (increasingly more realistic) sets of assumptions. In the simplest toy model galaxies are created locally and linearly biased at a single formation time, and subsequently move with the dark matter (no velocity bias) conserving their comoving number density (no merging). We show that, after this formation time, the bias becomes unavoidably nonlocal and nonlinear at large scales. We identify the nonlocal gravitationally induced fields in which the galaxy overdensity can be expanded, showing that they can be constructed out of the invariants of the deformation tensor (Galileons), the main signature of which is a quadrupole field in second-order perturbation theory. In addition, we show that this result persists if we include an arbitrary evolution of the comoving number density of tracers. We then include velocity bias, and show that new contributions appear; these are related to the breaking of Galilean invariance of the bias relation, a dipole field being the signature at second order. We test these predictions by studying the dependence of halo overdensities in cells of fixed dark matter density: measurements in simulations show that departures from the mean bias relation are strongly correlated with the nonlocal gravitationally induced fields identified by our formalism, suggesting that the halo distribution at the present time is indeed more closely related to the mass distribution at an earlier rather than present time. However, the nonlocality seen in the simulations is not fully captured by assuming local bias in Lagrangian space. The effects on nonlocal bias seen in the simulations are most important for the most biased halos, as expected from our predictions. Accounting for these

  20. Energy driven pattern formation in a non-local Cahn-Hilliard energy

    NASA Astrophysics Data System (ADS)

    Goldman, Dorian

    We study the asymptotic behavior of the Ohta-Kawasaki energy in dimension 2. In that model, two phases appear, and they interact via a nonlocal Coulomb type energy. We focus on the regime where one of the phases has very small volume fraction, thus creating "droplets" of that phase in a sea of the other phase. We compute the Gamma-limit of the leading order energy and yield averaged information for almost minimizers, namely that the density of droplets should be uniform and almost spherical. We then derive a next order Gamma-limit energy determines which the geoemtric arrangement of the droplets. Without appealing at all to the Euler-Lagrange equation, we establish here for all configurations which have "almost minimal energy," the asymptotic roundness and radius of the droplets, and the fact that they asymptotically shrink to points whose arrangement should minimize this energy, in some averaged sense. This leads to expecting to see hexagonal lattices of droplets. In addition, we prove that the density of droplets of non-minimizing critical points of the energy is also uniform and that droplets are spherical in some averaged sense. Next we study a non-local isoperimetric problem in mathbb{R}2 and mathbb{T}2. We are able to show that the connectedcritical points are determined by perimeter alone, under mild assumptions on the boundary, in the small energy/mass regime. These results differ from the recent results of Julin and Muratov-Knupfer in that they concern general critical points rather than global minimizers to the energy. Our method demonstrates that not only does the perimeter dominate the non-locality when minimizing, but also that the change in perimeter slaves to the change of the non-local term in this scaling regime.

  1. Heuristic theory of nonlocally broken gyro-Bohm scaling

    SciTech Connect

    Waltz, R.E.; Candy, J.

    2005-07-15

    Global gyrokinetic simulations of ion temperature gradient turbulent transport with piecewise-flat profiles are given to illustrate the breaking of gyro-Bohm scaling by a nonlocal mechanism. The nonlocal drainage of the turbulence from unstable regions spreading into stable (or less unstable) regions breaks the gyro-Bohm scaling toward Bohm in unstable regions and toward super-gyro-Bohm in stable (or less unstable) regions. A heuristic model for this nonlocal process is formulated in terms of a nonlocal growth rate resulting from a locally weighted radial average of the local linear ballooning mode growth rate. A nonlocality length L measured in ion gyroradii provides the exponential scale for the local weighting. The nonlocal growth rate can be incorporated into a local gyro-Bohm-scaled transport model in place of the local growth rate. The resulting nonlocal transport model will provide some transport in stable regions. A heuristic theory of this nonlocal transport mechanism based on the partial formation of global modes in toroidal geometry is detailed. The theory argues that the nonlocality length L increases with relative gyroradius and decreases with the linear growth rate.

  2. ACCELERATED MRI USING ITERATIVE NON-LOCAL SHRINKAGE

    PubMed Central

    Mohsin, Yasir Q.; Ongie, Gregory; Jacob, Mathews

    2015-01-01

    We introduce a fast iterative non-local shrinkage algorithm to recover MRI data from undersampled Fourier measurements. This approach is enabled by the reformulation of current non-local schemes as an alternating algorithm to minimize a global criterion. The proposed algorithm alternates between a non-local shrinkage step and a quadratic subproblem. The resulting algorithm is observed to be considerably faster than current alternating non-local algorithms. We use efficient continuation strategies to minimize local minima issues. The comparisons of the proposed scheme with state-of-the-art regularization schemes show a considerable reduction in alias artifacts and preservation of edges. PMID:25570265

  3. Survey on nonlocal games and operator space theory

    NASA Astrophysics Data System (ADS)

    Palazuelos, Carlos; Vidick, Thomas

    2016-01-01

    This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states.

  4. Circumferential nonlocal effect on the buckling and vibration of nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Cheng Yuan; Li, Xiao Hu; Luo, Ying

    2016-04-01

    The nonlocal beam theories are widely used to study the mechanics of cylindrical nanotubes (NTs). The one-dimensional models however are unable to account for the nonlocal effect in the circumferential direction, which may substantially affect the applicability of the nonlocal beam models. To address the issue this letter examines the circumferential nonlocal effect (CNE) on the buckling and vibration of the NTs. Here the CNE is characterized by the difference between the nonlocal beam model considering the axial nonlocal effect only and the nonlocal shell model with both axial and circumferential nonlocal effects. The aspect ratio and radius-dependence of the CNE are calculated for the singlewall carbon NTs selected as a typical example. The results show that the CNE is substantial for the buckling and vibration of the NTs with small radius (e.g., <1 nm) and aspect ratio (e.g., <15). It however decreases with the rising radius and the aspect ratio, and turns out to be small for relatively wide and long NTs. The nonlocal beam theories thus may overestimate the buckling load and vibration frequency for the thin and short NTs.

  5. Nonlocal Polyakov-Nambu-Jona-Lasinio model with wave function renormalization at finite temperature and chemical potential

    SciTech Connect

    Contrera, G. A.; Orsaria, M.; Scoccola, N. N.

    2010-09-01

    We study the phase diagram of strongly interacting matter in the framework of a nonlocal SU(2) chiral quark model which includes wave function renormalization and coupling to the Polyakov loop. Both nonlocal interactions based on the frequently used exponential form factor, and on fits to the quark mass and renormalization functions obtained in lattice calculations are considered. Special attention is paid to the determination of the critical points, both in the chiral limit and at finite quark mass. In particular, we study the position of the critical end point as well as the value of the associated critical exponents for different model parametrizations.

  6. A model for high temperature creep of single crystal superalloys based on nonlocal damage and viscoplastic material behavior

    NASA Astrophysics Data System (ADS)

    Trinh, B. T.; Hackl, K.

    2014-07-01

    A model for high temperature creep of single crystal superalloys is developed, which includes constitutive laws for nonlocal damage and viscoplasticity. It is based on a variational formulation, employing potentials for free energy, and dissipation originating from plasticity and damage. Evolution equations for plastic strain and damage variables are derived from the well-established minimum principle for the dissipation potential. The model is capable of describing the different stages of creep in a unified way. Plastic deformation in superalloys incorporates the evolution of dislocation densities of the different phases present. It results in a time dependence of the creep rate in primary and secondary creep. Tertiary creep is taken into account by introducing local and nonlocal damage. Herein, the nonlocal one is included in order to model strain localization as well as to remove mesh dependence of finite element calculations. Numerical results and comparisons with experimental data of the single crystal superalloy LEK94 are shown.

  7. Nonlocalization of Nonlocal Symmetry and Symmetry Reductions of the Burgers Equation

    NASA Astrophysics Data System (ADS)

    Jin, Yan; Jia, Man; Lou, Sen-Yue

    2012-12-01

    Symmetry reduction method is one of the best ways to find exact solutions. In this paper, we study the possibility of symmetry reductions of the well known Burgers equation including the nonlocal symmetry. The related new group invariant solutions are obtained. Especially, the interactions among solitons, Airy waves, and Kummer waves are explicitly given.

  8. Spatially varying geometric phase in classically entangled vector beams of light

    NASA Astrophysics Data System (ADS)

    King-Smith, Andrew; Leary, Cody

    We present theoretical results describing a spatially varying geometric (Pancharatnam) phase present in vector modes of light, in which the polarization and transverse spatial mode degrees of freedom exhibit classical entanglement. We propose an experimental setup capable of characterizing this effect, in which a vector mode propagates through a Mach-Zehnder interferometer with a birefringent phase retarder present in one arm. Since the polarization state of a classically entangled light beam exhibits spatial variation across the transverse mode profile, the phase retarder gives rise to a spatially varying geometric phase in the beam propagating through it. When recombined with the reference beam from the other interferometer arm, the presence of the geometric phase is exhibited in the resulting interference pattern. We acknowledge funding from the Research Corporation for Science Advancement by means of a Cottrell College Science Award.

  9. Fundamental monogamy relation between contextuality and nonlocality.

    PubMed

    Kurzyński, Paweł; Cabello, Adán; Kaszlikowski, Dagomir

    2014-03-14

    We show that the no-disturbance principle imposes a tradeoff between locally contextual correlations violating the Klyachko-Can-Biniciogˇlu-Shumovski inequality and spatially separated correlations violating the Clauser-Horne-Shimony-Holt inequality. The violation of one inequality forbids the violation of the other. We also obtain the corresponding monogamy relation imposed by quantum theory for a qutrit-qubit system. Our results show the existence of fundamental monogamy relations between contextuality and nonlocality that suggest that entanglement might be a particular form of a more fundamental resource. PMID:24679270

  10. Relativistic three-partite non-locality

    NASA Astrophysics Data System (ADS)

    Moradpour, Hooman; Montakhab, Afshin

    2016-05-01

    Bell-like inequalities have been used in order to distinguish non-local quantum pure states by various authors. The behavior of such inequalities under Lorentz transformation (LT) has been a source of debate and controversies in the past. In this paper, we consider the two most commonly studied three-particle pure states, that of W and Greenberger-Horne-Zeilinger (GHZ) states which exhibit distinctly different types of entanglement. We discuss the various types of three-particle inequalities used in previous studies and point to their corresponding shortcomings and strengths. Our main result is that if one uses Czachor’s relativistic spin operator and Svetlichny’s inequality as the main measure of non-locality and uses the same angles in the rest frame (S) as well as the moving frame (S‧), then maximally violated inequality in S will decrease in the moving frame, and will eventually lead to lack of non-locality (i.e. satisfaction of inequality) in the v→c limit. This is shown for both the GHZ and W states and in two different configurations which are commonly studied (Cases 1 and 2). Our results are in line with a more familiar case of two particle case. We also show that the satisfaction of Svetlichny’s inequality in the v→c limit is independent of initial particles’ velocity. Our study shows that whenever we use Czachor’s relativistic spin operator, results draws a clear picture of three-particle non-locality making its general properties consistent with previous studies on two-particle systems regardless of the W state or the GHZ state is involved. Throughout the paper, we also address the results of using Pauli’s operator in investigating the behavior of |Sv| under LT for both of the GHZ and W states and two cases (Cases 1 and 2). Our investigation shows that the violation of |Sv| in moving frame depends on the particle’s energy in the lab frame, which is in agreement with some previous works on two and three-particle systems. Our work may

  11. Entanglement swapping for generalized nonlocal correlations

    SciTech Connect

    Short, A. J.; Popescu, S.; Gisin, N.

    2006-01-15

    We consider an analog of entanglement-swapping for a set of black boxes with the most general nonlocal correlations consistent with relativity (including correlations which are stronger than any attainable in quantum theory). In an attempt to incorporate this phenomenon, we consider expanding the space of objects to include not only correlated boxes, but 'couplers', which are an analog for boxes of measurements with entangled eigenstates in quantum theory. Surprisingly, we find that no couplers exist for two binary-input-binary-output boxes, and hence that there is no analog of entanglement swapping for such boxes.

  12. Fundamental Monogamy Relation between Contextuality and Nonlocality

    NASA Astrophysics Data System (ADS)

    Kurzyński, Paweł; Cabello, Adán; Kaszlikowski, Dagomir

    2014-03-01

    We show that the no-disturbance principle imposes a tradeoff between locally contextual correlations violating the Klyachko-Can-Binicioǧlu-Shumovski inequality and spatially separated correlations violating the Clauser-Horne-Shimony-Holt inequality. The violation of one inequality forbids the violation of the other. We also obtain the corresponding monogamy relation imposed by quantum theory for a qutrit-qubit system. Our results show the existence of fundamental monogamy relations between contextuality and nonlocality that suggest that entanglement might be a particular form of a more fundamental resource.

  13. [Effects of quantum nonlocality in the water activation process].

    PubMed

    Zatsepina, O V; Stekhin, A A; Yakovleva, G V

    2014-01-01

    The dynamic alterations of the magnetic flux density of the water volume, activated with structurally stressed calcium carbonate in micellar form have been investigated. The phase of the associated water was established to exhibit electrical and magnetic properties, recorded by in B&E meter in the frequency range of 5Hz - 2kHz. Alterations in water Eh (redox) potential and the magnetic flux density B testify to synchronous auto-oscillatory changes. This gives evidence of non-linearity of the relationship between auto-oscillatory processes excited in the water; and reflects the nonlocal in time the relationship between the states of water, manifesting in a change of water activity on the 1st and 2nd day in negative time. The mechanism of action of associated water phase is shown to be described by de Broglie concept of matter waves with taking into account delocalized in time states of phase of electron wave packet in accordance with the transactional interpretation of quantum physics. PMID:24749297

  14. Geometric reduction of dynamical nonlocality in nanoscale quantum circuits

    PubMed Central

    Strambini, E.; Makarenko, K. S.; Abulizi, G.; de Jong, M. P.; van der Wiel, W. G.

    2016-01-01

    Nonlocality is a key feature discriminating quantum and classical physics. Quantum-interference phenomena, such as Young’s double slit experiment, are one of the clearest manifestations of nonlocality, recently addressed as dynamical to specify its origin in the quantum equations of motion. It is well known that loss of dynamical nonlocality can occur due to (partial) collapse of the wavefunction due to a measurement, such as which-path detection. However, alternative mechanisms affecting dynamical nonlocality have hardly been considered, although of crucial importance in many schemes for quantum information processing. Here, we present a fundamentally different pathway of losing dynamical nonlocality, demonstrating that the detailed geometry of the detection scheme is crucial to preserve nonlocality. By means of a solid-state quantum-interference experiment we quantify this effect in a diffusive system. We show that interference is not only affected by decoherence, but also by a loss of dynamical nonlocality based on a local reduction of the number of quantum conduction channels of the interferometer. With our measurements and theoretical model we demonstrate that this mechanism is an intrinsic property of quantum dynamics. Understanding the geometrical constraints protecting nonlocality is crucial when designing quantum networks for quantum information processing. PMID:26732751

  15. Geometric reduction of dynamical nonlocality in nanoscale quantum circuits

    NASA Astrophysics Data System (ADS)

    Strambini, E.; Makarenko, K. S.; Abulizi, G.; de Jong, M. P.; van der Wiel, W. G.

    2016-01-01

    Nonlocality is a key feature discriminating quantum and classical physics. Quantum-interference phenomena, such as Young’s double slit experiment, are one of the clearest manifestations of nonlocality, recently addressed as dynamical to specify its origin in the quantum equations of motion. It is well known that loss of dynamical nonlocality can occur due to (partial) collapse of the wavefunction due to a measurement, such as which-path detection. However, alternative mechanisms affecting dynamical nonlocality have hardly been considered, although of crucial importance in many schemes for quantum information processing. Here, we present a fundamentally different pathway of losing dynamical nonlocality, demonstrating that the detailed geometry of the detection scheme is crucial to preserve nonlocality. By means of a solid-state quantum-interference experiment we quantify this effect in a diffusive system. We show that interference is not only affected by decoherence, but also by a loss of dynamical nonlocality based on a local reduction of the number of quantum conduction channels of the interferometer. With our measurements and theoretical model we demonstrate that this mechanism is an intrinsic property of quantum dynamics. Understanding the geometrical constraints protecting nonlocality is crucial when designing quantum networks for quantum information processing.

  16. Nonlocal effects on the polarization state of a photon, induced by distant absorbers

    NASA Technical Reports Server (NTRS)

    Ryff, Luis Carlos B.

    1994-01-01

    A variant of a Franson's two-photon correlation experiment is discussed, in which the linear polarization state of one of the photons depends on the path followed in the interferometer. It is shown that although the path difference is greater than the coherence length, the photon can be found in a polarization state represented by the superposition of the polarization states associated to the paths when there is coincident detection. Since the photons, produced via parametric down-conversion, are fairly well localized in space and time, the situation in which one of the photons is detected before the other can reach the interferometer raises an intriguing point: it seems that in some cases the second photon would have to be described by two wave packets simultaneously. Unlike previous experiments, in which nonlocal effects were induced by means of polarizers of phase shifters, in the proposed experiment nonlocal effects can be induced by means of variable absorbers.

  17. Identification, characterization and evolution of non-local quasi-Lagrangian structures in turbulence

    NASA Astrophysics Data System (ADS)

    Yang, Yue

    2016-02-01

    The recent progress on non-local Lagrangian and quasi-Lagrangian structures in turbulence is reviewed. The quasi-Lagrangian structures, e.g., vortex surfaces in viscous flow, gas-liquid interfaces in multi-phase flow, and flame fronts in premixed combustion, can show essential Lagrangian following properties, but they are able to have topological changes in the temporal evolution. In addition, they can represent or influence the turbulent flow field. The challenges for the investigation of the non-local structures include their identification, characterization, and evolution. The improving understanding of the quasi-Lagrangian structures is expected to be helpful to elucidate crucial dynamics and develop structure-based predictive models in turbulence.

  18. Implementing a Nonlocal Toffoli Gate Using Partially Entangled Qubit Pairs

    NASA Astrophysics Data System (ADS)

    Chen, Li-Bing; Lu, Hong

    2011-11-01

    We investigate the local implementation of a nonlocal quantum Toffoli gate via partially entangled states. Firstly, we show how the nonlocal Toffoli gate can be implemented with unit fidelity and a certain probability by employing two partially entangled qubit pairs as quantum channels. The quantum circuit that does this proposed implementation is built entirely of local single-level and two-level gates if the target node harness a three-level qudit as a catalyser. This enables the construction of this key nonlocal quantum gate with existing technology. Then, we put forward a scheme to realize deterministic and exact implementation of this nonlocal gate via more partially entangled pairs. In this scheme, the control nodes' local positive operator valued measurements (POVMs) lies at the heart. We construct the required POVMs. The fact that the deterministic and exact implementation of a nonlocal multi-qubit gate could be realized by using partially entangled qubit pairs and comparatively fewer resources cost is notable.

  19. Nonlocal electrodynamics of Josephson vortices in superconducting circuits

    NASA Astrophysics Data System (ADS)

    Abdumalikov, A. A., Jr.; Alfimov, G. L.; Malishevskii, A. S.

    2009-02-01

    A review of the main analytical, numerical and experimental results of nonlocal Josephson electrodynamics in different types of junctions is presented. Several mechanisms of nonlocality are discussed. Linear electromagnetic waves and vortices (kinks) propagating along junctions are examined in detail. The main attention is paid to bulk junctions with internal nonlocality and to narrow junctions with geometrical nonlocality. Theoretical conceptions of Cherenkov excitation of plasma waves, discretization of kink velocities and forming of multikinks by binding of elementary vortices are considered. Experimental results for narrow junctions are surveyed. It is shown that the positions of Fiske steps and Cherenkov resonances at current-voltage characteristics which have been obtained in experiments can be properly explained by a nonlocal model that takes into account stray magnetic fields outside the junction.

  20. Hierarchy of multipartite nonlocality in the nonsignaling scenario

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoxu; Zhang, Chengjie; Chen, Qing; Yu, Sixia; Yuan, Haidong; Oh, C. H.

    2016-08-01

    We propose a hierarchy of Bell-type inequalities for arbitrary n -partite systems that identifies the different degrees of nonlocality ranging from standard to genuine multipartite nonlocality. After introducing the definition of nonsignaling m locality, we show that the observed joint probabilities in any nonsignaling m -local realistic models should satisfy the (m -1 )th Bell-type inequality. When m =2 , the corresponding inequality reduces to the one shown earlier [Q. Chen et al., Phys. Rev. Lett. 112, 140404 (2014), 10.1103/PhysRevLett.112.140404] whose violation indicates genuine multipartite nonlocality, and when m =n , the corresponding inequality is just Hardy's inequality whose violation indicates standard multipartite nonlocality. Furthermore, several examples are provided to demonstrate their hierarchy of multipartite nonlocality.

  1. Origin and effect of nonlocality in a layered composite.

    SciTech Connect

    Silling, Stewart Andrew

    2014-01-01

    A simple demonstration of nonlocality in a heterogeneous material is presented. By analysis of the microscale deformation of a two-component layered medium, it is shown that nonlocal interactions necessarily appear in a homogenized model of the system. Explicit expressions for the nonlocal forces are determined. The way these nonlocal forces appear in various nonlocal elasticity theories is derived. The length scales that emerge involve the constituent material properties as well as their geometrical dimen- sions. A peridynamic material model for the smoothed displacement eld is derived. It is demonstrated by comparison with experimental data that the incorporation of non- locality in modeling dramatically improves the prediction of the stress concentration in an open hole tension test on a composite plate.

  2. Testing Quantum Gravity Induced Nonlocality via Optomechanical Quantum Oscillators.

    PubMed

    Belenchia, Alessio; Benincasa, Dionigi M T; Liberati, Stefano; Marin, Francesco; Marino, Francesco; Ortolan, Antonello

    2016-04-22

    Several quantum gravity scenarios lead to physics below the Planck scale characterized by nonlocal, Lorentz invariant equations of motion. We show that such nonlocal effective field theories lead to a modified Schrödinger evolution in the nonrelativistic limit. In particular, the nonlocal evolution of optomechanical quantum oscillators is characterized by a spontaneous periodic squeezing that cannot be generated by environmental effects. We discuss constraints on the nonlocality obtained by past experiments, and show how future experiments (already under construction) will either see such effects or otherwise cast severe bounds on the nonlocality scale (well beyond the current limits set by the Large Hadron Collider). This paves the way for table top, high precision experiments on massive quantum objects as a promising new avenue for testing some quantum gravity phenomenology. PMID:27152787

  3. Testing Quantum Gravity Induced Nonlocality via Optomechanical Quantum Oscillators

    NASA Astrophysics Data System (ADS)

    Belenchia, Alessio; Benincasa, Dionigi M. T.; Liberati, Stefano; Marin, Francesco; Marino, Francesco; Ortolan, Antonello

    2016-04-01

    Several quantum gravity scenarios lead to physics below the Planck scale characterized by nonlocal, Lorentz invariant equations of motion. We show that such nonlocal effective field theories lead to a modified Schrödinger evolution in the nonrelativistic limit. In particular, the nonlocal evolution of optomechanical quantum oscillators is characterized by a spontaneous periodic squeezing that cannot be generated by environmental effects. We discuss constraints on the nonlocality obtained by past experiments, and show how future experiments (already under construction) will either see such effects or otherwise cast severe bounds on the nonlocality scale (well beyond the current limits set by the Large Hadron Collider). This paves the way for table top, high precision experiments on massive quantum objects as a promising new avenue for testing some quantum gravity phenomenology.

  4. Infrared image denoising by nonlocal means filtering

    NASA Astrophysics Data System (ADS)

    Dee-Noor, Barak; Stern, Adrian; Yitzhaky, Yitzhak; Kopeika, Natan

    2012-05-01

    The recently introduced non-local means (NLM) image denoising technique broke the traditional paradigm according to which image pixels are processed by their surroundings. Non-local means technique was demonstrated to outperform state-of-the art denoising techniques when applied to images in the visible. This technique is even more powerful when applied to low contrast images, which makes it tractable for denoising infrared (IR) images. In this work we investigate the performance of NLM applied to infrared images. We also present a new technique designed to speed-up the NLM filtering process. The main drawback of the NLM is the large computational time required by the process of searching similar patches. Several techniques were developed during the last years to reduce the computational burden. Here we present a new techniques designed to reduce computational cost and sustain optimal filtering results of NLM technique. We show that the new technique, which we call Multi-Resolution Search NLM (MRS-NLM), reduces significantly the computational cost of the filtering process and we present a study of its performance on IR images.

  5. Simulation of low-pressure inductively coupled plasmas: Non-local effects and pulsed power operation

    NASA Astrophysics Data System (ADS)

    Ramamurthi, Badri

    For modeling of low-pressure Inductively Coupled Plasma (ICP) discharges, a number of approaches have been proposed with varying degree of complexity. A self-consistent 1-D model was developed in this work to study the effects of non-local electron conductivity on power absorption and plasma density profiles in a planar inductively coupled argon discharge at low pressures (< 10 mTorr). The self-consistent kinetic description of the discharge included three modules: (1) an EEDF module to compute a non-Maxwellian EEDF, (2) a non-local electron conductivity module which predicted current distribution in the plasma as an integral over the electric field and solved Maxwell's equations to find the self-consistent electric field as well as the non-local power deposition profile and (3) a Heavy Species Transport (HST) module which solved for the ion and metastable atom density and velocity. Results from the full model were then compared with those obtained by using a local conductivity model (Ohm's law) for the RF current. For 10 mTorr, the EEDF was found to be almost Maxwellian with electron temperature ˜ 3 V. As a result, the plasma density profiles obtained from the local and non-local cases were almost identical for the same total power. Interestingly, a similar result was obtained even for a pressure of 1 mTorr where the EEDF was non-Maxwellian. This suggests that as far as species density and flux are concerned, local conductivity models, with lesser computational expense, can be employed even in the non-local regime. Comparisons between simulation and experiment for RF field and current density showed better agreement for non-local model compared with local model. A two-dimensional (r,z) continuum model was then developed to study the spatio-temporal dynamics of a pulsed power (square-wave modulated) discharge in argon (electropositive) and chlorine (electronegative) sustained in an inductively coupled plasma (ICP) reactor with a planar coil. The self

  6. Nonlocal Mumford-Shah regularizers for color image restoration.

    PubMed

    Jung, Miyoun; Bresson, Xavier; Chan, Tony F; Vese, Luminita A

    2011-06-01

    We propose here a class of restoration algorithms for color images, based upon the Mumford-Shah (MS) model and nonlocal image information. The Ambrosio-Tortorelli and Shah elliptic approximations are defined to work in a small local neighborhood, which are sufficient to denoise smooth regions with sharp boundaries. However, texture is nonlocal in nature and requires semilocal/non-local information for efficient image denoising and restoration. Inspired from recent works (nonlocal means of Buades, Coll, Morel, and nonlocal total variation of Gilboa, Osher), we extend the local Ambrosio-Tortorelli and Shah approximations to MS functional (MS) to novel nonlocal formulations, for better restoration of fine structures and texture. We present several applications of the proposed nonlocal MS regularizers in image processing such as color image denoising, color image deblurring in the presence of Gaussian or impulse noise, color image inpainting, color image super-resolution, and color filter array demosaicing. In all the applications, the proposed nonlocal regularizers produce superior results over the local ones, especially in image inpainting with large missing regions. We also prove several characterizations of minimizers based upon dual norm formulations. PMID:21078579

  7. Effects of nonlocal potentials on (p ,d ) transfer reactions

    NASA Astrophysics Data System (ADS)

    Ross, A.; Titus, L. J.; Nunes, F. M.; Mahzoon, M. H.; Dickhoff, W. H.; Charity, R. J.

    2015-10-01

    Background: Although local phenomenological optical potentials have been standardly used to interpret nuclear reactions, recent studies suggest the effects of nonlocality should not be neglected. Purpose: In this work we investigate the effects of nonlocality in (p ,d ) transfer reactions using nonlocal optical potentials. We compare results obtained with the dispersive optical model to those obtained using the Perey-Buck interaction. Method: We solve the scattering and bound-state equations for the nonlocal version of the dispersive optical model. Then, using the distorted-wave Born approximation, we calculate the transfer cross section for (p ,d ) on 40Ca at Ep=20 , 35, and 50 MeV. Results: The inclusion of nonlocality in the bound state has a larger effect than that in the scattering states. The overall effect on the transfer cross section is very significant. We found an increase due to nonlocality in the transfer cross section of ≈30 - 50 % when using the Perey-Buck interaction and of ≈15 - 50 % when using the dispersive optical potential. Conclusions: Although the details of the nonlocal interaction can change the magnitude of the effects, our study shows that qualitatively the results obtained using the dispersive optical potential and the Perey-Buck interaction are consistent, in both cases the transfer cross sections are significantly increased.

  8. Switching non-local median filter

    NASA Astrophysics Data System (ADS)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2015-06-01

    This paper describes a novel image filtering method for removal of random-valued impulse noise superimposed on grayscale images. Generally, it is well known that switching-type median filters are effective for impulse noise removal. In this paper, we propose a more sophisticated switching-type impulse noise removal method in terms of detail-preserving performance. Specifically, the noise detector of the proposed method finds out noise-corrupted pixels by focusing attention on the difference between the value of a pixel of interest (POI) and the median of its neighboring pixel values, and on the POI's isolation tendency from the surrounding pixels. Furthermore, the removal of the detected noise is performed by the newly proposed median filter based on non-local processing, which has superior detail-preservation capability compared to the conventional median filter. The effectiveness and the validity of the proposed method are verified by some experiments using natural grayscale images.

  9. Nonlocal means denoising of ECG signals.

    PubMed

    Tracey, Brian H; Miller, Eric L

    2012-09-01

    Patch-based methods have attracted significant attention in recent years within the field of image processing for a variety of problems including denoising, inpainting, and super-resolution interpolation. Despite their prevalence for processing 2-D signals, they have received little attention in the 1-D signal processing literature. In this letter, we explore application of one such method, the nonlocal means (NLM) approach, to the denoising of biomedical signals. Using ECG as an example, we demonstrate that a straightforward NLM-based denoising scheme provides signal-to-noise ratio improvements very similar to state of the art wavelet-based methods, while giving ~3 × or greater reduction in metrics measuring distortion of the denoised waveform. PMID:22829361

  10. Single-electron entanglement and nonlocality

    NASA Astrophysics Data System (ADS)

    Dasenbrook, David; Bowles, Joseph; Bohr Brask, Jonatan; Hofer, Patrick P.; Flindt, Christian; Brunner, Nicolas

    2016-04-01

    Motivated by recent progress in electron quantum optics, we revisit the question of single-electron entanglement, specifically whether the state of a single electron in a superposition of two separate spatial modes should be considered entangled. We first discuss a gedanken experiment with single-electron sources and detectors, and demonstrate deterministic (i. e. without post-selection) Bell inequality violation. This implies that the single-electron state is indeed entangled and, furthermore, nonlocal. We then present an experimental scheme where single-electron entanglement can be observed via measurements of the average currents and zero-frequency current cross-correlators in an electronic Hanbury Brown–Twiss interferometer driven by Lorentzian voltage pulses. We show that single-electron entanglement is detectable under realistic operating conditions. Our work settles the question of single-electron entanglement and opens promising perspectives for future experiments.

  11. A nonlocal spatial model for Lyme disease

    NASA Astrophysics Data System (ADS)

    Yu, Xiao; Zhao, Xiao-Qiang

    2016-07-01

    This paper is devoted to the study of a nonlocal and time-delayed reaction-diffusion model for Lyme disease with a spatially heterogeneous structure. In the case of a bounded domain, we first prove the existence of the positive steady state and a threshold type result for the disease-free system, and then establish the global dynamics for the model system in terms of the basic reproduction number. In the case of an unbound domain, we obtain the existence of the disease spreading speed and its coincidence with the minimal wave speed. At last, we use numerical simulations to verify our analytic results and investigate the influence of model parameters and spatial heterogeneity on the disease infection risk.

  12. Nonlocal kinetic-energy-density functionals

    SciTech Connect

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E. |

    1996-04-01

    In this paper we present nonlocal kinetic-energy functionals {ital T}[{ital n}] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. {copyright} {ital 1996 The American Physical Society.}

  13. Nonlocal Constitutive Relation for Steady Granular Flow

    NASA Astrophysics Data System (ADS)

    Kamrin, Ken; Koval, Georg

    2012-04-01

    Extending recent modeling efforts for emulsions, we propose a nonlocal fluidity relation for flowing granular materials, capturing several known finite-size effects observed in steady flow. We express the local Bagnold-type granular flow law in terms of a fluidity ratio and then extend it with a particular Laplacian term that is scaled by the grain size. The resulting model is calibrated against a sequence of existing discrete element method data sets for two-dimensional annular shear, where it is shown that the model correctly describes the divergence from a local rheology due to the grain size as well as the rate-independence phenomenon commonly observed in slowly flowing zones. The same law is then applied in two additional inhomogeneous flow geometries, and the predicted velocity profiles are compared against corresponding discrete element method simulations utilizing the same grain composition as before, yielding favorable agreement in each case.

  14. Origins of nonlocality near the neutrality point in graphene.

    PubMed

    Renard, Julien; Studer, Matthias; Folk, Joshua A

    2014-03-21

    We present an experimental study of nonlocal electrical signals near the Dirac point in graphene. The in-plane magnetic field dependence of the nonlocal signal confirms the role of spin in this effect, as expected from recent predictions of the Zeeman spin Hall effect in graphene, but our experiments show that thermo-magneto-electric effects also contribute to nonlocality, and the effect is sometimes stronger than that due to spin. Thermal effects are seen to be very sensitive to sample details that do not influence other transport parameters. PMID:24702396

  15. Linear delta-f simulations of nonlocal electron heat transport

    SciTech Connect

    Brunner, S.; Valeo, E.; Krommes, J.A.

    2000-01-27

    Nonlocal electron heat transport calculations are carried out by making use of some of the techniques developed previously for extending the delta f method to transport time scale simulations. By considering the relaxation of small amplitude temperature perturbations of a homogeneous Maxwellian background, only the linearized Fokker-Planck equation has to be solved, and direct comparisons can be made with the equivalent, nonlocal hydrodynamic approach. A quasineutrality-conserving algorithm is derived for computing the self-consistent electric fields driving the return currents. In the low-collisionality regime, results illustrate the importance of taking account of nonlocality in both space and time.

  16. Quantitative relations between measurement incompatibility, quantum steering, and nonlocality

    NASA Astrophysics Data System (ADS)

    Cavalcanti, D.; Skrzypczyk, P.

    2016-05-01

    The certification of Bell nonlocality or quantum steering implies the use of incompatible measurements. Here we make this connection quantitative. We show how to strengthen robustness-based steering and nonlocality quantifiers in order that they give strong lower bounds to previously proposed incompatibility quantifiers. Our results can be seen from two perspectives. On the one hand, they can be used to estimate how much steering or nonlocality can be demonstrated with a given set of measurements. On the other hand, they give one-sided device-independent and device-independent ways of estimating measurement incompatibility.

  17. Large nonlocal nonlinear optical response of castor oil

    NASA Astrophysics Data System (ADS)

    Souza, Rogério F.; Alencar, Márcio A. R. C.; Meneghetti, Mario R.; Hickmann, Jandir M.

    2009-09-01

    The nonlocal nonlinearity of castor oil was investigated using the Z-scan technique in the CW regime at 514 nm and in femtosecond regime at 810 nm. Large negative nonlinear refractive indexes of thermal origin, thermo-optical coefficients and degree of nonlocality were obtained for both laser excitation wavelengths. The results indicate that the electronic part of the nonlinear refractive index and nonlinear absorption were negligible. Our results suggest that castor oil is promising candidate as a nonlinear medium for several nonlocal optical applications, such as in spatial soliton propagation, as well as a dispersant agent in the measurement of absorptive properties of nanoparticles.

  18. Nonlinear structure formation in nonlocal gravity

    SciTech Connect

    Barreira, Alexandre; Li, Baojiu; Hellwing, Wojciech A.; Baugh, Carlton M.; Pascoli, Silvia E-mail: baojiu.li@durham.ac.uk E-mail: c.m.baugh@durham.ac.uk

    2014-09-01

    We study the nonlinear growth of structure in nonlocal gravity models with the aid of N-body simulation and the spherical collapse and halo models. We focus on a model in which the inverse-squared of the d'Alembertian operator acts on the Ricci scalar in the action. For fixed cosmological parameters, this model differs from ΛCDM by having a lower late-time expansion rate and an enhanced and time-dependent gravitational strength ∼ 6% larger today). Compared to ΛCDM today, in the nonlocal model, massive haloes are slightly more abundant (by ∼ 10% at M ∼ 10{sup 14} M{sub ⊙}/h) and concentrated ≈ 8% enhancement over a range of mass scales), but their linear bias remains almost unchanged. We find that the Sheth-Tormen formalism describes the mass function and halo bias very well, with little need for recalibration of free parameters. The fitting of the halo concentrations is however essential to ensure the good performance of the halo model on small scales. For k ∼> 1 h/Mpc, the amplitude of the nonlinear matter and velocity divergence power spectra exhibits a modest enhancement of ∼ 12% to 15%, compared to ΛCDM today. This suggests that this model might only be distinguishable from ΛCDM by future observational missions. We point out that the absence of a screening mechanism may lead to tensions with Solar System tests due to local time variations of the gravitational strength, although this is subject to assumptions about the local time evolution of background averaged quantities.

  19. A Combinatorial Approach to Nonlocality and Contextuality

    NASA Astrophysics Data System (ADS)

    Acín, Antonio; Fritz, Tobias; Leverrier, Anthony; Sainz, Ana Belén

    2015-03-01

    So far, most of the literature on (quantum) contextuality and the Kochen-Specker theorem seems either to concern particular examples of contextuality, or be considered as quantum logic. Here, we develop a general formalism for contextuality scenarios based on the combinatorics of hypergraphs, which significantly refines a similar recent approach by Cabello, Severini and Winter (CSW). In contrast to CSW, we explicitly include the normalization of probabilities, which gives us a much finer control over the various sets of probabilistic models like classical, quantum and generalized probabilistic. In particular, our framework specializes to (quantum) nonlocality in the case of Bell scenarios, which arise very naturally from a certain product of contextuality scenarios due to Foulis and Randall. In the spirit of CSW, we find close relationships to several graph invariants. The recently proposed Local Orthogonality principle turns out to be a special case of a general principle for contextuality scenarios related to the Shannon capacity of graphs. Our results imply that it is strictly dominated by a low level of the Navascués-Pironio-Acín hierarchy of semidefinite programs, which we also apply to contextuality scenarios. We derive a wealth of results in our framework, many of these relating to quantum and supraquantum contextuality and nonlocality, and state numerous open problems. For example, we show that the set of quantum models on a contextuality scenario can in general not be characterized in terms of a graph invariant. In terms of graph theory, our main result is this: there exist two graphs and with the properties

  20. Calculating nonlocal optical properties of structures with arbitrary shape.

    SciTech Connect

    McMahon, J. M.; Gray, S. K.; Schatz, G. C.; Northwestern Univ.

    2010-07-16

    In a recent Letter [J. M. McMahon, S. K. Gray, and G. C. Schatz, Phys. Rev. Lett. 103, 097403 (2009)], we outlined a computational method to calculate the optical properties of structures with a spatially nonlocal dielectric function. In this paper, we detail the full method and verify it against analytical results for cylindrical nanowires. Then, as examples of our method, we calculate the optical properties of Au nanostructures in one, two, and three dimensions. We first calculate the transmission, reflection, and absorption spectra of thin films. Because of their simplicity, these systems demonstrate clearly the longitudinal (or volume) plasmons characteristic of nonlocal effects, which result in anomalous absorption and plasmon blueshifting. We then study the optical properties of spherical nanoparticles, which also exhibit such nonlocal effects. Finally, we compare the maximum and average electric field enhancements around nanowires of various shapes to local theory predictions. We demonstrate that when nonlocal effects are included, significant decreases in such properties can occur.

  1. Popescu-Rohrlich correlations imply efficient instantaneous nonlocal quantum computation

    NASA Astrophysics Data System (ADS)

    Broadbent, Anne

    2016-08-01

    In instantaneous nonlocal quantum computation, two parties cooperate in order to perform a quantum computation on their joint inputs, while being restricted to a single round of simultaneous communication. Previous results showed that instantaneous nonlocal quantum computation is possible, at the cost of an exponential amount of prior shared entanglement (in the size of the input). Here, we show that a linear amount of entanglement suffices, (in the size of the computation), as long as the parties share nonlocal correlations as given by the Popescu-Rohrlich box. This means that communication is not required for efficient instantaneous nonlocal quantum computation. Exploiting the well-known relation to position-based cryptography, our result also implies the impossibility of secure position-based cryptography against adversaries with nonsignaling correlations. Furthermore, our construction establishes a quantum analog of the classical communication complexity collapse under nonsignaling correlations.

  2. Nonlocality-driven supercontinuum white light generation in plasmonic nanostructures

    NASA Astrophysics Data System (ADS)

    Krasavin, A. V.; Ginzburg, P.; Wurtz, G. A.; Zayats, A. V.

    2016-05-01

    Structured plasmonic metals are widely employed for achieving nonlinear functionalities at the nanoscale due to their ability to confine and enhance electromagnetic fields and strong, inherent nonlinearity. Optical nonlinearities in centrosymmetric metals are dominated by conduction electron dynamics, which at the nanoscale can be significantly affected by the nonlocal effects. Here we show that nonlocal corrections, being usually small in the linear optical response, define nonlinear properties of plasmonic nanostructures. Using a full non-perturbative time-domain hydrodynamic description of electron plasma under femtosecond excitation, we numerically investigate harmonic generation in metallic Archimedean nanospirals, revealing the interplay between geometric and nonlocal effects. The quantum pressure term in the nonlinear hydrodynamic model results in the emergence of fractional nonlinear harmonics leading to broadband coherent white-light generation. The described effects present a novel class of nonlinear phenomena in metallic nanostructures determined by nonlocality of the electron response.

  3. Nonlocal microscopic theory of quantum friction between parallel metallic slabs

    SciTech Connect

    Despoja, Vito

    2011-05-15

    We present a new derivation of the friction force between two metallic slabs moving with constant relative parallel velocity, based on T=0 quantum-field theory formalism. By including a fully nonlocal description of dynamically screened electron fluctuations in the slab, and avoiding the usual matching-condition procedure, we generalize previous expressions for the friction force, to which our results reduce in the local limit. Analyzing the friction force calculated in the two local models and in the nonlocal theory, we show that for physically relevant velocities local theories using the plasmon and Drude models of dielectric response are inappropriate to describe friction, which is due to excitation of low-energy electron-hole pairs, which are properly included in nonlocal theory. We also show that inclusion of dissipation in the nonlocal electronic response has negligible influence on friction.

  4. Nonlocality-driven supercontinuum white light generation in plasmonic nanostructures

    PubMed Central

    Krasavin, A. V.; Ginzburg, P.; Wurtz, G. A.; Zayats, A. V.

    2016-01-01

    Structured plasmonic metals are widely employed for achieving nonlinear functionalities at the nanoscale due to their ability to confine and enhance electromagnetic fields and strong, inherent nonlinearity. Optical nonlinearities in centrosymmetric metals are dominated by conduction electron dynamics, which at the nanoscale can be significantly affected by the nonlocal effects. Here we show that nonlocal corrections, being usually small in the linear optical response, define nonlinear properties of plasmonic nanostructures. Using a full non-perturbative time-domain hydrodynamic description of electron plasma under femtosecond excitation, we numerically investigate harmonic generation in metallic Archimedean nanospirals, revealing the interplay between geometric and nonlocal effects. The quantum pressure term in the nonlinear hydrodynamic model results in the emergence of fractional nonlinear harmonics leading to broadband coherent white-light generation. The described effects present a novel class of nonlinear phenomena in metallic nanostructures determined by nonlocality of the electron response. PMID:27157982

  5. Nonlocality-driven supercontinuum white light generation in plasmonic nanostructures.

    PubMed

    Krasavin, A V; Ginzburg, P; Wurtz, G A; Zayats, A V

    2016-01-01

    Structured plasmonic metals are widely employed for achieving nonlinear functionalities at the nanoscale due to their ability to confine and enhance electromagnetic fields and strong, inherent nonlinearity. Optical nonlinearities in centrosymmetric metals are dominated by conduction electron dynamics, which at the nanoscale can be significantly affected by the nonlocal effects. Here we show that nonlocal corrections, being usually small in the linear optical response, define nonlinear properties of plasmonic nanostructures. Using a full non-perturbative time-domain hydrodynamic description of electron plasma under femtosecond excitation, we numerically investigate harmonic generation in metallic Archimedean nanospirals, revealing the interplay between geometric and nonlocal effects. The quantum pressure term in the nonlinear hydrodynamic model results in the emergence of fractional nonlinear harmonics leading to broadband coherent white-light generation. The described effects present a novel class of nonlinear phenomena in metallic nanostructures determined by nonlocality of the electron response. PMID:27157982

  6. Quantum nonlocality via local contextuality with qubit-qubit entanglement

    NASA Astrophysics Data System (ADS)

    Saha, Debashis; Cabello, Adán; Choudhary, Sujit K.; Pawłowski, Marcin

    2016-04-01

    Quantum nonlocality can be revealed "via local contextuality" in qudit-qudit entangled systems with d >2 , that is, through the violation of inequalities containing Alice-Bob correlations that admit a local description, and Alice-Alice correlations (between the results of sequences of measurements on Alice's subsystem) that admit a local (but contextual) description. A fundamental question to understand the respective roles of entanglement and local contextuality is whether nonlocality via local contextuality exists when the parties have only qubit-qubit entanglement. Here we respond affirmatively to this question. This result further clarifies the connection between contextuality and nonlocality and opens the door for observing nonlocality via local contextuality in actual experiments.

  7. Nonlocal Polarization Feedback in a Fractional Quantum Hall Ferromagnet

    NASA Astrophysics Data System (ADS)

    Hennel, Szymon; Braem, Beat A.; Baer, Stephan; Tiemann, Lars; Sohi, Pirouz; Wehrli, Dominik; Hofmann, Andrea; Reichl, Christian; Wegscheider, Werner; Rössler, Clemens; Ihn, Thomas; Ensslin, Klaus; Rudner, Mark S.; Rosenow, Bernd

    2016-04-01

    In a quantum Hall ferromagnet, the spin polarization of the two-dimensional electron system can be dynamically transferred to nuclear spins in its vicinity through the hyperfine interaction. The resulting nuclear field typically acts back locally, modifying the local electronic Zeeman energy. Here we report a nonlocal effect arising from the interplay between nuclear polarization and the spatial structure of electronic domains in a ν =2 /3 fractional quantum Hall state. In our experiments, we use a quantum point contact to locally control and probe the domain structure of different spin configurations emerging at the spin phase transition. Feedback between nuclear and electronic degrees of freedom gives rise to memristive behavior, where electronic transport through the quantum point contact depends on the history of current flow. We propose a model for this effect which suggests a novel route to studying edge states in fractional quantum Hall systems and may account for so-far unexplained oscillatory electronic-transport features observed in previous studies.

  8. Nonlocal Polarization Feedback in a Fractional Quantum Hall Ferromagnet.

    PubMed

    Hennel, Szymon; Braem, Beat A; Baer, Stephan; Tiemann, Lars; Sohi, Pirouz; Wehrli, Dominik; Hofmann, Andrea; Reichl, Christian; Wegscheider, Werner; Rössler, Clemens; Ihn, Thomas; Ensslin, Klaus; Rudner, Mark S; Rosenow, Bernd

    2016-04-01

    In a quantum Hall ferromagnet, the spin polarization of the two-dimensional electron system can be dynamically transferred to nuclear spins in its vicinity through the hyperfine interaction. The resulting nuclear field typically acts back locally, modifying the local electronic Zeeman energy. Here we report a nonlocal effect arising from the interplay between nuclear polarization and the spatial structure of electronic domains in a ν=2/3 fractional quantum Hall state. In our experiments, we use a quantum point contact to locally control and probe the domain structure of different spin configurations emerging at the spin phase transition. Feedback between nuclear and electronic degrees of freedom gives rise to memristive behavior, where electronic transport through the quantum point contact depends on the history of current flow. We propose a model for this effect which suggests a novel route to studying edge states in fractional quantum Hall systems and may account for so-far unexplained oscillatory electronic-transport features observed in previous studies. PMID:27081998

  9. Nonlocal coherence in normal metal-superconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Cadden-Zimansky, Paul

    One of the central features of the now half-century old theory of the microscopic origins of superconductivity in elemental materials is the correlations between pairs of electrons with opposite spin and momentum. The constituent electrons of these Cooper pairs have the unusual property that their mean spatial separation is much larger than atomic length scales, extending hundreds of nanometers in some materials. The central question motivating this thesis is whether one can see effects of these electronic correlations by placing normal metal probes on a superconductor within this length scale of each other. In particular we search for empirical evidence of two predicted processes, crossed Andreev reflection and elastic cotunneling, in which the Cooper pairs in a superconductor coherently couple electrons in two normal metal probes. We present results showing that such coupling does indeed occur and its observed behavior is consistent with the predicted processes. Specifically, we show that signals can be sent between normal metal probes which are nonlocal, phase coherent, and decay on the order of the Cooper pair correlation length. In addition, our data give new insights into the interaction between normal electrons and Cooper pairs when they coexist in a normal metal.

  10. Cosmological evolution of generalized non-local gravity

    NASA Astrophysics Data System (ADS)

    Zhang, Xue; Wu, Ya-Bo; Li, Song; Liu, Yu-Chen; Chen, Bo-Hai; Chai, Yun-Tian; Shu, Shuang

    2016-07-01

    We construct a class of generalized non-local gravity (GNLG) model which is the modified theory of general relativity (GR) obtained by adding a term m2n‑2 R□‑nR to the Einstein-Hilbert action. Concretely, we not only study the gravitational equation for the GNLG model by introducing auxiliary scalar fields, but also analyse the classical stability and examine the cosmological consequences of the model for different exponent n. We find that the half of the scalar fields are always ghost-like and the exponent n must be taken even number for a stable GNLG model. Meanwhile, the model spontaneously generates three dominant phases of the evolution of the universe, and the equation of state parameters turn out to be phantom-like. Furthermore, we clarify in another way that exponent n should be even numbers by the spherically symmetric static solutions in Newtonian gauge. It is worth stressing that the results given by us can include ones in refs. [28, 34] as the special case of n=2.

  11. Non-local F(R)-mimetic gravity

    NASA Astrophysics Data System (ADS)

    Myrzakulov, Ratbay; Sebastiani, Lorenzo

    2016-06-01

    In this paper, we study non-local F(R)-mimetic gravity. We implement mimetic gravity in the framework of non-local F(R)-theories of gravity. Given some specific class of models and using a potential on the mimetic field, we investigate some scenarios related to the early-time universe, namely the inflation and the cosmological bounce, which bring to Einstein's gravity with cold dark matter at the late-time.

  12. Protecting quantum entanglement and nonlocality for tripartite states under decoherence

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Yin, Yu Hao; Ma, Wen Chao; Ye, Liu

    2016-06-01

    Quantum entanglement and nonlocality will suffer inevitable harm from decoherence environment. Based on GHZ state, we study the harm of the generalized amplitude damping (GAD) operation and the protection by the single local filtering (SLF) operation in this paper. We verify that the SLF functions to depress the loss of entanglement and nonlocality from GAD. This conclusion will guide us to select the best method to protect the GHZ state from GAD decoherence.

  13. Stabilization of vortex solitons in nonlocal nonlinear media

    SciTech Connect

    Minzoni, Antonmaria A.; Smyth, Noel F.; Worthy, Annette L.; Kivshar, Yuri S.

    2007-12-15

    We study the evolution of vortex solitons in optical media with a nonlocal nonlinear response. We employ a modulation theory for the vortex parameters based on an averaged Lagrangian, and analyze the azimuthal evolution of both the vortex width and diffractive radiation. We describe analytically the physical mechanism for vortex stabilization due to the long-range nonlocal nonlinear response, the effect observed earlier in numerical simulations only.

  14. From local to nonlocal Fermi liquid in doped antiferromagnets

    SciTech Connect

    Prelovsek, P. |; Jaklic, J.; Bedell, K.

    1999-07-01

    The variation of single-particle spectral functions with doping is studied numerically within the t-J model. Results suggest that the corresponding self-energies change from local ones at the intermediate doping to strongly nonlocal ones for a weakly doped antiferromagnet. The nonlocality shows up most clearly in the pseudogap emerging in the density of states, due to the onset of short-range antiferromagnetic correlations. {copyright} {ital 1999} {ital The American Physical Society}

  15. Nonlocality in pure and mixed n-qubit X states

    NASA Astrophysics Data System (ADS)

    Batle, J.; Ooi, C. H. Raymond; Farouk, Ahmed; Abdalla, S.

    2016-04-01

    Nonlocality for general multiqubit X states is studied in detail. Pure and mixed states are analyzed as far as their maximum amount of nonlocality is concerned, and analytic results are obtained for important families of these states. The particular form of nonzero diagonal and antidiagonal matrix elements makes the corresponding study easy enough to obtain exact results. We also provide a numerical recipe to randomly generate an important family of X states endowed with a given degree of mixture.

  16. Homoclinic behaviors and chaotic motions of double layered viscoelastic nanoplates based on nonlocal theory and extended Melnikov method

    SciTech Connect

    Wang, Yu; Wang, Yi-Ze; Li, Feng-Ming

    2015-06-15

    The nonlinear dynamical equations are established for the double layered viscoelastic nanoplates (DLNP) subjected to in-plane excitation based on the nonlocal theory and von Kármán large deformation theory. The extended high dimensional homoclinic Melnikov method is employed to study the homoclinic phenomena and chaotic motions for the parametrically excited DLNP system. The criteria for the homoclinic transverse intersection for both the asynchronous and synchronous buckling cases are proposed. Lyapunov exponents and phase portraits are obtained to verify the Melnikov-type analysis. The influences of structural parameters on the transverse homoclinic orbits and homoclinic bifurcation sets are discussed for the two buckling cases. Some novel phenomena are observed in the investigation. It should be noticed that the nonlocal effect on the homoclinic behaviors and chaotic motions is quite remarkable. Hence, the small scale effect should be taken into account for homoclinic and chaotic analysis for nanostructures. It is significant that the nonlocal effect on the homoclinic phenomena for the asynchronous buckling case is quite different from that for the synchronous buckling case. Moreover, due to the van der Walls interaction between the layers, the nonlocal effect on the homoclinic behaviors and chaotic motions for high order mode is rather tiny under the asynchronous buckling condition.

  17. Homoclinic behaviors and chaotic motions of double layered viscoelastic nanoplates based on nonlocal theory and extended Melnikov method.

    PubMed

    Wang, Yu; Li, Feng-Ming; Wang, Yi-Ze

    2015-06-01

    The nonlinear dynamical equations are established for the double layered viscoelastic nanoplates (DLNP) subjected to in-plane excitation based on the nonlocal theory and von Kármán large deformation theory. The extended high dimensional homoclinic Melnikov method is employed to study the homoclinic phenomena and chaotic motions for the parametrically excited DLNP system. The criteria for the homoclinic transverse intersection for both the asynchronous and synchronous buckling cases are proposed. Lyapunov exponents and phase portraits are obtained to verify the Melnikov-type analysis. The influences of structural parameters on the transverse homoclinic orbits and homoclinic bifurcation sets are discussed for the two buckling cases. Some novel phenomena are observed in the investigation. It should be noticed that the nonlocal effect on the homoclinic behaviors and chaotic motions is quite remarkable. Hence, the small scale effect should be taken into account for homoclinic and chaotic analysis for nanostructures. It is significant that the nonlocal effect on the homoclinic phenomena for the asynchronous buckling case is quite different from that for the synchronous buckling case. Moreover, due to the van der Walls interaction between the layers, the nonlocal effect on the homoclinic behaviors and chaotic motions for high order mode is rather tiny under the asynchronous buckling condition. PMID:26117102

  18. Color Image Restoration Using Nonlocal Mumford-Shah Regularizers

    NASA Astrophysics Data System (ADS)

    Jung, Miyoun; Bresson, Xavier; Chan, Tony F.; Vese, Luminita A.

    We introduce several color image restoration algorithms based on the Mumford-Shah model and nonlocal image information. The standard Ambrosio-Tortorelli and Shah models are defined to work in a small local neighborhood, which are sufficient to denoise smooth regions with sharp boundaries. However, textures are not local in nature and require semi-local/non-local information to be denoised efficiently. Inspired from recent work (NL-means of Buades, Coll, Morel and NL-TV of Gilboa, Osher), we extend the standard models of Ambrosio-Tortorelli and Shah approximations to Mumford-Shah functionals to work with nonlocal information, for better restoration of fine structures and textures. We present several applications of the proposed nonlocal MS regularizers in image processing such as color image denoising, color image deblurring in the presence of Gaussian or impulse noise, color image inpainting, and color image super-resolution. In the formulation of nonlocal variational models for the image deblurring with impulse noise, we propose an efficient preprocessing step for the computation of the weight function w. In all the applications, the proposed nonlocal regularizers produce superior results over the local ones, especially in image inpainting with large missing regions. Experimental results and comparisons between the proposed nonlocal methods and the local ones are shown.

  19. Nonlocal transport in a hybrid two-dimensional topological insulator

    NASA Astrophysics Data System (ADS)

    Xing, Yanxia; Sun, Qing-feng

    2014-02-01

    We study nonlocal resistance in an H-shaped two-dimensional HgTe/CdTe quantum well consisting of an injector and a detector, both of which can be tuned in the quantum spin Hall or metallic spin Hall regime. Because of strong spin-orbit interaction, there always exists the spin Hall effect and nonlocal resistance in the HgTe/CdTe quantum well. We find that when both the detector and the injector are in the quantum spin Hall regime, the nonlocal resistance is quantized at 0.25he2, which is robust against weak disorder scattering and small magnetic field. When the detector or injector is beyond this regime, the nonlocal resistance decreases rapidly and will be strongly suppressed by disorder and magnetic field. In the presence of a strong magnetic field, the quantum spin Hall regime will be switched into the quantum Hall regime, and the nonlocal resistance will disappear. The nonlocal signal and its various manifestations in different hybrid regimes originate from the special band structure of the HgTe/CdTe quantum well, and they can be considered as the fingerprint of the helical quantum spin Hall edge states in a two-dimensional topological insulator.

  20. Connecting the behavior of granular layers on inclined planes to the nonlocal fluidity model

    NASA Astrophysics Data System (ADS)

    Kamrin, Ken; Henann, David

    2014-03-01

    Recently, a grain-size-sensitive rheology for granular flow has been proposed based on the nonlocal fluidity concept. While primarily intended to describe the effect that grain size has on developed flow fields, this talk will show how the same framework also explains the Hstop phenomenon commonly observed in thin granular layers on inclined planes, in which thinner layers appear to be stronger than thicker ones. Moreover, the experimental phase diagram for flow vs no-flow of a layer of glass beads in this geometry is well-predicted using the same modeling parameters that describe the steady flow of those beads in split-bottom cells and other geometries.

  1. Non-local Optical Topological Transitions and Critical States in Electromagnetic Metamaterials

    NASA Astrophysics Data System (ADS)

    Ishii, Satoshi; Narimanov, Evgenii

    2015-12-01

    Just as the topology of the Fermi surface defines the properties of the free electrons in metals and semiconductors, the geometry of the iso-frequency surface in the phase space of the propagating electromagnetic waves, determines the optical properties of the corresponding optical materials. Furthermore, in the direct analog to the Lifshitz transition in condensed matter physics, a change in the topology of iso-frequency surface has a dramatic effect on the emission, propagation and scattering of the electromagnetic waves. Here, we uncover a new class of such optical topological transitions in metamaterials, induced by the non-locality of the electromagnetic response inherent to these composites.

  2. Non-local Optical Topological Transitions and Critical States in Electromagnetic Metamaterials

    PubMed Central

    Ishii, Satoshi; Narimanov, Evgenii

    2015-01-01

    Just as the topology of the Fermi surface defines the properties of the free electrons in metals and semiconductors, the geometry of the iso-frequency surface in the phase space of the propagating electromagnetic waves, determines the optical properties of the corresponding optical materials. Furthermore, in the direct analog to the Lifshitz transition in condensed matter physics, a change in the topology of iso-frequency surface has a dramatic effect on the emission, propagation and scattering of the electromagnetic waves. Here, we uncover a new class of such optical topological transitions in metamaterials, induced by the non-locality of the electromagnetic response inherent to these composites. PMID:26670600

  3. Non-local Optical Topological Transitions and Critical States in Electromagnetic Metamaterials.

    PubMed

    Ishii, Satoshi; Narimanov, Evgenii

    2015-01-01

    Just as the topology of the Fermi surface defines the properties of the free electrons in metals and semiconductors, the geometry of the iso-frequency surface in the phase space of the propagating electromagnetic waves, determines the optical properties of the corresponding optical materials. Furthermore, in the direct analog to the Lifshitz transition in condensed matter physics, a change in the topology of iso-frequency surface has a dramatic effect on the emission, propagation and scattering of the electromagnetic waves. Here, we uncover a new class of such optical topological transitions in metamaterials, induced by the non-locality of the electromagnetic response inherent to these composites. PMID:26670600

  4. A micromechanics-based nonlocal constitutive equation incorporating three-point statistics for random linear elastic composite materials

    NASA Astrophysics Data System (ADS)

    Drugan, W. J.; Willis, J. R.

    2016-06-01

    A variational formulation employing the minimum potential and complementary energy principles is used to derive a micromechanics-based nonlocal constitutive equation for random linear elastic composite materials, relating ensemble averages of stress and strain in the most general situation when mean fields vary spatially. All information contained in the energy principles is retained; we employ stress polarization trial fields utilizing one-point statistics so that the resulting nonlocal constitutive equation incorporates up through three-point statistics. The variational structure is developed first for arbitrary heterogeneous linear elastic materials, then for randomly inhomogeneous materials, then for general n-phase composite materials, and finally for two-phase composite materials, in which case explicit variational upper and lower bounds on the nonlocal effective modulus tensor operator are derived. For statistically uniform infinite-body composites, these bounds are determined even more explicitly in Fourier transform space. We evaluate these in detail in an example case: longitudinal shear of an aligned fiber or void composite. We determine the full permissible ranges of the terms involving two- and three-point statistics in these bounds, and thereby exhibit explicit results that encompass arbitrary isotropic in-plane phase distributions; we also develop a nonlocal "Milton parameter", the variation of whose eigenvalues throughout the interval [0, 1] describes the full permissible range of the three-point term. Example plots of the new bounds show them to provide substantial improvement over the (two-point) Hashin-Shtrikman bounds on the nonlocal operator tensor, for all permissible values of the two- and three-point parameters. We next discuss further applications of the general nonlocal operator bounds: to any three-dimensional scalar transport problem e.g. conductivity, for which explicit results are given encompassing the full permissible ranges of the

  5. Nonlocal similarity based DEM super resolution

    NASA Astrophysics Data System (ADS)

    Xu, Zekai; Wang, Xuewen; Chen, Zixuan; Xiong, Dongping; Ding, Mingyue; Hou, Wenguang

    2015-12-01

    This paper discusses a new topic, DEM super resolution, to improve the resolution of an original DEM based on its partial new measurements obtained with high resolution. A nonlocal algorithm is introduced to perform this task. The original DEM was first divided into overlapping patches, which were classified either as "test" or "learning" data depending on whether or not they are related to high resolution measurements. For each test patch, the similar patches in the learning dataset were identified via template matching. Finally, the high resolution DEM of the test patch was restored by the weighted sum of similar patches under the condition that the reconstruction weights were the same in different resolution cases. A key assumption of this strategy is that there are some repeated or similar modes in the original DEM, which is quite common. Experiments were done to demonstrate that we can restore a DEM by preserving the details without introducing artifacts. Statistic analysis was also conducted to show that this method can obtain higher accuracy than traditional interpolation methods.

  6. On locally and nonlocally related potential systems

    NASA Astrophysics Data System (ADS)

    Cheviakov, Alexei F.; Bluman, George W.

    2010-07-01

    For any partial differential equation (PDE) system, a local conservation law yields potential equations in terms of some potential variable, which normally is a nonlocal variable. The current paper examines situations when such a potential variable is a local variable, i.e., is a function of the independent and dependent variables of a given PDE system, and their derivatives. In the case of two independent variables, a simple necessary and sufficient condition is presented for the locality of such a potential variable, and this is illustrated by several examples. As a particular example, two-dimensional reductions of equilibrium equations for fluid and plasma dynamics are considered. It is shown that such reductions with respect to helical, axial, and translational symmetries have conservation laws which yield local potential variables. This leads to showing that the well-known Johnson-Frieman-Kruskal-Oberman (JFKO) and Bragg-Hawthorne (Grad-Shafranov) equations are locally related to the corresponding helically and axially symmetric PDE systems of fluid/plasma dynamics. For the axially symmetric case, local symmetry classifications and arising invariant solutions are compared for the original PDE system and the Bragg-Hawthorne (potential) equation. The potential equation is shown to have additional symmetries, denoted as restricted symmetries. Restricted symmetries leave invariant a family of solutions of a given PDE system but not the whole solution manifold, and hence are not symmetries of the given PDE system. Corresponding reductions are shown to yield solutions, which are not obtained as invariant solutions from local symmetry reduction.

  7. Diagnostics of nonlocal plasmas: advanced techniques

    NASA Astrophysics Data System (ADS)

    Mustafaev, Alexander; Grabovskiy, Artiom; Strakhova, Anastasiya; Soukhomlinov, Vladimir

    2014-10-01

    This talk generalizes our recent results, obtained in different directions of plasma diagnostics. First-method of flat single-sided probe, based on expansion of the electron velocity distribution function (EVDF) in series of Legendre polynomials. It will be demonstrated, that flat probe, oriented under different angles with respect to the discharge axis, allow to determine full EVDF in nonlocal plasmas. It is also shown, that cylindrical probe is unable to determine full EVDF. We propose the solution of this problem by combined using the kinetic Boltzmann equation and experimental probe data. Second-magnetic diagnostics. This method is implemented in knudsen diode with surface ionization of atoms (KDSI) and based on measurements of the magnetic characteristics of the KDSI in presence of transverse magnetic field. Using magnetic diagnostics we can investigate the wide range of plasma processes: from scattering cross-sections of electrons to plasma-surface interactions. Third-noncontact diagnostics method for direct measurements of EVDF in remote plasma objects by combination of the flat single-sided probe technique and magnetic polarization Hanley method.

  8. Nonlocal theory and finite element modeling of nano-composites

    NASA Astrophysics Data System (ADS)

    Alvinasab, Ali

    This research is concerned with fundamentals of modeling nano-composites. The study contains two major parts, namely, numerical modeling of nanocomposites and nonlocal theory based approach for predicting behavior of Carbon Nanotubes (CNTs). Computational modeling of glass (silica) fibers having micro-scale outer dimensions and nano-scale internal structures was performed to assess its mechanical behavior. Self-assembly technique was used to synthesize the individual fibers of approximately 5 mum in length with a hexagonal cross-section (2mum between two opposite sides) and honeycomb-like internal nano-structures. These fibers have several potential applications including synthesis of multifunctional composite materials. Numerical modeling of the individual fibers was performed using continuum mechanics based approach wherein linear elastic elements were utilized within a commercial finite element (FE) analysis software. A representative volume element approach was adopted for computational efficiency. Appropriate loads and boundary conditions were used to derive stress-strain relationship (stiffness matrix) which has six independent constants for the individual fiber. Force-displacement relationships under simulated nanoindentation were obtained for the actual fiber (with six independent constants) and under transversely isotropic approximation. The contact problem was solved for the transversely isotropic case, which indicated a much stiffer fiber compared to the FE predictions. This difference is likely due to the geometric nonlinearity considered in FE analysis yielding accurate results for large displacements. The effective mechanical properties of randomly oriented nano-structured glass fiber composite are evaluated by using a continuum mechanics based FE model. The longitudinal and transverse properties of aligned fiber are calculated. Then the equivalent material properties for tilted fiber with different fiber orientations are obtained. Based on equivalent

  9. Non-local magnetoresistance in YIG/Pt nanostructures

    SciTech Connect

    Goennenwein, Sebastian T. B. Pernpeintner, Matthias; Gross, Rudolf; Huebl, Hans; Schlitz, Richard; Ganzhorn, Kathrin; Althammer, Matthias

    2015-10-26

    We study the local and non-local magnetoresistance of thin Pt strips deposited onto yttrium iron garnet. The local magnetoresistive response, inferred from the voltage drop measured along one given Pt strip upon current-biasing it, shows the characteristic magnetization orientation dependence of the spin Hall magnetoresistance. We simultaneously also record the non-local voltage appearing along a second, electrically isolated, Pt strip, separated from the current carrying one by a gap of a few 100 nm. The corresponding non-local magnetoresistance exhibits the symmetry expected for a magnon spin accumulation-driven process, confirming the results recently put forward by Cornelissen et al. [“Long-distance transport of magnon spin information in a magnetic insulator at room temperature,” Nat. Phys. (published online 14 September 2015)]. Our magnetotransport data, taken at a series of different temperatures as a function of magnetic field orientation, rotating the externally applied field in three mutually orthogonal planes, show that the mechanisms behind the spin Hall and the non-local magnetoresistance are qualitatively different. In particular, the non-local magnetoresistance vanishes at liquid Helium temperatures, while the spin Hall magnetoresistance prevails.

  10. Nonlocal dielectric effects in core-shell nanowires.

    SciTech Connect

    McMahon, J. M.; Gray, S. K.; Schatz, G. C.

    2010-01-01

    We study the optical spectra and near fields of core-shell nanowires (nanoshells), using a recently developed finite-difference method that allows for a spatially nonlocal dielectric response. We first analyze the parameters of the nonlocal model by making comparisons with related experimental data and previous theoretical work. We then investigate how nonlocal effects are dependent on nanoshell features, such as shell thickness, overall size, and the ratio of core radius to shell radius. We demonstrate that the shell thickness along the longitudinal direction of the incident light is the primary controlling factor of nonlocal effects, which appear as anomalous absorption resonances and blueshifts in the localized surface plasmon resonance (LSPR) positions, relative to local theory. In addition, we show that the amount of blueshift depends on the order of the LSPR. The optical responses of nanoshells immersed in various refractive index (RI) environments are also studied. We show that the nonlocal anomalous absorption features are relatively insensitive to RI changes, but the blueshift of the dipolar LSPR varies nonlinearly.

  11. Examining the effect of nonlocality in (d ,n ) transfer reactions

    NASA Astrophysics Data System (ADS)

    Ross, A.; Titus, L. J.; Nunes, F. M.

    2016-07-01

    Background: In the past year we have been exploring the effect of the explicit inclusion of nonlocality in (d ,p ) reactions. Purpose: The goal of this paper is to extend previous studies to (d ,n ) reactions, which, although similar to (d ,p ) reactions, have specific properties that merit inspection. Method: We apply our methods (both the distorted-wave Born approximation and the adiabatic wave approximation) to (d ,n ) reactions on 16O,40Ca,48Ca,126Sn,132Sn , and 208Pb at 20 and 50 MeV. Results: We look separately at the modifications introduced by nonlocality in the final bound and scattering states as well as the consequences reflected on the differential angular distributions. The cross sections obtained when using nonlocality explicitly are significantly different than those using the local approximation, just as in (d ,p ) reactions. Due to the particular role of the Coulomb force in the bound state, often we found the effects of nonlocality to be larger in (d ,n ) than in (d ,p ) reactions. Conclusions: Our results confirm the importance of including nonlocality explicitly in deuteron-induced reactions.

  12. Nonlocal regularization of inverse problems: a unified variational framework.

    PubMed

    Yang, Zhili; Jacob, Mathews

    2013-08-01

    We introduce a unifying energy minimization framework for nonlocal regularization of inverse problems. In contrast to the weighted sum of square differences between image pixels used by current schemes, the proposed functional is an unweighted sum of inter-patch distances. We use robust distance metrics that promote the averaging of similar patches, while discouraging the averaging of dissimilar patches. We show that the first iteration of a majorize-minimize algorithm to minimize the proposed cost function is similar to current nonlocal methods. The reformulation thus provides a theoretical justification for the heuristic approach of iterating nonlocal schemes, which re-estimate the weights from the current image estimate. Thanks to the reformulation, we now understand that the widely reported alias amplification associated with iterative nonlocal methods are caused by the convergence to local minimum of the nonconvex penalty. We introduce an efficient continuation strategy to overcome this problem. The similarity of the proposed criterion to widely used nonquadratic penalties (e.g., total variation and lp semi-norms) opens the door to the adaptation of fast algorithms developed in the context of compressive sensing; we introduce several novel algorithms to solve the proposed nonlocal optimization problem. Thanks to the unifying framework, these fast algorithms are readily applicable for a large class of distance metrics. PMID:23014745

  13. Local and nonlocal conductance enhancement due to Cooper pair splitting

    NASA Astrophysics Data System (ADS)

    Wei, Jian; Chandrasekhar, V.

    2012-12-01

    Enhanced local conductance due to Andreev reflection is well known for high transparency Normal metal-Superconductor (NS) interface. For low transparency NS junctions, observation of two-electron tunneling contribution (enhanced Andreev reflection) to current was also reported previously. In our recent work [J Wei and V Chandrasekhar, Nat. Phys. 6, 494 (2010)], for a three-terminal Cooper pair splitter geometry, i.e., with two closely placed NS junctions sharing the same S terminal, we were able do a 2D scan of both local and nonlocal differential resistance, since for our ideal tunneling junctions there is little current redistribution (flow from one normal-metal lead to the other via the superconducting lead). In contrast to previous 1D nonlocal resistance measurements, 2D scans clearly show regime with pronounced contribution of the nonlocal processes to both local and nonlocal conductance enhancement. The enhanced local conductance and negative nonlocal resistance are consistent with enhanced Cooper pair splitting, and dynamical Coulomb blockade could be the origin of this enhancement.

  14. Efficient test to demonstrate genuine three particle nonlocality

    NASA Astrophysics Data System (ADS)

    Mukherjee, Kaushiki; Paul, Biswajit; Sarkar, Debasis

    2015-11-01

    According to the studies of genuine tripartite nonlocality in discrete variable quantum systems conducted so far, Svetlichny inequality is considered as the best Bell-type inequality to detect genuine (three way) nonlocality of pure tripartite genuine entangled states. In the present work, we have considered another Bell-type inequality (which has been reported as the 99th facet of NS 2 local polytope in Bancal et al (2013 Phys. Rev. A 88 014102), to reveal genuine tripartite nonlocality of generalized GHZ (Greenberger-Horne-Zeilinger) class and a subclass of extended GHZ class states Acín et al (2000 Phys. Rev. Lett. 85 1560) thereby proving the conjecture given by Bancal et al (2013 Phys. Rev. A 88 014102) for the GGHZ class and the subclass of extended GHZ states. We compare the violation of this inequality with Svetlichny inequality which reveals the efficiency of the former inequality over the latter to demonstrate genuine nonlocality using the above classes of quantum states. Even in some cases discord monogamy score can be used as a better measure of quantum correlation over Svetlichny inequality for those classes of pure states. Besides, the 99th facet inequality is found efficient not only for revealing genuine nonlocal behavior of correlations emerging in systems using pure entangled states but also in some cases of mixed entangled states over Svetlichny inequality and some well known measures of entanglement.

  15. Nonlocal regularization of inverse problems: a unified variational framework

    PubMed Central

    Yang, Zhili; Jacob, Mathews

    2014-01-01

    We introduce a unifying energy minimization framework for nonlocal regularization of inverse problems. In contrast to the weighted sum of square differences between image pixels used by current schemes, the proposed functional is an unweighted sum of inter-patch distances. We use robust distance metrics that promote the averaging of similar patches, while discouraging the averaging of dissimilar patches. We show that the first iteration of a majorize-minimize algorithm to minimize the proposed cost function is similar to current non-local methods. The reformulation thus provides a theoretical justification for the heuristic approach of iterating non-local schemes, which re-estimate the weights from the current image estimate. Thanks to the reformulation, we now understand that the widely reported alias amplification associated with iterative non-local methods are caused by the convergence to local minimum of the nonconvex penalty. We introduce an efficient continuation strategy to overcome this problem. The similarity of the proposed criterion to widely used non-quadratic penalties (eg. total variation and `p semi-norms) opens the door to the adaptation of fast algorithms developed in the context of compressive sensing; we introduce several novel algorithms to solve the proposed non-local optimization problem. Thanks to the unifying framework, these fast algorithms are readily applicable for a large class of distance metrics. PMID:23014745

  16. Nonperturbative embedding for highly nonlocal Hamiltonians

    NASA Astrophysics Data System (ADS)

    Subaşı, Yiǧit; Jarzynski, Christopher

    2016-07-01

    The need for Hamiltonians with many-body interactions arises in various applications of quantum computing. However, interactions beyond two-body are difficult to realize experimentally. Perturbative gadgets were introduced to obtain arbitrary many-body effective interactions using Hamiltonians with at most two-body interactions. Although valid for arbitrary k -body interactions, their use is limited to small k because the strength of interaction is k th order in perturbation theory. In this paper we develop a nonperturbative technique for obtaining effective k -body interactions using Hamiltonians consisting of at most l -body interactions with l nonlocal Hamiltonian. This technique does not suffer from the aforementioned shortcoming of perturbative methods and requires only one ancilla qubit for each k -body interaction irrespective of the value of k . It works best for Hamiltonians with a few many-body interactions involving a large number of qubits and can be used together with perturbative gadgets to embed Hamiltonians of considerable complexity in proper subspaces of two-local Hamiltonians. We describe how our technique can be implemented in a hybrid (gate-based and adiabatic) as well as solely adiabatic quantum computing scheme.

  17. Nonlocal means filter-based speckle tracking.

    PubMed

    Afsham, Narges; Rasoulian, Abtin; Najafi, Mohammad; Abolmaesumi, Purang; Rohling, Robert

    2015-08-01

    The objective of sensorless freehand 3-D ultrasound imaging is to eliminate the need for additional tracking hardware and reduce cost and complexity. However, the accuracy of current out-of-plane pose estimation is main obstacle for full 6-degree-of-freedom (DoF) tracking. We propose a new filter-based speckle tracking framework to increase the accuracy of out-of-plane displacement estimation. In this framework, we use the displacement estimation not only for the specific speckle pattern, but for the entire image. We develop a nonlocal means (NLM) filter based on a probabilistic normal variance mixture model of ultrasound, known as Rician-inverse Gaussian (RiIG). To aggregate the local displacement estimations, Stein's unbiased risk estimate (SURE) is used as a quality measure of the estimations. We derive an explicit analytical form of SURE for the RiIG model and use it as a weight factor. The proposed filter-based speckle tracking framework is formulated and evaluated for three commonly used noise models, including the RiIG model. The out-of-plane estimations are compared with our previously proposed model-based algorithm in a set of ex vivo experiments for different tissue types. We show that the proposed RiIG filter-based method is more accurate and less tissue-dependent than the other methods. The proposed method is also evaluated in vivo on the spines of five different subjects to assess the feasibility of a clinical application. The 6-DoF transform parameters are estimated and compared with the electromagnetic tracker measurements. The results show higher tracking accuracy for typical small lateral displacements and tilt rotations between image pairs. PMID:26276959

  18. Nonlocal Closures for Plasma Fluid Simulations

    NASA Astrophysics Data System (ADS)

    Held, Eric

    2003-10-01

    Theoretical tools applied to lab and astrophysical plasmas tend toward two extremes: kinetic models rife with physics but operating for short times and fluid models employing simplified closure relations but operating for long times. Until computers are fast enough to calculate kinetic physics over resistive times, efforts to extend plasma fluid models to handle a wider range of physics are critical. In this work, we generalize the program of fluid closure to capture kinetic effects in nonlocal, integral forms for higher-order fluid moments. These closures embody collisional, particle-trapping and Landau physics by integrating the fluid drives and closure moments along characteristics of the distribution function, F. The inversion of an operator that includes these physical effects begins with an expansion in eigenfunctions of the collision operator. Next, the characteristics of F are identified by diagonalizing the resultant system of hyperbolic equations. Integrating and taking the closure moments of F results in coupled Volterra equations involving the fluid drives and closures. It is shown that the collisional and nearly collisionless limits of these integral equations match onto previous expressions. In addition to significantly advancing the realism of previous fluid closures, integration along comparatively few ( ˜ 100)characteristics represents a significant reduction in work compared to kinetic treatments that follow millions of particles. These characteristics uncover the essential velocity-space dependence of F and hence render this closure scheme suitable for simulation of long time scale behavior. As a specific example, we conclude this talk by discussing the incorporation of these closures in plasma fluid simulations of neoclassical tearing modes in ITER-relevant discharges.

  19. Non-local wave propagation in embedded armchair TWBNNTs conveying viscous fluid using DQM

    NASA Astrophysics Data System (ADS)

    Abdollahian, M.; Ghorbanpour Arani, A.; Mosallaie Barzoki, A. A.; Kolahchi, R.; Loghman, A.

    2013-06-01

    In this study, nonlocal electro-thermo-mechanical wave propagation in an embedded armchair three-walled boron nitride nanotube (TWBNNT) conveying viscous fluid under torsional load is investigated. The interaction between two adjacent layers is considered using van der Waals (vdW) forces. The surrounded elastic medium is taken into account using Winkler and Pasternak models. The energy method and Hamilton's principle are used to establish the equations of motion. Given the relationship between the piezoelectric coefficient of armchair boron nitride nanotubes (BNNTs) and stresses, the first-order shear deformation theory (FSDT) is applied to obtain the equations of motion in terms of displacements. The set of coupled governing equations of motion for the TWBNNT are then numerically solved by the differential quadrature method (DQM). The effects of small scale, fluid flow, elastic foundation and temperature on the phase velocity of TWBNNT, critical fluid velocity and critical torsional load are presented graphically. Results show the importance of applying nonlocal elasticity theory on the phase velocity of TWBNNT.

  20. Nonlocal Ployakov-Nambu-Jona-Lasinio model and imaginary chemical potential

    SciTech Connect

    Kashiwa K.; Hell, T.; Weise, W.

    2011-09-21

    With the aim of setting constraints for the modeling of the QCD phase diagram, the phase structure of the two-flavor Polyakov-loop-extended Nambu and Jona-Lasinio (PNJL) model is investigated in the range of imaginary chemical potentials ({mu}{sub I}) and compared with available N{sub f} = 2 lattice QCD results. The calculations are performed using the advanced nonlocal version of the PNJL model with the inclusion of vector-type quasiparticle interactions between quarks, and with wave-function-renormalization corrections. It is demonstrated that the nonlocal PNJL model reproduces important features of QCD at finite {mu}{sub I}, such as the Roberge-Weiss (RW) periodicity and the RW transition. Chiral and deconfinement transition temperatures for N{sub f} = 2 turn out to coincide both at zero chemical potential and at finite {mu}{sub I}. Detailed studies are performed concerning the RW endpoint and its neighborhood where a first-order transition occurs.

  1. Nonlocal reactive transport with physical, chemical, and biological heterogeneity

    NASA Astrophysics Data System (ADS)

    Hu, Bill X.; Cushman, John H.; Deng, Fei-Wen

    When a natural porous medium is viewed from an eulerian perspective, incomplete characterization of the hydraulic conductivity, chemical reactivity, and biological activity leads to nonlocal constitutive theories, irrespective of whether the medium has evolving heterogeneity with fluctuations over all scales. Within this framework a constitutive theory involving nonlocal dispersive and convective fluxes and nonlocal sources/sinks is developed for chemicals undergoing random linear nonequilibrium reactions and random equilibrium first-order decay in a random conductivity field. The resulting transport equations are solved exactly in Fourier-Laplace space and then numerically inverted to real space. Mean concentration contours and various spatial moments are presented graphically for several covariance structures. 1997 Published by Elsevier Science Ltd. All rights reserved

  2. Dynamics of entropic measurement-induced nonlocality in structured reservoirs

    SciTech Connect

    Hu, Ming-Liang; Fan, Heng

    2012-09-15

    We propose the entropic measurement-induced nonlocality (MIN) as the maximal increment of von Neumann entropy induced by the locally non-disturbing measurement, and study its behaviors in both the independent and common structured reservoirs. We present schemes for preserving the MIN, and show that for certain initial states the MIN, including the quantum correlations, can even be enhanced by the common reservoir. Additionally, we also show that the different measures of MIN may give different qualitative characterizations of nonlocal properties, i.e., it is rather measure dependent than state dependent. - Highlights: Black-Right-Pointing-Pointer Features of the entropic measurement-induced nonlocality (MIN). Black-Right-Pointing-Pointer Comparison of MIN with other quantum correlation measures. Black-Right-Pointing-Pointer Enhancement of MIN and other quantum correlations by common reservoir. Black-Right-Pointing-Pointer Relativity of the geometric and entropic MIN measures.

  3. Bound on Hardy's nonlocality from the principle of information causality

    SciTech Connect

    Ahanj, Ali; Kunkri, Samir; Rai, Ashutosh; Rahaman, Ramij; Joag, Pramod S.

    2010-03-15

    Recently, the principle of nonviolation of information causality [Nature 461, 1101 (2009)] has been proposed as one of the foundational properties of nature. We explore the Hardy's nonlocality theorem for two-qubit systems, in the context of generalized probability theory, restricted by the principle of nonviolation of information causality. Applying a sufficient condition for information causality violation, we derive an upper bound on the maximum success probability of Hardy's nonlocality argument. We find that the bound achieved here is higher than that allowed by quantum mechanics but still much less than what the no-signaling condition permits. We also study the Cabello type nonlocality argument (a generalization of Hardy's argument) in this context.

  4. Bounding the persistency of the nonlocality of W states

    NASA Astrophysics Data System (ADS)

    Diviánszky, Péter; Trencsényi, Réka; Bene, Erika; Vértesi, Tamás

    2016-04-01

    The nonlocal properties of the W states are investigated under particle loss. By removing all but two particles from an N -qubit W state, the resulting two-qubit state is still entangled. Hence, the W state has high persistency of entanglement. We ask an analogous question regarding the persistency of nonlocality [see N. Brunner and T. Vértesi, Phys. Rev. A 86, 042113 (2012), 10.1103/PhysRevA.86.042113]. Namely, we inquire what is the minimal number of particles that must be removed from the W state so that the resulting state becomes local. We bound this value in function of N qubits by considering Bell nonlocality tests with two alternative settings per site. In particular, we find that this value is between 2 N /5 and N /2 for large N . We also develop a framework to establish bounds for more than two settings per site.

  5. Jammed Clusters and Non-locality in Dense Granular Flows

    NASA Astrophysics Data System (ADS)

    Kharel, Prashidha; Rognon, Pierre

    We investigate the micro-mechanisms underpinning dense granular flow behaviour from a series of DEM simulations of pure shear flows of dry grains. We observe the development of transient clusters of jammed particles within the flow. Typical size of such clusters is found to scale with the inertial number with a power law that is similar to the scaling of shear-rate profile relaxation lengths observed previously. Based on the simple argument that transient clusters of size l exist in the dense flow regime, the formulation of steady state condition for non-homogeneous shear flow results in a general non-local relation, which is similar in form to the non-local relation conjectured for soft glassy flows. These findings suggest the formation of jammed clusters to be the key micro-mechanism underpinning non-local behaviour in dense granular flows. Particles and Grains Laboratory, School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia.

  6. A caveat on building nonlocal models of cosmology

    SciTech Connect

    Tsamis, N.C.; Woodard, R.P. E-mail: woodard@phys.ufl.edu

    2014-09-01

    Nonlocal models of cosmology might derive from graviton loop corrections to the effective field equations from the epoch of primordial inflation. Although the Schwinger-Keldysh formalism would automatically produce causal and conserved effective field equations, the models so far proposed have been purely phenomenological. Two techniques have been employed to generate causal and conserved field equations: either varying an invariant nonlocal effective action and then enforcing causality by the ad hoc replacement of any advanced Green's function with its retarded counterpart, or else introducing causal nonlocality into a general ansatz for the field equations and then enforcing conservation. We point out here that the two techniques access very different classes of models, and that neither one of them may represent what would actually arise from fundamental theory.

  7. Hardy's proof of nonlocality in the presence of noise

    SciTech Connect

    Ghirardi, GianCarlo; Marinatto, Luca

    2006-12-15

    We extend the validity of Hardy's nonlocality without inequalities proof to cover the case of special one-parameter classes of nonpure statistical operators. These mixed states are obtained by mixing the Hardy states with a completely chaotic noise or with a colored noise and they represent a realistic description of imperfect preparation processes of (pure) Hardy states in nonlocality experiments. Within such a framework we are able to exhibit a precise range of values of the parameter measuring the noise affecting the nonoptimal preparation of an arbitrary Hardy state, for which it is still possible to put into evidence genuine nonlocal effects. Equivalently, our work exhibits particular classes of bipartite mixed states whose constituents do not admit any local and deterministic hidden variable model reproducing the quantum mechanical predictions.

  8. Generalized conservation laws in non-local field theories

    NASA Astrophysics Data System (ADS)

    Kegeles, Alexander; Oriti, Daniele

    2016-04-01

    We propose a geometrical treatment of symmetries in non-local field theories, where the non-locality is due to a lack of identification of field arguments in the action. We show that the existence of a symmetry of the action leads to a generalized conservation law, in which the usual conserved current acquires an additional non-local correction term, obtaining a generalization of the standard Noether theorem. We illustrate the general formalism by discussing the specific physical example of complex scalar field theory of the type describing the hydrodynamic approximation of Bose-Einstein condensates. We expect our analysis and results to be of particular interest for the group field theory formulation of quantum gravity.

  9. A Framework for Bounding Nonlocality of State Discrimination

    NASA Astrophysics Data System (ADS)

    Childs, Andrew M.; Leung, Debbie; Mančinska, Laura; Ozols, Maris

    2013-11-01

    We consider the class of protocols that can be implemented by local quantum operations and classical communication (LOCC) between two parties. In particular, we focus on the task of discriminating a known set of quantum states by LOCC. Building on the work in the paper Quantum nonlocality without entanglement (Bennett et al., Phys Rev A 59:1070-1091, 1999), we provide a framework for bounding the amount of nonlocality in a given set of bipartite quantum states in terms of a lower bound on the probability of error in any LOCC discrimination protocol. We apply our framework to an orthonormal product basis known as the domino states and obtain an alternative and simplified proof that quantifies its nonlocality. We generalize this result for similar bases in larger dimensions, as well as the “rotated” domino states, resolving a long-standing open question (Bennett et al., Phys Rev A 59:1070-1091, 1999).

  10. Nonlocal thermal transport across embedded few-layer graphene sheets

    DOE PAGESBeta

    Liu, Ying; Huxtable, Scott T.; Yang, Bao; Sumpter, Bobby G.; Qiao, Rui

    2014-11-13

    Thermal transport across the interfaces between few-layer graphene sheets and soft materials exhibits intriguing anomalies when interpreted using the classical Kapitza model, e.g., the conductance of the same interface differs greatly for different modes of interfacial thermal transport. Using atomistic simulations, we show that such thermal transport follows a nonlocal flux-temperature drop constitutive law and is characterized jointly by a quasi-local conductance and a nonlocal conductance instead of the classical Kapitza conductance. Lastly, the nonlocal model enables rationalization of many anomalies of the thermal transport across embedded few-layer graphene sheets and should be used in studies of interfacial thermal transportmore » involving few-layer graphene sheets or other ultra-thin layered materials.« less

  11. Nonlocal thermal transport across embedded few-layer graphene sheets

    SciTech Connect

    Liu, Ying; Huxtable, Scott T.; Yang, Bao; Sumpter, Bobby G.; Qiao, Rui

    2014-11-13

    Thermal transport across the interfaces between few-layer graphene sheets and soft materials exhibits intriguing anomalies when interpreted using the classical Kapitza model, e.g., the conductance of the same interface differs greatly for different modes of interfacial thermal transport. Using atomistic simulations, we show that such thermal transport follows a nonlocal flux-temperature drop constitutive law and is characterized jointly by a quasi-local conductance and a nonlocal conductance instead of the classical Kapitza conductance. Lastly, the nonlocal model enables rationalization of many anomalies of the thermal transport across embedded few-layer graphene sheets and should be used in studies of interfacial thermal transport involving few-layer graphene sheets or other ultra-thin layered materials.

  12. Effects of nonlocal heat transport on laser implosion

    SciTech Connect

    Mima, K.; Honda, M.; Miyamoto, S.; Kato, S.

    1996-05-01

    A numerical simulation code describing the spherically symmetric implosion hydrodynamics has been developed to investigate the nonlocal heat transport effects on stable high velocity implosion and fast ignition. In the implosion simulation code HIMICO, the Fokker Planck equation for electron transport is solved to describe the nonlocal effects. For high ablation pressure implosion with a pressure higher than 200 Mbar, the isentrope is found higher by a factor 2 in the nonlocal transport model than in the Spitzer Harm model. As for the fast ignition simulation, the neutron yield for the high density compression with 10 KJ laser increases to be 20 times by injecting an additional heating pulse of 10 KJ with 1 psec. {copyright} {ital 1996 American Institute of Physics.}

  13. Highly nonlocal optical nonlinearities in atoms trapped near a waveguide

    NASA Astrophysics Data System (ADS)

    Shahmoon, Ephraim; Grisins, Pjotrs; Stimming, Hans Peter; Mazets, Igor; Kurizki, Gershon

    2016-05-01

    Nonlinear optical phenomena are typically local. Here we predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nano-waveguide, where long-range interactions between the atoms can be tailored. When the atoms are in an electromagnetically-induced transparency configuration, the atomic interactions are translated to long-range interactions between photons and thus to highly nonlocal optical nonlinearities. We derive and analyze the governing nonlinear propagation equation, finding a roton-like excitation spectrum for light and the emergence of long-range order in its output intensity. These predictions open the door to studies of unexplored wave dynamics and many-body physics with highly-nonlocal interactions of optical fields in one dimension.

  14. Nonlocal Transport Model for Two-Component Plasmas

    NASA Astrophysics Data System (ADS)

    Zheng, Zhen

    My PhD thesis concerns nonlocal effects on the transport processes in two-component (electron and ion) plasmas. My objective is to construct a self-consistent nonlocal transport model that is applicable in fully-ionized homogeneous Maxwellian plasmas with small-amplitude perturbations for arbitrary particle collisionalities. The fundamental method starts with a rigorous solution of the full set of linearized Fokker-Planck kinetic equations with the Landau collision operators for two-component plasmas. Then a procedure is implemented for derivation of the linear fluid equations which are closed by the transport relations. Thereby a complete list of transport coefficients for each component is computed in the broad range of temporal and spatial scales. Some new transport coefficients are found from the nonlocal hydrodynamic formulation. Ion collisions are self-consistently included in all the calculations. The electric susceptibilities and dispersion relation can thus be derived from this linear nonlocal hydrodynamics for both isothermal and non-isothermal cases. With the aid of these formulations, some important plasma quantities are successfully calculated and some practical fitting formulae are proposed, i.e., the mode frequencies and damping rates of ion acoustic wave (IAW) and entropy wave (ENW). In addition, this linear nonlocal hydrodynamics has been applied to a derivation of the dynamic form factor S(k,w) that serves to describe and explain correctly the features of the frequency spectra observed in Thomson scattering experiments. The most significant accomplishment in my research work is a thorough investigation and a deep analysis of nonlocal ion effects on longitudinal low-frequency plasma fluctuations.

  15. Nonlocal vibration analysis of circular double-layered graphene sheets resting on an elastic foundation subjected to thermal loading

    NASA Astrophysics Data System (ADS)

    Ansari, Reza; Torabi, Jalal

    2016-06-01

    Based on the nonlocal elasticity theory, the vibration behavior of circular double-layered graphene sheets (DLGSs) resting on the Winkler- and Pasternak-type elastic foundations in a thermal environment is investigated. The governing equation is derived on the basis of Eringen's nonlocal elasticity and the classical plate theory (CLPT). The initial thermal loading is assumed to be due to a uniform temperature rise throughout the thickness direction. Using the generalized differential quadrature (GDQ) method and periodic differential operators in radial and circumferential directions, respectively, the governing equation is discretized. DLGSs with clamped and simply-supported boundary conditions are studied and the influence of van der Waals (vdW) interaction forces is taken into account. In the numerical results, the effects of various parameters such as elastic medium coefficients, radius-to-thickness ratio, thermal loading and nonlocal parameter are examined on both in-phase and anti-phase natural frequencies. The results show that the thermal load and elastic foundation respectively decreases and increases the fundamental frequencies of DLGSs.

  16. Strong Local-Nonlocal Coupling for Integrated Fracture Modeling

    SciTech Connect

    Littlewood, David John; Silling, Stewart A.; Mitchell, John A.; Seleson, Pablo D.; Bond, Stephen D.; Parks, Michael L.; Turner, Daniel Z.; Burnett, Damon J.; Ostien, Jakob; Gunzburger, Max

    2015-09-01

    Peridynamics, a nonlocal extension of continuum mechanics, is unique in its ability to capture pervasive material failure. Its use in the majority of system-level analyses carried out at Sandia, however, is severely limited, due in large part to computational expense and the challenge posed by the imposition of nonlocal boundary conditions. Combined analyses in which peridynamics is em- ployed only in regions susceptible to material failure are therefore highly desirable, yet available coupling strategies have remained severely limited. This report is a summary of the Laboratory Directed Research and Development (LDRD) project "Strong Local-Nonlocal Coupling for Inte- grated Fracture Modeling," completed within the Computing and Information Sciences (CIS) In- vestment Area at Sandia National Laboratories. A number of challenges inherent to coupling local and nonlocal models are addressed. A primary result is the extension of peridynamics to facilitate a variable nonlocal length scale. This approach, termed the peridynamic partial stress, can greatly reduce the mathematical incompatibility between local and nonlocal equations through reduction of the peridynamic horizon in the vicinity of a model interface. A second result is the formulation of a blending-based coupling approach that may be applied either as the primary coupling strategy, or in combination with the peridynamic partial stress. This blending-based approach is distinct from general blending methods, such as the Arlequin approach, in that it is specific to the coupling of peridynamics and classical continuum mechanics. Facilitating the coupling of peridynamics and classical continuum mechanics has also required innovations aimed directly at peridynamic models. Specifically, the properties of peridynamic constitutive models near domain boundaries and shortcomings in available discretization strategies have been addressed. The results are a class of position-aware peridynamic constitutive laws for

  17. Nonlocal Stochastic Model for the Free Scalar Field Theory

    NASA Astrophysics Data System (ADS)

    Namsrai, Kh.

    1981-05-01

    The free scalar field is investigated within the framework of the Davidson stochastic model and of the hypothesis on space-time stochasticity. It is shown that the resulting Markov field obtained by averaging in this space-time is equivalent to a nonlocal Euclidean Markov field with the times scaled by a common factor which depends on the diffusion parameter ν. Our result generalizes Guerra and Ruggiero's procedure of stochastic quantization of scalar fields. On the basis of the assumption about unobservability of ν in quantum field theory, the Efimov nonlocal theory is obtained from Euclidean Markov field with form factors of the class of entire analytical functions.

  18. Fine-grained uncertainty relation and nonlocality of tripartite systems

    NASA Astrophysics Data System (ADS)

    Pramanik, T.; Majumdar, A. S.

    2012-02-01

    The upper bound of the fine-grained uncertainty relation is different for classical physics, quantum physics, and no-signaling theories with maximal nonlocality (superquantum correlation), as was shown in the case of bipartite systems [J. Oppenheim and S. Wehner, ScienceSCIEAS0036-807510.1126/science.1192065 330, 1072 (2010)]. Here, we extend the fine-grained uncertainty relation to the case of tripartite systems. We show that the fine-grained uncertainty relation determines the nonlocality of tripartite systems as manifested by the Svetlichny inequality, discriminating between classical physics, quantum physics, and superquantum correlations.

  19. Local and nonlocal parallel heat transport in general magnetic fields

    SciTech Connect

    Del-Castillo-Negrete, Diego B; Chacon, Luis

    2011-01-01

    A novel approach for the study of parallel transport in magnetized plasmas is presented. The method avoids numerical pollution issues of grid-based formulations and applies to integrable and chaotic magnetic fields with local or nonlocal parallel closures. In weakly chaotic fields, the method gives the fractal structure of the devil's staircase radial temperature profile. In fully chaotic fields, the temperature exhibits self-similar spatiotemporal evolution with a stretched-exponential scaling function for local closures and an algebraically decaying one for nonlocal closures. It is shown that, for both closures, the effective radial heat transport is incompatible with the quasilinear diffusion model.

  20. Lévy flights and nonlocal quantum dynamics

    NASA Astrophysics Data System (ADS)

    Garbaczewski, Piotr; Stephanovich, Vladimir

    2013-07-01

    We develop a fully fledged theory of quantum dynamical patterns of behavior that are nonlocally induced. To this end we generalize the standard Laplacian-based framework of the Schrödinger picture quantum evolution to that employing nonlocal (pseudodifferential) operators. Special attention is paid to the Salpeter (here, m ⩾ 0) quasirelativistic equation and the evolution of various wave packets, in particular to their radial expansion in 3D. Foldy's synthesis of "covariant particle equations" is extended to encompass free Maxwell theory, which however is devoid of any "particle" content. Links with the photon wave mechanics are explored.

  1. Two-Dimensional Heterojunctions from Nonlocal Manipulations of the Interactions.

    PubMed

    Rösner, M; Steinke, C; Lorke, M; Gies, C; Jahnke, F; Wehling, T O

    2016-04-13

    We propose to create lateral heterojunctions in two-dimensional materials based on nonlocal manipulations of the Coulomb interaction using structured dielectric environments. By means of ab initio calculations for MoS2 as well as generic semiconductor models, we show that the Coulomb interaction-induced self-energy corrections in real space are sufficiently nonlocal to be manipulated externally, but still local enough to induce spatially sharp interfaces within a single homogeneous monolayer to form heterojunctions. We find a type-II heterojunction band scheme promoted by a laterally structured dielectric environment, which exhibits a sharp band gap crossover within less than 5 unit cells. PMID:26918626

  2. To the non-local theory of cold nuclear fusion.

    PubMed

    Alexeev, Boris V

    2014-10-01

    In this paper, we revisit the cold fusion (CF) phenomenon using the generalized Bolzmann kinetics theory which can represent the non-local physics of this CF phenomenon. This approach can identify the conditions when the CF can take place as the soliton creation under the influence of the intensive sound waves. The vast mathematical modelling leads to affirmation that all parts of soliton move with the same velocity and with the small internal change of the pressure. The zone of the high density is shaped on the soliton's front. It means that the regime of the 'acoustic CF' could be realized from the position of the non-local hydrodynamics. PMID:26064528

  3. Quantum nonlocal effects on optical properties of spherical nanoparticles

    SciTech Connect

    Moradi, Afshin

    2015-02-15

    To study the scattering of electromagnetic radiation by a spherical metallic nanoparticle with quantum spatial dispersion, we develop the standard nonlocal Mie theory by allowing for the excitation of the quantum longitudinal plasmon modes. To describe the quantum nonlocal effects, we use the quantum longitudinal dielectric function of the system. As in the standard Mie theory, the electromagnetic fields are expanded in terms of spherical vector wavefunctions. Then, the usual Maxwell boundary conditions are imposed plus the appropriate additional boundary conditions. Examples of calculated extinction spectra are presented, and it is found that the frequencies of the subsidiary peaks, due to quantum bulk plasmon excitations exhibit strong dependence on the quantum spatial dispersion.

  4. Nonlocal Poisson-Fermi model for ionic solvent

    NASA Astrophysics Data System (ADS)

    Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

    2016-07-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

  5. Superlinear nonlocal fractional problems with infinitely many solutions

    NASA Astrophysics Data System (ADS)

    Binlin, Zhang; Molica Bisci, Giovanni; Servadei, Raffaella

    2015-07-01

    In this paper we study the existence of infinitely many weak solutions for equations driven by nonlocal integrodifferential operators with homogeneous Dirichlet boundary conditions. A model for these operators is given by the fractional Laplacian where s ∈ (0, 1) is fixed. We consider different superlinear growth assumptions on the nonlinearity, starting from the well-known Ambrosetti-Rabinowitz condition. In this framework we obtain three different results about the existence of infinitely many weak solutions for the problem under consideration, by using the Fountain Theorem. All these theorems extend some classical results for semilinear Laplacian equations to the nonlocal fractional setting.

  6. A theory of non-local linear drift wave transport

    SciTech Connect

    Moradi, S.; Anderson, J.; Weyssow, B.

    2011-06-15

    Transport events in turbulent tokamak plasmas often exhibit non-local or non-diffusive action at a distance features that so far have eluded a conclusive theoretical description. In this paper a theory of non-local transport is investigated through a Fokker-Planck equation with fractional velocity derivatives. A dispersion relation for density gradient driven linear drift modes is derived including the effects of the fractional velocity derivative in the Fokker-Planck equation. It is found that a small deviation (a few percent) from the Maxwellian distribution function alters the dispersion relation such that the growth rates are substantially increased and thereby may cause enhanced levels of transport.

  7. Faithful test of nonlocal realism with entangled coherent states

    SciTech Connect

    Lee, Chang-Woo; Jeong, Hyunseok; Paternostro, Mauro

    2011-02-15

    We investigate the violation of Leggett's inequality for nonlocal realism using entangled coherent states and various types of local measurements. We prove mathematically the relation between the violation of the Clauser-Horne-Shimony-Holt form of Bell's inequality and Leggett's one when tested by the same resources. For Leggett inequalities, we generalize the nonlocal realistic bound to systems in Hilbert spaces larger than bidimensional ones and introduce an optimization technique that allows one to achieve larger degrees of violation by adjusting the local measurement settings. Our work describes the steps that should be performed to produce a self-consistent generalization of Leggett's original arguments to continuous-variable states.

  8. Phonons in nonlocal van der Waals density functional theory

    NASA Astrophysics Data System (ADS)

    Sabatini, Riccardo; Küçükbenli, Emine; Pham, Cong Huy; de Gironcoli, Stefano

    2016-06-01

    We extend the formulation of density functional perturbation theory to treat nonlocal density functionals, accounting for van der Waals interactions, in a rigorous and efficient way. We provide a general formalism, suitable for any functional in this family, and give specific equations for the most widely used ones. We then study the lattice dynamics of graphite, comparing several nonlocal functionals and the local density approximation, showing that our recent revision of the VV10 functional [R. Sabatini et al., Phys. Rev. B 87, 041108(R) (2013), 10.1103/PhysRevB.87.041108] gives the best comparison with experiments.

  9. Ring dark and antidark solitons in nonlocal media.

    PubMed

    Horikis, Theodoros P; Frantzeskakis, Dimitrios J

    2016-02-01

    Ring dark and antidark solitons in nonlocal media are found. These structures have, respectively, the form of annular dips or humps on top of a stable CW background, and exist in a weak or strong nonlocality regime, defined by the sign of a characteristic parameter. It is demonstrated analytically that these solitons satisfy an effective cylindrical Kadomtsev-Petviashvili (aka Johnson's) equation and, as such, can be written explicitly in closed form. Numerical simulations show that they propagate undistorted and undergo quasi-elastic collisions, attesting to their stability properties. PMID:26907429

  10. Self-induced mode transformation in nonlocal nonlinear media.

    PubMed

    Izdebskaya, Yana V; Desyatnikov, Anton S; Kivshar, Yuri S

    2013-09-20

    We report on the first experimental observation of self-induced optical mode transformations in nonlocal nonlinear media. We show that the quadrupole Hermite-Gaussian mode experiences complex nonlinear dynamics in a nematic liquid crystal, including power-dependent conversion into a radially symmetric Laguerre-Gaussian mode. The physical mechanism responsible for self-induced transformation is the excitation of internal modes of a metastable quadrupole nonlocal soliton and its subsequent transmutation into a robust soliton with a bright peak surrounded by a bright ring. We also observe the onset of transformations of higher-order modes, proving the generic character of this nonlinear phenomenon. PMID:24093262

  11. A radial basis function Galerkin method for inhomogeneous nonlocal diffusion

    DOE PAGESBeta

    Lehoucq, Richard B.; Rowe, Stephen T.

    2016-02-01

    We introduce a discretization for a nonlocal diffusion problem using a localized basis of radial basis functions. The stiffness matrix entries are assembled by a special quadrature routine unique to the localized basis. Combining the quadrature method with the localized basis produces a well-conditioned, sparse, symmetric positive definite stiffness matrix. We demonstrate that both the continuum and discrete problems are well-posed and present numerical results for the convergence behavior of the radial basis function method. As a result, we explore approximating the solution to anisotropic differential equations by solving anisotropic nonlocal integral equations using the radial basis function method.

  12. Nonlocal Poisson-Fermi model for ionic solvent.

    PubMed

    Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

    2016-07-01

    We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution. PMID:27575084

  13. Quasi-periodic transformations of nonlocal spatial solitons.

    PubMed

    Buccoliero, Daniel; Desyatnikov, Anton S

    2009-06-01

    We study quasi-periodic transformations between nonlocal spatial solitons of different symmetries triggered by modulational instability and resembling a self-induced mode converter. Transformation dynamics of solitons with zero angular momentum, e.g. the quadrupole-type soliton, reveal the equidistant spectrum of spatial field oscillations typical for the breather-type solutions. In contrast, the transformations of nonlocal solitons carrying orbital angular momentum, such as 2x3 soliton matrix, are accompanied by their spiralling and corresponding spectra of field oscillations show mixing of three characteristic spatial frequencies. PMID:19506609

  14. Characterizing the geometrical edges of nonlocal two-qubit gates

    SciTech Connect

    Balakrishnan, S.; Sankaranarayanan, R.

    2009-05-15

    Nonlocal two-qubit gates are geometrically represented by tetrahedron known as Weyl chamber within which perfect entanglers form a polyhedron. We identify that all edges of the Weyl chamber and polyhedron are formed by single parametric gates. Nonlocal attributes of these edges are characterized using entangling power and local invariants. In particular, SWAP{sup -{alpha}} family of gates with 0{<=}{alpha}{<=}1 constitutes one edge of the Weyl chamber with SWAP{sup -1/2} being the only perfect entangler. Finally, optimal constructions of controlled-NOT using SWAP{sup -1/2} gate and gates belong to three edges of the polyhedron are presented.

  15. Non-local heat transport in static solar coronal loops

    NASA Astrophysics Data System (ADS)

    Ciaravella, A.; Peres, G.; Serio, S.

    1991-04-01

    The limits of applicability of the Spitzer-Harm thermal conductivity in solar coronal loops is investigated, and it is shown that the ratio of electron mean-free path to temperature scale height in large-scale structures can approach the limits of the Spitzer-Harm theory. A nonlocal formulation of heat transport is used to compute a grid of loop models: the effects of nonlocal transport on the distribution of differential emission measure are particularly important in the coronal part of loops longer than the pressure scale height.

  16. Heralded phase-contrast imaging using an orbital angular momentum phase-filter

    NASA Astrophysics Data System (ADS)

    Aspden, Reuben S.; Morris, Peter A.; He, Ruiqing; Chen, Qian; Padgett, Miles J.

    2016-05-01

    We utilise the position and orbital angular momentum (OAM) correlations between the signal and idler photons generated in the down-conversion process to obtain ghost images of a phase object. By using an OAM phase filter, which is non-local with respect to the object, the images exhibit isotropic edge-enhancement. This imaging technique is the first demonstration of a full-field, phase-contrast imaging system with non-local edge enhancement, and enables imaging of phase objects using significantly fewer photons than standard phase-contrast imaging techniques.

  17. A higher-order nonlocal elasticity and strain gradient theory and its applications in wave propagation

    NASA Astrophysics Data System (ADS)

    Lim, C. W.; Zhang, G.; Reddy, J. N.

    2015-05-01

    In recent years there have been many papers that considered the effects of material length scales in the study of mechanics of solids at micro- and/or nano-scales. There are a number of approaches and, among them, one set of papers deals with Eringen's differential nonlocal model and another deals with the strain gradient theories. The modified couple stress theory, which also accounts for a material length scale, is a form of a strain gradient theory. The large body of literature that has come into existence in the last several years has created significant confusion among researchers about the length scales that these various theories contain. The present paper has the objective of establishing the fact that the length scales present in nonlocal elasticity and strain gradient theory describe two entirely different physical characteristics of materials and structures at nanoscale. By using two principle kernel functions, the paper further presents a theory with application examples which relates the classical nonlocal elasticity and strain gradient theory and it results in a higher-order nonlocal strain gradient theory. In this theory, a higher-order nonlocal strain gradient elasticity system which considers higher-order stress gradients and strain gradient nonlocality is proposed. It is based on the nonlocal effects of the strain field and first gradient strain field. This theory intends to generalize the classical nonlocal elasticity theory by introducing a higher-order strain tensor with nonlocality into the stored energy function. The theory is distinctive because the classical nonlocal stress theory does not include nonlocality of higher-order stresses while the common strain gradient theory only considers local higher-order strain gradients without nonlocal effects in a global sense. By establishing the constitutive relation within the thermodynamic framework, the governing equations of equilibrium and all boundary conditions are derived via the variational

  18. Modulational instability and solitons in nonlocal media with competing nonlinearities

    SciTech Connect

    Esbensen, B. K.; Bache, M.; Bang, O.; Wlotzka, A.; Krolikowski, W.

    2011-11-15

    We investigate analytically and numerically propagation and spatial localization of light in nonlocal media with competing nonlinearities. In particular, we discuss conditions for the modulational instability of plane waves and formation of spatial solitons. We show that the competing focusing and defocusing nonlinearities enable coexistence of dark or bright spatial solitons in the same medium by varying the intensity of the beam.

  19. Incorporating anatomical side information into PET reconstruction using nonlocal regularization.

    PubMed

    Nguyen, Van-Giang; Lee, Soo-Jin

    2013-10-01

    With the introduction of combined positron emission tomography (PET)/computed tomography (CT) or PET/magnetic resonance imaging (MRI) scanners, there is an increasing emphasis on reconstructing PET images with the aid of the anatomical side information obtained from X-ray CT or MRI scanners. In this paper, we propose a new approach to incorporating prior anatomical information into PET reconstruction using the nonlocal regularization method. The nonlocal regularizer developed for this application is designed to selectively consider the anatomical information only when it is reliable. As our proposed nonlocal regularization method does not directly use anatomical edges or boundaries which are often used in conventional methods, it is not only free from additional processes to extract anatomical boundaries or segmented regions, but also more robust to the signal mismatch problem that is caused by the indirect relationship between the PET image and the anatomical image. We perform simulations with digital phantoms. According to our experimental results, compared to the conventional method based on the traditional local regularization method, our nonlocal regularization method performs well even with the imperfect prior anatomical information or in the presence of signal mismatch between the PET image and the anatomical image. PMID:23744678

  20. Nonlocal electron transport in magnetized plasmas with arbitrary atomic number

    SciTech Connect

    Bennaceur-Doumaz, D.; Bendib, A.

    2006-09-15

    The numerical solution of the steady-state electron Fokker-Planck equation perturbed with respect to a global equilibrium is presented in magnetized plasmas with arbitrary atomic number Z. The magnetic field is assumed to be constant and the electron-electron collisions are described by the Landau collision operator. The solution is derived in the Fourier space and in the framework of the diffusive approximation which captures the spatial nonlocal effects. The transport coefficients are deduced and used to close a complete set of nonlocal electron fluid equations. This work improves the results of A. Bendib et al. [Phys. Plasmas 9, 1555 (2002)] and of A. V. Brantov et al. [Phys. Plasmas 10, 4633 (2003)] restricted to the local and nonlocal high-Z plasma approximations, respectively. The influence of the magnetic field on the nonlocal effects is discussed. We propose also accurate numerical fits of the relevant transport coefficients with respect to the collisionality parameter {lambda}{sub ei}/L and the atomic number Z, where L is the typical scale length and {lambda}{sub ei} is the electron-ion mean-free-path.

  1. Vortex stabilization by means of spatial solitons in nonlocal media

    NASA Astrophysics Data System (ADS)

    Izdebskaya, Yana; Krolikowski, Wieslaw; Smyth, Noel F.; Assanto, Gaetano

    2016-05-01

    We investigate how optical vortices, which tend to be azimuthally unstable in local nonlinear materials, can be stabilized by a copropagating coaxial spatial solitary wave in nonlocal, nonlinear media. We focus on the formation of nonlinear vortex-soliton vector beams in reorientational soft matter, namely nematic liquid crystals, and report on experimental results, as well as numerical simulations.

  2. Non-local rheology for dense granular flows in avalanches

    NASA Astrophysics Data System (ADS)

    Izzet, Adrien; Clement, Eric; Andreotti, Bruno

    A local constitutive relation was proposed to describe dense granular flows (GDR MiDi, EPJE 2004). It provides a rather good prediction of the flowing regime but does not foresee the existence of a ``creep regime'' as observed by Komatsu et al. (PRL 2001). In the context of a 2D shear cell, a relaxation length for the velocity profile was measured (Bouzid et al., PRL 2013) which confirmed the existence of a flow below the standard Coulomb yield threshold. A correction for the local rheology was proposed. To test further this non-local constitutive relation, we built an inclined narrow channel within which we monitor the flow from the side. We managed to observe the ``creep regime'' over five orders of magnitude in velocity and fit the velocity profiles in the depth with an asymptotic solution of the non-local equation. However, the boundary condition at the free surface needs to be selected in order to calibrate the non-local rheology over the whole range of stresses in the system. In this perspective, we complement the experimental results with 2D simulations of hard and frictional discs on an inclined plane in which we introduce a surface friction force proportional to the effective pressure in the granular. We analyze these results in the light of the non-local rheology.

  3. Nonlocal Hamiltonian gauge theories and their connection with lattice Hamiltonians

    SciTech Connect

    Ktorides, C.N.; Mavromatos, N.E.

    1985-06-15

    We introduce the concept of primitive Hamiltonian density for nonlocal Abelian gauge theories. We subsequently study the local limit both with respect to the continuum and with respect to a lattice structure introduced via hypercubic cells. The non-Abelian case is also discussed.

  4. Flare loop radiative hydrodynamics. III - Nonlocal radiative transfer effects

    NASA Technical Reports Server (NTRS)

    Canfield, R. C.; Fisher, G. H.; Mcclymont, A. N.

    1983-01-01

    The study has three goals. The first is to demonstrate that processes exist whose intrinsic nonlocal nature cannot be represented by local approximations. The second is to elucidate the physical nature and origins of these nonlocal processes. The third is to suggest that the methods and results described here may prove useful in constructing semiempirical models of the chromosphere by means more efficient than trial and error. Matrices are computed that describe the effect of a temperature perturbation at an arbitrary point in the loop on density, hydrogen ionized fraction, total radiative loss rate, and radiative loss rate of selected hydrogen lines and continua at all other points. It is found that the dominant nonlocal radiative transfer effects can be separated into flux divergence coefficient effects and upper level population effects. The former are most important when the perturbation takes place in a region of significant opacity. Upper level population effects arise in both optically thick and thin regions in response to nonlocal density, ionization, and interlocking effects.

  5. Non-local order in Mott insulators, duality and Wilson loops

    SciTech Connect

    Rath, Steffen Patrick; Simeth, Wolfgang; Endres, Manuel; Zwerger, Wilhelm

    2013-07-15

    It is shown that the Mott insulating and superfluid phases of bosons in an optical lattice may be distinguished by a non-local ‘parity order parameter’ which is directly accessible via single site resolution imaging. In one dimension, the lattice Bose model is dual to a classical interface roughening problem. We use known exact results from the latter to prove that the parity order parameter exhibits long range order in the Mott insulating phase, consistent with recent experiments by Endres et al. [M. Endres, M. Cheneau, T. Fukuhara, C. Weitenberg, P. Schauß, C. Gross, L. Mazza, M.C. Bañuls, L. Pollet, I. Bloch, et al., Science 334 (2011) 200]. In two spatial dimensions, the parity order parameter can be expressed in terms of an equal time Wilson loop of a non-trivial U(1) gauge theory in 2+1 dimensions which exhibits a transition between a Coulomb and a confining phase. The negative logarithm of the parity order parameter obeys a perimeter law in the Mott insulator and is enhanced by a logarithmic factor in the superfluid. -- Highlights: •Number statistics of cold atoms in optical lattices show non-local correlations. •These correlations are measurable via single site resolution imaging. •Incompressible phases exhibit an area law in particle number fluctuations. •This leads to long-range parity order of Mott-insulators in one dimension. •Parity order in 2d is connected with a Wilson-loop in a lattice gauge theory.

  6. Nonlocal density-functional description constructed from a correlated many-body wave function

    NASA Astrophysics Data System (ADS)

    Umezawa, Naoto; Tsuneyuki, Shinji

    2004-03-01

    We suggest a new approach to the nonlocal density-functional theory. In our method, the nonlocal correlation functional is derived from a correlated many-body wave function using the transcorrelated similarity transformation [1,2]. Our formalism is rigorous in principle if the v-representable density is assumed. In practice, Jastrow-Slater-type wave function is adopted and the correlation functional consists of many-body interactions originated from the Jastrow factor. Instead of struggling with these higher order interactions, we retain only 2-body interactions multiplying an adjusting parameter so that it can reproduce the exact correlation energy for the homogeneous electron gas. Therefore, the computational cost is comparable to the exact exchange method. Moreover, parameters in the Jastrow factor are determined by the two conditions: the cusp conditions and the random-phase approximation without empirical fitting. We found that our correlation functional gives fairly good results for small atoms and ions (He, Li^+, Be^2+, Li, and Be). [1]S. F. Boys and N. C. Handy, Proc. Roy. Soc. A, 309, 209; 310, 43; 310, 63; 311, 309. [2] N. Umezawa and S. Tsuneyuki, J. Chem. Phys. 119, 10015 (2003).

  7. Rationale for switching to nonlocal functionals in density functional theory

    NASA Astrophysics Data System (ADS)

    Lazić, P.; Atodiresei, N.; Caciuc, V.; Brako, R.; Gumhalter, B.; Blügel, S.

    2012-10-01

    Density functional theory (DFT) has been steadily improving over the past few decades, becoming the standard tool for electronic structure calculations. The early local functionals (LDA) were eventually replaced by more accurate semilocal functionals (GGA) which are in use today. A major persisting drawback is the lack of the nonlocal correlation which is at the core of dispersive (van der Waals) forces, so that a large and important class of systems remains outside the scope of DFT. The vdW-DF correlation functional of Langreth and Lundqvist, published in 2004, was the first nonlocal functional which could be easily implemented. Beyond expectations, the nonlocal functional has brought significant improvement to systems that were believed not to be sensitive to nonlocal correlations. In this paper, we use the example of graphene nanodomes growing on the Ir(111) surface, where with an increase of the size of the graphene islands the character of the bonding changes from strong chemisorption towards almost pure physisorption. We demonstrate how the seamless character of the vdW-DF functionals makes it possible to treat all regimes self-consistently, proving to be a systematic and consistent improvement of DFT regardless of the nature of bonding. We also discuss the typical surface science example of CO adsorption on (111) surfaces of metals, which shows that the nonlocal correlation may also be crucial for strongly chemisorbed systems. We briefly discuss open questions, in particular the choice of the most appropriate exchange part of the functional. As the vdW-DF begins to appear implemented self-consistently in a number of popular DFT codes, with numerical costs close to the GGA calculations, we draw the attention of the DFT community to the advantages and benefits of the adoption of this new class of functionals.

  8. On wave propagation characteristics in fluid saturated porous materials by a nonlocal Biot theory

    NASA Astrophysics Data System (ADS)

    Tong, Lihong; Yu, Yang; Hu, Wentao; Shi, Yufeng; Xu, Changjie

    2016-09-01

    A nonlocal Biot theory is developed by combing Biot theory and nonlocal elasticity theory for fluid saturated porous material. The nonlocal parameter is introduced as an independent variable for describing wave propagation characteristics in poroelastic material. A physical insight on nonlocal term demonstrates that the nonlocal term is a superposition of two effects, one is inertia force effect generated by fluctuation of porosity and the other is pore size effect inherited from nonlocal constitutive relation. Models for situations of excluding fluid nonlocal effect and including fluid nonlocal effect are proposed. Comparison with experiment confirms that model without fluid nonlocal effect is more reasonable for predicting wave characteristics in saturated porous materials. The negative dispersion is observed theoretically which agrees well with the published experimental data. Both wave velocities and quality factors as functions of frequency and nonlocal parameter are examined in practical cases. A few new physical phenomena such as backward propagation and disappearance of slow wave when exceeding critical frequency and disappearing shear wave in high frequency range, which were not predicted by Biot theory, are demonstrated.

  9. Quasi-local approximation of non-local exchange-correlation kernels in the adiabatic-connection fluctuation-dissipation theorem

    NASA Astrophysics Data System (ADS)

    Lu, Deyu

    The adiabatic-connection fluctuation-dissipation theorem (ACFDT) is a formal theoretical framework to treat van der Waals (vdW) dispersion interactions. Under the random phase approximation (RPA), it yields the correct asymptotic behavior at large distances, but the short-range correlation is overestimated. It has been demonstrated that non-local exchange-correlation kernels can systematically correct the errors of RPA for homogenous electron gas. However, direct extension of non-local kernels derived from the electron gas model to inhomogeneous systems raises several issues. In addition to the high computational expense, the non-local kernels worsen the rare gas dimer binding curve as compared to RPA. In this study, we propose a quasi-local approximation of the non-local kernel in order to address these issues. This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704.

  10. Effects of Nonlocality in Cubic Superconductor V3Si

    NASA Astrophysics Data System (ADS)

    Yethiraj, M.; Christen, D. K.; Paul, D. McK.; Dewhurst, C.; Cubitt, R.

    2004-03-01

    Non-locality in superconductors is an important effect which produces an anisotropic distribution of current flow around the core of a flux-line in the mixed state of a type II superconductor. Such anistropic interactions produce varying forces between the fluxlines as a function of their seperation and hence changes in the symmetry of the flux line lattice (FLL) with field. V3Si has a cubic crystal symmetry and the material shows no evidence of any structure in the energy gap, making this an ideal model system for studies of the influence of "non-locality" on the FLL. We report on the structural changes of the FLL in this clean system with changes in applied field and temperature with particular emphasis on the region near HC2, where this effect weakens. We compare these results with what happens in other systems where nodal structure can also lead to changes in morphology for the FLL.

  11. Experimentally testing Bell's theorem based on Hardy's nonlocal ladder proofs

    NASA Astrophysics Data System (ADS)

    Guo, WeiJie; Fan, DaiHe; Wei, LianFu

    2015-02-01

    Bell's theorem argues the existence of quantum nonlocality which goes basically against the hidden variable theory (HVT). Many experiments have been done via testing the violations of Bell's inequalities to statistically verify the Bell's theorem. Alternatively, by testing the Hardy's ladder proofs we experimentally demonstrate the deterministic violation of HVT and thus confirm the quantum nonlocality. Our tests are implemented with non-maximal entangled photon pairs generated by spontaneous parametric down conversions (SPDCs). We show that the degree freedom of photon entanglement could be significantly enhanced by using interference filters. As a consequence, the Hardy's ladder proofs could be tested and Bell's theorem is verified robustly. The probability of violating the locality reach to 41.9%, which is close to the expectably ideal value 46.4% for the photon pairs with degree of entanglement ɛ = 0.93. The higher violating probability is possible by further optimizing the experimental parameters.

  12. Demonstration of Quantum Nonlocality in the Presence of Measurement Dependence

    NASA Astrophysics Data System (ADS)

    Aktas, Djeylan; Tanzilli, Sébastien; Martin, Anthony; Pütz, Gilles; Thew, Rob; Gisin, Nicolas

    2015-06-01

    Quantum nonlocality stands as a resource for device independent quantum information processing (DIQIP), such as, for instance, device independent quantum key distribution. We investigate, experimentally, the assumption of limited measurement dependence, i.e., that the measurement settings used in Bell inequality tests or DIQIP are partially influenced by the source of entangled particle and/or by an adversary. Using a recently derived Bell-like inequality [G. Pütz, Phys. Rev. Lett. 113, 190402 (2014)] and a 99% fidelity source of partially entangled polarization photonic qubits, we obtain a clear violation of the inequality, excluding a much larger range of measurement dependent local models than would be possible with an adapted Clauser-Horne-Shimony-Holt (CHSH) inequality. It is therefore shown that the measurement independence assumption can be widely relaxed while still demonstrating quantum nonlocality.

  13. Demonstration of Quantum Nonlocality in the Presence of Measurement Dependence.

    PubMed

    Aktas, Djeylan; Tanzilli, Sébastien; Martin, Anthony; Pütz, Gilles; Thew, Rob; Gisin, Nicolas

    2015-06-01

    Quantum nonlocality stands as a resource for device independent quantum information processing (DIQIP), such as, for instance, device independent quantum key distribution. We investigate, experimentally, the assumption of limited measurement dependence, i.e., that the measurement settings used in Bell inequality tests or DIQIP are partially influenced by the source of entangled particle and/or by an adversary. Using a recently derived Bell-like inequality [G. Pütz, Phys. Rev. Lett. 113, 190402 (2014)] and a 99% fidelity source of partially entangled polarization photonic qubits, we obtain a clear violation of the inequality, excluding a much larger range of measurement dependent local models than would be possible with an adapted Clauser-Horne-Shimony-Holt (CHSH) inequality. It is therefore shown that the measurement independence assumption can be widely relaxed while still demonstrating quantum nonlocality. PMID:26196606

  14. Position-momentum Bell nonlocality with entangled photon pairs

    NASA Astrophysics Data System (ADS)

    Schneeloch, James; Knarr, Samuel H.; Lum, Daniel J.; Howell, John C.

    2016-01-01

    Witnessing continuous-variable Bell nonlocality is a challenging endeavor, but Bell himself showed how one might demonstrate this nonlocality. Although Bell nearly showed a violation using the Clauser-Horne-Shimony-Holt (CHSH) inequality with sign-binned position-momentum statistics of entangled pairs of particles measured at different times, his demonstration is subject to approximations not realizable in a laboratory setting. Moreover, he does not give a quantitative estimation of the maximum achievable violation for the wave function he considers. In this article, we show how his strategy can be reimagined using the transverse positions and momenta of entangled photon pairs measured at different propagation distances, and we find that the maximum achievable violation for the state he considers is actually very small relative to the upper limit of 2 √{2 } . Although Bell's wave function does not produce a large violation of the CHSH inequality, other states may yet do so.

  15. Maximum nonlocality and minimum uncertainty using magic states

    NASA Astrophysics Data System (ADS)

    Howard, Mark

    2015-04-01

    We prove that magic states from the Clifford hierarchy give optimal solutions for tasks involving nonlocality and entropic uncertainty with respect to Pauli measurements. For both the nonlocality and uncertainty tasks, stabilizer states are the worst possible pure states, so our solutions have an operational interpretation as being highly nonstabilizer. The optimal strategy for a qudit version of the Clauser-Horne-Shimony-Holt game in prime dimensions is achieved by measuring maximally entangled states that are isomorphic to single-qudit magic states. These magic states have an appealingly simple form, and our proof shows that they are "balanced" with respect to all but one of the mutually unbiased stabilizer bases. Of all equatorial qudit states, magic states minimize the average entropic uncertainties for collision entropy and also, for small prime dimensions, min-entropy, a fact that may have implications for cryptography.

  16. Evidence for Nonlocal Electrodynamics in Planar Josephson Junctions

    NASA Astrophysics Data System (ADS)

    Boris, A. A.; Rydh, A.; Golod, T.; Motzkau, H.; Klushin, A. M.; Krasnov, V. M.

    2013-09-01

    We study the temperature dependence of the critical current modulation Ic(H) for two types of planar Josephson junctions: a low-Tc Nb/CuNi/Nb and a high-Tc YBa2Cu3O7-δ bicrystal grain-boundary junction. At low T both junctions exhibit a conventional behavior, described by the local sine-Gordon equation. However, at elevated T the behavior becomes qualitatively different: the Ic(H) modulation field ΔH becomes almost T independent and neither ΔH nor the critical field for the penetration of Josephson vortices vanish at Tc. Such an unusual behavior is in good agreement with theoretical predictions for junctions with nonlocal electrodynamics. We extract absolute values of the London penetration depth λ from our data and show that a crossover from local to nonlocal electrodynamics occurs with increasing T when λ(T) becomes larger than the electrode thickness.

  17. Effective nonlocal spin injection through low-resistance oxide junctions

    NASA Astrophysics Data System (ADS)

    Cai, Yunjiao; Luo, Yongming; Qin, Chuan; Chen, Shuhan; Wu, Yizheng; Ji, Yi

    2016-05-01

    Many (>40) nonlocal spin valves on the same substrate have been characterized at 6 K and 295 K by using a probe station. Low-resistance oxide junctions (0.2-0.8 Ω) are used to inject spin current into mesoscopic Cu channels. Spin signals exceeding 10 mΩ at 6 K have been consistently observed, indicating efficient spin injection and detection. However, complex switching behavior and possible variations between devices pose a challenge to using a standard fitting method to quantify the spin signals. Two methods are used for quantitative analysis. The range of the effective spin polarizations can be estimated by assuming a reasonable range for the Cu spin diffusion lengths. A nonlocal spin polarization is introduced to evaluate the spin current in the Cu channels.

  18. Accurate Sparse-Projection Image Reconstruction via Nonlocal TV Regularization

    PubMed Central

    Zhang, Yi; Zhang, Weihua; Zhou, Jiliu

    2014-01-01

    Sparse-projection image reconstruction is a useful approach to lower the radiation dose; however, the incompleteness of projection data will cause degeneration of imaging quality. As a typical compressive sensing method, total variation has obtained great attention on this problem. Suffering from the theoretical imperfection, total variation will produce blocky effect on smooth regions and blur edges. To overcome this problem, in this paper, we introduce the nonlocal total variation into sparse-projection image reconstruction and formulate the minimization problem with new nonlocal total variation norm. The qualitative and quantitative analyses of numerical as well as clinical results demonstrate the validity of the proposed method. Comparing to other existing methods, our method more efficiently suppresses artifacts caused by low-rank reconstruction and reserves structure information better. PMID:24592168

  19. Non-local MRI denoising using random sampling.

    PubMed

    Hu, Jinrong; Zhou, Jiliu; Wu, Xi

    2016-09-01

    In this paper, we propose a random sampling non-local mean (SNLM) algorithm to eliminate noise in 3D MRI datasets. Non-local means (NLM) algorithms have been implemented efficiently for MRI denoising, but are always limited by high computational complexity. Compared to conventional methods, which raster through the entire search window when computing similarity weights, the proposed SNLM algorithm randomly selects a small subset of voxels which dramatically decreases the computational burden, together with competitive denoising result. Moreover, structure tensor which encapsulates high-order information was introduced as an optimal sampling pattern for further improvement. Numerical experiments demonstrated that the proposed SNLM method can get a good balance between denoising quality and computation efficiency. At a relative sampling ratio (i.e. ξ=0.05), SNLM can remove noise as effectively as full NLM, meanwhile the running time can be reduced to 1/20 of NLM's. PMID:27114338

  20. Nonlocal damage approach to analysis of the fracture process zone

    NASA Astrophysics Data System (ADS)

    Xia, S.; Takezono, S.; Tao, K.

    1994-05-01

    A two-zone fracture process model with a crack-bridging zone (CBZ) and a microcracking zone (MCZ) is proposed to describe the fracture process around the tip of a macrocrack. A nonlocal damage approach based on previous work is used to determined the size of the fracture process zone (FPZ). The experimental analysis given by Horii and Ichinomiya (1991) supports the proposal that the existence of the crack bridging effect brings out an increase in load-carrying capacity of materials, whereas microcracking leads to the deterioration of the capacity. Based on the above and utilizing Westergaard's complex function, the distribution functions of stress and damage in the FPZ are given. Applying these to the concrete-like material mortar, we can determine the distribution functions of stress and damage in the FPZ if load and crack opening displacement (COD) at a point are given. Additionally, a nonlocal damage failure criterion is proposed to judge the propagation of the macrocrack.

  1. On the no-signaling approach to quantum nonlocality

    SciTech Connect

    Méndez, J. M. Urías, Jesús

    2015-03-15

    The no-signaling approach to nonlocality deals with separable and inseparable multiparty correlations in the same set of probability states without conflicting causality. The set of half-spaces describing the polytope of no-signaling probability states that are admitted by the most general class of Bell scenarios is formulated in full detail. An algorithm for determining the skeleton that solves the no-signaling description is developed upon a new strategy that is partially pivoting and partially incremental. The algorithm is formulated rigorously and its implementation is shown to be effective to deal with the highly degenerate no-signaling descriptions. Several applications of the algorithm as a tool for the study of quantum nonlocality are mentioned. Applied to a large set of bipartite Bell scenarios, we found that the corresponding no-signaling polytopes have a striking high degeneracy that grows up exponentially with the size of the Bell scenario.

  2. Improved inline model for nonlocal electron transport in HYDRA

    NASA Astrophysics Data System (ADS)

    Marinak, M. M.; Kerbel, G. D.; Patel, M. V.; Robey, H.; Ridgers, C. P.; Kingham, R. J.

    2014-10-01

    The nonlocal electron transport model in HYDRA has been improved in several respects. The original multigroup model has been extended to include the cascade in energy as particles slow down, yielding a more accurate range. The model was also extended to account for contributions to the energy loss rate due to bound electrons. These are among the important modifications that have enabled the package to simulate classes of suprathermal electrons. We show recent calculations using the model that suggest superthermal electrons could be having a significant effect on performance of cryogenic capsule implosions on the National Ignition Facility. We evaluate the nonlocal transport model's accuracy by comparison with an electron VFP code. Comparisons assess the accuracy of the calculated thermal transport for plasmas relevant to NIF experiments. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  3. Symmetries and nonlocal conservation laws of the general magma equation

    NASA Astrophysics Data System (ADS)

    Khamitova, Raisa

    2009-11-01

    In this paper the general magma equation modelling a melt flow in the Earth's mantle is discussed. Applying the new theorem on nonlocal conservation laws [Ibragimov NH. A new conservation theorem. J Math Anal Appl 2007;333(1):311-28] and using the symmetries of the model equation nonlocal conservation laws are computed. In accordance with Ibragimov [Ibragimov NH. Quasi-self-adjoint differential equations. Preprint in Archives of ALGA, vol. 4, BTH, Karlskrona, Sweden: Alga Publications; 2007. p. 55-60, ISSN: 1652-4934] it is shown that the general magma equation is quasi-self-adjoint for arbitrary m and n and self-adjoint for n = -m. These important properties are used for deriving local conservation laws.

  4. Explaination of nonlocal granular fluidity in terms of microscopic fluctuations

    NASA Astrophysics Data System (ADS)

    Zhang, Qiong; Kamrin, Ken

    A recently proposed granular constitutive law has shown capability to predict nonlocal granular rheology using a variable denoted ``granular fluidity''. This work is aimed at finding the microscopic physical meaning of fluidity in terms of fluctuations such as fluctuation of normalized shear stress and fluctuation of velocity. We try to predict the fluidity as a function of the fluctuation of normalized shear stress, and also test Eyring equation and kinetic theory based on the theoretical prediction proposed in other work. We find a consistent definition for the fluidity to be proportional to the product of the velocity fluctuations and some function of packing fraction divided by the average diameter of the grains. This definition shows predictive ability in multiple geometries for which flow behavior is nonlocal. It is notable that the fluidity is well-defined as a function of kinematic state variables, as one would hope for a quantity of this nature.

  5. Minimality via Second Variation for a Nonlocal Isoperimetric Problem

    NASA Astrophysics Data System (ADS)

    Acerbi, E.; Fusco, N.; Morini, M.

    2013-09-01

    We discuss the local minimality of certain configurations for a nonlocal isoperimetric problem used to model microphase separation in diblock copolymer melts. We show that critical configurations with positive second variation are local minimizers of the nonlocal area functional and, in fact, satisfy a quantitative isoperimetric inequality with respect to sets that are L 1-close. The link with local minimizers for the diffuse-interface Ohta-Kawasaki energy is also discussed. As a byproduct of the quantitative estimate, we get new results concerning periodic local minimizers of the area functional and a proof, via second variation, of the sharp quantitative isoperimetric inequality in the standard Euclidean case. As a further application, we address the global and local minimality of certain lamellar configurations.

  6. On a class of nonlocal wave equations from applications

    NASA Astrophysics Data System (ADS)

    Beyer, Horst Reinhard; Aksoylu, Burak; Celiker, Fatih

    2016-06-01

    We study equations from the area of peridynamics, which is a nonlocal extension of elasticity. The governing equations form a system of nonlocal wave equations. We take a novel approach by applying operator theory methods in a systematic way. On the unbounded domain ℝn, we present three main results. As main result 1, we find that the governing operator is a bounded function of the governing operator of classical elasticity. As main result 2, a consequence of main result 1, we prove that the peridynamic solutions strongly converge to the classical solutions by utilizing, for the first time, strong resolvent convergence. In addition, main result 1 allows us to incorporate local boundary conditions, in particular, into peridynamics. This avenue of research is developed in companion papers, providing a remedy for boundary effects. As main result 3, employing spherical Bessel functions, we give a new practical series representation of the solution which allows straightforward numerical treatment with symbolic computation.

  7. Dynamical quenching with non-local α and downward pumping

    NASA Astrophysics Data System (ADS)

    Brandenburg, A.; Hubbard, A. Käpylä, P. J.

    2015-01-01

    In light of new results, the one-dimensional mean-field dynamo model of Brandenburg & Käpylä (2007) with dynamical quenching and a nonlocal Babcock-Leighton \\alpha effect is re-examined for the solar dynamo. We extend the one-dimensional model to include the effects of turbulent downward pumping (Kitchatinov & Olemskoy 2011), and to combine dynamical quenching with shear. We use both the conventional dynamical quenching model of Kleeorin & Ruzmaikin (1982) and the alternate one of Hubbard & Brandenburg (2011), and confirm that with varying levels of non-locality in the \\alpha effect, and possibly shear as well, the saturation field strength can be independent of the magnetic Reynolds number.

  8. Deterministic error correction for nonlocal spatial-polarization hyperentanglement

    PubMed Central

    Li, Tao; Wang, Guan-Yu; Deng, Fu-Guo; Long, Gui-Lu

    2016-01-01

    Hyperentanglement is an effective quantum source for quantum communication network due to its high capacity, low loss rate, and its unusual character in teleportation of quantum particle fully. Here we present a deterministic error-correction scheme for nonlocal spatial-polarization hyperentangled photon pairs over collective-noise channels. In our scheme, the spatial-polarization hyperentanglement is first encoded into a spatial-defined time-bin entanglement with identical polarization before it is transmitted over collective-noise channels, which leads to the error rejection of the spatial entanglement during the transmission. The polarization noise affecting the polarization entanglement can be corrected with a proper one-step decoding procedure. The two parties in quantum communication can, in principle, obtain a nonlocal maximally entangled spatial-polarization hyperentanglement in a deterministic way, which makes our protocol more convenient than others in long-distance quantum communication. PMID:26861681

  9. Electrostatic ion-cyclotron waves in magnetospheric plasmas Nonlocal aspects

    NASA Technical Reports Server (NTRS)

    Ganguli, G.; Bakshi, P.; Palmadesso, P.

    1984-01-01

    The importance of the effect of the magnetic shear and the finite size of current channel on the electrostatic ion-cyclotron instability for the space plasmas is illustrated. A non-local treatment is used. When the channel width Lc, is larger than the shear length Ls, there is a large reduction in the growth rate along with a noteworthy reduction of the band of the unstable perpendicular wavelengths. For Lc less than or = Ls/10 the growth rate is not much altered from its local value, however for Lc/pi i less than or = 10 to the second power the growth rate starts falling below the local value and vanishes for Lc pi i. The non-local effects lead to enhanced coherence in the ion cyclotron waves. Previously announced in STAR as N84-14917

  10. Deterministic error correction for nonlocal spatial-polarization hyperentanglement.

    PubMed

    Li, Tao; Wang, Guan-Yu; Deng, Fu-Guo; Long, Gui-Lu

    2016-01-01

    Hyperentanglement is an effective quantum source for quantum communication network due to its high capacity, low loss rate, and its unusual character in teleportation of quantum particle fully. Here we present a deterministic error-correction scheme for nonlocal spatial-polarization hyperentangled photon pairs over collective-noise channels. In our scheme, the spatial-polarization hyperentanglement is first encoded into a spatial-defined time-bin entanglement with identical polarization before it is transmitted over collective-noise channels, which leads to the error rejection of the spatial entanglement during the transmission. The polarization noise affecting the polarization entanglement can be corrected with a proper one-step decoding procedure. The two parties in quantum communication can, in principle, obtain a nonlocal maximally entangled spatial-polarization hyperentanglement in a deterministic way, which makes our protocol more convenient than others in long-distance quantum communication. PMID:26861681

  11. Deterministic error correction for nonlocal spatial-polarization hyperentanglement

    NASA Astrophysics Data System (ADS)

    Li, Tao; Wang, Guan-Yu; Deng, Fu-Guo; Long, Gui-Lu

    2016-02-01

    Hyperentanglement is an effective quantum source for quantum communication network due to its high capacity, low loss rate, and its unusual character in teleportation of quantum particle fully. Here we present a deterministic error-correction scheme for nonlocal spatial-polarization hyperentangled photon pairs over collective-noise channels. In our scheme, the spatial-polarization hyperentanglement is first encoded into a spatial-defined time-bin entanglement with identical polarization before it is transmitted over collective-noise channels, which leads to the error rejection of the spatial entanglement during the transmission. The polarization noise affecting the polarization entanglement can be corrected with a proper one-step decoding procedure. The two parties in quantum communication can, in principle, obtain a nonlocal maximally entangled spatial-polarization hyperentanglement in a deterministic way, which makes our protocol more convenient than others in long-distance quantum communication.

  12. To the non-local theory of cold nuclear fusion

    PubMed Central

    Alexeev, Boris V.

    2014-01-01

    In this paper, we revisit the cold fusion (CF) phenomenon using the generalized Bolzmann kinetics theory which can represent the non-local physics of this CF phenomenon. This approach can identify the conditions when the CF can take place as the soliton creation under the influence of the intensive sound waves. The vast mathematical modelling leads to affirmation that all parts of soliton move with the same velocity and with the small internal change of the pressure. The zone of the high density is shaped on the soliton's front. It means that the regime of the ‘acoustic CF’ could be realized from the position of the non-local hydrodynamics. PMID:26064528

  13. Contourlet based seismic reflection data non-local noise suppression

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Gao, Jinghuai

    2013-08-01

    In this paper, we propose a non-local, transform domain noise suppression framework to improve the quality of seismic reflection data. The original non-local means (NLM) algorithm measures similarities in the data domain and we generalize it in the nonsubsampled contourlet transform (NSCT) domain. NSCT gives a multiscale, multiresolution and anisotropy representation of the noisy input. The redundancy information in NSCT subbands can be utilized to enhance the structures in the original seismic data. Like the wavelet transform, NSCT coefficients in each subband follow the generalized Gaussian distribution and the parameters can be estimated using appropriate techniques. These parameters are used to construct our proposed NSCT domain filtering algorithm. Applications for synthetic and real seismic data of the proposed algorithm demonstrate its effectiveness on seismic data random noise suppression.

  14. Deinterlacing algorithm with an advanced non-local means filter

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Jeon, Gwanggil; Jeong, Jechang

    2012-04-01

    The authors introduce an efficient intra-field deinterlacing algorithm using an advanced non-local means filter. The non-local means (NLM) method has received considerable attention due to its high performance and simplicity. The NLM method adaptively obtains the missing pixel by the weighted average of the gray values of all pixels within the image, and then automatically eliminates unrelated neighborhoods from the weighted average. However, spatial location distance is another important issue for the deinterlacing method. Therefore we introduce an advanced NLM (ANLM) filter while consider neighborhood similarity and patch distance. Moreover, the search region of the conventional NLM is the whole image, while, the ANLM can just utilize the limited search region and achieve good performance and high efficiency. When compared with existing deinterlacing algorithms, the proposed algorithm improves the peak signal-to-noise-ratio while maintaining high efficiency.

  15. Nonlocal energy-optimized kernel: Recovering second-order exchange in the homogeneous electron gas

    NASA Astrophysics Data System (ADS)

    Bates, Jefferson E.; Laricchia, Savio; Ruzsinszky, Adrienn

    2016-01-01

    In order to remedy some of the shortcomings of the random phase approximation (RPA) within adiabatic connection fluctuation-dissipation (ACFD) density functional theory, we introduce a short-ranged, exchange-like kernel that is one-electron self-correlation free and exact for two-electron systems in the high-density limit. By tuning a free parameter in our model to recover an exact limit of the homogeneous electron gas correlation energy, we obtain a nonlocal, energy-optimized kernel that reduces the errors of RPA for both homogeneous and inhomogeneous solids. Using wave-vector symmetrization for the kernel, we also implement RPA renormalized perturbation theory for extended systems, and demonstrate its capability to describe the dominant correlation effects with a low-order expansion in both metallic and nonmetallic systems. The comparison of ACFD structural properties with experiment is also shown to be limited by the choice of norm-conserving pseudopotential.

  16. Can non-local or higher derivative theories provide alternatives to inflation?

    SciTech Connect

    Geshnizjani, Ghazal; Ahmadi, Nahid E-mail: nahmadi@ut.ac.ir

    2013-11-01

    The standard mechanism for producing the observed scale-invariant power spectrum from adiabatic vacuum fluctuations relies on first order derivative of fields in the action for curvature perturbations. It has been proven [1] that, under this ansatz, any theory of early universe that matches cosmological observations should include a phase of accelerated expansion (i.e. inflation) or it has to break at least one of the following tenets of classical general relativity: Null Energy Conditions (NEC), subluminal signal propagation, or sub-Planckian energy densities. We extend this proof to a large class of theories with higher (spatial) derivative or non-local terms in the action. Interestingly, only theories in the neighborhood of Lifshitz points with ω{sub k}∝k{sup 0} and k{sup 3} remain viable.

  17. Nonlocal topological magnetoelectric effect by Coulomb interaction at a topological insulator-ferromagnet interface

    NASA Astrophysics Data System (ADS)

    Rex, Stefan; Nogueira, Flavio S.; Sudbø, Asle

    2016-01-01

    The interface between a topological insulator and a ferromagnetic insulator exhibits an interesting interplay of topological Dirac electrons and magnetism. As has been shown recently, the breaking of time-reversal invariance by magnetic order generates a Chern-Simons term in the action, that in turn leads to a Berry phase and a magnetoelectric effect of topological origin. Here, we consider the system in the presence of a long-range Coulomb interaction between the Dirac electrons, and find that the magnetoelectric effect of the fluctuating electric field becomes nonlocal. We derive a Landau-Lifshitz equation for the fluctuation-induced magnetization dynamics and the Euler-Lagrange equation of the Coulomb field by explicit one-loop calculations. Via the Coulomb interaction, divergences in the in-plane magnetization affect the magnetization dynamics over large distances in a topologically protected way.

  18. Nonlocalized modulation of periodic reaction diffusion waves: The Whitham equation

    NASA Astrophysics Data System (ADS)

    Johnson, Mathew A.; Noble, Pascal; Rodrigues, L. Miguel; Zumbrun, Kevin

    2013-02-01

    In a companion paper, we established nonlinear stability with detailed diffusive rates of decay of spectrally stable periodic traveling-wave solutions of reaction diffusion systems under small perturbations consisting of a nonlocalized modulation plus a localized ( L 1) perturbation. Here, we determine time-asymptotic behavior under such perturbations, showing that solutions consist of a leading order of a modulation whose parameter evolution is governed by an associated Whitham averaged equation.

  19. Nonlocal Intuition: Replication and Paired-subjects Enhancement Effects.

    PubMed

    Rezaei, Saeed; Mirzaei, Maryam; Zali, Mohammad Reza

    2014-03-01

    This article reports the results of a study of repeat entrepreneurs in Tehran, Iran, in which nonlocal intuition was investigated in a replication and extension of experiment using measures of heart rate variability (HRV). Nonlocal intuition is the perception of information about a distant or future event by the body's psychophysiological systems, which is not based on reason or memories of prior experience. This study follows up on the McCraty, Radin, and Bradley studies, which found evidence of nonlocal intuition. We used Radin's experimental protocol, with the addition of HRV measures as in the McCraty studies involving computer administration of a random sequence of calm and emotional pictures as the stimulus, and conducted two experiments on mutually exclusive samples-the first on a group of single participants (N=15) and the second on a group of co-participant pairs (N=30)-to investigate the question of the "amplification" of intuition effects by social connection. Each experiment was conducted over 45 trials while heart rate rhythm activity was recorded continuously. Results, using random permutation analysis, a statistically conservative procedure, show significant pre-stimulus results-that is, for the period before the computer had randomly selected the picture stimulus-for both experiments. Moreover, while significant separation between the emotional and calm HRV curves was observed in the single-participant experiment, an even larger separation was apparent for the experiment on co-participant pairs; the difference between the two groups was also significant. Overall, the results of the single-participant experiment confirm previous finding: that electrophysiological measures, especially changes in the heart rhythm, can detect intuitive foreknowledge. This result is notable because it constitutes cross-cultural corroboration in a non-Western context-namely, Iran. In addition, the results for co-participant pairs offer new evidence on the amplification of

  20. Bose-condensed atomic systems with nonlocal interaction potentials

    NASA Astrophysics Data System (ADS)

    Yukalov, V. I.; Yukalova, E. P.

    2016-04-01

    The general approach for describing systems with a Bose-Einstein condensate, where atoms interact through nonlocal pair potentials, is presented. Special attention is paid to nonintegrable potentials, such as the dipolar interaction potential. The potentials that are not absolutely integrable can have not well-defined Fourier transforms. Using formally these not defined Fourier transforms leads to unphysical conclusions. To make the Fourier transform well defined, the interaction potential has to be regularised. This is illustrated by the example of dipolar interactions.

  1. Genuinely high-dimensional nonlocality optimized by complementary measurements

    NASA Astrophysics Data System (ADS)

    Lim, James; Ryu, Junghee; Yoo, Seokwon; Lee, Changhyoup; Bang, Jeongho; Lee, Jinhyoung

    2010-10-01

    Qubits exhibit extreme nonlocality when their state is maximally entangled and this is observed by mutually unbiased local measurements. This criterion does not hold for the Bell inequalities of high-dimensional systems (qudits), recently proposed by Collins-Gisin-Linden-Massar-Popescu and Son-Lee-Kim. Taking an alternative approach, called the quantum-to-classical approach, we derive a series of Bell inequalities for qudits that satisfy the criterion as for the qubits. In the derivation each d-dimensional subsystem is assumed to be measured by one of d possible measurements with d being a prime integer. By applying to two qubits (d=2), we find that a derived inequality is reduced to the Clauser-Horne-Shimony-Holt inequality when the degree of nonlocality is optimized over all the possible states and local observables. Further applying to two and three qutrits (d=3), we find Bell inequalities that are violated for the three-dimensionally entangled states but are not violated by any two-dimensionally entangled states. In other words, the inequalities discriminate three-dimensional (3D) entanglement from two-dimensional (2D) entanglement and in this sense they are genuinely 3D. In addition, for the two qutrits we give a quantitative description of the relations among the three degrees of complementarity, entanglement and nonlocality. It is shown that the degree of complementarity jumps abruptly to very close to its maximum as nonlocality starts appearing. These characteristics imply that complementarity plays a more significant role in the present inequality compared with the previously proposed inequality.

  2. Nonlocal form factors for curved-space antisymmetric fields

    NASA Astrophysics Data System (ADS)

    Netto, Tibério de Paula; Shapiro, Ilya L.

    2016-07-01

    In a recent paper, Buchbinder, Kirillova, and Pletnev presented formal arguments concerning the quantum equivalence of free massive antisymmetric tensor fields of the second and third rank to the free Proca theory and massive scalar field with minimal coupling to gravity, respectively. We confirm this result using explicit covariant calculations of nonlocal form factors based on the heart-kernel technique and discuss the discontinuity of quantum contributions in the massless limit.

  3. Structure formation in a nonlocally modified gravity model

    SciTech Connect

    Park, Sohyun; Dodelson, Scott

    2013-01-01

    We study a nonlocally modified gravity model proposed by Deser and Woodard which gives an explanation for current cosmic acceleration. By deriving and solving the equations governing the evolution of the structure in the Universe, we show that this model predicts a pattern of growth that differs from standard general relativity (+dark energy) at the 10-30% level. These differences will be easily probed by the next generation of galaxy surveys, so the model should be tested shortly.

  4. Nonlocal Intuition: Replication and Paired-subjects Enhancement Effects

    PubMed Central

    Mirzaei, Maryam; Zali, Mohammad Reza

    2014-01-01

    This article reports the results of a study of repeat entrepreneurs in Tehran, Iran, in which nonlocal intuition was investigated in a replication and extension of experiment using measures of heart rate variability (HRV). Nonlocal intuition is the perception of information about a distant or future event by the body's psychophysiological systems, which is not based on reason or memories of prior experience. This study follows up on the McCraty, Radin, and Bradley studies, which found evidence of nonlocal intuition. We used Radin's experimental protocol, with the addition of HRV measures as in the McCraty studies involving computer administration of a random sequence of calm and emotional pictures as the stimulus, and conducted two experiments on mutually exclusive samples—the first on a group of single participants (N=15) and the second on a group of co-participant pairs (N=30)—to investigate the question of the “amplification” of intuition effects by social connection. Each experiment was conducted over 45 trials while heart rate rhythm activity was recorded continuously. Results, using random permutation analysis, a statistically conservative procedure, show significant pre-stimulus results—that is, for the period before the computer had randomly selected the picture stimulus—for both experiments. Moreover, while significant separation between the emotional and calm HRV curves was observed in the single-participant experiment, an even larger separation was apparent for the experiment on co-participant pairs; the difference between the two groups was also significant. Overall, the results of the single-participant experiment confirm previous finding: that electrophysiological measures, especially changes in the heart rhythm, can detect intuitive foreknowledge. This result is notable because it constitutes cross-cultural corroboration in a non-Western context—namely, Iran. In addition, the results for co-participant pairs offer new evidence on the

  5. Maxwell-Garnett effective medium theory: Quantum nonlocal effects

    SciTech Connect

    Moradi, Afshin

    2015-04-15

    We develop the Maxwell-Garnett theory for the effective medium approximation of composite materials with metallic nanoparticles by taking into account the quantum spatial dispersion effects in dielectric response of nanoparticles. We derive a quantum nonlocal generalization of the standard Maxwell-Garnett formula, by means the linearized quantum hydrodynamic theory in conjunction with the Poisson equation as well as the appropriate additional quantum boundary conditions.

  6. Prey-predator model with a nonlocal consumption of prey.

    PubMed

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology. PMID:27586616

  7. Nonlocal Reformulations of Water and Internal Waves and Asymptotic Reductions

    NASA Astrophysics Data System (ADS)

    Ablowitz, Mark J.

    2009-09-01

    Nonlocal reformulations of the classical equations of water waves and two ideal fluids separated by a free interface, bounded above by either a rigid lid or a free surface, are obtained. The kinematic equations may be written in terms of integral equations with a free parameter. By expressing the pressure, or Bernoulli, equation in terms of the surface/interface variables, a closed system is obtained. An advantage of this formulation, referred to as the nonlocal spectral (NSP) formulation, is that the vertical component is eliminated, thus reducing the dimensionality and fixing the domain in which the equations are posed. The NSP equations and the Dirichlet-Neumann operators associated with the water wave or two-fluid equations can be related to each other and the Dirichlet-Neumann series can be obtained from the NSP equations. Important asymptotic reductions obtained from the two-fluid nonlocal system include the generalizations of the Benney-Luke and Kadomtsev-Petviashvili (KP) equations, referred to as intermediate-long wave (ILW) generalizations. These 2+1 dimensional equations possess lump type solutions. In the water wave problem high-order asymptotic series are obtained for two and three dimensional gravity-capillary solitary waves. In two dimensions, the first term in the asymptotic series is the well-known hyperbolic secant squared solution of the KdV equation; in three dimensions, the first term is the rational lump solution of the KP equation.

  8. Conformal symmetry and nonlinear extensions of nonlocal gravity

    NASA Astrophysics Data System (ADS)

    Cusin, Giulia; Foffa, Stefano; Maggiore, Michele; Mancarella, Michele

    2016-04-01

    We study two nonlinear extensions of the nonlocal R □-2R gravity theory. We extend this theory in two different ways suggested by conformal symmetry, either replacing □-2 with (-□+R /6 )-2, which is the operator that enters the action for a conformally-coupled scalar field, or replacing □-2 with the inverse of the Paneitz operator, which is a four-derivative operator that enters in the effective action induced by the conformal anomaly. We show that the former modification gives an interesting and viable cosmological model, with a dark energy equation of state today wDE≃-1.01 , which very closely mimics Λ CDM and evolves asymptotically into a de Sitter solution. The model based on the Paneitz operator seems instead excluded by the comparison with observations. We also review some issues about the causality of nonlocal theories, and we point out that these nonlocal models can be modified so to nicely interpolate between Starobinski inflation in the primordial universe and accelerated expansion in the recent epoch.

  9. Non-local crime density estimation incorporating housing information

    PubMed Central

    Woodworth, J. T.; Mohler, G. O.; Bertozzi, A. L.; Brantingham, P. J.

    2014-01-01

    Given a discrete sample of event locations, we wish to produce a probability density that models the relative probability of events occurring in a spatial domain. Standard density estimation techniques do not incorporate priors informed by spatial data. Such methods can result in assigning significant positive probability to locations where events cannot realistically occur. In particular, when modelling residential burglaries, standard density estimation can predict residential burglaries occurring where there are no residences. Incorporating the spatial data can inform the valid region for the density. When modelling very few events, additional priors can help to correctly fill in the gaps. Learning and enforcing correlation between spatial data and event data can yield better estimates from fewer events. We propose a non-local version of maximum penalized likelihood estimation based on the H1 Sobolev seminorm regularizer that computes non-local weights from spatial data to obtain more spatially accurate density estimates. We evaluate this method in application to a residential burglary dataset from San Fernando Valley with the non-local weights informed by housing data or a satellite image. PMID:25288817

  10. Ladar range image denoising by a nonlocal probability statistics algorithm

    NASA Astrophysics Data System (ADS)

    Xia, Zhi-Wei; Li, Qi; Xiong, Zhi-Peng; Wang, Qi

    2013-01-01

    According to the characteristic of range images of coherent ladar and the basis of nonlocal means (NLM), a nonlocal probability statistics (NLPS) algorithm is proposed in this paper. The difference is that NLM performs denoising using the mean of the conditional probability distribution function (PDF) while NLPS using the maximum of the marginal PDF. In the algorithm, similar blocks are found out by the operation of block matching and form a group. Pixels in the group are analyzed by probability statistics and the gray value with maximum probability is used as the estimated value of the current pixel. The simulated range images of coherent ladar with different carrier-to-noise ratio and real range image of coherent ladar with 8 gray-scales are denoised by this algorithm, and the results are compared with those of median filter, multitemplate order mean filter, NLM, median nonlocal mean filter and its incorporation of anatomical side information, and unsupervised information-theoretic adaptive filter. The range abnormality noise and Gaussian noise in range image of coherent ladar are effectively suppressed by NLPS.

  11. Image fusion via nonlocal sparse K-SVD dictionary learning.

    PubMed

    Li, Ying; Li, Fangyi; Bai, Bendu; Shen, Qiang

    2016-03-01

    Image fusion aims to merge two or more images captured via various sensors of the same scene to construct a more informative image by integrating their details. Generally, such integration is achieved through the manipulation of the representations of the images concerned. Sparse representation plays an important role in the effective description of images, offering a great potential in a variety of image processing tasks, including image fusion. Supported by sparse representation, in this paper, an approach for image fusion by the use of a novel dictionary learning scheme is proposed. The nonlocal self-similarity property of the images is exploited, not only at the stage of learning the underlying description dictionary but during the process of image fusion. In particular, the property of nonlocal self-similarity is combined with the traditional sparse dictionary. This results in an improved learned dictionary, hereafter referred to as the nonlocal sparse K-SVD dictionary (where K-SVD stands for the K times singular value decomposition that is commonly used in the literature), and abbreviated to NL_SK_SVD. The performance of the NL_SK_SVD dictionary is applied for image fusion using simultaneous orthogonal matching pursuit. The proposed approach is evaluated with different types of images, and compared with a number of alternative image fusion techniques. The resultant superior fused images using the present approach demonstrates the efficacy of the NL_SK_SVD dictionary in sparse image representation. PMID:26974648

  12. Isoperimetry and Stability Properties of Balls with Respect to Nonlocal Energies

    NASA Astrophysics Data System (ADS)

    Figalli, A.; Fusco, N.; Maggi, F.; Millot, V.; Morini, M.

    2015-05-01

    We obtain a sharp quantitative isoperimetric inequality for nonlocal s-perimeters, uniform with respect to s bounded away from 0. This allows us to address local and global minimality properties of balls with respect to the volume-constrained minimization of a free energy consisting of a nonlocal s-perimeter plus a non-local repulsive interaction term. In the particular case s = 1, the s-perimeter coincides with the classical perimeter, and our results improve the ones of Knuepfer and Muratov (Comm. Pure Appl. Math. 66(7):1129-1162, 2013; Comm. Pure Appl. Math., 2014) concerning minimality of balls of small volume in isoperimetric problems with a competition between perimeter and a nonlocal potential term. More precisely, their result is extended to its maximal range of validity concerning the type of nonlocal potentials considered, and is also generalized to the case where local perimeters are replaced by their nonlocal counterparts.

  13. Nonlocal effects: relevance for the spontaneous emission rates of quantum emitters coupled to plasmonic structures.

    PubMed

    Filter, Robert; Bösel, Christoph; Toscano, Giuseppe; Lederer, Falk; Rockstuhl, Carsten

    2014-11-01

    The spontaneous emission rate of dipole emitters close to plasmonic dimers are theoretically studied within a nonlocal hydrodynamic model. A nonlocal model has to be used since quantum emitters in the immediate environment of a metallic nanoparticle probe its electronic structure. Compared to local calculations, the emission rate is significantly reduced. The influence is mostly pronounced if the emitter is located close to sharp edges. We suggest to use quantum emitters to test nonlocal effects in experimentally feasible configurations. PMID:25361293

  14. Exact solutions of fractional Schroedinger-like equation with a nonlocal term

    SciTech Connect

    Jiang Xiaoyun; Xu Mingyu; Qi Haitao

    2011-04-15

    We study the time-space fractional Schroedinger equation with a nonlocal potential. By the method of Fourier transform and Laplace transform, the Green function, and hence the wave function, is expressed in terms of H-functions. Graphical analysis demonstrates that the influence of both the space-fractal parameter {alpha} and the nonlocal parameter {nu} on the fractional quantum system is strong. Indeed, the nonlocal potential may act similar to a fractional spatial derivative as well as fractional time derivative.

  15. The collapse and revival of Bell-nonlocality of two macroscopic fields interacting with resonant atoms

    NASA Astrophysics Data System (ADS)

    Luo, Cheng-Li; Liao, Chang-Geng; Chen, Zi-Hong

    2010-08-01

    We investigate the nonlocality dynamics of two initially entangled macroscopic fields each interacting with a resonant two-level atom. The nonlocality of macroscopic field is characterized by the extent to which the Bell Clauser-Horne-Shimony-Holt (CHSH)'s inequality for continuous-variable states is violated. We show that the collapse and revival of the Bell-nonlocality are similar to the collapse and revival of the atomic population inversion of the Jaynes-Cummings model (JCM).

  16. Onto resolving spurious wave reflection problem with changing nonlocality among various length scales

    NASA Astrophysics Data System (ADS)

    Rahman, R.; Foster, J. T.

    2016-05-01

    In this work an effective method was proposed in order to resolve the wave reflection problems between local/nonlocal models as well as multiple nonlocal models with varying nonlocality. Spurious wave reflection has been a primary concern in developing a robust multiscale-multiresolution model. In the current work a power-law based nonlocal peridynamic model has been proposed in order to mitigate this issue in a versatile manner. The fractional power-law eliminates the spurious wave reflection at the interfaces between local/nonlocal regions or regions with different nonlocalities. By controlling the exponent of the power-law it is possible to vary the frequency components of short or long waves without requiring a large handshake region. Using this underlying idea, 1 | x - x‧/| 1 + α, ∀ 0 < α < 2 can be used as a kernel function in order to define nonlocal interaction between x and x‧. It was shown that by controlling α it is possible to change the nature of nonlocal interaction within any given cutoff range. Besides power law, Gaussian kernel is another good choice in minimizing the wave reflection issue. However, Gaussian function has some limitations with large variation in nonlocality or waves with higher frequency. In that context the proposed model demonstrated its effectiveness by removing any spurious wave reflections originated in various cases.

  17. Free vibrations analysis of carbon nanotubes resting on Winkler foundations based on nonlocal models

    NASA Astrophysics Data System (ADS)

    Rahmanian, M.; Torkaman-Asadi, M. A.; Firouz-Abadi, R. D.; Kouchakzadeh, M. A.

    2016-03-01

    In the present study, free vibrations of single walled carbon nanotubes (SWCNT) on an elastic foundation is investigated by nonlocal theory of elasticity with both beam and shell models. The nonlocal boundary conditions are derived explicitly and effectiveness of nonlocal parameter appearing in nonlocal boundary conditions is studied. Also it is demonstrated that the beam model is comparatively incapable of capturing size effects while shell model captures size effects more precisely. Moreover, the effects of some parameters such as mechanical properties, foundation stiffness, length and radius ratios on the natural frequencies are studied and some conclusions are drawn.

  18. Nonlocal Magnetoresistance Mediated by Spin Superfluidity

    NASA Astrophysics Data System (ADS)

    Takei, So; Tserkovnyak, Yaroslav

    2015-10-01

    The electrical response of two diffusive metals is studied when they are linked by a magnetic insulator hosting a topologically stable (superfluid) spin current. We discuss how charge currents in the metals induce a spin supercurrent state, which in turn generates a magnetoresistance that depends on the topology of the electrical circuit. This magnetoresistance relies on phase coherence over the entire magnet and gives direct evidence for spin superfluidity. We show that driving the magnet with an ac current allows coherent spin transport even in the presence of U(1)-breaking magnetic anisotropy that can preclude dc superfluid transport. Spin transmission in the ac regime shows a series of resonance peaks as a function of frequency. The peak locations, heights, and widths can be used to extract static interfacial properties, e.g., the spin-mixing conductance and effective spin Hall angle, and to probe dynamic properties such as the spin-wave dispersion. Thus, ac transport may provide a simpler route to realizing nonequilbrium coherent spin transport and a useful way to characterize the magnetic system, serving as a precursor to the realization of dc superfluid spin transport.

  19. Phase multistability in a dynamical small world network.

    PubMed

    Shabunin, A V

    2015-01-01

    The effect of phase multistability is explored in a small world network of periodic oscillators with diffusive couplings. The structure of the network represents a ring with additional non-local links, which spontaneously arise and vanish between arbitrary nodes. The dynamics of random couplings is modeled by "birth" and "death" stochastic processes by means of the cellular automate approach. The evolution of the network under gradual increasing of the number of random couplings goes through stages of phases fluctuations and spatial cluster formation. Finally, in the presence of non-local couplings the phase multistability "dies" and only the in-phase regime survives. PMID:25637920

  20. Phase multistability in a dynamical small world network

    SciTech Connect

    Shabunin, A. V.

    2015-01-15

    The effect of phase multistability is explored in a small world network of periodic oscillators with diffusive couplings. The structure of the network represents a ring with additional non-local links, which spontaneously arise and vanish between arbitrary nodes. The dynamics of random couplings is modeled by “birth” and “death” stochastic processes by means of the cellular automate approach. The evolution of the network under gradual increasing of the number of random couplings goes through stages of phases fluctuations and spatial cluster formation. Finally, in the presence of non-local couplings the phase multistability “dies” and only the in-phase regime survives.

  1. Nonlocal contour dynamics model for chemical front motion

    NASA Astrophysics Data System (ADS)

    Petrich, Dean M.; Goldstein, Raymond E.

    1994-02-01

    Pattern formation exhibited by a two-dimensional reaction-diffusion system in the fast inhibitor limit is considered for the point of view of interface motion. A dissipative nonlocal equation of motion for the boundary between high and low concentrations of the slow species is derived heuristically. Under these dynamics, a compact domain of high concentration may develop into a space-filling labyrinthine structure in which nearby fronts repel. Similar patterns have been observed recently by Lee, McCormick, Ouyang, and Swinney in a reacting chemical system.

  2. Cosmological observations in non-local F( R) cosmology

    NASA Astrophysics Data System (ADS)

    Farajollahi, H.; Tayebi, F.; Milani, F.; Enayati, M.

    2012-02-01

    In this article in a generalization of our previous work (Farajollahi and Milani in Mod. Phys. Lett. A 25:2349-2362, 2010), we investigate the dynamics of the non-local F( R) gravity after casting it into local form. The non-singular bouncing behavior and quintom model of dark energy are achieved without involving negative kinetic energy fields. Two cosmological tests are performed to constrain the model parameters. In case of phantom crossing the distance modulus predicted by the model best-fits the observational data. In comparison with the CPL parametrization for drift velocity, the model in some redshift intervals is in good agreement with the data.

  3. Teleportation capability, distillability, and nonlocality on three-qubit states

    SciTech Connect

    Lee, Soojoon; Joo, Jaewoo; Kim, Jaewan

    2007-07-15

    In this paper, we consider teleportation capability, distillability, and nonlocality on three-qubit states. In order to investigate some relations among them, we first find the explicit formulas of the quantities about the maximal teleportation fidelity on three-qubit states. We show that if any three-qubit state is useful for three-qubit teleportation then the three-qubit state is distillable into a Greenberger-Horne-Zeilinger state, and that if any three-qubit state violates a specific form of Mermin inequality then the three-qubit state is useful for three-qubit teleportation.

  4. Apparatus independence in proofs of non-locality

    NASA Astrophysics Data System (ADS)

    Arntzenius, Frank

    1992-12-01

    In standard proofs of non-locality in quantum mechanics assumptions regarding the statistical independence of the states of the measuring apparatuses are made. Recently, proofs by A. Elby [1], and by R. Clifton, M. Redhead, and J. Butterfield [2,3] have been put forward in which it is claimed that such assumptions are not needed. In this paper I argue that Elby's proof and the first proof of Clifton, Redhead, and Butterfield are fallacious, and that their second proof, though valid, does make assumptions regarding the statistical independence of apparatus states. I further argue that any valid proof must make assumptions regarding the probabilities of apparatus states.

  5. Local energy transfer and nonlocal interactions in homogeneous, isotropic turbulence

    NASA Technical Reports Server (NTRS)

    Domaradzki, J. Andrzej; Rogallo, Robert S.

    1990-01-01

    Detailed computations were made of energy transfer among the scales of motion in incompressible turbulent fields at low Reynolds numbers, generated by direct numerical simulations. It was observed that, although the transfer resulted from triad interactions that were nonlocal in k space, the energy always transferred locally. The energy transfer calculated from the eddy-damped quasi-normal Markovian (EDQNM) theory of turbulence at low Reynolds numbers is in excellent agreement with the results of the numerical simulations. At high Reynolds numbers, the EDQNM theory predicts the same transfer mechanism in the inertial range that is observed at low Reynolds numbers.

  6. Gas-discharge plasma sources for nonlocal plasma technology

    SciTech Connect

    Demidov, V. I.; DeJoseph, C. A. Jr.; Simonov, V. Ya.

    2007-11-12

    Nonlocal plasma technology is based on the effect of self-trapping of fast electrons in the plasma volume [V. I. Demidov, C. A. DeJoseph, Jr., and A. A. Kudryavtsev, Phys. Rev. Lett. 95, 215002 (2006)]. This effect can be achieved by changing the ratio of fast electron flux to ion flux incident on the plasma boundaries. This in turn leads to a significant change in plasma properties and therefore can be useful for technological applications. A gas-discharge device which demonstrates control of the plasma properties by this method is described.

  7. Testing Hardy's nonlocality proof with genuine energy-time entanglement

    SciTech Connect

    Vallone, Giuseppe; Gianani, Ilaria; Inostroza, Enrique B.; Saavedra, Carlos; Lima, Gustavo; Cabello, Adan; Mataloni, Paolo

    2011-04-15

    We show two experimental realizations of Hardy's ladder test of quantum nonlocality using energy-time correlated photons, following the scheme proposed by Cabello et al.[Phys. Rev. Lett. 102, 040401 (2009)]. Unlike previous energy-time Bell experiments, these tests require precisely tailored nonmaximally entangled states. One of them is equivalent to the two-setting and two-outcome Bell test requiring a minimum detection efficiency. The reported experiments are still affected by the locality and detection loopholes, but are free of the post-selection loophole of previous energy-time and time-bin Bell tests.

  8. Planar laser-driven ablation model for nonlocalized absorption

    SciTech Connect

    Dahmani, F.; Kerdja, T. )

    1991-05-01

    A model for planar laser-driven ablation is presented. Nonlocalized inverse bremsstrahlung absorption of laser energy at a density {ital n}{sub 1}{lt}{ital n}{sub {ital c}} is assumed. A steady-state solution in the conduction zone is joined to a rarefaction wave in the underdense plasma. The calculations relate all steady-state fluid quantities to only the material, absorbed intensity, and laser wavelength. The theory agrees well with results from a computer hydrodynamics code MEDUSA (Comput. Phys. Commun. {bold 7}, 271 (1974)) and experiments.

  9. Local and nonlocal thermopower in three-terminal nanostructures

    NASA Astrophysics Data System (ADS)

    Michałek, G.; Urbaniak, M.; Bułka, B. R.; Domański, T.; Wysokiński, K. I.

    2016-06-01

    The thermoelectric effects in three-terminal structures with a quantum dot are considered. We propose the experimentally consistent protocol for determination of the transport coefficients in terms of the local and nonlocal conductances and thermopowers that can be measured in two steps, applying the "four-probe technique". This proposal is compared with other approaches discussed in the literature. As an example, we study in detail the thermopower induced by the superconducting electrode in a subgap regime which might be useful for analysis of novel hybrid devices.

  10. Entanglement-based signature of nonlocal dispersion cancellation

    SciTech Connect

    Wasak, Tomasz; Szankowski, Piotr; Wasilewski, Wojciech; Banaszek, Konrad

    2010-11-15

    We derive an inequality bounding the strength of temporal correlations for a pair of light beams prepared in a separable state and propagating through dispersive media with opposite signs of group-velocity dispersion. The presented inequality can be violated by entangled states of light, such as photon pairs produced in spontaneous parametric down-conversion. Because the class of separable states covers the entire category of classical fields as a particular case, this result provides an unambiguously quantum feature of nonlocal dispersion cancellation that cannot be reproduced within the classical theory of electromagnetic radiation.

  11. Residual entanglement of accelerated fermions is not nonlocal

    SciTech Connect

    Friis, Nicolai; Koehler, Philipp; Bertlmann, Reinhold A.; Martin-Martinez, Eduardo

    2011-12-15

    We analyze the operational meaning of the residual entanglement in noninertial fermionic systems in terms of the achievable violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality. We demonstrate that the quantum correlations of fermions, which were previously found to survive in the infinite acceleration limit, cannot be considered to be nonlocal. The entanglement shared by an inertial and an accelerated observer cannot be utilized for the violation of the CHSH inequality in case of high accelerations. Our results are shown to extend beyond the single-mode approximation commonly used in the literature.

  12. Nonlocal microscopic theory of Casimir forces at finite temperature

    SciTech Connect

    Despoja, V.; Marusic, L.

    2011-04-15

    The interaction energy between two metallic slabs in the retarded limit at finite temperature is expressed in terms of surface polariton propagators for separate slabs, avoiding the usual matching procedure, with both diamagnetic and paramagnetic excitations included correctly. This enables appropriate treatment of arbitrary electron density profiles and fully nonlocal electronic response, including both collective and single-particle excitations. The results are verified by performing the nonretarded and long-wavelength (local) limits and showing that they reduce to the previously obtained expressions. Possibilities for practical use of the theory are explored by applying it to calculation of various contributions to the Casimir energy between two silver slabs.

  13. The philosophical implications of quantum non-locality

    NASA Astrophysics Data System (ADS)

    Jeffries, Paul Christopher

    2000-07-01

    The overarching metaphysics encompassing almost all of science incorporates notions readily recognizable as basic intuitions, such as the separability of nature into parts, and a causal architecture necessitating that influences going from one place to another transit every point in between. Astonishingly, developments in quantum mechanics have all but proven this metaphysics false. An overview of Bell's Theorem sets the stage for a discussion of the philosophical significance of quantum non-locality. An account of the overarching metaphysics of Western science explicates why the violation of the Bell Inequalities is so astonishing, drawing particular attention to the historical and metaphysical issues surrounding action-at-a-distance, and the demands for causal continuity and a finite propagation speed for causal influences. The Chapter Three exegesis of the Einstein-Podolsky-Rosen (EPR) argument contends that a modified version of their ``reality criterion'' side-steps the impression that the argument only goes through under an overly strong realist position, but the truly surprising story underlying the EPR correlations-unforeseen by Einstein and Bohr-comes in the next chapter's examination of Jon P. Jarrett's analysis of non-locality into two composite conditions associated with Einstein's underlying metaphysical principles. This in turn leads to a deeper analysis of the philosophical basis for Einstein's resistance to quantum mechanics. Having seen that a range of ordinary causal and common- cause explanations for the EPR correlations are excluded or burdened with untoward implications, Chapter Seven proposes an information-theoretic analysis of the holistic connection exhibited in quantum phenomena, helping us to better understand in what way constraints on relational holism are responsible for the world appearing to be causally classical. These constraints lead to ``local locality'': the apparent manifestation of a local causal structure when the domain is

  14. Using nonlocal means to separate cardiac and respiration sounds

    NASA Astrophysics Data System (ADS)

    Rudnitskii, A. G.

    2014-11-01

    The paper presents the results of applying nonlocal means (NLMs) approach in the problem of separating respiration and cardiac sounds in a signal recorded on a human chest wall. The performance of the algorithm was tested both by simulated and real signals. As a quantitative efficiency measure of NLM filtration, the angle of divergence between isolated and reference signal was used. It is shown that for a wide range of signal-to-noise ratios, the algorithm makes it possible to efficiently solve this problem of separating cardiac and respiration sounds in the sum signal recorded on a human chest wall.

  15. Strong nonlocal interaction stabilizes cavity solitons with a varying size plateau

    NASA Astrophysics Data System (ADS)

    Fernandez-Oto, Cristian; Tlidi, Mustapha; Escaff, Daniel; Clerc, Marcel; Kockaert, Pascal

    2014-05-01

    Cavity solitons are localized light peaks in the transverse section of nonlinear resonators. These structures are usually formed under a coexistence condition between a homogeneous background of radiation and a self- organized patterns resulting from a Turing type of instabilities. In this issue, most of studies have been realized ignoring the nonlocal effects. Non-local effects can play an important role in the formation of cavity solitons in optics, population dynamics and plant ecology. Depending on the choice of the nonlocal interaction function, the nonlocal coupling can be strong or weak. When the nonlocal coupling is strong, the interaction between fronts is controlled by the whole non-local interaction function. Recently it has shown that this type of nonlocal coupling strongly affects the dynamics of fronts connecting two homogeneous steady states and leads to the stabilization of cavity solitons with a varying size plateau. Here, we consider a ring passive cavity filled with a Kerr medium like a liquid crystal or left-handed materials and driven by a coherent injected beam. We show that cavity solitons resulting for strong front interaction are stable in one and two-dimensional setting out of any type of Turing instability. Their spatial profile is characterized by a varying size plateau. Our results can apply to large class of spatially extended systems with strong nonlocal coupling.

  16. Existence and uniqueness of steady state solutions of a nonlocal diffusive logistic equation

    NASA Astrophysics Data System (ADS)

    Sun, Linan; Shi, Junping; Wang, Yuwen

    2013-08-01

    In this paper, we consider a dynamical model of population biology which is of the classical Fisher type, but the competition interaction between individuals is nonlocal. The existence, uniqueness, and stability of the steady state solution of the nonlocal problem on a bounded interval with homogeneous Dirichlet boundary conditions are studied.

  17. a New Nonlocal Beam Theory with Thickness Stretching Effect for Nanobeams

    NASA Astrophysics Data System (ADS)

    Tounsi, Abdelouahed; Benguediab, Soumia; Houari, Mohammed Sid Ahmed; Semmah, Abdelwahed

    2013-08-01

    This paper presents a new nonlocal thickness-stretching sinusoidal shear deformation beam theory for the static and vibration of nanobeams. The present model incorporates the length scale parameter (nonlocal parameter) which can capture the small scale effect, and it accounts for both shear deformation and thickness stretching effects by a sinusoidal variation of all displacements through the thickness without using shear correction factor. Based on the nonlocal differential constitutive relations of Eringen, the equations of motion of the nanobeam are derived using Hamilton's principle. The effects of nonlocal parameter, aspect ratio and the thickness stretching on the static and dynamic responses of the nanobeam are discussed. The theoretical development presented herein may serve as a reference for nonlocal theories as applied to the bending and dynamic behaviors of complex-nanobeam-system such as complex carbon nanotube system.

  18. Detecting nonlocality of noisy multipartite states with the Clauser-Horne-Shimony-Holt inequality

    NASA Astrophysics Data System (ADS)

    Chaves, Rafael; Acín, Antonio; Aolita, Leandro; Cavalcanti, Daniel

    2014-04-01

    The Clauser-Horne-Shimony-Holt inequality was originally proposed as a Bell inequality to detect nonlocality in bipartite systems. However, it can also be used to certify the nonlocality of multipartite quantum states. We apply this to study the nonlocality of multipartite Greenberger-Horne-Zeilinger (GHZ), W, and graph states under local decoherence processes. We derive lower bounds on the critical local-noise strength tolerated by the states before becoming local. In addition, for the whole noisy dynamics, we derive lower bounds on the corresponding nonlocal content for the three classes of states. All the bounds presented can be calculated efficiently and, in some cases, provide significantly tighter estimates than with any other known method. For example, they reveal that N -qubit GHZ states undergoing local dephasing are, for all N , nonlocal throughout all the dephasing dynamics.

  19. Shear deformable deformation of carbon nanotubes based on a new analytical nonlocal Timoshenko beam nodel

    SciTech Connect

    Zhang, Jianming; Yang, Yang

    2015-03-10

    According to Hamilton’s principle, a new mathematical model and analytical solutions for nonlocal Timoshenko beam model (ANT) is established based on nonlocal elastic continuum theory when shear deformation and nonlocal effect are considered. The new ANT equilibrium equations and boundary conditions are derived for bending analysis of carbon nanotubes (CNTs) with simply supported, clamped and cantilever. The ANT deflection solutions demonstrate that the CNT stiffness is enhanced by the presence of nonlocal stress effects. Furthermore, the new ANT model concluded verifiable bending behaviors for a cantilever CNT with point load at the free end, which depends on the strength of nonlocal stress. Therefore, this new model will gives a better prediction for mechanical behaviors of nanostructures.

  20. A nonlocal, ordinary, state-based plasticity model for peridynamics.

    SciTech Connect

    Mitchell, John Anthony

    2011-05-01

    An implicit time integration algorithm for a non-local, state-based, peridynamics plasticity model is developed. The flow rule was proposed in [3] without an integration strategy or yield criterion. This report addresses both of these issues and thus establishes the first ordinary, state-based peridynamics plasticity model. Integration of the flow rule follows along the lines of the classical theories of rate independent J{sub 2} plasticity. It uses elastic force state relations, an additive decomposition of the deformation state, an elastic force state domain, a flow rule, loading/un-loading conditions, and a consistency condition. Just as in local theories of plasticity (LTP), state variables are required. It is shown that the resulting constitutive model does not violate the 2nd law of thermodynamics. The report also develops a useful non-local yield criterion that depends upon the yield stress and horizon for the material. The modulus state for both the ordinary elastic material and aforementioned plasticity model is also developed and presented.

  1. Nonlocal Drag of Magnons in a Ferromagnetic Bilayer.

    PubMed

    Liu, Tianyu; Vignale, G; Flatté, Michael E

    2016-06-10

    Quantized spin waves, or magnons, in a magnetic insulator are assumed to interact weakly with the surroundings, and to flow with little dissipation or drag, producing exceptionally long diffusion lengths and relaxation times. In analogy to Coulomb drag in bilayer two-dimensional electron gases, in which the contribution of the Coulomb interaction to the electric resistivity is studied by measuring the interlayer resistivity (transresistivity), we predict a nonlocal drag of magnons in a ferromagnetic bilayer structure based on semiclassical Boltzmann equations. Nonlocal magnon drag depends on magnetic dipolar interactions between the layers and manifests in the magnon current transresistivity and the magnon thermal transresistivity, whereby a magnon current in one layer induces a chemical potential gradient and/or a temperature gradient in the other layer. The largest drag effect occurs when the magnon current flows parallel to the magnetization; however, for oblique magnon currents a large transverse current of magnons emerges. We examine the effect for practical parameters, and find that the predicted induced temperature gradient is readily observable. PMID:27341254

  2. The Importance of Nonlocal Terms in Superfluid Turbulence

    NASA Astrophysics Data System (ADS)

    Zieve, Rena; Dix, Owen

    2015-03-01

    Simulations of vortex motion in superfluid helium based on the Biot-Savart law plus vortex reconnections can model homogeneous superfluid turbulence. However, the quantitative properties of the turbulent tangle are disturbingly sensitive to details of how the computations are carried out, and in some cases the tangle degenerates unphysically into an arrangement of parallel straight vortices. These problems have been attributed to the reconnection procedure, to the periodic boundary conditions used for most calculations, and to the localized induction approximation (LIA) which often replaces the (non-local) Biot-Savart integral. Previous work using numerical calculation of the complete Biot-Savart integral does not show the same issues as the LIA calculations, but these are time-consuming calculations. We show here that numerical integration over a relatively small region can suffice, as long as the size of the region exceeds the typical intervortex spacing. This result explains why the non-local contribution has a strong effect. It contributes an attraction between nearby vortices that ultimately leads to reconnections, which prevent the vortices from settling into an array of parallel lines.

  3. Nonlocal Drag of Magnons in a Ferromagnetic Bilayer

    NASA Astrophysics Data System (ADS)

    Liu, Tianyu; Vignale, G.; Flatté, Michael E.

    2016-06-01

    Quantized spin waves, or magnons, in a magnetic insulator are assumed to interact weakly with the surroundings, and to flow with little dissipation or drag, producing exceptionally long diffusion lengths and relaxation times. In analogy to Coulomb drag in bilayer two-dimensional electron gases, in which the contribution of the Coulomb interaction to the electric resistivity is studied by measuring the interlayer resistivity (transresistivity), we predict a nonlocal drag of magnons in a ferromagnetic bilayer structure based on semiclassical Boltzmann equations. Nonlocal magnon drag depends on magnetic dipolar interactions between the layers and manifests in the magnon current transresistivity and the magnon thermal transresistivity, whereby a magnon current in one layer induces a chemical potential gradient and/or a temperature gradient in the other layer. The largest drag effect occurs when the magnon current flows parallel to the magnetization; however, for oblique magnon currents a large transverse current of magnons emerges. We examine the effect for practical parameters, and find that the predicted induced temperature gradient is readily observable.

  4. Screening of Cosmological Constant in Non-Local Cosmology

    NASA Astrophysics Data System (ADS)

    Zhang, Ying-Li; Sasaki, Misao

    We consider a model of non-local gravity with a large bare cosmological constant, Λ, and study its cosmological solutions. The model is characterized by a function f(ψ) = f0eαψ, where ψ = □-1R and α is a real dimensionless parameter. In the absence of matter, we find an expanding universe solution a ∝ tn with n < 1, that is, a universe with decelerated expansion without any fine-tuning of the parameter. Thus the effect of the cosmological constant is effectively shielded in this solution. It has been known that solutions in non-local gravity often suffer from the existence of ghost modes. In the present case, we find the solution is ghost-free if α > αcr ≈ 0.17. This is quite a weak condition. We argue that the solution is stable against the inclusion of matter fields. Thus our solution opens up new possibilities for solution to the cosmological constant problem.

  5. Nonlocal transport of passive scalars in turbulent penetrative convection

    PubMed

    Miesch; Brandenburg; Zweibel

    2000-01-01

    We present a Green's function approach for quantifying the transport of a passive scalar (tracer) field in three-dimensional simulations of turbulent convection. Nonlocal, nondiffusive behavior is described by a transilient matrix (the discretized Green's function), whose elements contain the fractional tracer concentrations moving from one subvolume to another as a function of time. The approach was originally developed for and applied to geophysical flows, but here we extend the formalism and apply it in an astrophysical context to three-dimensional simulations of turbulent compressible convection with overshoot into convectively stable bounding regions. We introduce a novel technique to compute this matrix in a single simulation by advecting labeled particles rather than solving the passive scalar equation for a large number of different initial conditions. The transilient matrices thus computed are used as a diagnostic tool to quantitatively describe nonlocal transport via matrix moments and transport coefficients in a generalized, multiorder diffusion equation. Results indicate that transport in both the vertical and horizontal directions is strongly influenced by the presence of coherent velocity structures, generally resembling ballistic advection more than diffusion. The transport of a small fraction of tracer particles deep into the underlying stable region is reasonably efficient, a result which has possible implications for the problem of light-element depletion in late-type stars. PMID:11046285

  6. Nonlocal hyperconcentration on entangled photons using photonic module system

    NASA Astrophysics Data System (ADS)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen; Zhang, Ru; Wang, Chuan

    2016-06-01

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  7. Retro-causation, Minimum Contradictions and Non-locality

    NASA Astrophysics Data System (ADS)

    Kafatos, Menas; Nassikas, Athanassios A.

    2011-11-01

    Retro-causation has been experimentally verified by Bem and proposed by Kafatos in the form of space-time non-locality in the quantum framework. Every theory includes, beyond its specific axioms, the principles of logical communication (logical language), through which it is defined. This communication obeys the Aristotelian logic (Classical Logic), the Leibniz Sufficient Reason Principle, and a hidden axiom, which basically states that there is anterior-posterior relationship everywhere in communication. By means of a theorem discussed here, it can be proved that the communication mentioned implies contradictory statements, which can only be transcended through silence, i.e. the absence of any statements. Moreover, the breaking of silence is meaningful through the claim for minimum contradictions, which implies the existence of both a logical and an illogical dimension; contradictions refer to causality, implying its opposite, namely retro-causation, and the anterior posterior axiom, implying space-time non-locality. The purpose of this paper is to outline a framework accounting for retro-causation, through both purely theoretical and reality based points of view.

  8. Notes on nonlocal projective measurements in relativistic systems

    SciTech Connect

    Lin, Shih-Yuin

    2014-12-15

    In quantum mechanical bipartite systems, naive extensions of von Neumann’s projective measurement to nonlocal variables can produce superluminal signals and thus violate causality. We analyze the projective quantum nondemolition state-verification in a two-spin system and see how the projection introduces nonlocality without entanglement. For the ideal measurements of “R-nonlocal” variables, we argue that causality violation can be resolved by introducing further restrictions on the post-measurement states, which makes the measurement “Q-nonlocal”. After we generalize these ideas to quantum mechanical harmonic oscillators, we look into the projective measurements of the particle number of a single mode or a wave-packet of a relativistic quantum field in Minkowski space. It turns out that the causality-violating terms in the expectation values of the local operators, generated either by the ideal measurement of the “R-nonlocal” variable or the quantum nondemolition verification of a Fock state, are all suppressed by the IR and UV cutoffs of the theory. Thus relativistic quantum field theories with such projective measurements are effectively causal.

  9. Kondo physics in non-local metallic spin transport devices

    NASA Astrophysics Data System (ADS)

    O'Brien, L.; Erickson, M. J.; Spivak, D.; Ambaye, H.; Goyette, R. J.; Lauter, V.; Crowell, P. A.; Leighton, C.

    2014-05-01

    The non-local spin-valve is pivotal in spintronics, enabling separation of charge and spin currents, disruptive potential applications and the study of pressing problems in the physics of spin injection and relaxation. Primary among these problems is the perplexing non-monotonicity in the temperature-dependent spin accumulation in non-local ferromagnetic/non-magnetic metal structures, where the spin signal decreases at low temperatures. Here we show that this effect is strongly correlated with the ability of the ferromagnetic to form dilute local magnetic moments in the NM. This we achieve by studying a significantly expanded range of ferromagnetic/non-magnetic combinations. We argue that local moments, formed by ferromagnetic/non-magnetic interdiffusion, suppress the injected spin polarization and diffusion length via a manifestation of the Kondo effect, thus explaining all observations. We further show that this suppression can be completely quenched, even at interfaces that are highly susceptible to the effect, by insertion of a thin non-moment-supporting interlayer.

  10. Kondo physics in non-local metallic spin transport devices.

    PubMed

    O'Brien, L; Erickson, M J; Spivak, D; Ambaye, H; Goyette, R J; Lauter, V; Crowell, P A; Leighton, C

    2014-01-01

    The non-local spin-valve is pivotal in spintronics, enabling separation of charge and spin currents, disruptive potential applications and the study of pressing problems in the physics of spin injection and relaxation. Primary among these problems is the perplexing non-monotonicity in the temperature-dependent spin accumulation in non-local ferromagnetic/non-magnetic metal structures, where the spin signal decreases at low temperatures. Here we show that this effect is strongly correlated with the ability of the ferromagnetic to form dilute local magnetic moments in the NM. This we achieve by studying a significantly expanded range of ferromagnetic/non-magnetic combinations. We argue that local moments, formed by ferromagnetic/non-magnetic interdiffusion, suppress the injected spin polarization and diffusion length via a manifestation of the Kondo effect, thus explaining all observations. We further show that this suppression can be completely quenched, even at interfaces that are highly susceptible to the effect, by insertion of a thin non-moment-supporting interlayer. PMID:24873934

  11. Mixed noise removal by weighted encoding with sparse nonlocal regularization.

    PubMed

    Jiang, Jielin; Zhang, Lei; Yang, Jian

    2014-06-01

    Mixed noise removal from natural images is a challenging task since the noise distribution usually does not have a parametric model and has a heavy tail. One typical kind of mixed noise is additive white Gaussian noise (AWGN) coupled with impulse noise (IN). Many mixed noise removal methods are detection based methods. They first detect the locations of IN pixels and then remove the mixed noise. However, such methods tend to generate many artifacts when the mixed noise is strong. In this paper, we propose a simple yet effective method, namely weighted encoding with sparse nonlocal regularization (WESNR), for mixed noise removal. In WESNR, there is not an explicit step of impulse pixel detection; instead, soft impulse pixel detection via weighted encoding is used to deal with IN and AWGN simultaneously. Meanwhile, the image sparsity prior and nonlocal self-similarity prior are integrated into a regularization term and introduced into the variational encoding framework. Experimental results show that the proposed WESNR method achieves leading mixed noise removal performance in terms of both quantitative measures and visual quality. PMID:24760906

  12. Nonlocalized clustering: a new concept in nuclear cluster structure physics.

    PubMed

    Zhou, Bo; Funaki, Y; Horiuchi, H; Ren, Zhongzhou; Röpke, G; Schuck, P; Tohsaki, A; Xu, Chang; Yamada, T

    2013-06-28

    We investigate the α+^{16}O cluster structure in the inversion-doublet band (Kπ=0(1)±}) states of 20Ne with an angular-momentum-projected version of the Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function, which was successful "in its original form" for the description of, e.g., the famous Hoyle state. In contrast with the traditional view on clusters as localized objects, especially in inversion doublets, we find that these single THSR wave functions, which are based on the concept of nonlocalized clustering, can well describe the Kπ=0(1)- band and the Kπ=0(1)+ band. For instance, they have 99.98% and 99.87% squared overlaps for 1- and 3- states (99.29%, 98.79%, and 97.75% for 0+, 2+, and 4+ states), respectively, with the corresponding exact solution of the α+16O resonating group method. These astounding results shed a completely new light on the physics of low energy nuclear cluster states in nuclei: The clusters are nonlocalized and move around in the whole nuclear volume, only avoiding mutual overlap due to the Pauli blocking effect. PMID:23848866

  13. Nonlocal matching condition and scale-invariant spectrum in bouncing cosmology

    SciTech Connect

    Chu, C.-S.; Furuta, K.; Lin, F.-L.

    2006-05-15

    In cosmological scenarios such as the pre-big bang scenario or the ekpyrotic scenario, a matching condition between the metric perturbations in the pre-big bang phase and those in the post big bang phase is often assumed. Various matching conditions have been considered in the literature. Nevertheless obtaining a scale-invariant CMB spectrum via a concrete mechanism remains impossible. In this paper, we examine this problem from the point of view of local causality. We begin with introducing the notion of local causality and explain how it constrains the form of the matching condition. We then prove a no-go theorem: independent of the details of the matching condition, a scale-invariant spectrum is impossible as long as the local causality condition is satisfied. In our framework, it is easy to show that a violation of local causality around the bounce is needed in order to give a scale-invariant spectrum. We study a specific scenario of this possibility by considering a nonlocal effective theory inspired by noncommutative geometry around the bounce and show that a scale-invariant spectrum is possible. Moreover we demonstrate that the magnitude of the spectrum is compatible with observations if the bounce is assumed to occur at an energy scale which is a few orders of magnitude below the Planckian energy scale.

  14. Thermal evolution of hybrid stars within the framework of a nonlocal Nambu-Jona-Lasinio model

    NASA Astrophysics Data System (ADS)

    de Carvalho, S. M.; Negreiros, R.; Orsaria, M.; Contrera, G. A.; Weber, F.; Spinella, W.

    2015-09-01

    We study the thermal evolution of neutron stars containing deconfined quark matter in their core. Such objects are generally referred to as quark-hybrid stars. The confined hadronic matter in their core is described in the framework of nonlinear relativistic nuclear field theory. For the quark phase we use a nonlocal extension of the SU(3) Nambu-Jona-Lasinio model with vector interactions. The Gibbs condition is used to model phase equilibrium between confined hadronic matter and deconfined quark matter. Our study indicates that high-mass neutron stars may contain between 35 and 40% deconfined quark-hybrid matter in their cores. Neutron stars with canonical masses of around 1.4 M⊙ would not contain deconfined quark matter. The central proton fractions of the stars are found to be high, enabling them to cool rapidly. Very good agreement with the temperature evolution established for the neutron star in Cassiopeia A (Cas A) is obtained for one of our models (based on the popular NL3 nuclear parametrization), if the protons in the core of our stellar models are strongly paired, the repulsion among the quarks is mildly repulsive, and the mass of Cas A has a canonical value of 1.4 M⊙ .

  15. Temporal control in rats: analysis of nonlocalized effects from short interfood intervals.

    PubMed Central

    Higa, J J; Pierson, D

    1998-01-01

    The present experiment analyzed temporal control of postreinforcement pause duration during within-session changes in the criterion for reinforcement (interfood interval, IFI). Analysis of interval-by-interval changes in the pause revealed localized and nonlocalized effects from short intervals that caused specific changes in performance. In Phase 1, rats were presented with five consecutive 15-s IFIs intercalated into a series of 60-s IFIs. The 15-s set decreased the pause in adjacent and more remote 60-s intervals. In Phase 2, two sets of 15-s intervals were intercalated. The spacing between the two sets varied so that 0, 5, 10, or 15 60-s IFIs separated the sets. The postreinforcement pause tracked all changes in the IFI duration, and the localized effect from a short set extended beyond the next interval to the next few 60-s IFIs. Effects from one set, however, did not combine with a second set: Changes in the pause after two sets were the same regardless of the spacing between sets. PMID:9684344

  16. Nonlocal collisionless and collisional electron transport in low temperature plasmas

    NASA Astrophysics Data System (ADS)

    Kaganovich, Igor

    2009-10-01

    The purpose of the talk is to describe recent advances in nonlocal electron kinetics in low-pressure plasmas. A distinctive property of partially ionized plasmas is that such plasmas are always in a non-equilibrium state: the electrons are not in thermal equilibrium with the neutral species and ions, and the electrons are also not in thermodynamic equilibrium within their own ensemble, which results in a significant departure of the electron velocity distribution function from a Maxwellian. These non-equilibrium conditions provide considerable freedom to choose optimal plasma parameters for applications, which make gas discharge plasmas remarkable tools for a variety of plasma applications, including plasma processing, discharge lighting, plasma propulsion, particle beam sources, and nanotechnology. Typical phenomena in such discharges include nonlocal electron kinetics, nonlocal electrodynamics with collisionless electron heating, and nonlinear processes in the sheaths and in the bounded plasmas. Significant progress in understanding the interaction of electromagnetic fields with real bounded plasma created by this field and the resulting changes in the structure of the applied electromagnetic field has been one of the major achievements of the last decade in this area of research [1-3]. We show on specific examples that this progress was made possible by synergy between full scale particle-in-cell simulations, analytical models, and experiments. In collaboration with Y. Raitses, A.V. Khrabrov, Princeton Plasma Physics Laboratory, Princeton, NJ, USA; V.I. Demidov, UES, Inc., 4401 Dayton-Xenia Rd., Beavercreek, OH 45322, USA and AFRL, Wright-Patterson AFB, OH 45433, USA; and D. Sydorenko, University of Alberta, Edmonton, Canada. [4pt] [1] D. Sydorenko, A. Smolyakov, I. Kaganovich, and Y. Raitses, IEEE Trans. Plasma Science 34, 895 (2006); Phys. Plasmas 13, 014501 (2006); 14 013508 (2007); 15, 053506 (2008). [0pt] [2] I. D. Kaganovich, Y. Raitses, D. Sydorenko, and

  17. Analytical solutions of nonlocal Poisson dielectric models with multiple point charges inside a dielectric sphere.

    PubMed

    Xie, Dexuan; Volkmer, Hans W; Ying, Jinyong

    2016-04-01

    The nonlocal dielectric approach has led to new models and solvers for predicting electrostatics of proteins (or other biomolecules), but how to validate and compare them remains a challenge. To promote such a study, in this paper, two typical nonlocal dielectric models are revisited. Their analytical solutions are then found in the expressions of simple series for a dielectric sphere containing any number of point charges. As a special case, the analytical solution of the corresponding Poisson dielectric model is also derived in simple series, which significantly improves the well known Kirkwood's double series expansion. Furthermore, a convolution of one nonlocal dielectric solution with a commonly used nonlocal kernel function is obtained, along with the reaction parts of these local and nonlocal solutions. To turn these new series solutions into a valuable research tool, they are programed as a free fortran software package, which can input point charge data directly from a protein data bank file. Consequently, different validation tests can be quickly done on different proteins. Finally, a test example for a protein with 488 atomic charges is reported to demonstrate the differences between the local and nonlocal models as well as the importance of using the reaction parts to develop local and nonlocal dielectric solvers. PMID:27176425

  18. Analytical solutions of nonlocal Poisson dielectric models with multiple point charges inside a dielectric sphere

    NASA Astrophysics Data System (ADS)

    Xie, Dexuan; Volkmer, Hans W.; Ying, Jinyong

    2016-04-01

    The nonlocal dielectric approach has led to new models and solvers for predicting electrostatics of proteins (or other biomolecules), but how to validate and compare them remains a challenge. To promote such a study, in this paper, two typical nonlocal dielectric models are revisited. Their analytical solutions are then found in the expressions of simple series for a dielectric sphere containing any number of point charges. As a special case, the analytical solution of the corresponding Poisson dielectric model is also derived in simple series, which significantly improves the well known Kirkwood's double series expansion. Furthermore, a convolution of one nonlocal dielectric solution with a commonly used nonlocal kernel function is obtained, along with the reaction parts of these local and nonlocal solutions. To turn these new series solutions into a valuable research tool, they are programed as a free fortran software package, which can input point charge data directly from a protein data bank file. Consequently, different validation tests can be quickly done on different proteins. Finally, a test example for a protein with 488 atomic charges is reported to demonstrate the differences between the local and nonlocal models as well as the importance of using the reaction parts to develop local and nonlocal dielectric solvers.

  19. Observational tests of nonlocal gravity: Galaxy rotation curves and clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Rahvar, S.; Mashhoon, B.

    2014-05-01

    A classical nonlocal generalization of Einstein's theory of gravitation has recently been developed via the introduction of a scalar causal "constitutive" kernel that must ultimately be determined from observational data. It turns out that the nonlocal aspect of gravity in this theory can simulate dark matter; indeed, in the Newtonian regime of nonlocal gravity, we recover the phenomenological Tohline-Kuhn approach to modified gravity. A simple generalization of the Kuhn kernel in the context of nonlocal general relativity leads to a two-parameter modified Newtonian force law that involves an additional repulsive Yukawa-type interaction. We determine the parameters of our nonlocal kernel by comparing the predictions of the theory with observational data regarding the rotation curves of spiral galaxies. The best-fitting stellar mass-to-light ratio turns out to be in agreement with astrophysical models; moreover, our results are consistent with the Tully-Fisher relation for spiral galaxies. Light deflection in nonlocal gravity is consistent with general relativity at solar-system scales, while beyond galactic scales, an enhanced deflection angle is predicted that is compatible with lensing by the effective "dark matter." Furthermore, we extend our results to the internal dynamics of rich clusters of galaxies and show that the dynamical mass of the cluster obtained from nonlocal gravity is consistent with the measured baryonic mass.

  20. Non-Local Means Filter for Polarimetric SAR Speckle Reduction-Experiments Using Terrasar-X Data

    NASA Astrophysics Data System (ADS)

    Hu, J.; Guo, R.; Zhu, X.; Baier, G.; Wang, Y.

    2015-03-01

    The speckle is omnipresent in synthetic aperture radar (SAR) images as an intrinsic characteristic. However, it is unwanted in certain applications. Therefore, intelligent filters for speckle reduction are of great importance. It has been demonstrated in several literatures that the non-local means filter can reduce noise while preserving details. This paper discusses non-local means filter for polarimetric SAR (PolSAR) speckle reduction. The impact of different similarity approaches, weight kernels, and parameters in the filter were analysed. A data-driven adaptive weight kernel was proposed. Combined with different similarity measures, it is compared with existing algorithms, using fully polarimetric TerraSAR-X data acquired during the commissioning phase. The proposed approach has overall the best performance in terms of speckle reduction, detail preservation, and polarimetric information preservation. This study suggests the high potential of using the developed non- local means filer for speckle reduction of PolSAR data acquired by the next generation SAR missions, e.g. TanDEM-L and TerraSAR-X NG.

  1. Towards a more accurate microscopic description of the moving contact line problem - incorporating nonlocal effects through a statistical mechanics framework

    NASA Astrophysics Data System (ADS)

    Nold, Andreas; Goddard, Ben; Sibley, David; Kalliadasis, Serafim

    2014-03-01

    Multiscale effects play a predominant role in wetting phenomena such as the moving contact line. An accurate description is of paramount interest for a wide range of industrial applications, yet it is a matter of ongoing research, due to the difficulty of incorporating different physical effects in one model. Important small-scale phenomena are corrections to the attractive fluid-fluid and wall-fluid forces in inhomogeneous density distributions, which often previously have been accounted for by the disjoining pressure in an ad-hoc manner. We systematically derive a novel model for the description of a single-component liquid-vapor multiphase system which inherently incorporates these nonlocal effects. This derivation, which is inspired by statistical mechanics in the framework of colloidal density functional theory, is critically discussed with respect to its assumptions and restrictions. The model is then employed numerically to study a moving contact line of a liquid fluid displacing its vapor phase. We show how nonlocal physical effects are inherently incorporated by the model and describe how classical macroscopic results for the contact line motion are retrieved. We acknowledge financial support from ERC Advanced Grant No. 247031 and Imperial College through a DTG International Studentship.

  2. A nonlocal electron conduction model for multidimensional radiation hydrodynamics codes

    NASA Astrophysics Data System (ADS)

    Schurtz, G. P.; Nicolaï, Ph. D.; Busquet, M.

    2000-10-01

    Numerical simulation of laser driven Inertial Confinement Fusion (ICF) related experiments require the use of large multidimensional hydro codes. Though these codes include detailed physics for numerous phenomena, they deal poorly with electron conduction, which is the leading energy transport mechanism of these systems. Electron heat flow is known, since the work of Luciani, Mora, and Virmont (LMV) [Phys. Rev. Lett. 51, 1664 (1983)], to be a nonlocal process, which the local Spitzer-Harm theory, even flux limited, is unable to account for. The present work aims at extending the original formula of LMV to two or three dimensions of space. This multidimensional extension leads to an equivalent transport equation suitable for easy implementation in a two-dimensional radiation-hydrodynamic code. Simulations are presented and compared to Fokker-Planck simulations in one and two dimensions of space.

  3. A scalable quantum architecture using efficient non-local gates

    NASA Astrophysics Data System (ADS)

    Brennen, Gavin

    2003-03-01

    Many protocols for quantum information processing use a control sequence or circuit of interactions between qubits and control fields wherein arbitrary qubits can be made to interact with one another. The primary problem with many ``physically scalable" architectures is that the qubits are restricted to nearest neighbor interactions and quantum wires between distant qubits do not exist. Because of errors, nearest neighbor interactions often present difficulty with scalability. We describe a protocol that efficiently performs non-local gates between elements of separated static logical qubits using a bus of dynamic qubits as a refreshable entanglement resource. Imperfect resource preparation due to error propagation from noisy gates and measurement errors can purified within the bus channel. Because of the inherent parallelism of entanglement swapping, communication latency within the quantum computer can be significantly reduced.

  4. Nonlocal resonances in weak turbulence of gravity-capillary waves.

    PubMed

    Aubourg, Quentin; Mordant, Nicolas

    2015-04-10

    We report a laboratory investigation of weak turbulence of water surface waves in the gravity-capillary crossover. By using time-space-resolved profilometry and a bicoherence analysis, we observe that the nonlinear processes involve three-wave resonant interactions. By studying the solutions of the resonance conditions, we show that the nonlinear interaction is dominantly one dimensional and involves collinear wave vectors. Furthermore, taking into account the spectral widening due to weak nonlinearity explains why nonlocal interactions are possible between a gravity wave and high-frequency capillary ones. We observe also that nonlinear three-wave coupling is possible among gravity waves, and we raise the question of the relevance of this mechanism for oceanic waves. PMID:25910127

  5. Strong connections between quantum encodings, nonlocality, and quantum cryptography

    NASA Astrophysics Data System (ADS)

    Sikora, Jamie; Chailloux, André; Kerenidis, Iordanis

    2014-02-01

    Encoding information in quantum systems can offer surprising advantages but at the same time there are limitations that arise from the fact that measuring an observable may disturb the state of the quantum system. In our work, we provide an in-depth analysis of a simple question: What happens when we perform two measurements sequentially on the same quantum system? This question touches upon some fundamental properties of quantum mechanics, namely the uncertainty principle and the complementarity of quantum measurements. Our results have interesting consequences, for example, they can provide a simple proof of the optimal quantum strategy in the famous Clauser-Horne-Shimony-Holt game. Moreover, we show that the way information is encoded in quantum systems can provide a different perspective in understanding other fundamental aspects of quantum information, like nonlocality and quantum cryptography. We prove some strong equivalences between these notions and provide a number of applications in all areas.

  6. Large N matrices from a nonlocal spin system

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; Hartnoll, Sean A.; Huijse, Liza; Martin, Victoria L.

    2015-10-01

    Large N matrices underpin the best understood models of emergent spacetime. We suggest that large N matrices can themselves be emergent from simple quantum mechanical spin models with finite dimensional Hilbert spaces. We exhibit the emergence of large N matrices in a nonlocal statistical physics model of order N2 Ising spins. The spin partition function is shown to admit a large N saddle described by a matrix integral, which we solve. The matrix saddle is dominant at high temperatures, metastable at intermediate temperatures and ceases to exist below a critical order one temperature. The matrix saddle is disordered in a sense we make precise and competes with ordered low energy states. We verify our analytic results by Monte Carlo simulation of the spin system.

  7. Electron viscosity, current vortices and negative nonlocal resistance in graphene

    NASA Astrophysics Data System (ADS)

    Levitov, Leonid; Falkovich, Gregory

    2016-07-01

    Quantum-critical strongly correlated electron systems are predicted to feature universal collision-dominated transport resembling that of viscous fluids. However, investigation of these phenomena has been hampered by the lack of known macroscopic signatures of electron viscosity. Here we identify vorticity as such a signature and link it with a readily verifiable striking macroscopic d.c. transport behaviour. Produced by the viscous flow, vorticity can drive electric current against an applied field, resulting in a negative nonlocal voltage. We argue that the latter may play the same role for the viscous regime as zero electrical resistance does for superconductivity. Besides offering a diagnostic that distinguishes viscous transport from ohmic currents, the sign-changing electrical response affords a robust tool for directly measuring the viscosity-to-resistivity ratio. A strongly interacting electron-hole plasma in high-mobility graphene affords a unique link between quantum-critical electron transport and the wealth of fluid mechanics phenomena.

  8. Non-local mind from the perspective of social cognition

    PubMed Central

    Chatel-Goldman, Jonas; Schwartz, Jean-Luc; Jutten, Christian; Congedo, Marco

    2012-01-01

    Two main conceptual approaches have been employed to study the mechanisms of social cognition, whether one considers isolated or interacting minds. Using neuro-imaging of subjects in isolation, the former approach has provided knowledge on the neural underpinning of a variety of social processes. However, it has been argued that considering one brain alone cannot account for all mechanisms subtending online social interaction. This challenge has been tackled recently by using neuro-imaging of multiple interacting subjects in more ecological settings. The present short review aims at offering a comprehensive view on various advances done in the last decade. We provide a taxonomy of existing research in neuroscience of social interaction, situating them in the frame of general organization principles of social cognition. Finally, we discuss the putative enabling role of emerging non-local social mechanisms—such as interpersonal brain and body coupling—in processes underlying our ability to create a shared world. PMID:23565084

  9. Non-local mind from the perspective of social cognition.

    PubMed

    Chatel-Goldman, Jonas; Schwartz, Jean-Luc; Jutten, Christian; Congedo, Marco

    2013-01-01

    Two main conceptual approaches have been employed to study the mechanisms of social cognition, whether one considers isolated or interacting minds. Using neuro-imaging of subjects in isolation, the former approach has provided knowledge on the neural underpinning of a variety of social processes. However, it has been argued that considering one brain alone cannot account for all mechanisms subtending online social interaction. This challenge has been tackled recently by using neuro-imaging of multiple interacting subjects in more ecological settings. The present short review aims at offering a comprehensive view on various advances done in the last decade. We provide a taxonomy of existing research in neuroscience of social interaction, situating them in the frame of general organization principles of social cognition. Finally, we discuss the putative enabling role of emerging non-local social mechanisms-such as interpersonal brain and body coupling-in processes underlying our ability to create a shared world. PMID:23565084

  10. Ladder proof of nonlocality without inequalities and without probabilities

    NASA Astrophysics Data System (ADS)

    Cabello, Adán

    1998-09-01

    The ladder proof of nonlocality without inequalities for two spin-12 particles proposed by Hardy [in New Developments on Fundamental Problems in Quantum Physics, edited by M. Ferrero and A. van der Merwe (Kluwer, Dordrecht, 1997)] and Hardy and co-workers [Phys. Rev. Lett. 79, 2755 (1997)] works only for nonmaximally entangled states and goes through for 50% of pairs at the most. A similar ladder proof for two spin-1 particles in a maximally entangled state is presented. In its simplest form, the proof goes through for 17% of pairs. An extended version works for 100% of pairs. The proof can be extended to any maximally entangled state of two spin-s particles (with s>=1).

  11. Nonlocalized receptivity of boundary layers to three-dimensional disturbances

    NASA Astrophysics Data System (ADS)

    Crouch, J. D.; Bertolotti, F. P.

    1992-01-01

    The nonlocalized receptivity of the Blasius boundary layer over a wavy surface is analyzed using two different approaches. First, a mode-interaction theory is employed to unveil basic mechanisms and to explore the interplay between different components of the disturbance field. The second approach is derived from the parabolized stability equations. These nonlinear equations incorporate the effects of the stream-wise divergence of the boundary layer. The analysis provides results for three-dimensional disturbances and also considers nonparallel effects. Results for two-dimensional disturbances demonstrate that nonparallel effects are negligible and substantiates the mechanism described by the mode-interaction theory. Nonparallel effects become significant with increasing three-dimensionality. Receptivity amplitudes are shown to be large over a broad range of surface wave numbers. When operative, this mechanism is likely to dominate the boundary-layer receptivity.

  12. Image deblurring based structural graph and nonlocal similarity regularization

    NASA Astrophysics Data System (ADS)

    Jiang, Fangfang; Chen, Huahua; Ye, Xueyi

    2013-07-01

    The distribution of image data points forms its geometrical structure. This structure characterizes the local variation, and provides valuable heuristics to the regularization of image restoration process. However, most of the existing approaches to sparse coding fail to consider this character of the image. In this paper, we address the deblurring problem of image restoration. We analyze the distribution of the input data points. Inspired by the theory of manifold learning algorithm, we build a k-NN graph to character the geometrical structure of the data, so the local manifold structure of the data can be explicitly taken into account. To enforce the invariance constraint, we introduce a patch-similarity based term into the cost function which penalizes the nonlocal invariance of the image. Experimental results have shown the effectiveness of the proposed scheme.

  13. Entanglement-based quantum communication secured by nonlocal dispersion cancellation

    NASA Astrophysics Data System (ADS)

    Lee, Catherine; Zhang, Zheshen; Steinbrecher, Gregory R.; Zhou, Hongchao; Mower, Jacob; Zhong, Tian; Wang, Ligong; Hu, Xiaolong; Horansky, Robert D.; Verma, Varun B.; Lita, Adriana E.; Mirin, Richard P.; Marsili, Francesco; Shaw, Matthew D.; Nam, Sae Woo; Wornell, Gregory W.; Wong, Franco N. C.; Shapiro, Jeffrey H.; Englund, Dirk

    2014-12-01

    Quantum key distribution (QKD) enables participants to exchange secret information over long distances with unconditional security. However, the performance of today's QKD systems is subject to hardware limitations, such as those of available nonclassical-light sources and single-photon detectors. By encoding photons in high-dimensional states, the rate of generating secure information under these technical constraints can be maximized. Here, we demonstrate a complete time-energy entanglement-based QKD system with proven security against the broad class of arbitrary collective attacks. The security of the system is based on nonlocal dispersion cancellation between two time-energy entangled photons. This resource-efficient QKD system is implemented at telecommunications wavelength, is suitable for optical fiber and free-space links, and is compatible with wavelength-division multiplexing.

  14. Nonlocal correlations induced by Hund's coupling: A cluster DMFT study

    NASA Astrophysics Data System (ADS)

    Nomura, Yusuke; Sakai, Shiro; Arita, Ryotaro

    2015-06-01

    We study spatial correlation effects in multiorbital systems, especially in a paramagnetic metallic state subject to Hund's coupling. We apply a cluster extension of the dynamical mean-field theory (DMFT) to the three-orbital Hubbard model away from half filling, where previous single-site DMFT studies revealed that local correlation effects caused by Hund's coupling bring about unusual strongly correlated metallic behaviors. We find that Hund's coupling significantly affects the nonlocal correlations too; it strongly modulates the electron distribution in the momentum space so as to make a momentum region almost half filled and hence strongly correlated. It leads to an anomalous electronic state distinct both from the Fermi liquid and the Mott insulator. We identify the mechanism of the anomalous state with the intersite ferromagnetic correlations induced by Hund's coupling.

  15. Inflationary magnetogenesis and non-local actions: the conformal anomaly

    NASA Astrophysics Data System (ADS)

    Kamal El-Menoufi, Basem

    2016-02-01

    We discuss the possibility of successful magnetogenesis during inflation by employing the one-loop effective action of massless QED. The action is strictly non-local and results from the long distance fluctuations of massless charged particles present at the inflationary scale. Most importantly, it encodes the conformal anomaly of QED which is crucial to avoid the vacuum preservation in classical electromagnetism. In particular, we find a blue spectrum for the magnetic field with spectral index nB simeq 2 - αe where αe depends on both the number of e-folds during inflation as well as the coefficient of the one-loop beta function. In particular, the sign of the beta function has important bearing on the final result. A low reheating temperature is required for the present day magnetic field to be consistent with the lower bound inferred on the field in the intergalactic medium.

  16. Stable and transient multicluster oscillation death in nonlocally coupled networks

    NASA Astrophysics Data System (ADS)

    Schneider, Isabelle; Kapeller, Marie; Loos, Sarah; Zakharova, Anna; Fiedler, Bernold; Schöll, Eckehard

    2015-11-01

    In a network of nonlocally coupled Stuart-Landau oscillators with symmetry-breaking coupling, we study numerically, and explain analytically, a family of inhomogeneous steady states (oscillation death). They exhibit multicluster patterns, depending on the cluster distribution prescribed by the initial conditions. Besides stable oscillation death, we also find a regime of long transients asymptotically approaching synchronized oscillations. To explain these phenomena analytically in dependence on the coupling range and the coupling strength, we first use a mean-field approximation, which works well for large coupling ranges but fails for coupling ranges, which are small compared to the cluster size. Going beyond standard mean-field theory, we predict the boundaries of the different stability regimes as well as the transient times analytically in excellent agreement with numerical results.

  17. Quantum nonlocality of four-qubit entangled states

    SciTech Connect

    Wu, Chunfeng; Yeo, Ye; Oh, C. H.; Kwek, L. C.

    2007-03-15

    We derive a Bell inequality for testing violation of local realism. Quantum nonlocality of several four-qubit states is investigated. These include the Greenberger-Zeilinger-Horne (GHZ) state, W state, linear cluster state, and the state |{chi}> that has recently been proposed in [Phys. Rev. Lett. 96, 060502 (2006)]. The Bell inequality is optimally violated by |{chi}> but not violated by the GHZ state. The linear cluster state also violates the Bell inequality though not optimally. The state |{chi}> can thus be discriminated from the linear cluster state by using the inequality. Different aspects of four-partite entanglement are also studied by considering the usefulness of a family of four-qubit mixed states as resources for two-qubit teleportation. Our results generalize those in [Phys. Rev. Lett. 72, 797 (1994)].

  18. Nonlocal memory effects allow perfect teleportation with mixed states

    PubMed Central

    Laine, Elsi-Mari; Breuer, Heinz-Peter; Piilo, Jyrki

    2014-01-01

    One of the most striking consequences of quantum physics is quantum teleportation – the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of nonlocal memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks. PMID:24714695

  19. Two-player conflicting interest Bayesian games and Bell nonlocality

    NASA Astrophysics Data System (ADS)

    Situ, Haozhen

    2016-01-01

    Nonlocality, one of the most remarkable aspects of quantum mechanics, is closely related to Bayesian game theory. Quantum mechanics can offer advantages to some Bayesian games, if the payoff functions are related to Bell inequalities in some way, most of these Bayesian games that have been discussed are common interest games. Recently, the first conflicting interest Bayesian game is proposed in Phys. Rev. Lett. 114, 020401 (2015). In the present paper, we present three new conflicting interest Bayesian games where quantum mechanics offers advantages. The first game is linked with Cereceda inequalities, the second game is linked with a generalized Bell inequality with three possible measurement outcomes, and the third game is linked with a generalized Bell inequality with three possible measurement settings.

  20. Nonlocal analysis of finite-beam-driven instabilities

    NASA Technical Reports Server (NTRS)

    Serizawa, Y.; Dum, C. T.

    1992-01-01

    The fully kinetic integral eigenmode equation in wave-number space is used to describe the nonlocal behavior of electrostatic waves in an electron-beam plasma, which are studied in the low-temperature-beam regime and the warm-beam regime. The case of strongly magnetized electrons and unmagnetized ions, which corresponds to the waves in a frequency range from the lower-hybrid to the electron plasma frequency, is examined. Three wave modes are found. The first group consists of modes that have dispersive properties similar to the uniform, infinite beam-plasma system. Depending on the beam width, the growth rates are strongly reduced. The second group, surface modes, are localized at the periphery of the beam region and are less unstable than the unstable modes of the first group. The third group represents natural oscillations of the background plasma. These modes are virtually unaffected by the beam.

  1. Nonlocal entanglement of coherent states, complementarity, and quantum erasure

    SciTech Connect

    Gerry, Christopher C.; Grobe, R.

    2007-03-15

    We describe a nonlocal method for generating entangled coherent states of a two-mode field wherein the field modes never meet. The proposed method is an extension of an earlier proposal [C. C. Gerry, Phys. Rev. A 59, 4095 (1999)] for the generation of superpositions of coherent states. A single photon injected into a Mach-Zehnder interferometer with cross-Kerr media in both arms coupling with two external fields in coherent states produces entangled coherent states upon detection at one of the output ports. We point out that our proposal can be alternatively viewed as a 'which path' experiment, and in the case of only one external field, we describe the implementation of a quantum eraser.

  2. Detection of nonlocal atomic entanglement assisted by single photons

    NASA Astrophysics Data System (ADS)

    Zhou, Lan; Sheng, Yu-Bo

    2014-08-01

    We present an efficient way for measuring the entanglement of atoms. The concurrence of atomic entanglement can be obtained according to the probability of picking up the singlet states of the atoms. In this protocol, we require the phenomenon of optical Faraday rotation, but the entangled atoms do not need to be in contact with each other and the atomic entanglement can be distributed nonlocally. Moreover, our way of measuring the concurrence for atoms can also be suitable for other solid systems, such as quantum dots inside microcavities and the nitrogen-vacancy (N-V) defect centers in diamonds, which can also induce the optical Faraday rotation. All these advantages provide important applications in future distributed quantum computations.

  3. Nonlocal memory effects allow perfect teleportation with mixed states.

    PubMed

    Laine, Elsi-Mari; Breuer, Heinz-Peter; Piilo, Jyrki

    2014-01-01

    One of the most striking consequences of quantum physics is quantum teleportation - the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of nonlocal memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks. PMID:24714695

  4. Nonlocal means SAR image despeckling using Principle Neighborhood Dictionaries

    NASA Astrophysics Data System (ADS)

    Zhong, Hua; Yang, Chen; Jiao, L. C.

    2011-11-01

    The Principle Neighborhood Dictionary (PND) filter projects the image patches onto a lower dimensional subspace using Principle Component analysis (PCA), based on which the similarity measure of image patch can be computed with a higher accuracy for the nonlocal means (NLM) algorithm. In this paper, a new PND filter for synthetic aperture radar (SAR) image despeckling is presented, in which a new distance that adapts to the multiplicative speckle noise is derived. Compared with the commonly used Euclidean distance in NLM, the new distance measure improves the accuracy of the similarity measure of speckled patches in SAR images. The proposed method is validated on simulated and real SAR images through comparisons with other classical despeckling methods.

  5. Z-scan for thin media with more than one nonlocal nonlinear response.

    PubMed

    Irivas, B A Martinez; Carrasco, M L Arroyo; Otero, M M Mendez; García, R Ramos; Castillo, M D Iturbe

    2016-06-13

    A model to characterize the response of a thin media that can exhibit more than one nonlocal nonlinear response when it is illuminated with a Gaussian beam in a z-scan experiment is proposed. The model considers that these nonlocal contributions can be treated as independent contributions in the refractive or absorptive nonlinear response. Numerical results for two nonlocal nonlinear contributions with different magnitudes between them are presented. Experimental results obtained from a hydrogenated amorphous silicon sample are used to corroborate this model. PMID:27410356

  6. A note on the nonlocal boundary value problem for a third order partial differential equation

    NASA Astrophysics Data System (ADS)

    Belakroum, Kheireddine; Ashyralyev, Allaberen; Guezane-Lakoud, Assia

    2016-08-01

    The nonlocal boundary-value problem for a third order partial differential equation d/3u (t ) d t3 +A d/u (t ) d t =f (t ), 0 nonlocal boundary value problem is established. In applications, the stability estimates for the solution of three nonlocal boundary value problems for the third order partial differential equations are obtained.

  7. Simple Explanation of the Quantum Limits of Genuine n-Body Nonlocality.

    PubMed

    Cabello, Adán

    2015-06-01

    Quantum n-body correlations cannot be explained with (n-1)-body nonlocality. However, this genuine n-body nonlocality cannot surpass certain bounds. Here we address the problem of identifying the principles responsible for these bounds. We show that, for any n≥2, the exclusivity principle, as derived from axioms about sharp measurements, and a technical assumption give the exact bounds predicted by quantum theory. This provides a unified explanation of the bounds of single-body contextuality and n-body nonlocality, and connects two programs towards understanding quantum theory. PMID:26196604

  8. Simple Explanation of the Quantum Limits of Genuine n -Body Nonlocality

    NASA Astrophysics Data System (ADS)

    Cabello, Adán

    2015-06-01

    Quantum n -body correlations cannot be explained with (n -1 )-body nonlocality. However, this genuine n -body nonlocality cannot surpass certain bounds. Here we address the problem of identifying the principles responsible for these bounds. We show that, for any n ≥2 , the exclusivity principle, as derived from axioms about sharp measurements, and a technical assumption give the exact bounds predicted by quantum theory. This provides a unified explanation of the bounds of single-body contextuality and n -body nonlocality, and connects two programs towards understanding quantum theory.

  9. Genuinely Multipartite Entangled Quantum States with Fully Local Hidden Variable Models and Hidden Multipartite Nonlocality.

    PubMed

    Bowles, Joseph; Francfort, Jérémie; Fillettaz, Mathieu; Hirsch, Flavien; Brunner, Nicolas

    2016-04-01

    The relation between entanglement and nonlocality is discussed in the case of multipartite quantum systems. We show that, for any number of parties, there exist genuinely multipartite entangled states that admit a fully local hidden variable model, i.e., where all parties are separated. Hence, although these states exhibit the strongest form of multipartite entanglement, they cannot lead to Bell inequality violation considering general nonsequential local measurements. Then, we show that the nonlocality of these states can nevertheless be activated using sequences of local measurements, thus revealing genuine multipartite hidden nonlocality. PMID:27081960

  10. Eringen's small length scale coefficient for buckling of nonlocal Timoshenko beam based on microstructured beam model

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Challamel, N.; Wang, C. M.

    2013-09-01

    This paper presents the determination of Eringen's small length scale coefficient e0 for buckling of nonlocal Timoshenko beam from a microstructured beam model. The microstructured beam model is composed of discrete rigid elements (of equal length), which are connected by rotational and shear springs that model the bending and shearing behaviors in a beam. The exact solution of e0 is given for nonlocal Timoshenko beam with small length scale term appearing in the normal stress-strain relation only. It is shown that e0 approaches 1/√12 ≈0.289 which coincides with the one calibrated for nonlocal Euler beams.

  11. Alleviation of catastrophic quenching in solar dynamo model with nonlocal alpha-effect

    NASA Astrophysics Data System (ADS)

    Kitchatinov, L. L.; Olemskoy, S. V.

    2011-06-01

    The nonlocal alpha-effect of Babcock-Leighton type is not prone to the catastrophic quenching due to conservation of magnetic helicity. This is shown with a dynamo model, which jointly applies the nonlocal alpha-effect, the diamagnetic pumping, and dynamical equation for the magnetic alpha-effect. The same model shows catastrophic quenching when the alpha-effect is changed to its local formulation. The nonlocal model shows a preferred excitation of magnetic fields of dipolar symmetry, which oscillate with a period of about ten years and have a toroidal-to-polar fields ratio of about a thousand.

  12. Evidences for and the Models of Fast Nonlocal Transport of Heat in Magnetic Fusion Devices

    NASA Astrophysics Data System (ADS)

    Kukushkin, A. B.; Cherepanov, K. V.

    2009-07-01

    The paper gives a short survey of (i) recent evidences for fast nonlocal transport of the heat in magnetically confined plasmas (above all, the "cold/heat pulse" experiments), (ii) interpretations of such phenomena in terms of nonlocal transport formalisms, based on the dominance of long mean-free-path energy carriers, including the interpretations of "cold pulse" experiments, and gives (iii) quantitative evidence for the domination of nonlocality in the spatial profile of electron cyclotron net radiated power in fusion reactor-grade tokamak (strong toroidal magnetic field, BT>5 T, highly reflecting walls, Rwall>0.5, and hot electron plasma, >10 keV).

  13. Nonlocal correction to the energy-momentum tensor for φ 3 theory in six dimensions

    NASA Astrophysics Data System (ADS)

    Wu, Feng

    2015-10-01

    Applying the background field method, we construct by explicit computation the leading-order nonlocal quantum correction to the on-shell effective action for φ ^3 theory in six dimensions. We then use the resulting action to obtain the nonlocal correction to the energy-momentum tensor. At leading order, we find that this nonlocal correction modifies the virial current when the scalar field is minimally coupled to gravity. This is to be compared to the classically Weyl invariant case, where it only corrects the traceless part of the energy-momentum tensor.

  14. Optical nonlocality induced Zitterbewegung near the Dirac point in metal-dielectric multilayer metamaterials.

    PubMed

    Sun, Lei; Gao, Jie; Yang, Xiaodong

    2016-04-01

    The optical nonlocality near the Dirac point in infinite periodic metal-dielectric multilayer metamaterials is investigated through the dispersion relation analysis according to the transfer-matrix method. It is revealed that both the symmetric and asymmetric surface plasmon polariton modes present the zero nonlocal effective permittivity, and the degeneracy of these two modes results in the emergence of the Dirac point. Furthermore, the Zitterbewegung effect near the Dirac point induced by the optical nonlocality is demonstrated due to the coherent coupling between the symmetric and asymmetric modes. PMID:27136999

  15. Non-locality in quantum field theory due to general relativity

    NASA Astrophysics Data System (ADS)

    Calmet, Xavier; Croon, Djuna; Fritz, Christopher

    2015-12-01

    We show that general relativity coupled to a quantum field theory generically leads to non-local effects in the matter sector. These non-local effects can be described by non-local higher dimensional operators which remarkably have an approximate shift symmetry. When applied to inflationary models, our results imply that small non-Gaussianities are a generic feature of models based on general relativity coupled to matter fields. However, these effects are too small to be observable in the cosmic microwave background.

  16. Exact solutions and spacetime singularities in nonlocal gravity

    NASA Astrophysics Data System (ADS)

    Li, Yao-Dong; Modesto, Leonardo; Rachwał, Lesław

    2015-12-01

    We hereby study exact solutions in a wide range of local higher-derivative and weakly nonlocal gravitational theories. In particular, we give a list of exact classical solutions for two classes of gravitational theories both weakly nonlocal, unitary, and super-renormalizable (or finite) at quantum level. We prove that maximally symmetric spacetimes are exact solutions in both classes, while in dimension higher than four we can also have Anti-de Sitter solutions in the presence of positive cosmological constant. It is explicitly shown under which conditions flat and Ricci-flat spacetimes are exact solutions of the equation of motion (EOM) for the first class of theories not involving the Weyl tensor in the action. We find that the well-known physical spacetimes like Schwarzschild, Kerr, (Anti-) de Sitter serve as solutions for standard matter content, when the EOM does not contain the Riemann tensor alone (operators made out of only the Riemann tensor.) We pedagogically show how to obtain these exact solutions. Furthermore, for the second class of gravity theories, with terms in the Lagrangian written using Weyl tensors, the Friedmann-Robertson-Walker (FRW) spacetimes are also exact solutions (exactly in the same way like in Einstein theory), when the matter content is given by conformal matter (radiation). We also comment on rather inevitable presence and universality of singularities and possible resolution of them in finite and conformally invariant theories. "Delocalization" is proposed as a way to solve the black hole singularity problem in the first class. In order to solve the problem of cosmological singularities in the second class, it seems crucial to have a conformally invariant or asymptotically free quantum gravitational theory.

  17. Nonlocal Quantum Information Transfer Without Superluminal Signalling and Communication

    NASA Astrophysics Data System (ADS)

    Walleczek, Jan; Grössing, Gerhard

    2016-01-01

    It is a frequent assumption that—via superluminal information transfers—superluminal signals capable of enabling communication are necessarily exchanged in any quantum theory that posits hidden superluminal influences. However, does the presence of hidden superluminal influences automatically imply superluminal signalling and communication? The non-signalling theorem mediates the apparent conflict between quantum mechanics and the theory of special relativity. However, as a `no-go' theorem there exist two opposing interpretations of the non-signalling constraint: foundational and operational. Concerning Bell's theorem, we argue that Bell employed both interpretations, and that he finally adopted the operational position which is associated often with ontological quantum theory, e.g., de Broglie-Bohm theory. This position we refer to as "effective non-signalling". By contrast, associated with orthodox quantum mechanics is the foundational position referred to here as "axiomatic non-signalling". In search of a decisive communication-theoretic criterion for differentiating between "axiomatic" and "effective" non-signalling, we employ the operational framework offered by Shannon's mathematical theory of communication, whereby we distinguish between Shannon signals and non-Shannon signals. We find that an effective non-signalling theorem represents two sub-theorems: (1) Non-transfer-control (NTC) theorem, and (2) Non-signification-control (NSC) theorem. Employing NTC and NSC theorems, we report that effective, instead of axiomatic, non-signalling is entirely sufficient for prohibiting nonlocal communication. Effective non-signalling prevents the instantaneous, i.e., superluminal, transfer of message-encoded information through the controlled use—by a sender-receiver pair —of informationally-correlated detection events, e.g., in EPR-type experiments. An effective non-signalling theorem allows for nonlocal quantum information transfer yet—at the same time

  18. Nonlocal Heat Transport by Longitudinal/Transverse EM Waves in Magnetically Confined Plasmas and Modelling of the Observed Nonlocal Phenomena in a Tokamak

    NASA Astrophysics Data System (ADS)

    Kukushkin, A. B.

    1996-11-01

    The nonlocal transport approach is formulated, based on anomalous cross-field energy transport (ACFET) by the longitudinal/tranverse EM waves of the mean free path of the order and much larger than plasma characteristic size and, correspondingly, on integral equation in space variables. Self-consistency of this approach is shown in interpreting those observed phenomena of nonlocality whose interpretation in "local", diffusion-like approaches gives instant jumps of thermal diffusivities in a large part of plasma volume. The modelling is carried out of the initial stage of recently observed phenomena of fast nonlocal energy transport: (i) net inward flux of energy during off-axis heating (vs. ECRH experiments on D-III-D); (ii) prompt rise of temperature in the core in "cold pulse" experiments (fast cooling of the periphery) on TEXT and TFTR; (iii) fast "volumetric" response of energy transport to plasma edge behavior during L-H transitions (in JET and JT-60U). The results suggest (a) universal and transparent physical explanation of the mechanism of nonlocal inward energy flux, which is lost in diffusion-like approaches, and (b) necessity to append existing numerical codes with nonlocal transport term, an integral in space variables.

  19. Probing the structural and dynamical properties of liquid water with models including non-local electron correlation

    NASA Astrophysics Data System (ADS)

    Del Ben, Mauro; Hutter, Jürg; VandeVondele, Joost

    2015-08-01

    Water is a ubiquitous liquid that displays a wide range of anomalous properties and has a delicate structure that challenges experiment and simulation alike. The various intermolecular interactions that play an important role, such as repulsion, polarization, hydrogen bonding, and van der Waals interactions, are often difficult to reproduce faithfully in atomistic models. Here, electronic structure theories including all these interactions at equal footing, which requires the inclusion of non-local electron correlation, are used to describe structure and dynamics of bulk liquid water. Isobaric-isothermal (NpT) ensemble simulations based on the Random Phase Approximation (RPA) yield excellent density (0.994 g/ml) and fair radial distribution functions, while various other density functional approximations produce scattered results (0.8-1.2 g/ml). Molecular dynamics simulation in the microcanonical (NVE) ensemble based on Møller-Plesset perturbation theory (MP2) yields dynamical properties in the condensed phase, namely, the infrared spectrum and diffusion constant. At the MP2 and RPA levels of theory, ice is correctly predicted to float on water, resolving one of the anomalies as resulting from a delicate balance between van der Waals and hydrogen bonding interactions. For several properties, obtaining quantitative agreement with experiment requires correction for nuclear quantum effects (NQEs), highlighting their importance, for structure, dynamics, and electronic properties. A computed NQE shift of 0.6 eV for the band gap and absorption spectrum illustrates the latter. Giving access to both structure and dynamics of condensed phase systems, non-local electron correlation will increasingly be used to study systems where weak interactions are of paramount importance.

  20. Probing the structural and dynamical properties of liquid water with models including non-local electron correlation.

    PubMed

    Del Ben, Mauro; Hutter, Jürg; VandeVondele, Joost

    2015-08-01

    Water is a ubiquitous liquid that displays a wide range of anomalous properties and has a delicate structure that challenges experiment and simulation alike. The various intermolecular interactions that play an important role, such as repulsion, polarization, hydrogen bonding, and van der Waals interactions, are often difficult to reproduce faithfully in atomistic models. Here, electronic structure theories including all these interactions at equal footing, which requires the inclusion of non-local electron correlation, are used to describe structure and dynamics of bulk liquid water. Isobaric-isothermal (NpT) ensemble simulations based on the Random Phase Approximation (RPA) yield excellent density (0.994 g/ml) and fair radial distribution functions, while various other density functional approximations produce scattered results (0.8-1.2 g/ml). Molecular dynamics simulation in the microcanonical (NVE) ensemble based on Møller-Plesset perturbation theory (MP2) yields dynamical properties in the condensed phase, namely, the infrared spectrum and diffusion constant. At the MP2 and RPA levels of theory, ice is correctly predicted to float on water, resolving one of the anomalies as resulting from a delicate balance between van der Waals and hydrogen bonding interactions. For several properties, obtaining quantitative agreement with experiment requires correction for nuclear quantum effects (NQEs), highlighting their importance, for structure, dynamics, and electronic properties. A computed NQE shift of 0.6 eV for the band gap and absorption spectrum illustrates the latter. Giving access to both structure and dynamics of condensed phase systems, non-local electron correlation will increasingly be used to study systems where weak interactions are of paramount importance. PMID:26254660

  1. Probing the structural and dynamical properties of liquid water with models including non-local electron correlation

    SciTech Connect

    Del Ben, Mauro Hutter, Jürg; VandeVondele, Joost

    2015-08-07

    Water is a ubiquitous liquid that displays a wide range of anomalous properties and has a delicate structure that challenges experiment and simulation alike. The various intermolecular interactions that play an important role, such as repulsion, polarization, hydrogen bonding, and van der Waals interactions, are often difficult to reproduce faithfully in atomistic models. Here, electronic structure theories including all these interactions at equal footing, which requires the inclusion of non-local electron correlation, are used to describe structure and dynamics of bulk liquid water. Isobaric-isothermal (NpT) ensemble simulations based on the Random Phase Approximation (RPA) yield excellent density (0.994 g/ml) and fair radial distribution functions, while various other density functional approximations produce scattered results (0.8-1.2 g/ml). Molecular dynamics simulation in the microcanonical (NVE) ensemble based on Møller-Plesset perturbation theory (MP2) yields dynamical properties in the condensed phase, namely, the infrared spectrum and diffusion constant. At the MP2 and RPA levels of theory, ice is correctly predicted to float on water, resolving one of the anomalies as resulting from a delicate balance between van der Waals and hydrogen bonding interactions. For several properties, obtaining quantitative agreement with experiment requires correction for nuclear quantum effects (NQEs), highlighting their importance, for structure, dynamics, and electronic properties. A computed NQE shift of 0.6 eV for the band gap and absorption spectrum illustrates the latter. Giving access to both structure and dynamics of condensed phase systems, non-local electron correlation will increasingly be used to study systems where weak interactions are of paramount importance.

  2. Effect of noise and enhancement of nonlocality in on/off photodetection

    SciTech Connect

    Invernizzi, Carmen; Olivares, Stefano; Paris, Matteo G.A.; Banaszek, Konrad

    2005-10-15

    Nonlocality of two-mode states of light is addressed by means of Clauser-Horne-Shimony-Holt (CHSH) inequality based on displaced on/off photodetection. Effects due to nonunit quantum efficiency and nonzero dark counts are taken into account. Nonlocality of both balanced and unbalanced superpositions of few photon-number states, as well as that of multiphoton twin beams, is investigated. We find that unbalanced superpositions show larger nonlocality than balanced ones when noise affects the photodetection process. De-Gaussification by means of (inconclusive) photon subtraction is shown to enhance nonlocality of twin beams in the low-energy regime. We also show that when the measurement is described by a positive operator-valued measure, rather than a set of projectors, the maximum achievable value of the Bell parameter in the CHSH inequality is decreased, and is no longer given by the Cirel'son bound.

  3. On the interplay between neoclassical tearing modes and nonlocal transport in toroidal plasmas.

    PubMed

    Ji, X Q; Xu, Y; Hidalgo, C; Diamond, P H; Liu, Yi; Pan, O; Shi, Z B; Yu, D L

    2016-01-01

    This Letter presents the first observation on the interplay between nonlocal transport and neoclassical tearing modes (NTMs) during transient nonlocal heat transport events in the HL-2A tokamak. The nonlocality is triggered by edge cooling and large-scale, inward propagating avalanches. These lead to a locally enhanced pressure gradient at the q = 3/2 (or 2/1) rational surface and hence the onset of the NTM in relatively low β plasmas (βN < 1). The NTM, in return, regulates the nonlocal transport by truncation of avalanches by local sheared toroidal flows which develop near the magnetic island. These findings have direct implications for understanding the dynamic interaction between turbulence and large-scale mode structures in fusion plasmas. PMID:27595773

  4. Nonlocality threshold for entanglement under general dephasing evolutions: a case study

    NASA Astrophysics Data System (ADS)

    Lo Franco, Rosario

    2016-06-01

    Determining relationships between different types of quantum correlations in open composite quantum systems is important since it enables the exploitation of a type by knowing the amount of another type. We here review, by giving a formal demonstration, a closed formula of the Bell function, witnessing nonlocality, as a function of the concurrence, quantifying entanglement, valid for a system of two noninteracting qubits initially prepared in extended Werner-like states undergoing any local pure-dephasing evolution. This formula allows for finding nonlocality thresholds for the concurrence depending only on the purity of the initial state. We then utilize these thresholds in a paradigmatic system where the two qubits are locally affected by a quantum environment with an Ohmic class spectrum. We show that steady entanglement can be achieved and provide the lower bound of initial state purity such that this stationary entanglement is above the nonlocality threshold thus guaranteeing the maintenance of nonlocal correlations.

  5. A New Method for Nonlocal Means Image Denoising Using Multiple Images

    PubMed Central

    Wang, Xingzheng; Wang, Haoqian; Yang, Jiangfeng; Zhang, Yongbing

    2016-01-01

    The basic principle of nonlocal means is to denoise a pixel using the weighted average of the neighbourhood pixels, while the weight is decided by the similarity of these pixels. The key issue of the nonlocal means method is how to select similar patches and design the weight of them. There are two main contributions of this paper: The first contribution is that we use two images to denoise the pixel. These two noised images are with the same noise deviation. Instead of using only one image, we calculate the weight from two noised images. After the first denoising process, we get a pre-denoised image and a residual image. The second contribution is combining the nonlocal property between residual image and pre-denoised image. The improved nonlocal means method pays more attention on the similarity than the original one, which turns out to be very effective in eliminating gaussian noise. Experimental results with simulated data are provided. PMID:27459293

  6. Surface-wave solitons between linear media and nonlocal nonlinear media

    SciTech Connect

    Shi Zhiwei; Li Huagang; Guo Qi

    2011-02-15

    We address surface solitons at the interface between linear media and nonlocal nonlinear media in the presence of a discontinuity in refractive index at the surface of these two materials. We investigated the influence of the degree of nonlocality on the stability, energy flow, and full width at half-maximum of the surface wave solitons. It is shown that surface solitons will be stable only if the degree of nonlocality exceeds a critical value. We find that the refractive index difference can affect the power distribution of the surface solitons in the two media. Also, different boundary values at the interface can lead to different relative peak positions of the surface solitons. However, neither the refractive index nor the boundary conditions can affect the stability of the solitons, for a given degree of nonlocality.

  7. A coupling strategy for nonlocal and local diffusion models with mixed volume constraints and boundary conditions

    SciTech Connect

    D'Elia, Marta; Perego, Mauro; Bochev, Pavel B.; Littlewood, David John

    2015-12-21

    We develop and analyze an optimization-based method for the coupling of nonlocal and local diffusion problems with mixed volume constraints and boundary conditions. The approach formulates the coupling as a control problem where the states are the solutions of the nonlocal and local equations, the objective is to minimize their mismatch on the overlap of the nonlocal and local domains, and the controls are virtual volume constraints and boundary conditions. When some assumptions on the kernel functions hold, we prove that the resulting optimization problem is well-posed and discuss its implementation using Sandia’s agile software components toolkit. As a result, the latter provides the groundwork for the development of engineering analysis tools, while numerical results for nonlocal diffusion in three-dimensions illustrate key properties of the optimization-based coupling method.

  8. A coupling strategy for nonlocal and local diffusion models with mixed volume constraints and boundary conditions

    DOE PAGESBeta

    D'Elia, Marta; Perego, Mauro; Bochev, Pavel B.; Littlewood, David John

    2015-12-21

    We develop and analyze an optimization-based method for the coupling of nonlocal and local diffusion problems with mixed volume constraints and boundary conditions. The approach formulates the coupling as a control problem where the states are the solutions of the nonlocal and local equations, the objective is to minimize their mismatch on the overlap of the nonlocal and local domains, and the controls are virtual volume constraints and boundary conditions. When some assumptions on the kernel functions hold, we prove that the resulting optimization problem is well-posed and discuss its implementation using Sandia’s agile software components toolkit. As a result,more » the latter provides the groundwork for the development of engineering analysis tools, while numerical results for nonlocal diffusion in three-dimensions illustrate key properties of the optimization-based coupling method.« less

  9. Fragility of Nonlocal Edge-Mode Transport in the Quantum Spin Hall State

    NASA Astrophysics Data System (ADS)

    Mani, Arjun; Benjamin, Colin

    2016-07-01

    Nonlocal currents and voltages are better at withstanding the deleterious effects of dephasing than local currents and voltages in nanoscale systems. This hypothesis is known to be true in quantum Hall setups. We test this hypothesis in a four-terminal quantum spin Hall setup wherein we compare the local resistance measurement with the nonlocal one. In addition to inelastic-scattering-induced dephasing, we also test the resilience of the resistance measurements in the aforesaid setups to disorder and spin-flip scattering. We find the axiom that nonlocal resistance is less affected by the detrimental effects of disorder and dephasing to be untrue, in general, for the quantum spin Hall case. This has important consequences since it is widely communicated that nonlocal transport through edge channels in topological insulators have potential applications in low-power information processing.

  10. Asymptotic Analysis of a Slightly Rarefied Gas with Nonlocal Boundary Conditions

    NASA Astrophysics Data System (ADS)

    Caflisch, Russel E.; Lombardo, Maria Carmela; Sammartino, Marco

    2011-05-01

    In this paper nonlocal boundary conditions for the Navier-Stokes equations are derived, starting from the Boltzmann equation in the limit for the Knudsen number being vanishingly small. In the same spirit of (Lombardo et al. in J. Stat. Phys. 130:69-82, 2008) where a nonlocal Poisson scattering kernel was introduced, a gaussian scattering kernel which models nonlocal interactions between the gas molecules and the wall boundary is proposed. It is proved to satisfy the global mass conservation and a generalized reciprocity relation. The asymptotic expansion of the boundary-value problem for the Boltzmann equation, provides, in the continuum limit, the Navier-Stokes equations associated with a class of nonlocal boundary conditions of the type used in turbulence modeling.

  11. Analysis of nonlocal effective permittivity and permeability in symmetric metal–dielectric multilayer metamaterials

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Yang, Xiaodong; Gao, Jie

    2016-06-01

    A generalized nonlocal effective medium theory is derived based on the transfer-matrix method to determine the nonlocal effective permittivity and permeability for the symmetric and periodic metal–dielectric multilayer metamaterials, with respect to both transverse-electric and transverse-magnetic polarized light at arbitrary angle of incidence. The nonlocal effective permittivity and permeability tensors are analyzed in detail as functions of the wavelength, the angle of incidence, and the multilayer period. Our generalized nonlocal effective medium theory in consideration of both permittivity and permeability can accurately predict the dispersion relation, the transmission and reflection spectra, and the optical field distributions of symmetric metal–dielectric multilayer stacks with either subwavelength or wavelength-scale period of the unit cell.

  12. Consistent theory for causal non-locality beyond the Born's rule

    NASA Astrophysics Data System (ADS)

    Son, Wonmin

    2014-02-01

    According to the theory of relativity and causality, a special type of correlation beyond quantum mechanics is possible in principle under the name of a non-local box. The concept has been introduced from the principle of non-locality, which satisfies relativistic causality. In this paper, we show that a correlation leading to the non-local box can be derived consistently if we release one of major axioms in quantum mechanics, Born's rule. This allows us to obtain a theory that in one end of the spectrum agrees with the classical probability and in the other end agrees with the theory of non-local causality. At the same time, we argue that the correlation lies in a space with special mathematical constraints such that a physical realization of the correlation through a probability measure is not possible in one direction of its limit, but is possible in the other limit.

  13. Quadrature rules for finite element approximations of 1D nonlocal problems

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoping; Gunzburger, Max; Ju, Lili

    2016-04-01

    It is well known that calculations of the entries of the stiffness matrix in the finite element approximations of nonlocal diffusion and mechanics models are often very time-consuming due to the double integration process over the domain and the singularities of the nonlocal kernel functions. In this paper, we propose some effective and accurate quadrature rules for computing these double integrals for one-dimensional nonlocal problems; in particular, for problems with highly singular kernels, the corresponding inner integrals can be first evaluated exactly in our method, and the outer one then will be approximated by some popular quadrature rules. With these quadrature rules, the assembly of the stiffness matrix in the finite element method for the nonlocal problems becomes similar to that for the classical partial differential equations and is thus quite efficient.

  14. On the interplay between neoclassical tearing modes and nonlocal transport in toroidal plasmas

    PubMed Central

    Ji, X. Q.; Xu, Y.; Hidalgo, C.; Diamond, P. H.; Liu, Yi; Pan, O.; Shi, Z. B.; Yu, D. L.

    2016-01-01

    This Letter presents the first observation on the interplay between nonlocal transport and neoclassical tearing modes (NTMs) during transient nonlocal heat transport events in the HL-2A tokamak. The nonlocality is triggered by edge cooling and large-scale, inward propagating avalanches. These lead to a locally enhanced pressure gradient at the q = 3/2 (or 2/1) rational surface and hence the onset of the NTM in relatively low β plasmas (βN < 1). The NTM, in return, regulates the nonlocal transport by truncation of avalanches by local sheared toroidal flows which develop near the magnetic island. These findings have direct implications for understanding the dynamic interaction between turbulence and large-scale mode structures in fusion plasmas. PMID:27595773

  15. On Local Boundary CFT and Non-Local CFT on the Boundary

    NASA Astrophysics Data System (ADS)

    Rehren, Karl-Henning

    The holographic relation between local boundary conformal quantum field theories (BCFT) and their non-local boundary restrictions is reviewed, and non-vacuum BCFT's, whose existence was conjectured previously, are constructed. (Based on joint work [18] with R. Longo.)

  16. Experimental demonstration of genuine multipartite quantum nonlocality without shared reference frames

    NASA Astrophysics Data System (ADS)

    Wang, Zhao; Zhang, Chao; Huang, Yun-Feng; Liu, Bi-Heng; Li, Chuan-Feng; Guo, Guang-Can

    2016-03-01

    Multipartite quantum nonlocality is an important diagnostic tool and resource for both researches in fundamental quantum mechanics and applications in quantum information protocols. Shared reference frames among all parties are usually required for experimentally observing quantum nonlocality, which is not possible in many circumstances. Previous results have shown violations of bipartite Bell inequalities with approaching unit probability, without shared reference frames. Here we experimentally demonstrate genuine multipartite quantum nonlocality without shared reference frames, using the Svetlichny inequality. A significant violation probability of 0.58 is observed with a high-fidelity three-photon Greenberger-Horne-Zeilinger state. Furthermore, when there is one shared axis among all the parties, which is the usual case in fiber-optic or earth-satellite links, the experimental results demonstrate the genuine three-partite nonlocality with certainty. Our experiment will be helpful for applications in multipartite quantum communication protocols.

  17. Influence of nonlocal damping on the field-driven domain wall motion

    NASA Astrophysics Data System (ADS)

    Yuan, H. Y.; Yuan, Zhe; Xia, Ke; Wang, X. R.

    2016-08-01

    We derive a general expression of nonlocal damping in noncollinear magnetization due to the nonuniform spin current pumped by precessional magnetization and incorporate it into a generalized Thiele equation to study its effects on the dynamics of the transverse and vortex domain walls (DWs) in ferromagnetic nanowires. We demonstrate that the transverse component of nonlocal damping slows down the field-driven DW propagation and increases the Walker breakdown field, whereas it is neglected in many previous works in literature. The experimentally measured DW mobility variation with the damping tuned by doping with heavy rare-earth elements that had discrepancy from micromagnetic simulation is now well understood with the nonlocal damping. Our results suggest that the nonlocal damping should be properly included as a prerequisite for quantitative studies of current-induced torques in noncollinear magnetization.

  18. Use of nonlocal helium microplasma for gas impurities detection by the collisional electron spectroscopy method

    SciTech Connect

    Kudryavtsev, Anatoly A.; Stefanova, Margarita S.; Pramatarov, Petko M.

    2015-10-15

    The collisional electron spectroscopy (CES) method, which lays the ground for a new field for analytical detection of gas impurities at high pressures, has been verified. The CES method enables the identification of gas impurities in the collisional mode of electron movement, where the advantages of nonlocal formation of the electron energy distribution function (EEDF) are fulfilled. Important features of dc negative glow microplasma and probe method for plasma diagnostics are applied. A new microplasma gas analyzer design is proposed. Admixtures of 0.2% Ar, 0.6% Kr, 0.1% N{sub 2}, and 0.05% CO{sub 2} are used as examples of atomic and molecular impurities to prove the possibility for detecting and identifying their presence in high pressure He plasma (50–250 Torr). The identification of the particles under analysis is made from the measurements of the high energy part of the EEDF, where maxima appear, resulting from the characteristic electrons released in Penning reactions of He metastable atoms with impurity particles. Considerable progress in the development of a novel miniature gas analyzer for chemical sensing in gas phase environments has been made.

  19. Use of nonlocal helium microplasma for gas impurities detection by the collisional electron spectroscopy method

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, Anatoly A.; Stefanova, Margarita S.; Pramatarov, Petko M.

    2015-10-01

    The collisional electron spectroscopy (CES) method, which lays the ground for a new field for analytical detection of gas impurities at high pressures, has been verified. The CES method enables the identification of gas impurities in the collisional mode of electron movement, where the advantages of nonlocal formation of the electron energy distribution function (EEDF) are fulfilled. Important features of dc negative glow microplasma and probe method for plasma diagnostics are applied. A new microplasma gas analyzer design is proposed. Admixtures of 0.2% Ar, 0.6% Kr, 0.1% N2, and 0.05% CO2 are used as examples of atomic and molecular impurities to prove the possibility for detecting and identifying their presence in high pressure He plasma (50-250 Torr). The identification of the particles under analysis is made from the measurements of the high energy part of the EEDF, where maxima appear, resulting from the characteristic electrons released in Penning reactions of He metastable atoms with impurity particles. Considerable progress in the development of a novel miniature gas analyzer for chemical sensing in gas phase environments has been made.

  20. Role of non-local exchange in the electronic structure of correlated oxides

    NASA Astrophysics Data System (ADS)

    Iori, Federico; Gatti, Matteo; Rubio Secades, Angel

    Transition-metal oxides (TMO) with partially filled d or f shells are a prototype of correlated materials. They exhibit very interesting properties, like metal-insulator phase transitions (MIT). In this work we consider several TMO insulators in which Kohn-Sham LDA band structures are metallic: VO2, V2O3, Ti2O3, LaTiO3 and YTiO3. In the past, this failure of LDA has been explained in terms of its inadequacy to capture the strong interactions taking place between correlated electrons. In the spirit of the Hubbard model, possible corrections to improve onsite correlation are the LDA +U and LDA +DMFT approaches. Here we make use of the HSE06 hybrid functional. We show that, without invoking strong-correlation effects, the contribution of the non-local Fock exchange is essential to correct the LDA results, by curing its delocalization error. In fact, HSE06 provides insulating band structures and correctly describes the MIT in all the considered compounds. We further discuss the advantages and the limitations of the HSE06 hybrid functional in correlated TMO

  1. Dynamic behavior of the incoherent optical spatial solitons in a nonlocal nonlinear medium

    NASA Astrophysics Data System (ADS)

    Zhen, Hui-Ling; Tian, Bo; Xie, Xi-Yang; Sun, Ya

    2015-06-01

    Dynamic behavior of the propagation of incoherent optical spatial solitons in a nonlocal nonlinear medium is investigated. By means of the Hirota method, we obtain the soliton solutions, based on which we find that ? is positively related to ?, but inversely related to ? and ?, whereas ? is independent of them, with ? as the slowly varying amplitude of the beam, ? as the refractive index change, ?, ?, and ? as the unperturbed refractive index, frequency of the propagating beam, and beam intensity distribution, respectively. Head-on and bound-state soliton interactions are both given, and one interaction period decreases with ? and ? increasing in the bound state one. With the external perturbations taken into consideration, the associated chaotic motions of the perturbed model are studied, and the corresponding power spectra and phase projections are obtained. Both the weak and developed chaotic states are investigated, and the difference between them roots in the relative magnitude of nonlinearities and perturbations. Such chaotic motions can be weakened via increasing ? and ? or decreasing ?. Periodic motion is obtained with the nonlinearities and perturbations balanced.

  2. Nonlocal interactions stabilize compact folding intermediates in reduced unfolded bovine pancreatic trypsin inhibitor.

    PubMed

    Gottfried, D S; Haas, E

    1992-12-15

    To further our understanding of the protein folding process, it is desirable to examine the structural intermediates (equilibrium and kinetic) that are populated between the statistical coil state and the folded molecule. X-ray crystallography and NMR structural studies are unable to determine long-range distances in proteins under denaturing solution conditions. Nonradiative (Förster) energy transfer, however, has been shown to be a spectroscopic ruler for the measurement of distance distributions and diffusion between selected sites in proteins under a range of different solution conditions. The distributions of distances between a donor probe at the N-terminal residue and an acceptor attached to one of the four lysine residues (15, 26, 41, 46) of reduced and unfolded (in 6 M guanidine hydrochloride and 20 mM dithiothreitol) bovine pancreatic trypsin inhibitor (BPTI) were measured as a function of temperature. Even in strong denaturant and reducing agent, BPTI does not exist as a statistical coil polypeptide. It appears that nonlocal (long-range) interactions are already beginning to "fold" the protein toward a more compact, native conformation. As the temperature is increased under these conditions, hydrophobic interactions lead to an even more compact structure consistent with the predictions of phase diagrams for globular proteins. PMID:1281424

  3. Dynamics and thermodynamics of a nonlocal Polyakov--Nambu--Jona-Lasinio model with running coupling

    SciTech Connect

    Hell, T.; Roessner, S.; Cristoforetti, M.; Weise, W.

    2009-01-01

    A nonlocal covariant extension of the two-flavor Nambu and Jona-Lasinio model is constructed, with built-in constraints from the running coupling of QCD at high-momentum and instanton physics at low-momentum scales. Chiral low-energy theorems and basic current algebra relations involving pion properties are shown to be reproduced. The momentum-dependent dynamical quark mass derived from this approach is in agreement with results from Dyson-Schwinger equations and lattice QCD. At finite temperature, inclusion of the Polyakov loop and its gauge invariant coupling to quarks reproduces the dynamical entanglement of the chiral and deconfinement crossover transitions as in the (local) Polyakov-loop-extended Nambu and Jona-Lasinio model, but now without the requirement of introducing an artificial momentum cutoff. Steps beyond the mean-field approximation are made including mesonic correlations through quark-antiquark ring summations. Various quantities of interest (pressure, energy density, speed of sound, etc.) are calculated and discussed in comparison with lattice QCD thermodynamics at zero chemical potential. The extension to finite quark chemical potential and the phase diagram in the (T,{mu})-plane are also discussed.

  4. Localization of the SFT inspired nonlocal linear models and exact solutions

    NASA Astrophysics Data System (ADS)

    Vernov, S. Yu.

    2011-05-01

    A general class of gravitational models driven by a nonlocal scalar field with a linear or quadratic potential is considered. We study the action with an arbitrary analytic function ℱ(□ g ), which has both simple and double roots. The way of localization of nonlocal Einstein equations is generalized on models with linear potentials. Exact solutions in the Friedmann-Robertson-Walker and Bianchi I metrics are presented.

  5. Dynamics of surface dipole and tripole solitons in nonlocal nonlinear media with optical lattice field

    NASA Astrophysics Data System (ADS)

    Hong, Woo-Pyo; Jung, Young-Dae

    2013-10-01

    We find the existence conditions for stationary dipole and tripole surface solitons formed at the interface of a nonlocal nonlinear medium and a lattice with linearly modulated frequency. We investigate how the degree of nonlocality, the depth, and the modulation frequency of the optical lattice field affect on the existence of the surface solitons and their dynamics. The relationship between the power and the model parameters is identified. The stability of the surface dipole and tripole solitons is numerically investigated.

  6. New Exact Solutions of the CDGSK Equation Related to a Non-local Symmetry

    NASA Astrophysics Data System (ADS)

    Lou, Senyue; Ruan, Hangyu; Chen, Weizhong; Wang, Zhenli; Chen, Lili

    1994-10-01

    A non-local symmetry of the Caudrey-Dodd-Gibbon-Sawada-Kotera (CDGSK) equation has been used for finding exact solution in two different ways. Firstly, using the standard prolongation approach, we obtain the finite Lie Bäcklund transformation and the single soliton solution. Secondly, combining some local symmetries and the nonlocal symmetry, we get the group invariant solution which is described by the Weierstrass elliptic function and is deduced to the so-called interacting soliton for a special parameter.

  7. Optimization of molecular structures by self-consistent and nonlocal density-functional theory

    NASA Astrophysics Data System (ADS)

    Fan, Liangyou; Ziegler, Tom

    1991-11-01

    An algorithm for the calculation of energy gradients has been implemented into the linear combination of atomic orbitals-Hartree-Fock-Slater (LCAO-HFS) program due to Baerends et al. [Chem. Phys. 2, 41 (1973)], and tested in connection with geometry optimizations of transition-metal complexes, organic molecules and compounds of main group elements. The algorithm is based on a self-consistent nonlocal density-functional method (NL-SCF) combining the nonlocal exchange correction by Becke [Phys. Rev. A 38, 3098 (1988)] with the nonlocal correlation correction by Perdew [Phys. Rev. B 33, 8822 (1986)]. It is shown that nonlocal corrections to the local-density approximation (LDA) improves the calculated metal-ligand bond distances considerably. Full optimizations of MnO-4, Cr(CO)6, Mo(CO)6, Fe(CO)5, Ni(CO)4, HMn(CO)5, HCo(CO)4, Fe(C5H5)2, and C5H5NiNO revealed that the LDA underestimates metal-ligand bond distances by an average of 0.05 Å, whereas nonlocal corrections, on the average, reduce the error to 0.01 Å. Nonlocal corrections are not as important for organic molecules and compounds of main group elements where LDA already affords bond distances in good agreement with experiment. Bond angles are, in general, not influenced much by nonlocal corrections. The nonlocal corrections increase the computational time involved by a factor of 4 on a scalar machine and a factor of 2 on a vector machine.

  8. Experimental demonstration of nonlocal effects in the partial-collapse measurement and reversal process

    SciTech Connect

    Xu Xiaoye; Xu Jinshi; Li Chuanfeng; Zou Yang; Guo Guangcan

    2011-01-15

    We demonstrate experimentally the nonlocal reversal of a partial-collapse quantum measurement of a two-photon entangled state. Both the partial-collapse measurement and the reversal operation are implemented in linear optics with two displaced Sagnac interferometers, characterized by single-qubit quantum-process tomography. The recovered state is measured by quantum-state tomography, and its nonlocality is characterized by testing the Bell inequality. Our result will be helpful in quantum communication and quantum error correction.

  9. Nonlocal plate model for free vibrations of single-layered graphene sheets

    NASA Astrophysics Data System (ADS)

    Ansari, R.; Sahmani, S.; Arash, B.

    2010-11-01

    Vibration analysis of single-layered graphene sheets (SLGSs) is investigated using nonlocal continuum plate model. To this end, Eringens's nonlocal elasticity equations are incorporated into the classical Mindlin plate theory for vibrations of rectangular nanoplates. In contrast to the classical model, the nonlocal model developed in this study has the capability to evaluate the natural frequencies of the graphene sheets with considering the size-effects on the vibrational characteristics of them. Solutions for frequencies of the free vibration of simply-supported and clamped SLGSs are computed using generalized differential quadrature (GDQ) method. Then, molecular dynamics (MD) simulations for the free vibration of various SLGSs with different values of side length and chirality are employed, the results of which are matched with the nonlocal model ones to derive the appropriate values of the nonlocal parameter relevant to each boundary condition. It is found that the value of the nonlocal parameter is independent of the magnitude of the geometrical variables of the system.

  10. Dynamics between the fishbone instability and nonlocal transient transport in HL-2A NBI plasmas

    NASA Astrophysics Data System (ADS)

    Chen, W.; Xu, Y.; Ding, X. T.; Shi, Z. B.; Jiang, M.; Zhong, W. L.; Ji, X. Q.; HL-2A Team

    2016-04-01

    Understanding of nonlocal electron heat transport is of key importance for current magnetic confinement fusion research. Global nonlocal response presents a fundamental challenge to the standard anomalous transport model based on local microinstabilities and turbulence. Here, we present for the first time a new nonlocal phenomenon triggered by the fishbone instability in HL-2A neutral beam injection plasmas. Rapid core heating leads to a simultaneous decrease in temperature at the plasma edge. The effect reveals fast anomalous transport of core heat pulses to the plasma edge, not compatible with diffusive time scales. More importantly, Δ {{T}\\text{e}}/< {{T}\\text{e}}> variations at different locations are restricted by the intensity of magnetic fluctuations. The Δ {{T}\\text{e}}/< {{T}\\text{e}}> and {{≤ft(δ {{B}θ}\\right)}\\text{rms}} form two types of hysteresis loops at two sides of the inversion radius. The ECEIs show that the 2D mode structure of the fishbone is intensive shearing/spiraling during the nonlocal transport. Experimental results suggest that magnetic perturbation, long-range correlation, mesoscale structure and E× B flow play crucial roles in the nonlocal response. The Hurst exponent and auto-correlation coefficient indicate that the nonlocal transport is potentially linked to the self-organized critical (SOC) dynamics. This work will be beneficial for understanding of the plasma dynamics in future fusion reactors.

  11. Perfect imaging, epsilon-near zero phenomena and waveguiding in the scope of nonlocal effects

    PubMed Central

    David, C.; Mortensen, N. A.; Christensen, J.

    2013-01-01

    Plasmons in metals can oscillate on a sub-wavelength length scale and this large-k response constitutes an inherent prerequisite for fascinating effects such as perfect imaging and intriguing wave phenomena associated with the epsilon-near-zero (ENZ) regime. While there is no upper cut-off within the local-response approximation (LRA) of the plasma polarization, nonlocal dynamics suppress response beyond ω/vF, where vF is the Fermi velocity of the electron gas. Nonlocal response has previously been found to pose limitations to field-enhancement phenomena. Accounting for nonlocal hydrodynamic response, we show that perfect imaging is surprisingly only marginally affected by nonlocal properties of a metal slab, even for a deep subwavelength case and an extremely thin film. Similarly, for the ENZ response we find no indications of nonlocal response jeopardizing the basic behaviors anticipated from the LRA. Finally, our study of waveguiding of gap plasmons even shows a positive nonlocal influence on the propagation length. PMID:23982271

  12. Novel non-local effects in three-terminal hybrid devices with quantum dot

    PubMed Central

    Michałek, G.; Domański, T.; Bułka, B.R.; Wysokiński, K.I.

    2015-01-01

    We predict non-local effect in the three-terminal hybrid device consisting of the quantum dot (QD) tunnel coupled to two normal and one superconducting reservoirs. It manifests itself as the negative non-local resistance and results from the competition between the ballistic electron transfer (ET) and the crossed Andreev scattering (CAR). The effect is robust both in the linear and non-linear regimes. In the latter case the screening of charges and the long-range interactions play significant role. We show that sign change of the non-local conductance depends on the subgap Shiba/Andreev states, and it takes place even in absence of the Coulomb interactions. The effect is large and can be experimentally verified using the four probe setup. Since the induced non-local voltage changes sign and magnitude upon varying the gate potential and/or coupling of the quantum dot to the superconducting lead, such measurement could hence provide a controlled and precise method to determine the positions of the Shiba/Andreev states. Our predictions ought to be contrasted with non-local effects observed hitherto in the three-terminal planar junctions where the residual negative non-local conductance has been observed at large voltages, related to the Thouless energy of quasiparticles tunneling through the superconducting slab. PMID:26415683

  13. Novel non-local effects in three-terminal hybrid devices with quantum dot

    NASA Astrophysics Data System (ADS)

    Michałek, G.; Domański, T.; Bułka, B. R.; Wysokiński, K. I.

    2015-09-01

    We predict non-local effect in the three-terminal hybrid device consisting of the quantum dot (QD) tunnel coupled to two normal and one superconducting reservoirs. It manifests itself as the negative non-local resistance and results from the competition between the ballistic electron transfer (ET) and the crossed Andreev scattering (CAR). The effect is robust both in the linear and non-linear regimes. In the latter case the screening of charges and the long-range interactions play significant role. We show that sign change of the non-local conductance depends on the subgap Shiba/Andreev states, and it takes place even in absence of the Coulomb interactions. The effect is large and can be experimentally verified using the four probe setup. Since the induced non-local voltage changes sign and magnitude upon varying the gate potential and/or coupling of the quantum dot to the superconducting lead, such measurement could hence provide a controlled and precise method to determine the positions of the Shiba/Andreev states. Our predictions ought to be contrasted with non-local effects observed hitherto in the three-terminal planar junctions where the residual negative non-local conductance has been observed at large voltages, related to the Thouless energy of quasiparticles tunneling through the superconducting slab.

  14. Parallelization strategies to deal with non-localities in the calculation of regional land-surface parameters

    NASA Astrophysics Data System (ADS)

    Schiele, Steffen; Möller, Markus; Blaar, Holger; Thürkow, Detlef; Müller-Hannemann, Matthias

    2012-07-01

    Hand in hand with the increasing availability of high resolution digital elevation models (DEMs), an efficient computation of land-surface parameters (LSPs) for large-scale digital elevation models becomes more and more important, in particular for web-based applications. Parallel processing using multi-threads on multi-core processors is a standard approach to decrease computing time for the calculation of local LSPs based on moving window operations (e.g. slope, curvature). LSPs which require non-localities for their calculation (e.g. hydrological connectivities of grid cells) make parallelization quite challenging due to data dependencies. On the example of the calculation of the LSP "flow accumulation", we test the two parallelization strategies "spatial decomposition" and "two phase approach" for their suitability to manage non-localities. Three datasets of digital elevation models with high spatial resolutions are used in our evaluation. These models are representative types of landscape of Central Europe with highly diverse geomorphic characteristics: a high mountains area, a low mountain range, and a floodplain area in the lowlands. Both parallelization strategies are evaluated with regard to their usability on these diversely structured areas. Besides the correctness analysis of calculated relief parameters (i.e. catchment areas), priority is given to the analysis of speed-ups achieved through the deployed strategies. As presumed, local surface parameters allow an almost ideal speed-up. The situation is different for the calculation of non-local parameters which requires specific strategies depending on the type of landscape. Nevertheless, still a significant decrease of computation time has been achieved. While the speed-ups of the computation of the high mountain dataset are higher by running the "spatial decomposition approach" (3.2 by using four processors and 4.2 by using eight processors), the speed-ups of the "two phase approach" have proved to be

  15. Dynamic instability of vibrating carbon nanotubes near small layers of graphite sheets based on nonlocal continuum elasticity

    NASA Astrophysics Data System (ADS)

    Sedighi, H. M.; Yaghootian, A.

    2016-01-01

    This article presents a new asymptotic method to predict dynamic pull-in instability of nonlocal clamped-clamped carbon nanotubes (CNTs) near graphite sheets. Nonlinear governing equations of carbon nanotubes actuated by an electric field are derived. With due allowance for the van der Waals effects, the pull-in instability and the natural frequency-amplitude relationship are investigated by a powerful analytical method, namely, the parameter expansion method. It is demonstrated that retaining two terms in series expansions is sufficient to produce an acceptable solution. The obtained results from numerical methods verify the strength of the analytical procedure. The qualitative analysis of system dynamics shows that the equilibrium points of the autonomous system include center points and unstable saddle points. The phase portraits of the carbon nanotube actuator exhibit periodic and homoclinic orbits.

  16. Investigation of the nonlocal nonlinear optical response of copper nanostructured thin films prepared by pulsed laser deposition

    SciTech Connect

    Farmanfarmaei, B; RashidianVaziri, M R; Hajiesmaeilbaigi, F

    2014-11-30

    Nanostructured copper thin films have been prepared using the pulsed laser deposition method. Optical absorption spectra of these films exhibit plasmonic absorption peaks around 619 nm, which suggests the formation of copper nanoparticles on their surfaces. Scanning electron micrographs of the films confirm the nanoparticle formation on the films surfaces. After laser beam passing through the thin films, the observed diffraction rings on a far-field screen have been recorded. Despite the smallness of the maximal axial phase shifts of the films, which have been obtained using the nonlocal z-scan theory, a series of low-intensity rings can be observed on the far field screen for some specific positions of the thin films from the focal point. It is shown that the best approach to determining the sign and magnitude of the nonlinear refractive index of thin samples is the application of the conventional closeaperture z-scan method. (nanostructures)

  17. Non-local damage rheology and size effect

    NASA Astrophysics Data System (ADS)

    Lyakhovsky, V.

    2011-12-01

    We study scaling relations controlling the onset of transiently-accelerating fracturing and transition to dynamic rupture propagation in a non-local damage rheology model. The size effect is caused principally by growth of a fracture process zone, involving stress redistribution and energy release associated with a large fracture. This implies that rupture nucleation and transition to dynamic propagation are inherently scale-dependent processes. Linear elastic fracture mechanics (LEFM) and local damage mechanics are formulated in terms of dimensionless strain components and thus do not allow introducing any space scaling, except linear relations between fracture length and displacements. Generalization of Weibull theory provides scaling relations between stress and crack length at the onset of failure. A powerful extension of the LEFM formulation is the displacement-weakening model which postulates that yielding is complete when the crack wall displacement exceeds some critical value or slip-weakening distance Dc at which a transition to kinetic friction is complete. Scaling relations controlling the transition to dynamic rupture propagation in slip-weakening formulation are widely accepted in earthquake physics. Strong micro-crack interaction in a process zone may be accounted for by adopting either integral or gradient type non-local damage models. We formulate a gradient-type model with free energy depending on the scalar damage parameter and its spatial derivative. The damage-gradient term leads to structural stresses in the constitutive stress-strain relations and a damage diffusion term in the kinetic equation for damage evolution. The damage diffusion eliminates the singular localization predicted by local models. The finite width of the localization zone provides a fundamental length scale that allows numerical simulations with the model to achieve the continuum limit. A diffusive term in the damage evolution gives rise to additional damage diffusive time

  18. Non-local ocean mixing model and a new plume model for deep convection

    NASA Astrophysics Data System (ADS)

    Canuto, V. M.; Cheng, Y.; Howard, A. M.

    Turbulent fluxes can be represented by a diffusivity tensor, the symmetric part of which describes " turbulent diffusion" while the anti-symmetric part describes " advection". Diffusion is a local process in the sense that it depends only on the local gradients of the mean fields while advection is non-local for it is represented by an integral over all length scales (all eddies) that can "fit" from say the bottom of the physical domain to the z where the fluxes are computed. In the ocean, there are two main regimes where non-local transport is important. One regime is where storms release a sudden burst of mechanical energy to the ocean surface that is then transported downward by energetic eddies that deepen the mixed layer. Even relatively simple non-local models yield results considerably more realistic than those of local models. The second regime is deep convection (DC) caused by loss of surface buoyancy, the description of which is required for a reliable assessment of water masses formation. At present, there is no reliable model for either of these non-local regimes individually or much less a formalism capable of accounting for both regimes simultaneously. The goal of this paper is to present a formalism that provides the expressions for the non-local fluxes for momentum, heat and salinity encompassing both cases. Since the resulting number of dynamic equations involves is however large, we work out two sub-models, one when only shear must be treated non-locally (e.g., when storms release mechanical energy) and one when only buoyancy is to be treated non-locally (the DC case). We employ the Reynolds Stress formalism in which non-locality is represented by the third-order moments which in turn depend on the fourth-order moments for which we employ a new model that has been tested against LES data, aircraft data and a full PBL simulation. For the DC case, we rewrite the non-local model in terms of Plumes since thus far the only non-local model used to treat

  19. Revealing Bell's nonlocality for unstable systems in high energy physics

    NASA Astrophysics Data System (ADS)

    Hiesmayr, Beatrix C.; Di Domenico, Antonio; Curceanu, Catalina; Gabriel, Andreas; Huber, Marcus; Larsson, Jan-Åke; Moskal, Pawel

    2012-01-01

    Entanglement and its consequences—in particular the violation of Bell inequalities, which defies our concepts of realism and locality—have been proven to play key roles in Nature by many experiments for various quantum systems. Entanglement can also be found in systems not consisting of ordinary matter and light, i.e. in massive meson-antimeson systems. Bell inequalities have been discussed for these systems, but up to date no direct experimental test to conclusively exclude local realism was found. This mainly stems from the fact that one only has access to a restricted class of observables and that these systems are also decaying. In this Letter we put forward a Bell inequality for unstable systems which can be tested at accelerator facilities with current technology. Herewith, the long awaited proof that such systems at different energy scales can reveal the sophisticated " dynamical" nonlocal feature of Nature in a direct experiment gets feasible. Moreover, the role of entanglement and mathcal{CP} violation, an asymmetry between matter and antimatter, is explored, a special feature offered only by these meson-antimeson systems.

  20. Physical characterization of quantum devices from nonlocal correlations

    NASA Astrophysics Data System (ADS)

    Bancal, Jean-Daniel; Navascués, Miguel; Scarani, Valerio; Vértesi, Tamás; Yang, Tzyh Haur

    2015-02-01

    In the device-independent approach to quantum information theory, quantum systems are regarded as black boxes that, given an input (the measurement setting), return an output (the measurement result). These boxes are then treated regardless of their actual internal working. In this paper we develop swap, a theoretical concept that, in combination with the tool of semidefinite methods for the characterization of quantum correlations, allows us to estimate physical properties of the black boxes from the observed measurement statistics. We find that the swap tool provides bounds orders of magnitude better than previously known techniques (e.g., for a Clauser-Horne-Shimony-Holt violation larger than 2.57, swap predicts a singlet fidelity greater than 70 % ). This method also allows us to deal with hitherto intractable cases such as robust device-independent self-testing of nonmaximally entangled two-qutrit states in the Collins-Gisin-Linden-Massar-Popescu scenario (for which Jordan's lemma does not apply) and the device-independent certification of entangled measurements. We further apply the swap method to relate nonlocal correlations to work extraction and quantum dimensionality, hence demonstrating that this tool can be used to study a wide variety of properties relying on the sole knowledge of accessible statistics.