25,832 research outputs found

    Estimates for multilinear commutators of generalized fractional integral operators on weighted Morrey spaces

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    Let LL be the infinitesimal generator of an analytic semigroup on L2(Rn)L^2(\mathbb{R}^n) with Gaussian kernel bounds, and let Lβˆ’Ξ±/2L^{-\alpha/2} be the fractional integrals of LL for 0<Ξ±<n0<\alpha<n. Assume that bβƒ—=(b1,b2,⋯ ,bm)\vec{b}=(b_1,b_2,\cdots,b_m) is a finite family of locally integrable functions, then the multilinear commutators generated by bβƒ—\vec{b} and Lβˆ’Ξ±/2L^{-\alpha/2} is defined by \begin{equation*} L_{\vec{b}}^{-\alpha/2}f=[b_m,\cdots,[b_2,[b_1,L^{-\alpha/2}]],\cdots,]f \end{equation*} when bj∈BMO(w)b_j\in BMO(w), j=1,2,⋯ ,mj=1,2,\cdots,m, the authors obtain the boundedness of Lbβƒ—βˆ’Ξ±/2L_{\vec{b}}^{-\alpha/2} on weighted Morrey spaces.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1203.4407 by other author

    Iterative Grassmannian Optimization for Robust Image Alignment

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    Robust high-dimensional data processing has witnessed an exciting development in recent years, as theoretical results have shown that it is possible using convex programming to optimize data fit to a low-rank component plus a sparse outlier component. This problem is also known as Robust PCA, and it has found application in many areas of computer vision. In image and video processing and face recognition, the opportunity to process massive image databases is emerging as people upload photo and video data online in unprecedented volumes. However, data quality and consistency is not controlled in any way, and the massiveness of the data poses a serious computational challenge. In this paper we present t-GRASTA, or "Transformed GRASTA (Grassmannian Robust Adaptive Subspace Tracking Algorithm)". t-GRASTA iteratively performs incremental gradient descent constrained to the Grassmann manifold of subspaces in order to simultaneously estimate a decomposition of a collection of images into a low-rank subspace, a sparse part of occlusions and foreground objects, and a transformation such as rotation or translation of the image. We show that t-GRASTA is 4 Γ—\times faster than state-of-the-art algorithms, has half the memory requirement, and can achieve alignment for face images as well as jittered camera surveillance images.Comment: Preprint submitted to the special issue of the Image and Vision Computing Journal on the theme "The Best of Face and Gesture 2013

    Multi-objective Differential Evolution with Helper Functions for Constrained Optimization

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    Solving constrained optimization problems by multi-objective evolutionary algorithms has scored tremendous achievements in the last decade. Standard multi-objective schemes usually aim at minimizing the objective function and also the degree of constraint violation simultaneously. This paper proposes a new multi-objective method for solving constrained optimization problems. The new method keeps two standard objectives: the original objective function and the sum of degrees of constraint violation. But besides them, four more objectives are added. One is based on the feasible rule. The other three come from the penalty functions. This paper conducts an initial experimental study on thirteen benchmark functions. A simplified version of CMODE is applied to solving multi-objective optimization problems. Our initial experimental results confirm our expectation that adding more helper functions could be useful. The performance of SMODE with more helper functions (four or six) is better than that with only two helper functions.Comment: Accepted by The 15th UK Workshop on Computational Intelligence (UKCI 2015

    Integrated Facility Location and Production Scheduling in Multi-Generation Energy Systems

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    In this paper, we investigate the energy system design problems with the multi-generation technologies, i.e., simultaneous generation of multiple types of energy. We propose a long-term planning model which integrates macro-level strategic decisions such as facility location and multi-generation technology investment, and micro-level operational decisions such as production planning and energy transportation. Our results illustrate the economic value of multi-generation technologies in lieu of the spatio-temporal demand uncertainty for energy. In particular, we show that the multi-generation technologies can reduce demand uncertainty by risk pooling both within and across different facilities

    The Multiparty Coherent Channel and its Implementation with Linear Optics

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    The continuous-variable coherent (conat) channel is a useful resource for coherent communication, producing coherent teleportation and coherent superdense coding. We extend the conat channel to multiparty conditions by proposing definitions about multiparty position-quadrature conat channel and multiparty momentum-quadrature conat channel. We additionally provide two methods to implement this channel using linear optics. One method is the multiparty version of coherent communication assisted by entanglement and classical communication (CCAECC). The other is multiparty coherent superdense coding.Comment: 13 pages, 4figure

    Three-flavor Nambu--Jona-Lasinio model at finite isospin chemical potential

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    QCD at finite isospin chemical potential ΞΌI\mu_{\text I} possesses a positively definite fermion determinant and the lattice simulation can be successfully performed. While the two-flavor effective models may be sufficient to describe the phenomenon of pion condensation, it is interesting to study the roles of the strangeness degree of freedom and the UA(1)_{\rm A}(1) anomaly. In this paper, we present a systematic study of the three-flavor Nambu--Jona-Lasinio model with a Kobayashi-Maskawa-'t Hooft (KMT) term that mimics the UA(1)_{\rm A}(1) anomaly at finite isospin chemical potential. In the mean-field approximation, the model predicts a phase transition from the vacuum to the pion superfluid phase, which takes place at ΞΌI\mu_{\rm I} equal to the pion mass mΟ€m_\pi. Due to the UA(1)_{\rm A}(1) anomaly, the strangeness degree of freedom couples to the light quark degrees of freedom and the strange quark effective mass depends on the pion condensate. However, the strange quark condensate and the strange quark effective mass change slightly in the pion superfluid phase, which verifies the validity of the two-flavor models. The effective four-fermion interaction of the Kobayashi-Maskawa-'t Hooft term in the presence of the pion condensation is constructed. Due to the UA(1)_{\rm A}(1) anomaly, the pion condensation generally induces scalar-pseudoscalar interaction. The Bethe-Salpeter equation for the mesonic excitations is established and the meson mass spectra are obtained at finite isospin chemical potential and temperature. Finally, the general expression for the topological susceptibility Ο‡\chi at finite isospin chemical potential ΞΌI\mu_{\rm I} is derived. In contrast to the finite temperature effect which suppresses Ο‡\chi, the isospin density effect leads to an enhancement of Ο‡\chi.Comment: Version punlished in PR

    Rotational Properties of the Odd-ZZ Transfermium Nucleus 255^{255}Lr by a Particle-number-conserving Method in the Cranked Shell Model

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    Experimentally observed ground state band based on the 1/2βˆ’[521]1/2^{-}[521] Nilsson state and the first exited band based on the 7/2βˆ’[514]7/2^{-}[514] Nilsson state in the odd-ZZ nucleus 255^{255}Lr are studied by the cranked shell model (CSM) with the paring correlations treated by the particle-number-conserving (PNC) method. This is the first time the detailed theoretical investigations being performed on these rotational bands. Both the experimental kinematic and dynamic moment of inertia (J(1)\mathcal{J}^{(1)} and J(2)\mathcal{J}^{(2)}) versus rotational frequency are reproduced quite well by the PNC-CSM calculations. By comparing the theoretical kinematic moment of inertia J(1)\mathcal{J}^{(1)} with the experimental ones extracted from different spin assignments, the spin 17/2βˆ’β†’13/2βˆ’17/2^{-}\rightarrow13/2^{-} is assigned to the lowest-lying 196.6(5)196.6(5) keV transition of the 1/2βˆ’[521]1/2^{-}[521] band, and 15/2βˆ’β†’11/2βˆ’15/2^{-}\rightarrow11/2^{-} to the 189(1)189(1) keV transition of the 7/2βˆ’[514]7/2^{-}[514] band, respectively. The proton N=7N=7 major shell is included in the calculations. The intruder of the highβˆ’j-j lowβˆ’Ξ©-\Omega orbitals 1j15/21j_{15/2} (1/2βˆ’[770]) (1/2^{-}[770]) at the high spin leads to the band-crossing at β„Ο‰β‰ˆ0.20\hbar\omega\approx0.20 (β„Ο‰β‰ˆ0.25\hbar\omega\approx0.25) MeV for the 7/2βˆ’[514]7/2^{-}[514] Ξ±=βˆ’1/2\alpha=-1/2 (Ξ±=+1/2\alpha=+1/2) band, and at β„Ο‰β‰ˆ0.175\hbar\omega\approx0.175 MeV for the 1/2βˆ’[521]1/2^{-}[521] Ξ±=βˆ’1/2\alpha=-1/2 band, respectively. Further investigations show that the band-crossing frequencies are quadrupole deformation dependent.Comment: arXiv admin note: text overlap with arXiv:1208.1156 by other author

    Post Newtonian Rigid Body

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    In this paper, it is the first time to construct a complete post-Newtonian (PN) model of a rigid body by means of a new constraint on the mass current density and mass density. In our PN rigid body model most of relations, such as spin vector proportional to the angular velocity, the definition on the moment of inertia tensor, the key relation between the mass quadrupole moment and the moment of inertia tensor, rigid rotating formulae of mass quadrupole moment and the moment of inertia tensor, are just the extension of the main relations in Newtonian rigid body model. When all of 1/c21/c^2 terms are neglected, the PN rigid body model and the corresponding formulae reduce to Newtonian version. The key relation is obtained in this paper for the first time, which might be very useful in the future application to problems in geodynamics and astronomy.Comment: Revtex4, 5 page

    Amplification effects in optomechanics via weak measurement

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    We revisit the scheme of single-photon weak-coupling optomechanics using post-selection, proposed by Pepper, Ghobadi, Jeffrey, Simon and Bouwmeester [Phys. Rev. Lett. 109, 023601 (2012)], by analyzing the exact solution of the dynamical evolution. Positive and negative amplification effects of the displacement of the mirror's position can be generated when the Kerr phase is considered. This effect occurs when the post-selected state of the photon is orthogonal to the initial state, which can not be explained by the usual weak measurement results. The amplification effect can be further modulated by a phase shifter, and the maximal displacement state can appear within a short evolution time

    Majorana corner states in a two-dimensional magnetic topological insulator on a high-temperature superconductor

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    Conventional nn-dimensional topological superconductors (TSCs) have protected gapless (nβˆ’1)(n - 1)-dimensional boundary states. In contrast to this, second-order TSCs are characterized by topologically protected gapless (nβˆ’2)(n - 2)-dimensional states with usual gapped (nβˆ’1)(n - 1)-boundaries. Here, we study a second-order TSC with a two-dimensional (2D) magnetic topological insulator (TI) proximity-coupled to a high-temperature superconductor, where Majorana bound states (MBSs) are localized at the corners of a square sample with gapped edge modes. Due to the mirror symmetry of the hybrid system considered here, there are two MBSs at each corner for both cases: d-wave and sΒ±s_{\pm}-wave superconducting pairing. We present the corresponding topological phase diagrams related to the role of the magnetic exchange interaction and the pairing amplitude. A detailed analysis, based on edge theory, reveals the origin of the existence of MBSs at the corners of the 2D sample, which results from the sign change of the Dirac mass emerging at the intersection of any two adjacent edges due to pairing symmetry. Possible experimental realizations are discussed. Our proposal offers a promising platform for realizing MBSs and performing possible non-Abelian braiding in 2D systems.Comment: 11 pages, 9 figures. Published versio
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