5,973 research outputs found

    Tuning Kinetic Magnetism of Strongly Correlated Electrons via Staggered Flux

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    We explore the kinetic magnetism of the infinite-UU repulsive Hubbard models at low hole densities on various lattices with nearest-neighbor hopping integrals modulated by a staggered magnetic flux ±ϕ\pm\phi. Tuning ϕ\phi from 0 to π\pi makes the ground state (GS) change from a Nagaoka-type ferromagnetic state to a Haerter-Shastry-type antiferromagnetic state at a critical ϕc\phi_c, with both states being of kinetic origin. Intra-plaquette spin correlation, as well as the GS energy, signals such a quantum criticality. This tunable kinetic magnetism is generic, and appears in chains, ladders and two-dimensional lattices with squares or triangles as elementary constituents.Comment: 4 pages, 5 figures, 1 tabl

    Fractional exclusion and braid statistics in one dimension: a study via dimensional reduction of Chern-Simons theory

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    The relation between braid and exclusion statistics is examined in one-dimensional systems, within the framework of Chern-Simons statistical transmutation in gauge invariant form with an appropriate dimensional reduction. If the matter action is anomalous, as for chiral fermions, a relation between braid and exclusion statistics can be established explicitly for both mutual and nonmutual cases. However, if it is not anomalous, the exclusion statistics of emergent low energy excitations is not necessarily connected to the braid statistics of the physical charged fields of the system. Finally, we also discuss the bosonization of one-dimensional anyonic systems through T-duality.Comment: 19 pages, fix typo

    Effects of tidally enhanced stellar wind on the horizontal branch morphology of globular clusters

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    Metallicity is the first parameter to influence the horizontal branch (HB) morphology of globular clusters (GCs). It has been found, however, that some other parameters may also play an important role in affecting the morphology. While the nature of these important parameters remains unclear, they are believed to be likely correlated with wind mass-loss of red giants, since this mass loss determines their subsequent locations on the HB. Unfortunately, the mass loss during the red giant stages of the stellar evolution is poorly understood at present. The stellar winds of red giants may be tidally enhanced by companion stars if they are in binary systems. We investigate evolutionary consequences of red giants in binaries by including tidally enhanced stellar winds, and examine the effects on the HB morphology of GCs. We find that red, blue, and extreme horizontal branch stars are all produced under the effects of tidally enhanced stellar wind without any additional assumptions on the mass-loss dispersion. Furthermore, the horizontal branch morphology is found to be insensitive to the tidal enhancement parameter, Bw. We compare our theoretical results with the observed horizontal branch morphology of globular cluster NGC 2808, and find that the basic morphology of the horizontal branch can be well reproduced. The number of blue horizontal branch stars in our calculations, however, is lower than that of NGC 2808.Comment: 7 pages, 4 figures, 2 tables, accepted for publication in Astronomy & Astrophysic

    A Study on the Motivational Mechanism of Creative Situations

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    Using the organismic dialectical metatheory and the empirical research approach, this study systemically explores the relationship between creative situations and creative behavior. The study finds that the opinion proposed by organismic dialectical metatheory, that needs and motivation mediate the situation and the behavior, is true. Also, support from leaders and the richness of resources are primary components of creative situations. Furthermore, the satisfaction of self-determination and competence is at the core of creative activity; enjoyment is the direct cause for creative behavior, and pursuit of challenges is the most important indirect cause

    Controlling soliton interactions in Bose-Einstein condensates by synchronizing the Feshbach resonance and harmonic trap

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    We present how to control interactions between solitons, either bright or dark, in Bose-Einstein condensates by synchronizing Feshbach resonance and harmonic trap. Our results show that as long as the scattering length is to be modulated in time via a changing magnetic field near the Feshbach resonance, and the harmonic trapping frequencies are also modulated in time, exact solutions of the one-dimensional nonlinear Schr\"{o}dinger equation can be found in a general closed form, and interactions between two solitons are modulated in detail in currently experimental conditions. We also propose experimental protocols to observe the phenomena such as fusion, fission, warp, oscillation, elastic collision in future experiments.Comment: 7 pages, 7 figure

    Single-shot determination of spin-polarization for ultrarelativistic electron beams via nonlinear Compton scattering

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    Impacts of spin-polarization of an ultrarelativistic electron beam head-on colliding with a strong laser pulse on emitted photon spectra and electron dynamics have been investigated in the quantum radiation regime. We simulate photon emissions quantum mechanically and electron dynamics semiclassically via taking spin-resolved radiation probabilities in the local constant field approximation. A small ellipticity of the laser field brings about an asymmetry in angle-resolved photon spectrum, which sensitively relies on the polarization of the electron beam. The asymmetry is particularly significant in high-energy photon spectra, and is employed for the polarization detection of a high-energy electron beam with extraordinary precision, e.g., better than 0.3\% for a few-GeV electron beam at a density of the scale of 101610^{16} cm3^{-3} with currently available strong laser fields. This method demonstrates for the first time a way of single-shot determination of polarization for ultrarelativistic electron beams via nonlinear Compton scattering. A similar method based on the asymmetry in the electron momentum distribution after the interaction due to spin-dependent radiation reaction is proposed as well

    Electron-Angular-Distribution Reshaping in Quantum Radiation-Dominated Regime

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    Dynamics of an electron beam head-on colliding with an ultraintense focused ultrashort circularly-polarized laser pulse are investigated in the quantum radiation-dominated regime. Generally, the ponderomotive force of the laser fields may deflect the electrons transversely, to form a ring structure on the cross-section of the electron beam. However, we find that when the Lorentz factor of the electron γ\gamma is approximately one order of magnitude larger than the invariant laser field parameter ξ\xi, the stochastic nature of the photon emission leads to electron aggregation abnormally inwards to the propagation axis of the laser pulse. Consequently, the electron angular distribution after the interaction exhibits a peak structure in the beam propagation direction, which is apparently distinguished from the "ring"-structure of the distribution in the classical regime, and therefore, can be recognized as a proof of the fundamental quantum stochastic nature of radiation. The stochasticity signature is robust with respect to the laser and electron parameters and observable with current experimental techniques
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