364 research outputs found

    Properties of an almost localized Fermi liquid in applied magnetic field revisited: Statistically consistent Gutzwiller approach

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    We discuss the Hubbard model in an applied magnetic field and analyze the properties of neutral spin-1/2 fermions within the so-called statistically consistent Gutzwiller approximation (SGA). The magnetization curve reproduces in a semiquantitative manner the experimental data for liquid 3 He in the regime of moderate correlations and in the presence of small number of vacant cells, modeled by a non-half filled-band situation, when a small number of vacancies (up to 5%) is introduced in the virtual fcc lattice. We also present the results for the magnetic susceptibility and the specific heat, in which a metamagnetic-like behavior is also singled out in a non-half-filled band case

    Superconducting properties of the hole-doped three-band \emph{d-p} model studied with minimal-size real-space \emph{d}-wave pairing operators

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    The three-band \emph{d-p} model is investigated by means of Variational Monte-Carlo (VMC) method with the BCS-like wave-function supplemented by the Gutzwiller and Jastrow correlators. The VMC optimization leads to dd-wavewave superconducting state with a characteristic dome-like shape of the order parameter for hole doping δ≲0.4\delta \lesssim 0.4, in a good agreement with the experimental observations. Also, the off-diagonal pair-pair correlation functions, calculated within VMC, vindicates the results obtained very recently within the diagrammatic expansion of the Gutzwiller wave function method (DE-GWF) [cf. Phys. Rev. B \textbf{99}, 104511 (2019)]. Subsequently, the nature of the dd-wavewave pairing is investigated by means of recently proposed \emph{minimal-size real-space d-wave pairing operators} [Phys. Rev. B \textbf{100}, 214502 (2019)]. An emergence of the long-range superconducting ordering for both dd and pp orbitals is reported by analysing the corresponding off-diagonal pair-pair correlation functions. The dominant character of \emph{d-wave} pairing on dd orbitals is confirmed. Additionally, the trial wave-function is used to investigate the magnetic properties of the system. The analysis of spin-spin correlation functions is carried out and shows antiferromagnetic q=(π,π)\mathbf{q}=(\pi,\pi), short-range order, as expected. For the sake of completeness, the charge gap has been estimated, which for the parent compound takes the value ΔCG≈1.78±0.51 eV\Delta_{CG}\approx1.78\pm0.51\text{ eV}, and agrees with values reported experimentally for the cuprates

    Neither backward masking of T2 nor task switching is necessary for the attentional blink

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    Identification of the second of two targets (T1, T2, inserted in a stream of distractors) is impaired when presented within 500 ms after the first (attentional blink, AB). Barring a T1-T2 task-switch, it is thought that T2 must be backward-masked to obtain an AB (Giesbrecht & Di Lollo, Journal of Experimental Psychology: Human Perception and Performance, 24, 1454- 1466, 1998). We tested the hypothesis that Giesbrecht & Di Lollo's findings were vitiated by ceiling constraints arising from either response scale (experiment 1) or data limitations (experiment 2). In experiment 1, digitdistractors were replaced with pseudoletters to increase task difficulty, bringing performance below ceiling. An AB occurred without backward masking of T2. In experiment 2, a ceiling-free procedure estimated the number of noise dots needed for 80% T2 identification. An AB was revealed: fewer noise dots were required during the AB period than outside it. Both outcomes confirm that an AB can be obtained without either masking of T2 or task switching
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