10 research outputs found

    Mott Insulator - Superfluid Transitions in a Two Band Model at Finite Temperature and Possible Application to Supersolid 4He

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    We study Mott insulator - superfluid transition in a two-band boson Hubbard model, which can be mapped onto a spin-1/2 XY model with spins coupled to an additional Ising degree of freedom. By using a modified mean field theory that include the effects of phase fluctuations, we show that the transition is first order at both zero and finite temperatures. On the Mott insulator side, there may be reentrance in phase transition. These features are consequences of the underlying transition between competing defect poor and defect rich phases. The relevance of the model and our results to supersolid 4He and cold bosonic atoms in optical lattices are discussed

    Scanning tunneling spectroscopy of a magnetic atom on graphene in the Kondo regime

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    The Kondo effect in the system consisting of a magnetic adatom on the graphene is studied. By using the non-equilibrium Green function method with the slave-boson mean field approximation, the local density of state (LDOS) and the conductance are calculated. For a doped graphene, the Kondo phase is present at all time. Surprisingly, two kinds of Kondo regimes are revealed. But for the undoped graphene, the Kondo phase only exists if the adatom's energy level is beyond a critical value. The conductance is similar to the LDOS, thus, the Kondo peak in the LDOS can be observed with the scanning tunneling spectroscopy. In addition, in the presence of a direct coupling between the STM tip and the graphene, the conductance may be dramatically enhanced, depending on the coupling site.Comment: 4 pages, 4 figures, accepted by EP

    Daniel Chee Tsui, 崔琦 1998 Nobel Laureate in Physics

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    Non-Rayleigh photon statistics of superbunching pseudothermal light

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    Superbunching pseudothermal light has important applications in studying the second- and higher-order interference of light in quantum optics. Unlike the photon statistics of thermal or pseudothermal light is well understood, the photon statistics of superbunching pseudothermal light has not been studied yet. In this paper, we will employ single-photon detectors to measure the photon statistics of superbunching pseudothermal light and calculate the degree of second-order coherence. It is found that the larger the value of the degree of second-order coherence of superbunching pseudothermal light is, the more the measured photon distribution deviates from the one of thermal or pseudothermal light in the tail part. The results are helpful to understand the physics of two-photon superbunching with classical light. It is suggested that superbunching pseudothermal light can be employed to generate non-Rayleigh temporal speckles.</jats:p

    Correction: Enhanced thermal conductance at the graphene–water interface based on functionalized alkane chains

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    Correction for ‘Enhanced thermal conductance at the graphene–water interface based on functionalized alkane chains’ by Shuyu Chen et al., RSC Adv., 2019, 9, 4563–4570.</p

    Safety and Efficacy of Remote Ischemic Conditioning in Patients With Intravenous Thrombolysis: The SERIC-IVT Trial

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    BACKGROUND: Approximately half of the patients with acute ischemic stroke who receive intravenous thrombolysis (IVT) do not achieve an excellent outcome. Remote ischemic conditioning (RIC) as a promising neuroprotective treatment may improve clinical outcomes in this population. This study aimed to assess the efficacy and safety of RIC in patients with IVT. METHODS: This multicenter, participant-blinded, blinded end point, randomized controlled clinical trial included 558 patients with acute ischemic stroke who underwent IVT in 18 hospitals from August 2021 to May 2023. After IVT, patients were randomized 1:1 to the RIC (unilateral upper limb; cuff pressure, 200 mm Hg, twice daily for 7 days) or sham RIC groups (the same procedure; cuff pressure, 60 mm Hg). The primary efficacy outcome was an excellent functional outcome (modified Rankin Scale score, 0–1) at 90 days after IVT. RESULTS: In total, 558 eligible patients were randomized, and 11 (2.0%) were excluded because they did not receive an RIC or sham RIC. Thus, 547 patients (RIC, n=274; sham RIC, n=273) were included in the modified intention-to-treat analysis, of whom 15 patients were lost to follow-up and 532 (95.3%) completed the trial. At 90 days, 62.7% of patients in the RIC group and 56.8% in the sham RIC group had an excellent functional outcome (unadjusted risk ratio, 1.10 [95% CI, 0.96–1.27]; P=0.169). The proportion of patients with any adverse events was 11.2% in the RIC group and 8.1% in the sham RIC group, with no significant difference (P=0.221). CONCLUSIONS: RIC was safe in patients with acute ischemic stroke who received IVT. However, it did not significantly improve excellent functional outcome
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