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<jats:p>We report the conductance and average current through a triple-quantum-dot interferometer coupled with two ferromagnetic leads using the nonequilibrium Green’s function. The results show that the interference between the resonant process and the non-resonant process leads to the formation of Fano resonance. More Fano resonances can be observed by applying a time-dependent external field. As a Zeeman magnetic field is applied, the spin-up electron transport is depressed in a certain range of electron energy levels. A spin-polarized pulse device can be realized by adjusting the spin polarization parameters of ferromagnetic leads. Moreover, the <jats:italic>I</jats:italic>–<jats:italic>V</jats:italic> characteristic curves show that under the influence of Fano resonance, the spin polarization is significantly enhanced by applying a relatively large reverse bias voltage. These results strongly suggest that the spin-polarized pulse device can be potentially applied as a spin-dependent quantum device.</jats:p>

<jats:p>We report an in-depth investigation on the out-of-plane lower critical field <jats:italic>H</jats:italic> <jats:sub>c1</jats:sub> of the KCa<jats:sub>2</jats:sub>(Fe<jats:sub>1−<jats:italic>x</jats:italic> </jats:sub> Co<jats:sub> <jats:italic>x</jats:italic> </jats:sub>)<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>F<jats:sub>2</jats:sub> (12442-type, <jats:italic>x</jats:italic> = 0, 0.1). The multi-gap feature is revealed by the kink in the temperature-dependent <jats:italic>H</jats:italic> <jats:sub>c1</jats:sub>(<jats:italic>T</jats:italic>) curve for the two samples with different doping levels. Based on a simplified two-gap model, the magnitudes of the two gaps are determined to be <jats:italic>Δ</jats:italic> <jats:sub>1</jats:sub> = 1.2 meV and <jats:italic>Δ</jats:italic> <jats:sub>2</jats:sub> = 5.0 meV for the sample with <jats:italic>x</jats:italic> = 0, <jats:italic>Δ</jats:italic> <jats:sub>1</jats:sub> = 0.86 meV and <jats:italic>Δ</jats:italic> <jats:sub>2</jats:sub> = 2.8 meV for that with <jats:italic>x</jats:italic> = 0.1. With the cobalt doping, the ratio of energy gap to critical transition temperature (<jats:italic>Δ</jats:italic>/<jats:italic>k</jats:italic> <jats:sub>B</jats:sub> <jats:italic>T</jats:italic> <jats:sub>c</jats:sub>) remains almost unchanged for the smaller gap and is suppressed by 20% for the larger gap. For the undoped KCa<jats:sub>2</jats:sub>Fe<jats:sub>4</jats:sub>As<jats:sub>4</jats:sub>F<jats:sub>2</jats:sub>, the obtained gap sizes are generally consistent with the results of angle-resolved photoemission spectroscopy experiments.</jats:p>

<jats:p>We report that the ferromagnetic resonance (FMR) response of the CoFeB/HfO<jats:sub>2</jats:sub> heterostructures is stabilized and reversibly manipulated by ionic gel. Ionic gel with excellent flexibility is used as a medium to form an electric field. When a 4 V gate voltage is applied, the resonance field <jats:italic>H</jats:italic> <jats:sub>r</jats:sub> and peak-to-peak linewidth Δ<jats:italic>H</jats:italic> <jats:sub>pp</jats:sub> at different angles are regulated. When <jats:italic>θ</jats:italic> = 20°, the <jats:italic>H</jats:italic> <jats:sub>r</jats:sub> is regulated up to 82 Oe. When <jats:italic>θ</jats:italic> = 70°, Δ<jats:italic>H</jats:italic> <jats:sub>pp</jats:sub> is tuned up to 75 Oe. When the gate voltage is repeatedly applied, the FMR spectra can be freely switched between the initial state and the gated state. Our study provides an effective method to manipulate the damping of the magnetic film stably and reversibly.</jats:p>

<jats:p>Semiconductor colloidal nanocrystals (NCs) can interact with each other to profoundly influence the charge transfer, transport and extraction processes after they have been assembled into a high-density film for optoelectronic device applications. These interactions normally occur among several nearby single colloidal NCs, which should be effectively separated from their surroundings to remove the ensemble average effect for fine optical characterizations. By means of atomic force microscopy (AFM) nanoxerography, here we prepare individual clusters of perovskite CsPbBr<jats:sub>3</jats:sub> NCs and perform single-particle measurements on their optical properties at the cryogenic temperature. While discrete photoluminescence bands can be resolved from the several single CsPbBr<jats:sub>3</jats:sub> NCs that are contained within an individual cluster, the shorter- and longer-wavelength bands are dramatically different in that their intensities show sub- and superlinear dependences on the laser excitation powers, respectively. This can be explained by the generation of charged excitons (trions) at high laser excitation powers, and their subsequent Dexter-type energy transfer from smaller- to larger-sized CsPbBr<jats:sub>3</jats:sub> NCs. Our findings not only suggest that these individual clusters prepared by AFM nanoxerography can serve as a potent platform to explore few-NC interactions but they also reveal the long-neglected role played by trions in channeling photo-excited energies among neighboring NCs.</jats:p>

<jats:p>Quantum sensing, using quantum properties of sensors, can enhance resolution, precision, and sensitivity of imaging, spectroscopy, and detection. An intriguing question is: Can the quantum nature (quantumness) of sensors and targets be exploited to enable schemes that are not possible for classical probes or classical targets? Here we show that measurement of the quantum correlations of a quantum target indeed allows for sensing schemes that have no classical counterparts. As a concrete example, in the case that the second-order classical correlation of a quantum target could be totally concealed by non-stationary classical noise, the higher-order quantum correlations can single out a quantum target from the classical noise background, regardless of the spectrum, statistics, or intensity of the noise. Hence a classical-noise-free sensing scheme is proposed. This finding suggests that the quantumness of sensors and targets is still to be explored to realize the full potential of quantum sensing. New opportunities include sensitivity beyond classical approaches, non-classical correlations as a new approach to quantum many-body physics, loophole-free tests of the quantum foundation, et cetera.</jats:p>

<jats:p>We investigate quantum heat transfer in a nonequilibrium qubit-phonon hybrid open system, dissipated by external bosonic thermal reservoirs. By applying coherent phonon states embedded in the dressed quantum master equation, we are capable of dealing with arbitrary qubit-phonon coupling strength. It is counterintuitively found that the effect of negative differential thermal conductance is absent at strong qubit-phonon hybridization, but becomes profound at weak qubit-phonon coupling regime. The underlying mechanism of decreasing heat flux by increasing the temperature bias relies on the unidirectional transitions from the up-spin displaced coherent phonon states to the down-spin counterparts, which seriously freezes the qubit and prevents the system from completing a thermodynamic cycle. Finally, the effects of perfect thermal rectification and giant heat amplification are unraveled, thanks to the effect of negative differential thermal conductance. These results of the nonequilibrium qubit-phonon open system would have potential implications in smart energy control and functional design of phononic hybrid quantum devices.</jats:p>

<jats:p>The advent of transformation thermotics has seen a boom in development of thermal metamaterials with a variety of thermal functionalities, including phenomena such as thermal cloaking and camouflage. However, most thermal metamaterials-based camouflage devices only tune in-plane heat conduction, which may fail to conceal a target from out-of-plane detection. We propose an adaptive radiative thermal camouflage via tuning out-of-plane transient heat conduction, and it is validated by both simulation and experiment. The physics underlying the performance of our adaptive thermal camouflage is based on real-time synchronous heat conduction through the camouflage device and the background plate, respectively. The proposed concept and device represent a promising new approach to fabrication of conductive thermal metamaterials, providing a feasible and effective way to achieve adaptive thermal camouflage.</jats:p>

<jats:p>By extending the conventional scattering canceling theory, we propose a new design method for thermal cloaks based on isotropic materials. When the objects are covered by the designed cloaks, they will not disturb the temperature profile in the background zone. In addition, if different inhomogeneity coefficients are selected in the thermal cloak design process, these cloaks can manipulate the temperature gradient of the objects, i.e., make the temperature gradients higher, lower, or equal to the thermal gradient in the background zone. Therefore, thermal transparency, heat concentration or heat shield effects can be realized under a unified framework.</jats:p>

<jats:p>We report a search for new physics signals using the low energy electron recoil events in the complete data set from PandaX-II, in light of the recent event excess reported by XENON1T. The data correspond to a total exposure of 100.7 ton⋅day with liquid xenon. With robust estimates of the dominant background spectra, we perform sensitive searches on solar axions and neutrinos with enhanced magnetic moment. It is found that the axion-electron coupling <jats:italic>g</jats:italic> <jats:sub>Ae</jats:sub> &lt; 4.6 × 10<jats:sup>–12</jats:sup> for an axion mass less than 0.1 keV/<jats:italic>c</jats:italic> <jats:sup>2</jats:sup> and the neutrino magnetic moment <jats:italic>μ<jats:sub>ν</jats:sub> </jats:italic> &lt; 4.9 × 10<jats:sup>–11</jats:sup> <jats:italic>μ</jats:italic> <jats:sub>B</jats:sub> at 90 % confidence level. The observed excess from XENON1T is within our experimental constraints.</jats:p>