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- periodic paperclip-shaped structure
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- UIN Suska Riau
- Xi'an University of the Science and Technology
- University of Riau
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Masked states of an atom coupled to a standing-wave cavity mode
摘要： The form of the eigenstates of an atom coupled to a cavity mode displaying a three-dimensional periodic profile are obtained. It is shown that the quantized motion leads to degenerate states where the atomic degrees of freedom are masked, that is, upon detection of one component of this composite system the others remain in an entangled state. When the system is extended to include drive and dissipation it is found to undergo a dissipative quantum phase transition at a critical drive amplitude. Unlike other phase transitions reported in the literature, the degeneracy prepares the system in a superposition of incompatible states upon detection of the electromagnetic field. Probing the field hints at an order above the transition point that, due to state masking, allows for atomic coherence to survive at long times.
关键词： atom-cavity coupling,atomic coherence,entangled state,dissipative quantum phase transition,state masking,degenerate states,quantized motion
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Coventry, United Kingdom (2019.10.9-2019.10.10)] 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Microscopic degradation and failure processes in high-power diode lasers
摘要： In practical mobile communication engineering applications, surfaces of antenna array deployment regions are usually uneven. Therefore, massive multi-input–multi-output (MIMO) communication systems usually transmit wireless signals by irregular antenna arrays. To evaluate the performance of irregular antenna arrays, the matrix correlation coefficient and the ergodic received gain are defined for massive MIMO communication systems with mutual coupling effects. Furthermore, the lower bound of the ergodic achievable rate, symbol error rate, and average outage probability is first derived for multi-user massive MIMO communication systems using irregular antenna arrays. Asymptotic results are also derived when the number of antennae approaches infinity. Numerical results indicate that there exists a maximum achievable rate when the number of antennae keeps increasing in massive MIMO communication systems using irregular antenna arrays. Moreover, the irregular antenna array outperforms the regular antenna array in the achievable rate of massive MIMO communication systems when the number of antennae is larger than or equal to a given threshold.
关键词： mutual coupling,irregular antenna array,achievable rate,Massive MIMO
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - The role of financing in realizing ultra-low solar electricity prices in the Middle East
摘要： A hybrid approach is proposed to signal integrity analysis of trace and vias in plate pair with an in?nitely large dimension. By using the domain decomposition method, trace domain and via domain are divided from the plate domain. Each individual domain of via and trace structure is modeled by the 3-D full-wave tool HFSS as a multimode network composed of TEM mode waveguide ports at top/bottom antipad interfaces and vertical lumped ports on the segmentation interfaces. The plate domain is dominated by TMZ 0 modes and network parameters are solved by boundary integral method. Connection of network of each domain enforces the ?eld continuity conditions along the segmentation interfaces and yields the ?nal S parameter of trace and via as well as trace/via to trace/via coupling. Once the via pattern and trace routing are determined, the coupling can be ef?ciently modeled by the proposed hybrid approach and the layouts of via structures and trace routing in a plate pair are ef?ciently optimized.
关键词： trace/via to trace/via coupling,domain decomposition method (DDM),Contour integral equation
更新于2025-09-23 15:19:57
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Coupled plasmona??phonon modes in monolayer MoS <sub/>2</sub>
摘要： We present a theoretical study of the plasmon–phonon coupling in a suspended monolayer MoS2 and a MoS2 substrate system using a diagrammatic self-consistent field theory. The four coupled plasmon–phonon modes and the four plasmon-surface phonon modes are observed due to the spin–orbit and electron-optic phonon interactions. The two of coupled plasmon–phonon and plasmon-surface phonon modes are optic-like and the other two are acoustic-like. The plasmon are strongly coupled with the optic-phonon in MoS2 and the surface optic-phonon in the substrates as the electron density or wave-vector increases. The strong plasmon–phonon coupling shows that the optoelectronic properties of monolayer MoS2 are evidently modulated by electron–phonon interactions. The hybrid plasmon–phonon polaritons can be achieved by strong light-mater interactions. This study is relevant to the application of MoS2 as novel plasmonic and nanophotonic devices.
关键词： plasmon–phonon coupling,plasmon,two dimensional materials
更新于2025-09-23 15:19:57
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Theoretical and experimental investigations on the bulk photovoltaic effect in lead-free perovskites MASnI <sub/>3</sub> and FASnI <sub/>3</sub>
摘要： Perovskite solar cells based on the lead free hybrid organic–inorganic CH3NH3SnI3 (MASnI3) and CH4N2SnI3 (FASnI3) perovskites were fabricated, and the photoelectric conversion e?ciency (PCE) was assessed. FASnI3's PCE was higher than MASnI3's e?ciency. To study the di?erent photovoltaic properties, we calculated their structural, electronic, and optical properties using density functional theory via the Perdew–Burke–Ernzerhof and spin–orbit coupling (PBE-SOC) methods. The results show that FASnI3 exhibits an appropriate band gap, substantial stability, marked optical properties, and signi?cant hole and electron conductive behavior compared with MASnI3. The interaction of organic cations (FA+) with the inorganic framework of FASnI3 was stronger than that with MASnI3, so they a?ected the band length and band angle distribution, causing the structure of the FASnI3 and MASnI3 to change. The calculations also demonstrated that energy splitting was evident in FASnI3 due to the spin–orbit coupling e?ect, however, it was moderate in MASnI3, which was caused by the H bond e?ect. This research not only furthers the understanding of these functional materials, but also can assist the development of highly e?cient and stable non-lead perovskite solar cells.
关键词： MASnI3,Perovskite solar cells,spin–orbit coupling,lead-free,density functional theory,photoelectric conversion efficiency,FASnI3
更新于2025-09-23 15:19:57
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Emergence of two-magnon modes below spin-reorientation transition and phonon-magnon coupling in bulk BiFeO3: An infrared spectroscopic study
摘要： We have studied the low-temperature magnetic and infrared measurements on the BiFeO3 ceramic sample to investigate the behavior of phonons and magnon-phonon coupling below 300 K. From the magnetic study, we noticed two magnetic transitions near 150 and 257 K due to the spin-reorientation. Besides, this sample is found to be a mean-field system rather than a glassy system. In our assignment of the infrared modes, all the 13 allowed phonon modes are accounted for rhombohedral BiFeO3 at room temperature itself. Almost all the modes show anomalous behavior in their frequency dependence, close to the observed magnetic transitions. In addition, the emergence of two-magnon modes at 106 and 111 cm-1 below 160 K is observed due to a modification in the noncollinear spin structure. These results indicate the presence of magnon-phonon coupling in multiferroic BiFeO3 below room temperature.
关键词： infrared spectroscopy,Multiferroics,magnetic properties,magnon-phonon coupling
更新于2025-09-23 15:19:57
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Enhancing electrostatic coupling in silicon quantum dot array by dual gate oxide thickness for large-scale integration
摘要： We propose a structure with word/bit line control for a two-dimensional quantum dot array, which allows random access for arbitrary quantum dots with a small number of control signals. To control multiple quantum dots with a single signal, every quantum dot should have a wide operating voltage allowance to overcome the property variations. We fabricate two-dimensional quantum dot arrays using silicon-complementary-metal-oxide-semiconductor technology with an alternating dual-standard gate oxide thickness. The quantum dots are designed to have an allowable operating voltage window of 0.2 V to control the number of electrons, which is a window one order of magnitude wider than that of previous works. The proposed structure enables both easy fabrication and operation for multiple quantum dots and will pave the way for practical use of large-scale quantum computers.
关键词： electrostatic coupling,dual gate oxide thickness,quantum dot array,large-scale integration,silicon-complementary-metal-oxide-semiconductor technology
更新于2025-09-23 15:19:57
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Gatea??Couplinga??Enabled Robust Hysteresis for Nonvolatile Memory and Programmable Rectifier in Van der Waals Ferroelectric Heterojunctions
摘要： Ferroelectric field-effect transistors (FeFETs) are one of the most interesting ferroelectric devices; however, they, usually suffer from low interface quality. The recently discovered 2D layered ferroelectric materials, combining with the advantages of van der Waals heterostructures (vdWHs), may be promising to fabricate high-quality FeFETs with atomically thin thickness. Here, dual-gated 2D ferroelectric vdWHs are constructed using MoS2, hexagonal boron nitride (h-BN), and CuInP2S6 (CIPS), which act as a high-performance nonvolatile memory and programmable rectifier. It is first noted that the insertion of h-BN and dual-gated coupling device configuration can significantly stabilize and effectively polarize ferroelectric CIPS. Through this design, the device shows a record-high performance with a large memory window, large on/off ratio (107), ultralow programming state current (10?13 A), and long-time endurance (104 s) as nonvolatile memory. As for programmable rectifier, a wide range of gate-tunable rectification behavior is observed. Moreover, the device exhibits a large rectification ratio (3 × 105) with stable retention under the programming state. This demonstrates the promising potential of ferroelectric vdWHs for new multifunctional ferroelectric devices.
关键词： nonvolatile memory,programmable rectifiers,ferroelectrics,dual-gated coupling,van der Waals heterostructures,2D
更新于2025-09-23 15:19:57
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Four-wave mixing in spin-orbit coupled Bose-Einstein condensates
摘要： We describe possibilities of spontaneous, degenerate four-wave mixing (FWM) processes in spin-orbit coupled Bose-Einstein condensates. Phase matching conditions (i.e., energy and momentum conservation laws) in such systems allow one to identify four different configurations characterized by involvement of distinct spinor states in which such a process can take place. We derived these conditions from first principles and then illustrated dynamics with direct numerical simulations. We found, among others, the unique configuration, where both probe waves have smaller group velocity than pump wave and proved numerically that it can be observed experimentally under proper choice of the parameters. We also reported the case when two different FWM processes can occur simultaneously. The described resonant interactions of matter waves is expected to play important role in the experiments of BEC with artificial gauge fields. Beams created by FWM processes are important source of correlated particles and can be used the experiments testing quantum properties of atomic ensembles.
关键词： four-wave mixing,Bose-Einstein condensate,Spin-orbit coupling
更新于2025-09-23 15:19:57
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[IEEE 2019 6th International Conference on Advanced Control Circuits and Systems (ACCS) & 2019 5th International Conference on New Paradigms in Electronics & information Technology (PEIT) - Hurgada, Egypt (2019.11.17-2019.11.20)] 2019 6th International Conference on Advanced Control Circuits and Systems (ACCS) & 2019 5th International Conference on New Paradigms in Electronics & information Technology (PEIT) - Compact Adiabatic Taper for SOI Waveguide
摘要： In this paper, we present a novel design of an adiabatic compact taper which can be used as a converter between a grating coupler and a single-mode optical fiber at 1550 nm wavelength. The proposed taper in this paper is coupling the light between a wide grating coupler with width 15μ and nanophotonic waveguide with width 500nm. Besides, the length of the proposed design is 22μm. Therefore, it is a compact design as it has a small footprint which leads to high efficiency and low costs in fabrication. The coupling efficiency is around 92%.
关键词： SOI,Coupling,Silicon Photonics
更新于2025-09-23 15:19:57