- 标题
- 摘要
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- 实验方案
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[IEEE 2019 IEEE International Electron Devices Meeting (IEDM) - San Francisco, CA, USA (2019.12.7-2019.12.11)] 2019 IEEE International Electron Devices Meeting (IEDM) - Integrated DFB Laser Diode and High-efficiency Mach-Zehnder Modulator using Membrane III-V Semiconductors on Si Photonics Platform
摘要： This paper presents a 3-D statistical channel impulse response (IR) model for urban line of sight (LOS) and non-LOS channels developed from 28- and 73-GHz ultrawide-band propagation measurements in New York City, useful in the design of 5G wireless systems that will operate in both the ultra-high frequency/microwave and millimeter-wave (mmWave) spectrum to increase channel capacities. A 3GPP-like stochastic IR channel model is developed from measured power delay profiles, angle of departure, and angle of arrival power spectra. The extracted statistics are used to implement a channel model and simulator capable of generating 3-D mmWave temporal and spatial channel parameters for arbitrary mmWave carrier frequency, signal bandwidth, and antenna beamwidth. The model presented here faithfully reproduces realistic IRs of measured urban channels, supporting air interface design of mmWave transceivers, filters, and multi-element antenna arrays.
关键词： 28 GHz,multipath,time cluster spatial lobe (TCSL),spatial lobe (SL),statistical simulator,5G,spatial channel model (SCM),73 GHz,Channel model,millimeter-wave (mmWave) propagation,3-D ray-tracing,time cluster (TC),impulse response (IR)
更新于2025-09-23 15:19:57
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Implementing a multi-target-qubit controlled-not gate with logical qubits outside a decoherence-free subspace and its application in creating quantum entangled states
摘要： In general, implementing a multi-logical-qubit gate by manipulating quantum states in a decoherence-free subspace (DFS) becomes more complex and difficult when increasing the number of logical qubits. In this work, we propose an idea to realize quantum gates by manipulating quantum states outside their DFS but having the states of the logical qubits remain in their DFS before and after the gate operation. This proposal has the following features: (i) because the states are manipulated outside the DFS, the multiqubit gate implementation can be simplified when compared to realizing a multiqubit gate via manipulating quantum states within the DFS, which usually requires unitary operations over a large DFS, and (ii) because the states of the logical qubits return to the DFS after the gate operation, the errors caused by decoherence during the gate operation are not accumulated for a long-running calculation, and the states of the logical qubits are immune to decoherence when they are stored. Based on this proposal, we then present a way for realizing a multi-target-qubit controlled-NOT gate using logical qubits encoded in a decoherence-free subspace against collective dephasing. This gate is realized by employing qutrits (three-level quantum systems) placed in a cavity or coupled to a resonator. This proposal has the following advantages: (i) the states of the logical qubits return to their DFS after the gate operation; (ii) the gate can be implemented with only a few basic operations; (iii) the gate operation time is independent of the number of logical qubits; (iv) this gate can be deterministically implemented because no measurement is needed; (v) the intermediate higher-energy level for all qutrits is not occupied during the entire operation, thus decoherence from this level is greatly suppressed; (vi) this proposal is universal and can be applied to realize the proposed gate using natural atoms or artificial atoms (e.g., quantum dots, nitrogen-vacancy centers, and various superconducting qutrits, etc.) placed in a cavity or coupled to a resonator. As an application, we also show how to apply this gate to create a Greenberger-Horne-Zeilinger (GHZ) entangled state of multiple logical qubits encoded in DFS, and further investigate the experimental feasibility for creating the GHZ state of three logical qubits in the DFS, by using six superconducting transmon qutrits coupled to a one-dimensional coplanar waveguide resonator.
关键词： decoherence-free subspace,qutrits,quantum gates,multi-target-qubit controlled-NOT gate,GHZ entangled states
更新于2025-09-23 15:19:57
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Synthesis of diameter controlled multiwall carbon nanotubes by microwave plasma-CVD on low-temperature and chemically processed Fe nanoparticle catalysts
摘要： Properties of carbon nanotubes sensitively depend on the structural configuration, e.g., chirality, diameter, layer number and the compositional characteristics. The size of catalyst nanoparticles used to grow the CNTs significantly controls its diameter. Generally, catalyst nanoparticles are size-optimized via high-temperature annealing of thin metal films. Presently, formation of size-controlled Fe nano-particles as the efficient catalyst has been pursued via a low-temperature (TCG) wet chemical process that bypasses the high-temperature annealing step and leads to a low average size of catalyst nanoparticles. Suitable progress of the oxidation–hydrolysis reactions of metal-bearing ferrite entities controls the crystallinity via dehydration of the intermediate constituent and diminution of the oxide component. Optimally low diameter Fe nanoparticles have been obtained at temperature around TCG ~ +10 °C via simultaneous prominent aerial oxidation and neutralization in a single step. In this present work multiwall carbon nanotubes of controlled diameter (~15–25 nm) have been produced by relatively low-temperature (~300 °C) plasma processing, using pre-designed shadow-mask assembly to create diffused and remote-plasma of (CH4 + H2) and CO2 as a weak oxidizing gas to selectively remove the surplus amorphous components, and also by controlling the size of catalyst Fe-nanoparticles on the substrate via low-temperature non-plasma synthesis process.
关键词： Carbon nanotube,Fe-nanoparticle synthesis,Diameter controlled growth,2.54 GHz microwave plasma,Raman scattering
更新于2025-09-23 15:19:57
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Verifying multipartite entangled Greenberger-Horne-Zeilinger states via multiple quantum coherences
摘要： The ability to generate and verify multipartite entanglement is an important benchmark for near-term quantum devices. We develop a scalable entanglement metric based on multiple quantum coherences and demonstrate experimentally on a 20-qubit superconducting device. We report a state fidelity of 0.5165 ± 0.0036 for an 18-qubit GHZ state, indicating multipartite entanglement across all 18 qubits. Our entanglement metric is robust to noise and only requires measuring the population in the ground state; it can be readily applied to other quantum devices to verify multipartite entanglement.
关键词： quantum coherence,multipartite entanglement,quantum computing,superconducting qubits,GHZ states
更新于2025-09-23 15:19:57
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[IEEE 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Sarajevo, Bosnia and Herzegovina (2019.9.2-2019.9.4)] 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Model of Fiber Optic Transmission System Based on the Red Pitaya
摘要： This paper presents numerical simulation results to study the impact of the co-existence between a fixed service (FS) system and 5G small cell networks at 28-, 38-, and 60-GHz millimeter-wave (mmWave) frequency bands. For this paper, two scenarios are considered: aggregation of interference from small cells into an FS receiver from base stations (BSs) to their associated user equipment (UE) (downlink) and the aggregation of cellular interference at the FS receiver from UEs to their associated BSs (downlink). Moreover, mmWave-specific propagation characteristics and attenuation factors are considered for a more precise simulation study. The simulation results determine how much interference rejection is required to protect the operation of FS. In addition, currently available mmWave modular antenna array (MAA) architectures are introduced. Based on the information, additional mmWave frequency sharing study is performed using the realistic MAA radiation patterns. Last, we compare and analyze the performance differences between ITU standard models and MAA solutions.
关键词： 28 GHz,frequency sharing study,modular antenna array,60 GHz,5G,Millimeter-wave,38 GHz
更新于2025-09-19 17:13:59
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Control power of high-dimensional controlled teleportation
摘要： To quantitatively analyze the control power of arbitrary d-dimensional controlled teleportation (CT), this paper investigates channels of entangled high-dimensional three-qudit standard Greenberger-Horne-Zeilinger (GHZ) and GHZ-type states. The upper bound on the controller’s power is established in the d-dimensional CT scheme. We identify a trade-off between the control power and the capacity of the quantum channels. The control power can be enhanced by reducing the dimension of the teleported information in a suitably high-dimensional quantum channel, or by increasing the dimension of the qudit held by the controller. Under controlled teleporting of a single qubit in a perfect CT scheme, the control power is maximized in the three-dimensional GHZ-type state channel. This maximum control power exceeds the highest predicted value in previous works and the upper bounds of control power in a two-dimensional quantum channel. Our studies provide a feasible method for achieving higher control power, and it may provide approaches to de?ne high-dimensional entanglement of multibody systems.
关键词： GHZ state,high-dimensional,GHZ-type state,controlled teleportation,control power
更新于2025-09-19 17:13:59
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Comment on a??Controlled mutual quantum entity authentication with an untrusted third partya??
摘要： Kang et al. (Quantum Inf Process 17(7):159, 2018) proposed a controlled mutual quantum entity authentication protocol with an untrusted third party. We reexamined its security and further found there is a secure ?aw, that is, the untrusted third party Charlie can get the shared key between Alice and Bob without being detected. In addition, we gave a strategy to avoid this secure ?aw.
关键词： GHZ-like states,Quantum cryptography,Bell states,Quantum entity authentication
更新于2025-09-19 17:13:59
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Liquid Crystal-Based Enclosed Coplanar Waveguide Phase Shifter for 54a??66 GHz Applications
摘要： A 0–10 V bias voltage-driven liquid crystal (LC) based 0–180? continuously variable phase shifter was designed, fabricated, and measured with insertion loss less than ?4 dB across the spectrum from 54 GHz to 66 GHz. The phase shifter was structured in an enclosed coplanar waveguide (ECPW) with LC as tunable dielectrics encapsulated by a unified ground plate in the design, which significantly reduced the instability due to floating effects and losses due to stray modes. By competing for spatial volume distribution of the millimeter-wave signal occupying lossy tunable dielectrics versus low-loss but non-tunable dielectrics, the ECPW’s geometry and materials are optimized to minimize the total of dielectric volumetric loss and metallic surface loss for a fixed phase-tuning range. The optimized LC-based ECPW was impedance matched with 1.85 mm connectors by the time domain reflectometry (TDR) method. Device fabrication featured the use of rolled annealed copper foil of lowest surface roughness with nickel-free gold-plating of optimal thickness. Measured from 54 GHz to 66 GHz, the phase shifter prototype presented a tangible improvement in phase shift effectiveness and signal-to-noise ratio, while exhibiting lower insertion and return losses, more ease of control, and high linearity as well as lower-cost fabrication as compared with up-to-date documentations targeting 60 GHz applications.
关键词： tunable circuits and devices,true time delay,millimeter-wave,60 GHz,liquid crystal,phase shifter,enclosed coplanar waveguide
更新于2025-09-19 17:13:59
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Single-input Multiple-output Multi-carrier Wireless Indoor Direction Finding in a Compact Multipath Scenario Using 2.4 GHz ISM Band2
摘要： Super-resolution direction of arrival (DoA) estimation of impinging signals from a line of sight (LOS) source and multiple point scatterers at the 2.4 GHz ISM band is considered within a compact area. The channel is partially frequency ?at in the interested range and all the impinging signals due to the point scatterers are correlated, which introduces the necessity of algorithms for decorrelation of signals. This paper introduces a frequency domain decorrelation scheme for the DoA estimation of a LOS source and point scatterers, which constraints a particular structure on the receiver antenna. The limitation in terms of resolution is demonstrated with respect to the coherence bandwidth of the channel for distinct cases of point scatterer locations with respect to the LOS source.
关键词： coherence bandwidth,line of sight (LOS),2.4 GHz ISM band,direction of arrival (DoA),frequency domain decorrelation
更新于2025-09-19 17:13:59
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A 16 ?? 16-Element Slot Array Fed by Double-Layered Gap Waveguide Distribution Network at 160 GHz
摘要： In this article, a slot array with double-layered full-corporate-fed distribution network by ridge gap waveguide (RGW) in the G-band is presented. The array antenna proposed in this article contains 16 × 16-element radiation slots fed by air-?lled ridge gap waveguide distribution network that achieves high-ef?ciency. Gap waveguide technology avoids the demand for perfect electrical contact in millimeter waves, therefore the expensive diffusion bonding and the laser welding processes are not demanded. Moreover, the high-accurate Computerized Numerical Control (CNC) machining is applied for the fabrication. Due to the limited layout space for the distribution network, two types of universal stepped cavity power dividers are presented in this article. The proposed array antenna is fed by a standard WR-5 waveguide at the bottom. Furthermore, the tested outcomes show that the proposed 16×16-element array has a gain larger than 30 dBi with over 50% antenna ef?ciency in the frequency range of 155-171 GHz.
关键词： slot array antenna,high-ef?ciency,Gap waveguide technology,160 GHz
更新于2025-09-19 17:13:59