Fault-tolerant quantum operation is a key requirement for the development of computing. This has been realized in various solid-state systems including isotopically purified silicon which provides nuclear spin free environment qubits, but not industry standard natural (unpurified) silicon. Here we demonstrate an addressable fault-tolerant qubit using double dot with micromagnet optimally designed fast control. optimized design allows us to achieve optimum Rabi oscillation quality factor Q =...

Abstract While single-shot detection of silicon spin qubits is now a laboratory routine, the need for quantum error correction in large-scale computing device demands non-demolition (QND) implementation. Unlike conventional counterparts, QND readout imposes minimal disturbance to probed polarization and can therefore be repeated extinguish measurement errors. Here, we show that an electron qubit measured highly manner by probing another neighboring dot Ising-coupled spin. The high fidelity...

This paper reports a 20 W Ka-band GaN high power MMIC (Monolithic Microwave Integrated Circuit) amplifier under continuous wave (CW) operation. The one-finger large signal models were made to take account of both the phase difference RF gate voltage at feeder and thermal effect. By using this model, pitch length unit cell transistor was optimally designed obtain maximum output as CW As result, 21.7W operation successfully achieved with added efficiency (PAE) 19.8% by single-ended MMIC. To...

Frequency-multiplexed radio-frequency (RF) reflectometry is a promising technique for large-scale quantum dot-based qubit systems because it enables simultaneous readout of multiple qubits and helps to reduce the wiring density in peripheral circuits. However, conventional L-C-type matching circuits, resonator frequency tunability limited by poor design flexibility shunt capacitance hence circuit. Recently, L-L-type circuits comprising series inductor have been proposed address this issue....

We report on the effects of a global top gate low-frequency noise in Schottky gate-defined quantum point contacts (QPCs) and dots (QDs) modulation-doped Si/SiGe heterostructure. For relatively large voltage, QPC current shows frequent switching with 1/f2 Lorentzian type charge noise. As voltage is decreased, pinch-off becomes less negative, rapidly suppressed homogeneous background 1/f apply this top-gating technique to double QDs stabilize state for electron number down zero.

A highly integrated RF frontend module including a three-stage power amplifier (PA), two-stage low noise (LNA) and switch (SW) is presented for high SHF wide-band massive MIMO in 5G. In order to achieve efficient operation over frequency, Doherty PA configuration using parasitic output capacitance neutralization technique proposed final stage PA. To improve LNA's gain flatness wide frequency band, two R-LC stabilization circuits with different resonance frequencies are proposed. They...

This letter reports on the development of an X-band GaN monolithic microwave integrated circuit (MMIC) high-power amplifier (HPA) which achieves a power-added efficiency (PAE) 54% and output power 70 W. Mitsubishi's field-effect transistors (FETs) with gate length 0.15 μm individual source via (ISV) structure are utilized. The developed MMIC HPA demonstrates 46.1-47.4 dBm (41-56 W), PAE 49-55%, gain 10.1-11.0 dB at frequency range 8.5-10.5 GHz drain voltage 30 V. Output 47.2-48.4 (53-70...

The fifth generation mobile communications (5G) are expected to accommodate the forthcoming huge traffic demands, and massive multiple input output (MIMO) technology utilizing hundreds of antenna elements has drawn attention as a key configuration for envisioned 5G. In order realize active phased array (APAA), highly integrated GaAs RF frontend module is developed at 28GHz-band. includes four-stage power amplifier (PA), three-stage low noise (LNA) switch. With units including modules,...

A RF leakage phenomenon in GaN HEMTs on Si substrates is analyzed with taking atomic diffusion at buffer/substrate interface into consideration, and a novel physical model of based the analysis proposed. The Al or Ga atoms are moved from buffer layer to substrate an epitaxial growth. Then, acceptor high hole density inversion electron formed substrate. As result, occurred by low resistance caused two layers. temperature dependence S22 simulated TCAD proposed model, results good agreement...

This paper reports on the extraction of equivalent circuit model parameters a physically defined silicon quantum dot at cryogenic temperature and design impedance matching circuits to improve performance charge sensor for radio-frequency (RF) reflectometry. The I-V characteristics S-parameters device are measured around Coulomb peak 4.2 K. results modeled by an RC parallel circuit, were obtained. We consider three RF reflectometry dot: shunt capacitor-series inductor type, inductor-series...

In this paper, a 2.5 to 10.5 GHz GaN MMIC power amplifier achieving output of over 20 W is reported. The developed two-stage composed non-uniform distributed for the first stage and reactively-matched second stage. Measured performance shows saturated 18 37 (28 on average), power-added efficiency 19 40% GHz. highest among amplifiers operated in fractional bandwidth greater than 100 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup> demonstrated.

The frequency dependence of conductance noise through a gate-defined quantum point contact fabricated on Si/SiGe modulation doped wafer is characterized. 1/f2 noise, which characteristic random telegraph reduced by application negative bias the global top gate to reduce local voltage. Direct leakage from large voltage also causes and therefore, there suitable operate dot measurement.

This paper describes a tile-type high-transmit-power TR module in order to realize low-profile AESA (active electronically scanned array) radars. The is based on newly developed multichip packaging technology featuring top-surface waste heat structure with flip-chip mounting and sinks. Measurements of the prototype show an output power over 43 dBm (20 W) noise figure 2.8 dB X-band. state-of-the-art level among ever reported X-band modules.

In this paper, a high output power and gain X-band GaN-on-Si MMIC amplifier with GaAs matching circuit is developed to achieve low-cost miniaturized module. A employed reduce loss. Measured performance of the shows 44.8 dBm (30.4 W), associated 29.8 dB PAE 30 % in X-band. The achieves highest power, among amplifiers ever reported. estimated be less than half cost GaN-on-SiC same size.

A 26-W X-band high efficiency GaN MMIC power amplifier with compact spurious suppression filters is presented. Generally, transmit modules need which cause loss and increase of size cost to satisfy specification. proposed developed. Measurement results the developed two-stage shows output 26 W, added (PAE) 55 %., associate gain 20 dB second harmonic less than -43 dBc. This result comparable state-of-the-art amplifiers ever reported. It indicates that has an advantage when it utilized in a module.

Department of Applied Physics, The University Tokyo, Hongo, Bunkyo-ku, 113-8656, Japan Quantum Nanoelectronics Research Center, Tokyo Institute Technology, O-okayama, Meguro-ku, 152-8552, PRESTO, Science and Technology Agency (JST), Honcho Kawaguchi, Saitama, Center for Silicon Nano-Science, Advanced Laboratories, City University, 8-15-1 Todoroki, Setagaya-ku, 158-0082, RIKEN, Emergent Matter (CEMS), Wako, 351-0198,

In order to realize a massive MIMO concept, small size and low power consumption over the wide-band frequency range are challenges for RF frontends module. This paper describes highly integrated frontend module high SHF in 5G. The is designed with 0.15 μm GaAs process assembled on 5 × mm2 QFN package. By employing Doherty amplifier configuration using parasitic output capacitance neutralization technique, it achieves wide band. architecture an attractive solution systems 5G, will contribute...