QTech2018
China-Japan International Workshop
on Quantum Technologies

University of Science andTechnology of China
QTech2018

Workshop ScheduleThursday 23th of August 2018

8:00 – 8:30 Opening remarks and welcome by sponsors
8:30 – 9:00 Jiangfeng Du University of Science and Technology of China
Nanoscale Spectroscopy: Technology and Applications
9:00 – 9:30 Hideo Kosaka Yokohama National University
Geometric spin qubits in an NV center in diamond for quantum repeaters
9:30 – 10:00 Hongqi Xu Peking University
Progress in Making Quantum Devices from 2D Materials
10:00 – 10:15 Coffee break
10:15 – 10:45 Satoru Masubuchi The University of TokyoAutonomous robotic searching and assembly of two-dimensional crystals tobuild van der Waals superlattices
10:45 – 11:15 Xiaosong Wu Peking UniversityIntercalation, a route towards introduction of magnetism and strong electronic
correlation to two-dimensional materials
11:15 – 11:45 Satoshi Iwamoto University of Tokyo
Topological edge states in semiconductor-based photonic crystals
12:00 – 13:00 Lunch
13:00 – 13:30 Yongqing Li Institute of Physics, CAS
Impurity effects on the quantum transport in 3D topological insulators
13:30 – 14:00 Minoru Kawamura RIKEN
Quantum phase transition in magnetic topological insulator studied bytransport measurement
14:00 – 14:30 Ming Xiao University of Science and Technology of China
Semiconductor Charge Qubits
14:30 – 14:45 Coffee break
14:45 – 15:15 Takashi Nakajima RIKEN
Quantum control of spin qubits in different encodings in a triple quantum dot
15:15 – 15:45 Gang Cao University of Science and Technology of China
Tunable Hybrid Qubit in multi-electron Quantum Dot System
15:45 – 16:15 Peter Stano RIKEN
Effects of an in-plane magnetic field on a quasi-2D quantum dot
16:15 – 16:30 Coffee break
16:30 – 17:00 Jianjun Zhang Institute of Physics, CAS
Si-based quantum materials for spin qubits
17:00 – 17:30 Zhimin Liao Peking University
Quantum transport in Dirac semimetal Cd3As2 nanowires
17:30 – 18:30 Poster Pitches
18:30 – Dinner Banquet

Friday 24th of August 2018

8:00 – 8:30 Shiro Saito NTT Basic Research Laboratories
Quantum sensing using superconducting circuits
8:30 – 9:00 Yasunobu Nakamura University of Tokyo
Quantum magnonics in a ferromagnetic sphere9:00 – 9:30 Shaoyun Huang Peking University
Anisotropic spin-orbit interaction effects of InAs and InSb nanowire quantumdots
9:30 – 10:00 Mingtang Deng State Key Laboratory of High Performance
ComputingMajorana bound states in superconductor-semiconductor nanowires
10:00 – 10:15 Coffee break
10:15 – 10:45 Haiou Li University of Science and Technology of China
10:45 – 11:15 Akira Fujiwara NTT Basic Research Laboratories
Tunable-barrier electron pump for quantum current standards andinformation-to-energy converters
11:15 – 11:45 Kai Chang Institute of Semiconductors, CAS
Exciton insulator phase in two-dimensional semiconductors
12:00 – 13:00 Lunch
13:00 – 13:30 Masayuki Hashisaka NTT Basic Research Laboratories
Tomonaga-Luttinger-liquid nature of quantum Hall edge excitations
13:30 – 14:00 Jianing Chen Institute of Physics, CAS
Progress on Plasmonics of low Dimension Materials
14:00 – 14:30 Yoshiro Hirayama Tohoku University
Resistively-detected nuclear resonance and its imaging
14:30 – 14:45 Coffee break
14:45 – 15:15 Xi Lin Peking University
3/2 fractional quantum Hall plateau in a single layer two-dimensional
electron gas
15:15 – 15:45 Guangwei Deng University of Electronic Science andTechnology of China
Exploring quantum nano-mechanics using 1D/2D NEMS
15:45– 16:45 Lab showing around and free talking17:00 – Departing to Yellow Mountain (partly)
18:30 – Dinner Banquet (partly)Effects of an in-plane magnetic field on a quasi-2D quantum dot
P. Stano1, C.-H. Hsu1, L. Camenzind2, L. Yu2, D. Zumbuhl2, D. Loss1,2
1

CEMS, RIKEN, 2Department of Physics, University of BaselE-mail: peter.stano@riken.jp

The topic falls under the research on spin qubits in gate-defined semiconductor nanostructures. They areamong the leading candidates for quantum information processing and are favorable for scaling to alarge number of qubits. Yet, so far there is no tool to characterize the quantum dot hosting the spin qubit
at the level of its orbitals, despite two decades of research and despite being a key factor for the qubit
performance. Here, I present, explain, and demonstrate a new spectroscopy tool which we havedeveloped. Using magnetic fields with various strengths and directions in the 2D plane, we can extract
the shape, size, and orientation of quantum-mechanical orbitals of a quasi-2D quantum dot.
The method exploits a renormalization of the mass tensor of the electron upon applying a strong inplane magnetic field. The arising spectral response reveals the information on the quantum dot properties.
I illustrate the method on the data measured in Ref. [3] (see the figure). It allows to, for example, to findthe spin-orbit lengths solely from the measured dot spectra. I will also discuss the implications for theg-factor of quantum dots, currently studied vigorously for various Si quantum dots.

Figure: Spectral response of aquantum dot upon applying in-planemagnetic field. Points: measured
data, Lines: analytical fit. It allows toquantify the quantum-dot
orientation, size, dimensionality, thewidth of the 2DEG, and the strengthof the spin-orbit fields.

[1] P. Stano, Ch-H. Hsu, L. C. Camenzind, L. Yu, D. Zumbühl, D. Loss, arxiv:1804.00128.
[2] L. C. Camenzind, L. Yu, P. Stano, J. Zimmerman, A. C. Gossard, D. Zumbühl, D. Loss,arxiv:1804.00162.
[3] L. C. Camenzind, L. Yu, P. Stano, J. Zimmerman, A. C. Gossard, D. Loss, D. M. Zumbühl,Hyperfine-phonon spin relaxation in a single-electron GaAs quantum dot, arxiv:1711.01474, to appear
in Nat. Commun.