报告题目：Manipulation of Spin-Orbit and Majorana Qubit in Hybrid Quantum Systems

报 告 人：张鹏 博士 日本乐天(Rakuten)

报告时间：2016年12月27日（星期二） 下午 15:00-16:00

报告地点：南校区双超所211会议室

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Abstract ：

Combining the long coherence times available in microscopic quantum systems with the strong

interactions and integration available in solid state systems is one major goal in the recent study on

quantum information. For such purpose, much effort has been taken to propose and realize functional

hybrid quantum systems. In this presentation, I will introduce our recent theoretical works on this

field. We propose a spin-orbit qubit in a nanowire quantum dot on the surface of a multiferroic

insulator with a cycloidal spiralmagnetic order. The spiral exchange field from the multiferroic

insulator causes an inhomogeneous Zeeman-like interaction on the electron spin in the quantum dot,

producing a spin-orbit qubit. The absence of an external magnetic field benefits the integration of

such a spin-orbit qubit into high-quality superconducting resonators. By exploiting the Rashba spin-

orbit coupling in the quantum dot via a gate voltage, one can obtain an effective spin-photon

coupling with an efficient on-off switching. We also propose a hybrid system composed of a

Majorana qubit and a nanomechanical resonator, implemented by a spin-orbit-coupled

superconducting nanowire, using a set of static and oscillating ferromagnetic gates. The

ferromagnetic gates induce Majorana bound states in the nanowire, which hybridize and constitute a

Majorana qubit. Due to the oscillation of one of these gates, the Majorana qubit can be coherently

rotated. By tuning the gate voltage to modulate the local spin-orbit coupling, it is possible to reach

the resonance of the qubit-oscillatorsystem for relatively strong couplings.

报告人简介：张鹏，2007年获中国科学技术大学物理专业学士学位，

2013年获中国科学技术大学凝聚态物理专业博士学位。

2014-2016年在日本理化学研究所（RIKEN）做博士后研

究工作，并于2014年获日本学术振兴会外国人特别研究

员基金（JSPS Fellowship）。目前在日本乐天（Rakuten）

从事数据科学的研究工作。主要的研究方向包括：自旋

电子学、量子现象和混合量子器件设计、凝聚态理论。