Towards compact quantum computers thanks to topology

NielsSchröter(左)和vladimir strocov在psi的瑞士光源SLS的实验站之一。这里的研究人员使用软X射线角度分辨光电子能谱来测量铟砷铟和铟锑酸铟下方的电子分布。
信贷:Paul Scherrer Institute / Mahir Dzambegicic

PSI的研究人员已经将电子分布与两个半导体的氧化物层下方的电子分布进行了比较。调查是开发特别稳定的量子位的努力的一部分 - 因此,反过来又特别有效的量子计算机。他们现在发布了他们的最新研究,这些研究部分由微软在科学期刊中得到支持Advanced Quantum Technologies

到目前为止,计算的未来是不可想象的,没有量子计算机。在大多数情况下,这些仍在研究阶段。与古典计算机相比,它们通过数量级来加速某些计算和模拟的承诺。

Quantum位或短的Qubits,形成量子计算机的基础。所谓的拓扑量子位是一种可能被证明优越的新型类型。要了解如何创建这些,研究人员的国际团队在PSI的瑞士光源SLS进行了测量。

更稳定的量子位

“Computer bits that follow the laws of quantum mechanics can be achieved in different ways,” explains Niels Schröter, one of the study’s authors. He was a researcher at PSI until April 2021, when he moved to the Max Planck Institute of Microstructure Physics in Halle, Germany. “Most types of qubits unfortunately lose their information quickly; you could say they are forgetful qubits.” There is a technical solution to this: Each qubit is backed up with a system of additional qubits that correct any errors that occur. But this means that the total number of qubits needed for an operational quantum computer quickly rises into the millions.

“微软的方法,我们现在正在合作,完全不同,”Schröter继续。“我们希望帮助创建一种新的Qubit,其免受信息泄漏。这将使我们只需使用几个QBits来实现纤细,运行的量子计算机。“

研究人员希望通过所谓的拓扑量子位获得这种免疫力。这些完全是一个完全新的东西,即没有研究小组已经能够创造出来。

Topological materials became more widely known through the Nobel Prize in Physics in 2016. Topology is originally a field of mathematics that explores, among other things, how geometric objects behave when they are deformed. However, the mathematical language developed for this can also be applied to other physical properties of materials. Quantum bits in topological materials would then be topological qubits.

Quasiparticles in semiconductor nanowires

众所周知,薄膜系统的某些半conductors and superconductors could lead to exotic electron states that would act as such topological qubits. Specifically, ultra-thin, short wires made of a semiconductor material could be considered for this purpose. These have a diameter of only 100 nanometres and are 1,000 nanometres (i.e., 0.0001 centimetres) long. On their outer surface, in the longitudinal direction, the top half of the wires is coated with a thin layer of a superconductor. The rest of the wire is not coated so that a natural oxide layer forms there. Computer simulations for optimising these components predict that the crucial, quantum mechanical electron states are only located at the interface between the semiconductor and the superconductor and not between the semiconductor and its oxide layer.

“The collective, asymmetric distribution of electrons generated in these nanowires can be physically described as so-called quasiparticles,” says Gabriel Aeppli, head of the Photon Science Division at PSI, who was also involved in the current study. “Now, if suitable semiconductor and superconductor materials are chosen, these electrons should give rise to special quasiparticles called Majorana fermions at the ends of the nanowires.”

Majorana fermions are topological states. They could therefore act as information carriers, ergo as quantum bits in a quantum computer. “Over the course of the last decade, recipes to create Majorana fermions have already been studied and refined by research groups around the world,” Aeppli continues. “But to continue with this analogy: we still didn’t know which cooking pot would give us the best results for this recipe.”

锑腺苷有优势

因此,目前研究项目的核心问题是两个“烹饪罐”的比较。研究人员研究了两种不同的半导体和它们的天然氧化物层:在一方面砷和其他铟锑苷酸上。

在SLS,PSI研究人员使用了一种调查方法,称为软X射线角分辨光电子能谱 - SX-ARPES。由Noa Marom的Carnegie Mellon University,美国与PSI的Vladimir Strocov开发的一款由Noa Marom的集团开发的新型计算机模型用于解释复杂的实验数据。“计算机模型用于现在导致了不管理大量的虚假效果。通过我们的新方法,我们现在可以看出所有结果,自动过滤出物理相关的结果,并正确解释实验结果,“Strowov解释说。

通过它们的SX-ARPES实验和计算机模型的组合,研究人员现在能够表明锑苷的铟具有特别低的氧化物层上的电子密度。这将是有利的,在计划纳米线中形成拓扑马太基亚球菌。

“From the point of view of electron distribution under the oxide layer, indium antimonide is therefore better suited than indium arsenide to serve as a carrier material for topological quantum bits,” concludes Niels Schröter. However, he points out that in the search for the best materials for a topological quantum computer, other advantages and disadvantages must certainly be weighed against each other. “Our advanced spectroscopic methods will certainly be instrumental in the quest for the quantum computing materials,” says Strocov. “PSI is currently taking big steps to expand quantum research and engineering in Switzerland, and SLS is an essential part of that.”

Text: Paul Scherrer Institute/Laura Hennemann

关于psi.

Paul Scherrer Institute PSI开发,建造和运营大型,复杂的研究设施,使其提供给国家和国际研究界。该研究所自己的主要研究优先事项在物质和材料,能源和环境和人类健康领域。PSI致力于培训后代。因此,我们工作人员的四分之一是文档后,毕业后或学徒。完全psi雇用了2100人,因此是瑞士最大的研究所。年度预算金额约为4亿瑞士法郎。PSI是ETH领域的一部分,其他成员是两位瑞士联邦技术研究院,ETH苏黎世和EPFL洛桑,以及EGAG(瑞士联邦水生科技学院),EMPA(瑞士联邦实验室为材料科学和技术)和WSL(瑞士联邦森林,雪和景观研究所)。

Further information

半导体到达量子世界 - 从2021年12月22日开始新闻稿
http://psi.ch/en/node/49225

探索异国情调材料的实际益处 - 从2021年9月1日开始
http://psi.ch/en/node/47097.

新材料还揭示了新的Quasipartiply - 从2019年5月7日开始新闻稿
http://psi.ch/en/node/28106.

接触

Vladimir N. Strocov博士
新材料研究群体光谱
Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
电话:+41 56 310 53 11,电子邮件:vladimir.strocov@psi.ch [英语,法语,俄语]

Dr. Niels Schröter
Max Planck Microdructure Mative,Weinberg 2,06120 Halle,德国
Telephone: +49 345 5582 793, e-mail: niels.schroeter@mpi-halle.mpg.de, niels.schroeter@psi.ch [German, English]

Gabriel Aeppli教授
Head of the Photon Science Division
Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
和物理系,苏黎世
and Topological Matter Laboratory, EPF Lausanne
电话:+41 56 310 42 32,电子邮件:gabriel.aeppli@psi.ch [德语,英语,法语]

Original Publication

INAS和INSB表面的电子结构:密度函数理论和角度分辨的光学激发光谱
沭阳杨尼尔斯B.M.Schröter,V.N.Schröter,S.Schuwalow,M.Rajpalk,K.H.H.Htani,P.Krogstrup,G.W.Winkler,J.Gukelberger,D. Gresch,G.Aeppli,R. M. Luchpli,R. M. luchpli,R. M. luchpli,N. Marom
Advanced Quantum Technologies20. January 2022
DOI:10.1002 / QUTE.202100033

杂志:高级量子技术
DOI:10.1002 / qute.202100033
Method of Research: Experimental study
研究主题:不适用
Article Title: Electronic structure of InAs and InSb surfaces: density functional theory and angle-resolved photoemission spectroscopy
文章出版日期:20-1月2022

媒体联系人

Sebastian Jutzi
Paul Scherrer Institute
sebastian.jutzi@psi.ch.
办公室:0041-563-102-940

媒体联系人

Sebastian Jutzi
Paul Scherrer Institute
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