New method to control electron spin paves the way for efficient quantum computers

The method, developed by Rochester scientists, overcomes the limitations of electron spin resonance.

Quantum science has the potential to revolutionize modern technology with more efficient computers, 沟通, 传感设备. 在实现这些技术目标方面仍然存在挑战, 然而,包括 how to precisely manipulate information in quantum systems.

In 一篇论文 发表在 自然物理，一组来自美国的十大网赌靠谱网址平台人员 十大网赌靠谱网址平台,包括 约翰·尼科尔, 物理学副教授, outlines a new method for controlling electron spin in silicon quantum dots—tiny, nanoscale semiconductors with remarkable properties—as a way to manipulate information in a quantum system.

“The results of the study provide a promising new mechanism for coherent control of qubits based on electron spin in semiconductor quantum dots, which could pave the way for the development of a practical silicon-based quantum computer,尼科尔说.

使用量子点作为量子位

A regular computer consists of billions of transistors, called bits. Quantum computers, on the other hand, are based on quantum bits, also known as qubits. 与普通晶体管不同, 可以是“0”(关闭)或“1”(打开), qubits are governed by the laws of quantum mechanics and can be both “0” and “1” at the same time.

Scientists have long considered using silicon quantum dots as qubits; controlling the spin of electrons in quantum dots would offer a way to manipulate the transfer of quantum information. Every electron in a quantum dot has intrinsic magnetism, like a tiny bar magnet. Scientists call this “electron spin”—the magnetic moment associated with each electron—because each electron is a negatively charged particle that behaves as though it were rapidly spinning, and it is this effective motion that gives rise to the magnetism.

电子自旋是一个很有前途的转移候选, 存储, and processing information in quantum computing because it offers long coherence times and high gate fidelities and is compatible with advanced semiconductor manufacturing techniques. The coherence time of a qubit is the time before the quantum information is lost due to interactions with a noisy environment; long coherence means a longer time to perform computations. High gate fidelity means that the quantum operation researchers are trying to perform is performed exactly as they want.

One major challenge in using silicon quantum dots as qubits, 然而, is controlling electron spin.

控制电子自旋

The standard method for controlling electron spin is electron spin resonance (ESR), which involves applying oscillating radiofrequency magnetic fields to the qubits. 然而, 这种方法有几个限制,包括 the need to generate and precisely control the oscillating magnetic fields in cryogenic environments, 大多数电子自旋量子位在哪里操作. 通常, 产生振荡磁场, 十大网赌靠谱网址平台人员通过导线发送电流, 这就产生了热量, 哪些会扰乱低温环境.

Nichol and his colleagues outline a new method for controlling electron spin in silicon quantum dots that does not rely on oscillating electromagnetic fields. 这种方法是基于一种叫做“自旋谷耦合”的现象,” which occurs when electrons in silicon quantum dots transition between different spin and valley states. While the spin state of an electron refers to its magnetic properties, the valley state refers to a different property related to the electron’s spatial profile.

The researchers apply a voltage pulse to harness the spin-valley coupling effect and manipulate the spin and valley states, 控制电子自旋.

这种连贯控制的方法, 通过自旋谷耦合, 允许对量子位进行通用控制, and can be performed without the need of oscillating magnetic fields, 这是ESR的局限性吗,尼科尔说. “This allows us a new pathway for using silicon quantum dots to manipulate information in quantum computers.”

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标签: 物理与天文学系, 约翰·尼科尔, 量子科学, 十大网赌靠谱网址平台发现, 文理学院

类别: 科学 & 技术