Thermal effects in solid state quantum computing

研究目的：研究导致固态量子比特(Qbit)噪声、退相干和错误的热效应。量子计算的快速发展已经看到了关于如何构建量子计算机的各种不同的提议。例子包括囚禁离子、光子和中性原子，仅举几例。然而，这些建议在实施上存在很大差异，并具有独特的优点和局限性。固态，特别是半导体量子比特也被提出并演示了，作为建立量子计算机的一种方法。至关重要的是，这种实现具有明显的优势，即有可能大规模制造，并与现有的互补金属氧化物半导体(CMOS)技术相结合。以及提供其他所需的特性，例如长的去相/弛豫时间和高保真的单量子比特门操作。然而，半导体量子比特仍然容易受到噪声和退相干的影响。因此限制了他们执行涉及大量门的量子计算的能力等。通常，众所周知，热效应在量子计算机中产生噪声和退相干起到了贡献因素。除了这些发展，量子热力学作为一个新的研究领域的出现。精确地研究量子尺度下的热效应。以及关于小尺度下经典热力学定义的更基本的问题。这个项目的目标是描述和探索在半导体量子比特中导致噪声、退相干和误差的热效应。找到缓解它们的方法，并探索建设性地使用这种效应进行量子计算的可能性。这个项目的新奇之处在于这些目标以及量子热力学作为研究它们的方法在半导体量子比特中的应用。通过了解和控制热效应，可以提高半导体量子比特的工作温度。这是构建可扩展量子计算机所需的重要一步。此外，量子计算的精确度可能会提高。该项目属于EPSRC量子技术主题。与IST奥地利的合作为我们提供了一些用于实验的必要半导体量子设备。这还不包括牛津大学内部的合作，提供关于更广泛的量子技术领域的知识和专业知识。

Research aim: Examine thermal effects that lead to noise, decoherence and errors in solid-state quantum bits (qubits).The rapid development of quantum computing has seen a variety of different proposals on how to construct a quantum computer. Examples include trapped ions, photonic and neutral atoms, to name a few. However, these proposals differ widely in their implementation, and come with unique merits and limitations. Solid state, particularly, semiconducting qubits have also been proposed, and demonstrated, as a method of building quantum computers. Crucially, this implementation has the distinct advantage of the possibility to be manufactured at a large scale, and with existing CMOS (Complementary Metal Oxide Semiconductor) techniques. As well as offering other desired properties, such as long dephasing/relaxation times and high-fidelity single qubit gate operations. Nevertheless, semiconducting qubits are still susceptible to noise and decoherence. Therefore limiting their ability to perform quantum computations involving large numbers of gates etc. Generally, it is known that thermal effects play a contributing factor in generating noise and decoherence in quantum computers.In addition to these developments, is the emergence of quantum thermodynamics as a nascent area of research. Dealing precisely with the study of thermal effects at a quantum scale. As well as more fundamental questions regarding the definition of classical thermodynamical quantities at a small scale. The objective of this project is to characterise and explore thermal effects that lead to noise, decoherence and errors in semiconducting qubits. Find ways of mitigating them, and explore the possibility of using such effects constructively for performing quantum computations. The novelty of this project lies in these objectives and the application of quantum thermodynamics as a method for studying them, in semiconducting qubits. By understanding and controlling thermal effects, the operational temperature of semiconductor qubits may be increased. A major step required for building a scalable quantum computer. Additionally, the accuracy of quantum computations may be improved.This project falls within the EPSRC quantum technologies theme.A collaboration with IST Austria provides us with some of the required semiconducting quantum devices used for experiments. This is in addition to collaborations within Oxford providing knowledge and expertise regarding the broader area of quantum technologies.