Noise in small-scale quantum computers

量子计算机使用量子力学行为的比特(量子比特)来比传统计算机更快、更好地解决重要问题。这包括分解大整数、搜索无序数据库、对角化矩阵以及模拟分子和材料。许多公司已经开发了基于超导技术的“嘈杂”量子计算机原型，现在可以通过云访问。然而，目前量子计算机中的噪声水平比纠错阈值高出10-100倍，阻碍了量子相对于传统计算机优势的展示。这项研究计划旨在建立固态量子计算机中噪声和退相干的新模型，并将它们与基于云的设备的输出相关联，以制定噪声缓解策略。这将通过发展一种新的磁(磁通)噪声理论来实现，其测量的频率和温度关系在几个实验中一直是一个巨大的难题。该提案旨在将通量噪声与量子技术中材料和界面的特性联系起来，并利用这些发现来改进基于云的设备中量子算法的输出。该研究计划将改进量子硬件和软件，以实现固态环境中的基本噪声限制。它的长期影响将是超越嘈杂的中型量子计算机时代，为在有用的应用中展示量子优势提供一条途径。

Quantum computers use bits that behave quantum mechanically (qubits) to solve important problems faster and better than conventional computers. This includes factoring large integers, searching disordered databases, diagonalizing matrices, and simulating molecules and materials. Prototype "noisy'' quantum computers based on superconducting technology have been developed by many companies, and are now accessible over the cloud. However, the level of noise in current quantum computers is 10-100 times higher than the error correction threshold, hindering demonstrations of quantum advantage over conventional computers. This research program aims to formulate new models of noise and decoherence in solid state quantum computers, and relate them to the output of cloud-based devices, in order to develop strategies for noise mitigation. This will be done through the development of a novel theory of magnetic (flux) noise, whose measured frequency and temperature dependence has been a great puzzle in several experiments. The proposal aims to relate flux noise to the character of the materials and interfaces in quantum technology, and use these findings to improve the output of quantum algorithms in cloud-based devices. The research program will improve both quantum hardware and software in order to achieve the fundamental noise limit in the solid state environment. Its long term impact will be to transcend the era of noisy intermediate-scale quantum computers, providing a route to the demonstration of quantum advantage in useful applications.