The Hamburg Quantum Computing (HQC) project conducts interdisciplinary research into various aspects of quantum computer hardware, programming and applications. The IHF is working on subproject High-Frequency Excitation (P8). An overview of all subprojects is available on the project website: https://www.physik.uni-hamburg.de/en/iqp/hqc.html

High-frequency signals are required to excite defined quantum states. The challenge here is to generate these signals with defined amplitudes and phases at frequencies in the double-digit gigahertz range. Current demonstrators typically use high-quality laboratory measurement technology and signal sources for this purpose. On the one hand, these are very expensive and, on the other hand, they are not tailored to the specific application. Therefore, the aim is to design a high-frequency signal source that is as flexible as possible and tailored to the special features of quantum computers, while at the same time allowing the excitation of defined quantum states in a cost-efficient and compact manner. The required output power is initially generated by a commercial amplifier. Signal generation is based on a software-defined radio approach, which uses programmable hardware to enable extremely fast control of magnitude and phase depending on the real signal, which is influenced by non-idealities of the entire quantum computer. In addition to this digital control electronics, the focus is on the actual signal generation and measurement technology for the non-ideal properties of the signals.