Superconducting electronic circuits are one of the key platforms for modern quantum technologies, with applications in quantum computing, simulations, and sensing. The use of such devices exploits the quantum behavior of electrical circuits at very low temperatures to perform tasks that surpass the capabilities of conventional (“classical”) electronics. Superconducting circuits emerged as a breakthrough platform soon after the discovery of the Josephson effect in 1962. They are used in applications ranging from precision measurements (magnetometry with SQUID devices) to scalable quantum processors. Modern qubits (quantum bits), such as transmons and fluxoniums, exhibit long coherence times and high fidelity of operations, enabling significant advances in quantum computing. Superconducting quantum circuits are currently the leading platform, as devices with a few hundred qubits are now commercially available. These circuits are typically modeled using circuit quantum electrodynamics (cQED), which allows precise quantization of key elements such as capacitors, inductors, and Josephson junctions.
Nevertheless, the theory of superconducting circuits faces significant challenges. One of the most prominent issues is the presence of quasiparticles, which disrupt the operation of quantum devices. Quasiparticles can arise due to cosmic radiation, insufficient noise filtering, or other mechanisms, causing errors that reduce the reliability of quantum operations. On the other hand, hybrid devices combining semiconductor and superconducting materials, such as Andreev spin qubits (ASQs), rely precisely on the use of quasiparticles for their operation. However, current models of superconducting circuits do not adequately account for quasiparticle dynamics. Most cQED models largely neglect quasiparticle effects and assume that all electrons in the superconductor form Cooper pairs.
The training program will focus on improving theoretical models for superconducting circuits and hybrid systems. The main goals are to develop a comprehensive framework that incorporates quasiparticle dynamics and thereby address key limitations of current methods, design new types of noise-resistant qubits, and explore the use of superconducting circuits as quantum simulators for solving complex physical problems.