Quantum Dynamics of Topologically Nontrivial Systems with Coulomb Blockade Effects

在这个项目下，我们计划发展混合超导系统量子动力学的理论描述，其中电荷输运性质既由电子隧穿的库仑阻塞控制，又由超导态的非平凡拓扑控制。电荷态和超导相拓扑结构相互作用的系统最简单的例子是单电子旋转门，它带有一个超导岛和置于随时间变化的磁场中的正常电极。由此产生的超导体中电荷隧穿和涡旋入口/出口的关联导致了不平凡的磁电效应。此外，涡旋态的变化对超导部分中准粒子的驰豫过程有显著影响。在最近的几个实验中，人们已经在电子旋转门和冷却器、超导量子比特和谐振器等系统中研究了这种效应。随着准粒子动力学理论的发展，它们在库仑阻挡区隧穿进入涡旋态对我们来说似乎是一个相关的问题，这对于描述这些实验以及在基于超导体定域Andreev态的量子计算领域中的可能应用是至关重要的。

Under this project we plan to develop theoretical description of quantum dynamics of hybrid superconducting systems where charge transport properties are governed both by Coulomb blockade of electron tunneling and by nontrivial topology of superconducting state. The simplest example of a system where the interplay of a charge state and topology of superconducting phase manifests itself is a single-electron turnstile with a superconducting island and normal electrodes placed in time-dependent magnetic field. The resulting correlation of the charge tunneling and the entrance/exit of vortices in a superconductor leads to nontrivial magnetoelectric effects. Besides, vortex state alternation influences significantly relaxation processes of quasiparticles in superconducting parts. This effect has been investigated in such systems as electronic turnstiles and coolers, superconducting qubits and resonators in several recent experiments. Development of an adequate theory of quasiparticle dynamics, their tunneling into vortex states in Coulomb blockade regime seems to us a relevant problem, which is essential for the description of these experiments, as well as for possible applications in the field of quantum computing based on localized Andreev states in superconductors.