Theory and design of active quantum circuit elements

Until the pioneering work of Chua in 1960s, it was taken for granted that there are three lumped circuit elements (two reactive: inductor, capacitor, and one active: resistor), which allow to describe an arbitrary electric circuit. From the considerations of symmetry, Chua showed that there must exist the fourth such element, memristor, which can be considered as a resistor with memory. A realisation of such a structure was only achieved in early 2000s.

Development of quantum technologies since 2000s produced qubit-based quantum analogues of capacitors and inductors, which can be in a quantum superposition of states with different values of C and L, respectively. It would seem that there exist no quantum analogues to resistors and memristors, because of the inherent dissipation. Nevertheless, such analogues are possible due to nonlocality of transport in mesoscopic structures. The PhD student will develop their quantitative theory and model experimental protocols for their investigation.