Contributor info: Prof. Valla Fatemi

A. Mert Bozkurt, Jasper Brookman, Valla Fatemi, Anton R. Akhmerov

SciPost Phys. 15, 204 (2023) · published 24 November 2023 | Toggle abstract · pdf

We present a systematic method to design arbitrary energy-phase relations using parallel arms of two series Josephson tunnel junctions each. Our approach employs Fourier engineering in the energy-phase relation of each arm and the position of the arms in real space. We demonstrate our method by engineering the energy-phase relation of a near-ideal superconducting diode, which we find to be robust against the imperfections in the design parameters. Finally, we show the versatility of our approach by designing various other energy-phase relations.

André Melo, Valla Fatemi, Anton R. Akhmerov

SciPost Phys. 12, 017 (2022) · published 12 January 2022 | Toggle abstract · pdf

The multi-terminal Josephson effect allows DC supercurrent to flow at finite commensurate voltages. Existing proposals to realize this effect rely on nonlocal Andreev processes in superconductor-normal-superconductor junctions. However, this approach requires precise control over microscopic states and is obscured by dissipative current. We show that standard tunnel Josephson circuits also support multiplet supercurrent mediated only by local tunneling processes. Furtheremore, we observe that the supercurrents persist even in the high charging energy regime in which only sequential Cooper transfers are allowed. Finally, we demonstrate that the multiplet supercurrent in these circuits has a quantum geometric component that is distinguinshable from the well-known adiabatic contribution.