SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 20: Superconductivity: Tunnelling and Josephson Junctions

TT 20.11: Talk

Tuesday, March 28, 2023, 12:15–12:30, HSZ 103

Quantum phases in a frustrated sawtooth chain of Josephson junctions — •Benedikt J.P. Pernack, Mikhail V. Fistul, and Ilya M. Eremin — Ruhr-Universität Bochum, Bochum Germany

We present a theoretical study of quantum phases occurring in a frustrated sawtooth chain of small Josephson junctions. In the model the frustration f arises due to the Josephson couplings having alternating signs (0 and π Josephson junctions) in a single lattice cell. At the critical value of f=3/4 such a system displays a phase transition from the ordered state into the frustrated one with a highly degenerate ground state characterized by penetration of topological (anti)vortices [1]. Introducing additional capacitances to the ground, we derive an effective Ising quantum spins model with a long-range interaction between well separated vortices/antivortices, and obtain various collective quantum phases and quantum phase transitions between them.

[1] A. Andreanov and M. V. Fistul, J. Phys. A: Math. Theor. 52, 105101 (2019)