Superconducting protected qubits aim to achieve sufficiently low error rates so as to allow realization of error-corrected, utility-scale quantum computers. A recent proposal encodes a protected qubit in the quasicharge degree of freedom of the conventional transmon device. Operating such a protected `quasicharge qubit' requires implementing new strategies. Here we show that an electronically-controllable tunnel junction formed by two topological superconductors can be used to implement single- and two-qubit gates on quasicharge qubits. Schemes for both these gates are based on the same dynamical 4π-periodic Josephson effect and therefore have the same gate times and error characteristics. We simulate the dynamics of a topological Josephson junction in a parameter regime with non-negligible charging energy, and characterize the robustness of such gate operations against charge noise. Our results point to a compelling strategy for implementation of quasicharge qubit gates based on junctions of minimal Kitaev chains of quantum dots.
@article{arxiv.2510.20127,
title = {Electronically-controlled one- and two-qubit gates for transmon quasicharge qubits},
author = {Nicholas M. Christopher and Deniz E. Stiegemann and Abhijeet Alase and Thomas M. Stace},
journal= {arXiv preprint arXiv:2510.20127},
year = {2026}
}