Altermagnetic Control of Superconducting Qubit Performance

Superconducting qubits are among the leading platforms for quantum computing, but further improvements in coherence, controllability, and scalability remain essential. At the same time, the recent discovery of altermagnets has revealed a new class of magnetic materials that combine vanishing net magnetization with spin-split electronic band structures. This raises the question: what happens when altermagnetism is integrated into superconducting qubit architectures?

In this talk, I present microscopic calculations of superconducting qubits incorporating altermagnetic Josephson junctions. Focusing primarily on transmon qubits, I show that the strength and orientation of the altermagnetic order provide new control knobs for qubit operation. The resulting qubit spectra, anharmonicity, decoherence rates, and single- and two-qubit gate times depend strongly on altermagnetic material properties and interface orientation. The calculations reveal that the system can simultaneously exhibit strong protection against decoherence and enhanced anharmonicity near 0-pi transitions and in phi-state regimes. I will present the physical origin of these effects and discuss how strain can be used to switch between protected operating points and faster-control regimes. These results show that altermagnetic materials may provide a route toward improved superconducting quantum hardware while also opening a new interface between altermagnetism and quantum information science.