Loopless multiterminal quantum circuits at odd parity

Antonio Manesco; Anton Akhmerov; Valla Fatemi

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arXiv · 2601.13369

Loopless multiterminal quantum circuits at odd parity

Antonio Manesco·Anton Akhmerov·Valla Fatemi

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Abstract

We theoretically investigate loopless multiterminal hybrid superconducting devices at odd fermion parity with time-reversal symmetry. We find that the energy-phase relationship has a double minimum corresponding to opposite windings of the superconducting phases. Spin-orbit coupling adds multi-axial spin splittings, which contrasts with two-terminal devices where spin dependence is uniaxial. Capacitive shunting localizes quantum circuit states in the wells and exponentially suppresses their splitting. For weak spin-orbit strength, the system has a four-dimensional spin-chirality low-energy subspace which can be universally controlled with electric fields only.

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Antonio Manesco, Anton Akhmerov, Valla Fatemi. 2026-01-19. Loopless multiterminal quantum circuits at odd parity. https://arxiv.org/abs/2601.13369

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