Anomalous magnetic flux via junction twist-angle in a triplet-superconducting transmon qubit

Fuente: arXiv
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Autori principali: Domínguez-Calderón, Sebastián, Scammell, Harley D.
Natura: Preprint
Pubblicazione: 2024
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author Domínguez-Calderón, Sebastián
Scammell, Harley D.
author_facet Domínguez-Calderón, Sebastián
Scammell, Harley D.
contents Superconducting transmon qubits with strong anharmonicity and insensitivity to offset charge are highly desirable for low-error implementation. In this work we propose a c-axis junction, comprising triplet superconductors, and set at a relative twist angle. Invoking spin-orbit coupling and spin polarization, which are known to occur in the material platform of choice, we examine the resulting transmon Hamiltonian. This junction allows for direct control of the single and double Cooper pair tunneling strength, and most remarkably, an anomalous magnetic flux -- i.e. a phase offset equivalent to magnetic flux, yet in zero magnetic field. Having control over these three parameters -- single and double pair tunneling and anomalous flux -- allows for optimal design of the transmon qubit. Interestingly, in this architecture, the anomalous flux is determined by the twist angle of the junction, thereby offering a novel zero-field functionality. Our key results rely on symmetry arguments, for concreteness we demonstrate the implementation of our concept using a model of moiré graphene-based c-axis junctions.
format Preprint
id arxiv_https___arxiv_org_abs_2403_07215
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Anomalous magnetic flux via junction twist-angle in a triplet-superconducting transmon qubit
Domínguez-Calderón, Sebastián
Scammell, Harley D.
Mesoscale and Nanoscale Physics
Superconductivity
Quantum Physics
Superconducting transmon qubits with strong anharmonicity and insensitivity to offset charge are highly desirable for low-error implementation. In this work we propose a c-axis junction, comprising triplet superconductors, and set at a relative twist angle. Invoking spin-orbit coupling and spin polarization, which are known to occur in the material platform of choice, we examine the resulting transmon Hamiltonian. This junction allows for direct control of the single and double Cooper pair tunneling strength, and most remarkably, an anomalous magnetic flux -- i.e. a phase offset equivalent to magnetic flux, yet in zero magnetic field. Having control over these three parameters -- single and double pair tunneling and anomalous flux -- allows for optimal design of the transmon qubit. Interestingly, in this architecture, the anomalous flux is determined by the twist angle of the junction, thereby offering a novel zero-field functionality. Our key results rely on symmetry arguments, for concreteness we demonstrate the implementation of our concept using a model of moiré graphene-based c-axis junctions.
title Anomalous magnetic flux via junction twist-angle in a triplet-superconducting transmon qubit
topic Mesoscale and Nanoscale Physics
Superconductivity
Quantum Physics
url https://arxiv.org/abs/2403.07215