Field-controlled breaking and restoration of parity-time symmetry in Josephson interference
Abstract
Symmetry plays a fundamental role in determining the phases and physical properties of quantum matter. Controlling symmetry in mesoscopic superconducting devices provides a route to reconfigure their phase-coherent transport. Here we demonstrate symmetry-selective Josephson interferometry in lateral NbTi/PtTe2/NbTi junctions by controlling the relative orientations of the current and magnetic field. From the supercurrent interference patterns, we construct a field-current symmetry map that identifies configurations exhibiting or violating the device-level parity (π«), time-reversal (π―) and their combined π«π― symmetry. In the absence of an in-plane field, the junction exhibits a symmetric Fraunhofer pattern. An in-plane field parallel to the current produces a pronounced side-lobe asymmetry, whereas reversing both the current and the complete magnetic-field configuration restores a generalized π― relation. Remarkably, orienting the in-plane field perpendicular to the current restores the π«π―-symmetric Fraunhofer response even at substantial field strengths. A microscopic model attributes this behavior to the interplay between disorder-induced potential variations and flux dipoles generated by in-plane-field Meissner focusing near the superconducting electrodes. Our results establish a reconfigurable Josephson interferometer in which the field-current geometry selects the symmetry operation being probed and switches the device between symmetry-broken and symmetry-restored interference states.
Related
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BibTeX
@misc{tsai2026fieldcontrolled,
title = {{Field-controlled breaking and restoration of parity-time symmetry in Josephson interference}},
author = {Yi-Chen Tsai and Yung-Yeh Chang and Tao-Yi Hsu and Thomas Kuo and Chia-Nung Kuo and Chin-Shan Lue and Kuei-Lin Chiu and Chen-Hsuan Hsu and Chung-Ting Ke},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.16414},
eprint = {2608.16414},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.16414},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Field-controlled breaking and restoration of parity-time symmetry in Josephson interference
AU - Yi-Chen Tsai
AU - Yung-Yeh Chang
AU - Tao-Yi Hsu
AU - Thomas Kuo
AU - Chia-Nung Kuo
AU - Chin-Shan Lue
AU - Kuei-Lin Chiu
AU - Chen-Hsuan Hsu
AU - Chung-Ting Ke
PY - 2026
DA - 2026/10/11
PB - arXiv
DO - 10.48550/arxiv.2608.16414
UR - https://arxiv.org/abs/2608.16414
AB - Symmetry plays a fundamental role in determining the phases and physical properties of quantum matter. Controlling symmetry in mesoscopic superconducting devices provides a route to reconfigure their phase-coherent transport. Here we demonstrate symmetry-selective Josephson interferometry in lateral NbTi/PtTe_2/NbTi junctions by controlling the relative orientations of the current and magnetic field. From the supercurrent interference patterns, we construct a field-current symmetry map that identifies configurations exhibiting or violating the device-level parity (π«), time-reversal (π―) and their combined π«π― symmetry. In the absence of an in-plane field, the junction exhibits a symmetric Fraunhofer pattern. An in-plane field parallel to the current produces a pronounced side-lobe asymmetry, whereas reversing both the current and the complete magnetic-field configuration restores a generalized π― relation. Remarkably, orienting the in-plane field perpendicular to the current restores the π«π―-symmetric Fraunhofer response even at substantial field strengths. A microscopic model attributes this behavior to the interplay between disorder-induced potential variations and flux dipoles generated by in-plane-field Meissner focusing near the superconducting electrodes. Our results establish a reconfigurable Josephson interferometer in which the field-current geometry selects the symmetry operation being probed and switches the device between symmetry-broken and symmetry-restored interference states.
ER -