Lattice-Renormalized Tunneling Models for Superconducting Qubit Materials

Fuente: arXiv
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Autores principales: Pritchard, P. G., Rondinelli, James M.
Formato: Preprint
Publicado: 2025
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author Pritchard, P. G.
Rondinelli, James M.
author_facet Pritchard, P. G.
Rondinelli, James M.
contents We present a lattice-renormalized formalism for configurational tunneling two-level systems (TLS) that overcomes limitations of minimum-energy-path and light-particle models. Derived from the nuclear Hamiltonian, our formulation introduces composite phonon coordinates to capture lattice distortions between degenerate potential wells. This approach resolves deficiencies in prior models and enables accurate computation of tunnel splittings and excitation spectra for hydrogen-based TLS in bcc Nb. Our results bound experimental tunnel splittings and reveal strong anharmonic couplings between tunneling atoms and lattice phonons, establishing a direct link between TLS dynamics and phonon-mediated strain interactions. The formalism further generalizes to multi-level systems (MLS), providing insight into defect-induced decoherence in superconducting qubits and guiding strategies for materials design to suppress TLS-related loss.
format Preprint
id arxiv_https___arxiv_org_abs_2512_18156
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Lattice-Renormalized Tunneling Models for Superconducting Qubit Materials
Pritchard, P. G.
Rondinelli, James M.
Quantum Physics
Materials Science
We present a lattice-renormalized formalism for configurational tunneling two-level systems (TLS) that overcomes limitations of minimum-energy-path and light-particle models. Derived from the nuclear Hamiltonian, our formulation introduces composite phonon coordinates to capture lattice distortions between degenerate potential wells. This approach resolves deficiencies in prior models and enables accurate computation of tunnel splittings and excitation spectra for hydrogen-based TLS in bcc Nb. Our results bound experimental tunnel splittings and reveal strong anharmonic couplings between tunneling atoms and lattice phonons, establishing a direct link between TLS dynamics and phonon-mediated strain interactions. The formalism further generalizes to multi-level systems (MLS), providing insight into defect-induced decoherence in superconducting qubits and guiding strategies for materials design to suppress TLS-related loss.
title Lattice-Renormalized Tunneling Models for Superconducting Qubit Materials
topic Quantum Physics
Materials Science
url https://arxiv.org/abs/2512.18156