Proximity effect in asymmetric-gap superconducting bilayers and regularization of transition rates

• URL: http://arxiv.org/abs/2512.17765v1
• Date: Fri, 19 Dec 2025 16:36:28 GMT
• Title: Proximity effect in asymmetric-gap superconducting bilayers and regularization of transition rates
• Authors: G. Marchegiani, G. Catelani,
• Abstract summary: Mean-field treatment of low-temperature superconductors leads to a square-root divergent density of states at the gap value.<n>We revisit their possible regularization based on the proximity effect between two superconducting films with different gaps.<n>We find that the smearing of the density of states grows with the gap asymmetry.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The standard mean-field treatment of low-temperature superconductors leads to a square-root divergent density of states at the gap value. This feature can lead to unphysical logarithmic divergences in various quantities, such as currents and qubit transition rates. We revisit their possible regularization based on the proximity effect between two superconducting films with different gaps. We derive analytical approximations for the density of states in each superconducting film. We find that the smearing of the density of states grows with the gap asymmetry. As a concrete example, we discuss the regularization of transition rates in qubits with frequency close to resonance with the gap asymmetry between the two films, and the consequent smoothening of the jump discontinuity in the qubit frequency shift.

Related papers

• Symmetry-protected topology and deconfined solitons in a multi-link $\mathbb{Z}_2$ gauge theory [45.88028371034407]
  We study a $mathbbZ$ lattice gauge theory defined on a multi-graph with links that can be visualized as great circles of a spherical shell.<n>We show that this leads to state-dependent tunneling amplitudes underlying a phenomenon analogous to the Peierls instability.<n>By performining a detailed analysis based on matrix product states, we prove that charge deconfinement emerges as a consequence of charge-fractionalization.
  arXiv  Detail & Related papers  (2026-03-02T22:59:25Z)
• Observation of disorder-induced superfluidity [121.09589727417034]
  We explore phases arising from the interplay between disorder, kinetic energy, and interactions on a superconducting processor.<n>Our results provide strong experimental evidence for disorder-induced superfluidity.
  arXiv  Detail & Related papers  (2025-12-24T20:38:43Z)
• Resonator-assisted quantum transduction between superconducting qubits and trapped atomic systems via Rydberg levels [45.88028371034407]
  We propose a scheme between superconducting qubits and qubit states encoded in trapped atomic systems.<n>The approach employs atomic Rydberg levels together with laser pulses that connect them to the low-lying qubit states.
  arXiv  Detail & Related papers  (2025-01-06T18:28:18Z)
• Quasiparticle effects in magnetic-field-resilient 3D transmons [0.0]
  We present measurements of the parity-switching time of a field-resilient 3D transmon with in-plane field up to 0.41T. We demonstrate that the superconducting-gap asymmetry plays a crucial role in the observed behavior. We establish that Al-AlO$_x$-Al JJs could be used in architectures for the parity-readout and manipulation of topological qubits.
  arXiv  Detail & Related papers  (2024-03-05T22:37:21Z)
• Probing quantum floating phases in Rydberg atom arrays [61.242961328078245]
  We experimentally observe the emergence of the quantum floating phase in 92 neutral-atom qubits. The site-resolved measurement reveals the formation of domain walls within the commensurate ordered phase. As the experimental system sizes increase, we show that the wave vectors approach a continuum of values incommensurate with the lattice.
  arXiv  Detail & Related papers  (2024-01-16T03:26:36Z)
• Fragmented superconductivity in the Hubbard model as solitons in Ginzburg-Landau theory [39.58317527488534]
  Superconductivity and charge density waves are observed in close vicinity in strongly correlated materials. We investigate the nature of such an intertwined state of matter stabilized in the phase diagram of the elementary $t$-$tprime$-$U$ Hubbard model. We provide conclusive evidence that the macroscopic wave functions of the superconducting fragments are well-described by soliton solutions of a Ginzburg-Landau equation.
  arXiv  Detail & Related papers  (2023-07-21T18:00:07Z)
• Coexistence of nonequilibrium density and equilibrium energy distribution of quasiparticles in a superconducting qubit [0.0]
  density of quasiparticles typically observed in superconducting qubits exceeds the value expected in equilibrium by many orders of magnitude. We measure the thermal activation of charge-parity switching in a transmon qubit with a difference in superconducting gap on the two sides of the Josephson junction.
  arXiv  Detail & Related papers  (2023-02-23T20:50:47Z)
• Quasiparticles in superconducting qubits with asymmetric junctions [0.0]
  We consider quasiparticle effects in superconducting qubits to account for asymmetry in the gap on the two sides of a Josephson junction. We find that different regimes can be encountered in which the quasiparticles have either similar densities in the two junction leads, or are largely confined to the lower-gap lead.
  arXiv  Detail & Related papers  (2022-05-12T12:43:42Z)
• Tuning long-range fermion-mediated interactions in cold-atom quantum simulators [68.8204255655161]
  Engineering long-range interactions in cold-atom quantum simulators can lead to exotic quantum many-body behavior. Here, we propose several tuning knobs, accessible in current experimental platforms, that allow to further control the range and shape of the mediated interactions.
  arXiv  Detail & Related papers  (2022-03-31T13:32:12Z)
• Quantum correlations, entanglement spectrum and coherence of two-particle reduced density matrix in the Extended Hubbard Model [62.997667081978825]
  We study the ground state properties of the one-dimensional extended Hubbard model at half-filling. In particular, in the superconducting region, we obtain that the entanglement spectrum signals a transition between a dominant singlet (SS) to triplet (TS) pairing ordering in the system.
  arXiv  Detail & Related papers  (2021-10-29T21:02:24Z)
• Photon-mediated Peierls Transition of a 1D Gas in a Multimode Optical Cavity [0.0]
  Peierls instability toward a charge density wave is a canonical example of phonon-driven strongly correlated physics. We propose a method to realize an analogous photon-mediated Peierls transition, using a system of interacting Bose or Fermi atoms trapped inside a multimode confocal cavity.
  arXiv  Detail & Related papers  (2020-02-27T17:49:55Z)
• Quantum emulation of coherent backscattering in a system of superconducting qubits [45.82374977939355]
  We use multi-pass Landau-Zener transitions at the avoided crossing of a highly-coherent superconducting qubit to emulate weak localization (WL) and universal conductance fluctuations (UCF) The higher coherence of this qubit enabled the realization of both effects, in contrast to earlier work arXiv:1204.6428, which successfully emulated UCF, but did not observe WL.
  arXiv  Detail & Related papers  (2019-12-28T17:11:53Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.