11 citations · 19 across the 9 of their papers we have counts for
10 papers
Spatial interference changes the symmetry class of a Josephson element
Takayuki Kubo
Spatial interference can break the inversion symmetry of an effective Josephson potential even in a laterally homogeneous junction with inversion-symmetric local energy. We derive…
Microscopic theory of the field-induced instability of the vortex-free state in superconducting thin-film strips
Takayuki Kubo
In the Pearl--London theory, the edge-barrier-disappearance field of a superconducting thin-film strip depends on an arbitrary short-distance core cutoff because the vortex is trea…
Microscopic equivalence of the vortex-entry current and the depairing current in a superconducting thin-film strip
Takayuki Kubo
The vortex-entry current density of a superconducting strip is usually defined, within phenomenological Pearl--London theory, as the current density at which the edge b…
Microscopic theory of the lower critical field in superconducting thin-film strips
Takayuki Kubo
The lower critical field of a narrow superconducting thin-film strip sets the thermodynamic scale for vortex-free operation in a perpendicular magnetic field. The standard…
Superheating field of clean superconductors near the type-I--type-II boundary: the low-temperature Meissner stability limit of niobium
Takayuki Kubo
We calculate the low-temperature superheating field of clean superconductors near the boundary between type-I and type-II superconductivity, with particular emphasis o…
Power attenuation in millimeter-wave and terahertz superconducting rectangular waveguides: linear response, TLS loss, and Higgs-mode nonlinearity
Takayuki Kubo
Superconducting waveguides are a promising platform for ultralow-loss transmission in the millimeter-wave to terahertz band under cryogenic conditions, with potential applications…
Higgs-mode-induced instability and kinetic inductance in strongly dc-biased dirty-limit superconductors
Takayuki Kubo
A perturbative ac field superposed on a dc bias () is known to excite the Higgs mode in superconductors. The dirty limit, where disorder enhances the Higgs resonance, provides…
How High a Field Can Be and Has Been Achieved in Superconducting Bulk Niobium Cavities Across Different RRR Values?
Takayuki Kubo
This Brief Note explores the relationship between residual resistivity ratio (RRR) and the maximum surface magnetic field in superconducting bulk niobium (Nb) cavities. Data from t…
On the Applicability Ranges of Tc Formulas for Proximity-Coupled Thin SN and SS Bilayers
Takayuki Kubo
This brief note revisits the well-established formulas for proximity-coupled thin superconductor-normal conductor (SN) and superconductor-superconductor (SS) bilayers, highli…
Significant Contributions of the Higgs Mode and Self-Energy Corrections to Low-Frequency Complex Conductivity in DC-Biased Superconducting Devices
Takayuki Kubo
We investigate the complex conductivity of superconductors under a DC bias based on the Keldysh-Eilenberger formalism of nonequilibrium superconductivity. This framework allows us…