Back to Search
Start Over
Phonon traps reduce the quasiparticle density in superconducting circuits
- Source :
- Zaguán: Repositorio Digital de la Universidad de Zaragoza, Universidad de Zaragoza, Applied physics letters 115(21), 212601-(2019). doi:10.1063/1.5124967, Zaguán. Repositorio Digital de la Universidad de Zaragoza, instname
- Publication Year :
- 2019
- Publisher :
- AIP Publishing, 2019.
-
Abstract
- Out of equilibrium quasiparticles (QPs) are one of the main sources of decoherence in superconducting quantum circuits and one that is particularly detrimental in devices with high kinetic inductance, such as high impedance resonators, qubits, and detectors. Despite significant progress in the understanding of QP dynamics, pinpointing their origin and decreasing their density remain outstanding tasks. The cyclic process of recombination and generation of QPs implies the exchange of phonons between the superconducting thin film and the underlying substrate. Reducing the number of substrate phonons with frequencies exceeding the spectral gap of the superconductor should result in a reduction of QPs. Indeed, we demonstrate that surrounding high impedance resonators made of granular aluminum (grAl) with lower gapped thin film aluminum islands increases the internal quality factors of the resonators in the single photon regime, suppresses the noise, and reduces the rate of observed QP bursts. The aluminum islands are positioned far enough from the resonators to be electromagnetically decoupled, thus not changing the resonator frequency nor the loading. We therefore attribute the improvements observed in grAl resonators to phonon trapping at frequencies close to the spectral gap of aluminum, well below the grAl gap.
- Subjects :
- 010302 applied physics
Physics
Superconductivity
Physics and Astronomy (miscellaneous)
Condensed matter physics
Phonon
Condensed Matter - Superconductivity
FOS: Physical sciences
02 engineering and technology
Substrate (electronics)
021001 nanoscience & nanotechnology
01 natural sciences
Noise (electronics)
Kinetic inductance
Superconductivity (cond-mat.supr-con)
High impedance
Resonator
Condensed Matter::Superconductivity
0103 physical sciences
Quasiparticle
ddc:530
0210 nano-technology
quasiparticles
phonons
qubit
Subjects
Details
- ISSN :
- 10773118 and 00036951
- Volume :
- 115
- Database :
- OpenAIRE
- Journal :
- Applied Physics Letters
- Accession number :
- edsair.doi.dedup.....87783dcc7dc30e3450069ba1fe1f8118
- Full Text :
- https://doi.org/10.1063/1.5124967