News & Analysis
/
Article

Ironing out kinks in quantum computing

JAN 31, 2025
Unique methods for measuring loss from superconducting resonators
Ironing out kinks in quantum computing internal name

Ironing out kinks in quantum computing lead image

While there are many ways to build a quantum computer, one popular platform that features superconducting qubits can leverage existing semiconductor fabrication processes and has demonstrated potential for scalability. Most commonly used is the transmon qubit, a micron-sized, nonlinear resonator made from superconducting films typically fabricated on silicon wafers.

But because of defects in the fabrication process, unintentional quantum states called “two-level systems” (TLS) can appear on the qubit surfaces, seriously hindering computing performance and information storage capacity.

One way to study them is to examine their effects on superconducting micro-resonators, which are parameterized by an internal quality factor (Qi) to quantify the parasitic loss from TLS. Measuring the Qi value is difficult, however, as it must be done in the single-photon limit to reflect the same regime in which the qubit operates.

Chen at al. addressed this challenge by presenting new strategies to mitigate the influence of the measurement noise on extracting the Qi value of a resonator.

“We introduce a hybrid approach that extracts certain resonator parameters from high-power measurements and re-applies them to analyze low-power data,” said author Cliff Chen.

Additionally, the researchers developed a new way to extract resonator parameters based on a mathematical tool that can algebraically transform raw data, thereby eliminating the need for nonlinear multi-parameter fitting.

“Our new methodology offers superior accuracy, efficiency, and robustness compared to conventional techniques,” said Chen. “We believe these improvements will help expedite the development of better superconducting qubits by simplifying data analysis and enabling more precise characterization of loss and decoherence in quantum circuits and materials.”

Source: “Efficient methods for extracting superconducting resonator loss in the single-photon regime,” by Cliff Chen, David Perello, Shahriar Aghaeimeibodi, Guillaume Marcaud, Ignace Jarrige, Hanho Lee, Warren Fon, Matt Matheny, and Jiansong Gao, Journal of Applied Physics (2025). The article can be accessed at https://doi.org/10.1063/5.0242201 .

More Science
/
Article
Method uses readily available materials to capture ultraintense laser intensities with submicrometer resolution.
AAS
/
Article
So far, searches for archival images that could confirm or rule out the asteroid’s impact have come up dry, but Webb observations in May could help pin down the orbit.
/
Article
Researchers photonically linked two ion-trap quantum processors, mediating deterministic two-qubit interactions.
APS
/
Article
Renate Pazourek develops software tools that Austrian government agencies use to audit tax returns and other financial documents.