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20212026
most citedSystematic Improvements in Transmon Qubit Coherence Enabled by Niobium Surface Encapsulation

123 citations · 165 across the 11 of their papers we have counts for

collaborators

15 papers

physics.ins-det2026

Quantitative characterization of superconducting qubits as particle detectors

Francesco De Dominicis, Raja Yasir Mehmood Khan, Dounia L Helis +22

Ionizing radiation is a major source of correlated errors in superconducting quantum processors, yet the mechanisms responsible for the qubit response to particle interactions rema…

quant-ph2026

Microwave dielectric properties of LiNbO and AlN at millikelvin temperatures and single-photon power

Alessandro Reineri, Francesco Crisa, Akshay Murthy +8

Efficient bidirectional microwave-optical photon conversion is a key capability for scaling superconducting quantum processors into distributed networks. However, achieving the nec…

quant-ph2026

Two-Level System Spectroscopy from Correlated Multilevel Relaxation in Superconducting Qubits

Tanay Roy, Xinyuan You, David van Zanten +5

Transmon qubits are a cornerstone of modern superconducting quantum computing platforms. Temporal fluctuations of energy relaxation in these qubits are widely attributed to microsc…

cond-mat.supr-con2026

Effect of metal encapsulation on bulk superconducting properties of niobium thin films used in qubits

Amlan Datta, Kamal R. Joshi, Sunil Ghimire +18

Niobium metal occupies nearly 100\% of the volume of a typical 2D transmon device. While the aluminum Josephson junction is of utmost importance, maintaining quantum coherence acro…

cond-mat.supr-con2026

Oxygen distribution and segregation at grain boundaries in Nb and Ta-encapsulated Nb thin films for superconducting qubits

Jaeyel Lee, Dieter Isheim, Zuhawn Sung +14

We report on atomic-scale analyses of oxygen distribution and segregation at grain boundaries (GBs) of Nb and Ta-encapsulated Nb (Ta/Nb) thin films for superconducting qubits using…

cond-mat.mes-hall2025★ 3 cited

Correlating Superconducting Qubit Performance Losses to Sidewall Near-Field Scattering via Terahertz Nanophotonics

Richard H. J. Kim, Samuel J. Haeuser, Joong-Mok Park +16

Elucidating dielectric losses, structural heterogeneity, and interface imperfections is critical for improving coherence in superconducting qubits. However, most diagnostics rely o…

quant-ph2025

Ultracoherent superconducting cavity-based multiqudit platform with error-resilient control

Taeyoon Kim, Tanay Roy, Xinyuan You +26

Realizing the promise of quantum computing requires simultaneously increasing Hilbert-space size and coherence times. While qubit-based architectures have long been the dominant pa…

quant-ph2025

Fast Sideband Control of a Weakly Coupled Multimode Bosonic Memory

Jordan Huang, Thomas J. DiNapoli, Gavin Rockwood +9

Circuit quantum electrodynamics (cQED) with superconducting cavities coupled to nonlinear circuits like transmons offers a promising platform for hardware-efficient quantum informa…

quant-ph2025

Identifying Materials-Level Sources of Performance Variation in Superconducting Transmon Qubits

Akshay A. Murthy, Mustafa Bal, Michael J. Bedzyk +46

The Superconducting Materials and Systems (SQMS) Center, a DOE National Quantum Information Science Research Center, has conducted a comprehensive and coordinated study using super…

quant-ph2024★ 2 cited

Disentangling the Impact of Quasiparticles and Two-Level Systems on the Statistics of Superconducting Qubit Lifetime

Shaojiang Zhu, Xinyuan You, Ugur Alyanak +8

Temporal fluctuations in the superconducting qubit lifetime, , bring up additional challenges in building a fault-tolerant quantum computer. While the exact mechanisms remain…

quant-ph2024

Evaluating radiation impact on transmon qubits in above and underground facilities

Francesco De Dominicis, Tanay Roy, Ambra Mariani +20

Superconducting qubits can be sensitive to abrupt energy deposits caused by cosmic rays and ambient radioactivity. While previous studies have explored correlated effects in time a…

cond-mat.mtrl-sci2023

Magnetic Fluctuations in Niobium Pentoxide

Y. Krasnikova, A. A. Murthy, F. Crisa +10

Using a spin-polarized muon beam we were able to capture magnetic dynamics in an amorphous niobium pentoxide thin film. Muons are used to probe internal magnetic fields produced by…

quant-ph2023★ 123 cited

Systematic Improvements in Transmon Qubit Coherence Enabled by Niobium Surface Encapsulation

Mustafa Bal, Akshay A. Murthy, Shaojiang Zhu +37

We present a novel transmon qubit fabrication technique that yields systematic improvements in T relaxation times. We fabricate devices using an encapsulation strategy that inv…

physics.app-ph2022

High quality superconducting Nb co-planar resonators on sapphire substrate

S. Zhu, F. Crisa, M. Bal +10

We present measurements and simulations of superconducting Nb co-planar waveguide resonators on sapphire substrate down to millikelvin temperature range with different readout powe…

cond-mat.supr-con2021★ 37 cited

Electrostatic field-driven supercurrent suppression in ionic-gated metallic Josephson nanotransistors

Federico Paolucci, Francesco Crisà, Giorgio De Simoni +5

Recent experiments have shown the possibility of tuning the transport properties of metallic nanosized superconductors through a gate voltage. These results renewed the longstandin…