245 citations · 1.7k across the 70 of their papers we have counts for
74 papers
Detection of high-frequency gravitational waves using SRF cavities
M. Wenskat, B. Giaccone, J. Branlard +21
Today, apart from some isolated R&D efforts, there are no gravitational wave (GW) experiments, yet which explore a large part of the vast frequency range above the LIGO/Virgo band.…
Discovery of Niobium Hydride Precipitates in Superconducting Qubits
Zuhawn Sung, Daniel Bafia, Arely Cano +6
We report the evidence of the formation of niobium hydride phase within niobium films on silicon substrates in superconducting qubits fabricated at Rigetti Computing. For this stud…
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…
Loss tangent fluctuations due to two-level systems in superconducting microwave resonators
André Vallières, Megan E. Russell, Xinyuan You +10
Superconducting microwave resonators are critical to quantum computing and sensing technologies. Additionally, they are common proxies for superconducting qubits when determining t…
An Improved Bound on Nonlinear Quantum Mechanics using a Cryogenic Radio Frequency Experiment
Oleksandr Melnychuk, Bianca Giaccone, Nicholas Bornman +9
There are strong arguments that quantum mechanics may be nonlinear in its dynamics. A discovery of nonlinearity would hint at a novel understanding of the interplay between gravity…
First characterisation of the MAGO cavity, a superconducting RF detector for kHz-MHz gravitational waves
Lars Fischer, Bianca Giaccone, Ivan Gonin +12
Heterodyne detection using microwave cavities is a promising method for detecting high-frequency gravitational waves or ultralight axion dark matter. In this work, we report on stu…
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…
Enhanced Superconducting Qubit Performance Through Ammonium Fluoride Etch
Cameron J. Kopas, Dominic P. Goronzy, Thang Pham +19
The performance of superconducting qubits is often limited by dissipation and two-level systems (TLS) losses. The dominant sources of these losses are believed to originate from am…
Direct Measurement of Microwave Loss in Nb Films for Superconducting Qubits
B. Abdisatarov, D. Bafia, A. Murthy +9
Niobium films are a key component in modern two-dimensional superconducting qubits, yet their contribution to the total qubit decay rate is not fully understood. The presence of di…
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…
Crosstalk-Robust Quantum Control in Multimode Bosonic Systems
Xinyuan You, Yunwei Lu, Taeyoon Kim +10
High-coherence superconducting cavities offer a hardware-efficient platform for quantum information processing. To achieve universal operations of these bosonic modes, the requisit…
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…
Exploration of Parameters That Affect High Field Q-Slope
K. Howard, Y. -K. Kim, D. Bafia +1
The onset of high field Q-slope (HFQS) around 25 MV/m prevents cavities in electropolished (EP) condition from reaching high quality factors at high gradients due to the precipitat…
The Collaborative Effects of Intrinsic and Extrinsic Impurities in Low RRR SRF Cavities
K. Howard, Y. -K. Kim, D. Bafia +1
The superconducting radio-frequency (SRF) community has shown that introducing certain impurities into high-purity niobium can improve quality factors and accelerating gradients. W…
HELEN: Traveling Wave SRF Linear Collider Higgs Factory
S. Belomestnykh, P. C. Bhat, A. Grassellino +7
Traveling wave SRF accelerating structures offer several advantages over the traditional standing wave structures: substantially lower and lower , ratios o…
Quasiparticle spectroscopy in technologically-relevant niobium using London penetration depth measurements
Sunil Ghimire, Kamal R. Joshi, Amlan Datta +10
London penetration depth was measured in niobium foils, thin films, single crystals, and superconducting radio-frequency (SRF) cavity pieces cut out from different places. The low-…
Phase-controlled improvement of photon lifetime in coupled superconducting cavities
Changqing Wang, Oleksandr S Melnychuk, Crispin Contreras-Martinez +9
High-quality cavities are crucial for various fundamental physical studies and applications. Here we find that by coupling two cavities directly or via a phase-tunable coupling cha…
First Direct Observation of Nanometer size Hydride Precipitations on Superconducting Niobium
Zu Hawn Sung, Arely Cano, Akshay Murthy +5
Superconducting niobium serves as a key enabling material for superconducting radio frequency (SRF) technology as well as quantum computing devices. At room temperature, hydrogen c…
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…
Completely Positive Map for Noisy Driven Quantum Systems Derived by Keldysh Expansion
Ziwen Huang, Yunwei Lu, Anna Grassellino +3
Accurate modeling of decoherence errors in quantum processors is crucial for analyzing and improving gate fidelities. To increase the accuracy beyond that of the Lindblad dynamical…
Millikelvin measurements of permittivity and loss tangent of lithium niobate
Silvia Zorzetti, Changqing Wang, Ivan Gonin +5
Lithium Niobate is an electro-optic material with many applications in microwave signal processing, communication, quantum sensing, and quantum computing. In this letter, we presen…
New Exclusion Limit for Dark Photons from an SRF Cavity-Based Search (Dark SRF)
A. Romanenko, R. Harnik, A. Grassellino +11
We conduct the first ``light-shining-through-wall" (LSW) search for dark photons using two state-of-the-art high quality-factor superconducting radio frequency (SRF) cavities and r…
Disentangling the sources of ionizing radiation in superconducting qubits
L. Cardani, I. Colantoni, A. Cruciani +27
Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we mea…
SRF cavities and Superconducting qubits for Gravitational Waves and Dark Photons detection
Roberto Menta, Anna Grassellino, Roni Harnik +1
A short review which focuses on the employment of a Superconducting Radio Frequency cavity for detection of Gravitational Waves. This first part is inspired by the works of Berlin…