相关论文: Argon milling induced decoherence mechanisms in su…
The coherence of state-of-the-art superconducting qubit devices is predominantly limited by two-level-system defects, found primarily at amorphous interface layers. Reducing microwave loss from these interfaces by proper surface treatments…
We address the scaling-up problem for superconducting quantum circuits by using lumped-element resonators based on an alternative fabrication method of aluminum -- aluminum oxide -- aluminum ($\mathrm{Al/AlO_x/Al}$) parallel-plate…
We study microwave-driven cooling in a superconducting flux qubit subjected to environment noises. For the weak decoherence, our analytical results agree well with the experimental observations near the degeneracy point and show that the…
Superconducting coplanar waveguide resonators are essential components in quantum processors, where their internal quality factor (Qi) constrains qubit coherence and readout fidelity. In niobium devices, microwave losses at millikelvin…
We present an experimental characterisation of the electrical properties of 3D-printed Niobium. The study was performed by inserting a 3D-printed Nb post inside an Aluminium cylindrical cavity, forming a 3D lumped element re-entrant…
Superconducting resonators and parametric amplifiers are important components in scientific systems such as kinetic inductance detector arrays, frequency-domain multiplexers for other superconducting bolometers, spin-ensemble based…
Extraneous high frequency chip modes parasitic to superconducting quantum circuits can result in decoherence when these modes are excited. To suppress these modes, superconducting air bridges (AB) are commonly used to electrically connect…
A minimal method to fabricate Al/AlO$_x$/Al Josephson junctions (JJs) using photolithography and argon etching, before metallization and oxidation, is demonstrated. JJs with areas ranging from 1 to 6 $\mu$m$^2$ can be fabricated and, with…
Decoherence in quantum bit circuits is presently a major limitation to their use for quantum computing purposes. We present experiments, inspired from NMR, that characterise decoherence in a particular superconducting quantum bit circuit,…
Optical coherence lifetimes and decoherence processes in erbium-doped lithium niobate (Er$^{3+}$:LiNbO$_3$) crystalline powders are investigated for materials that underwent different mechanical and thermal treatments. Several complimentary…
We report the finding of new surface treatments that permit to manipulate the niobium resonator nitrogen content in the first few nanometers in a controlled way, and the resonator fundamental Mattis-Bardeen surface resistance and residual…
The most commonly used physical realization of superconducting qubits for quantum circuits is a transmon. There are a number of superconducting quantum circuits applications, where Josephson junction critical current reproducibility over a…
In the fabrication of superconducting devices, both in situ and ex situ processes are utilized, making the removal of unwanted oxide layers and impurities under vacuum conditions crucial. Oxygen descumming and argon milling are standard in…
Quantum error correction will be an essential ingredient in realizing fault-tolerant quantum computing. However, most correction schemes rely on the assumption that errors are sufficiently uncorrelated in space and time. In superconducting…
We report the development of a superconducting acousto-optic phase modulator fabricated on a lithium niobate substrate. A titanium-diffused optical waveguide is placed in a surface acoustic wave resonator, where the electrodes for mirrors…
The high critical magnetic field and relatively high critical temperature of niobium nitride (NbN) make it a promising material candidate for applications in superconducting quantum technology. However, NbN-based devices and circuits are…
Using micromagnets to enable electron spin manipulation in silicon qubits has emerged as a very popular method, enabling single-qubit gate fidelities larger than 99:9%. However, these micromagnets also apply stray magnetic field gradients…
Several ion source alternatives for current focused ion beam (FIB) systems have been studied to achieve higher brightness, including cold atom ion sources. However, a study of ultracold ions interacting with often used materials is seldom…
Superconducting high kinetic inductance elements constitute a valuable resource for quantum circuit design and millimeter-wave detection. Granular aluminum (GrAl) in the superconducting regime is a particularly interesting material since it…
We demonstrate enhanced relaxation and dephasing times of transmon qubits, up to ~ 60 \mu s by fabricating the interdigitated shunting capacitors using titanium nitride (TiN). Compared to lift-off aluminum deposited simultaneously with the…