Related papers: Systematic Improvements in Transmon Qubit Coherenc…
We developed transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The…
Experiments to probe the basic quantum properties of motional degrees of freedom of mechanical systems have developed rapidly over the last decade. One promising approach is to use hybrid electromechanical systems incorporating…
The use of $\alpha$-tantalum in superconducting circuits has enabled a considerable improvement of the coherence time of transmon qubits. The standard approach to grow $\alpha$-tantalum thin films on silicon involves heating the substrate,…
Dissipation remains a central obstacle to improving superconducting quantum circuits, yet the microscopic origins of loss in widely used materials platforms are not fully understood. Here, we report the observation of interface…
The texture of high purity superconducting niobium sheets plays an important role in the physical and mechanical properties of high purity niobium sheet that are important for manufacturing of superconducting accelerator cavities. In a…
Recently, Nb superconducting radio frequency cavities vacuum heat treated between 300-400 C for a few hours have exhibited very high quality factors (~5x10^10 at 2.0 K). New secondary ion mass spectrometry measurements of O, N and C show…
Nonreciprocal interaction between two spatially separated subsystems plays a crucial role in signal processing and quantum networks. Here, we propose an efficient scheme to achieve nonreciprocal interaction and entanglement between two…
Superconducting qubits are among the most promising platforms for building a quantum computer. However, individual qubit coherence times are not far past the scalability threshold for quantum error correction, meaning that millions of…
Three types of metallic nanostructures comprising niobium were investigated experimentally; in all three types, electric transport at very low temperatures was governed by Coulomb blockade effects. 1. Thin film strips of niobium could be…
Recent advances in quantum information processing with superconducting qubits have fueled a growing demand for scaling and miniaturizing circuit layouts. Despite significant progress, predicting the Hamiltonian of complex circuits remains a…
The performance of state-of-the-art superconducting quantum devices is currently limited by microwave dielectric losses at different surfaces and interfaces. {\alpha}-tantalum is a superconductor that has proven effective in reducing…
We have developped a novel lift-off process for fabrication of high quality superconducting submicron niobium structures. The process makes use of a thermostable polymer with a high transition temperature T_{g}= 235 C and an excellent…
Superconducting qubits are one of the most promising physical systems for implementing quantum computers. However, executing quantum algorithms of practical computational advantage requires further improvements in the fidelities of qubit…
Acoustic devices offer significant advantages in size and loss, making them ubiquitous for mobile radio frequency signal processing. However, the usable bandwidth is often limited to the achievable electromechanical coupling, setting a hard…
Previous work has demonstrated that the radio frequency surface resistance of niobium resonators is dramatically reduced when nitrogen impurities are dissolved as interstitial in the material. The origin of this effect is attributed to the…
Superconducting 3D microwave cavities offer state-of-the-art coherence times and a well controlled environment for superconducting qubits. In order to realize at the same time fast readout and long-lived quantum information storage, one can…
Developing fault-tolerant quantum processors with error correction demands large arrays of physical qubits whose key performance metrics (coherence times, control fidelities) must remain within specifications over both short and long…
Recent studies have shown long-distance entanglement using NV centers, atoms, and quantum dots with single-photon time-bin encoding. We propose a method to entangle remote superconducting qubits via microwave-optical transduction using…
Structural and superconducting properties of high quality Niobium nanofilms with different thicknesses are investigated on silicon oxide and sapphire substrates. The role played by the different substrates and the superconducting properties…
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 amorphous materials and defects at interfaces and surfaces,…