Related papers: Low-frequency Noise in Josephson Junctions for Sup…
We present measurements of 1/f frequency noise in both linear and Josephson-junction-embedded superconducting aluminum resonators in the low power, low temperature regime - typical operating conditions for superconducting qubits. The…
We present low-temperature measurements of the low-frequency $1/f$ noise arising from an ensemble of two-level fluctuators in the oxide barrier of Al/AlO$_{x}$/Al Josephson junctions. The fractional noise power spectrum of the…
We have measured the low frequency critical current noise in Nb/AlO$_{\mathrm{x}}$/Nb Josephson junctions. Unshunted junctions biased above the gap voltage and resistively shunted junctions biased near the critical current, $I_{c}$, have…
We present a simple microscopic model to show how fluctuating two--level systems in the Josephson junction tunnel barrier of thickness $L$ can modify the potential energy of the barrier and produce critical current noise spectra. We find…
Critical current fluctuations with a 1/ f spectral density (f is frequency) are potentially a limiting source of intrinsic decoherence in superconducting quantum bits (qubits) based on Josephson tunnel junctions. Prior measurements of this…
We have directly measured quasiparticle number fluctuations in a thin film superconducting Al resonator in thermal equilibrium. The spectrum of these fluctuations provides a measure of both the density and the lifetime of the…
The zero-voltage state of a Josephson junction biased with constant current consists of a set of metastable quantum energy levels. We probe the spacings of these levels by using microwave spectroscopy to enhance the escape rate to the…
Josephson junctions made from aluminium and its oxide are the most commonly used functional elements for superconducting circuits and qubits. It is generally known that the disordered thin-film AlOx contains atomic tunneling systems.…
The accurate analytical solution for the low temperature $1/f$ noise in a microwave dielectric constant of amorphous films containing tunneling two-level systems (TLSs) is derived within the standard tunneling model including the weak…
We compute the decoherence caused by $1/f$ fluctuations at low frequency $f$ in the critical current $I_0$ of Josephson junctions incorporated into flux, phase, charge and hybrid flux-charge superconducting quantum bits (qubits). The…
We report that low frequency (up to 200 kHz) noise spectra of magnetic tunnel junctions with areas ~10^{-10}cm^2$ at 10 Kelvin deviate significantly from the typical 1/f behavior found in large area junctions at room temperature. In most…
We demonstrate Josephson tunneling in vacuum tunnel junctions formed between a superconducting scanning tunneling microscope tip and a Pb film, for junction resistances in the range 50-300 k$\Omega$. We show that the superconducting phase…
We have investigated decoherence in Josephson-junction flux qubits. Based on the measurements of decoherence at various bias conditions, we discriminate contributions of different noise sources. In particular, we present a Gaussian decay…
Self-shunted aluminum Josephson junctions with high-transparency barriers were fabricated using the shadow-evaporation technique and measured at low temperatures, T=25 mK. Due to high junction transparency, the IV-characteristics were found…
Tunneling defects in disordered materials form spurious two-level systems which are a major source of decoherence for micro-fabricated quantum devices. For superconducting qubits, defects in tunnel barriers of submicrometer-sized Josephson…
We investigated low-frequency current fluctuations, i.e. noise, in the quasi-two-dimensional (2D) van der Waals antiferromagnetic semiconductor FePS3 with the electronic bandgap of 1.5 eV. The electrical and noise characteristics of the…
We report that annealing Al-AlOx-Al tunnel junctions in a vacuum chamber at temperature of 400C reduces the characteristic 1/f noise in the junctions, in some cases by an order of magnitude. Both ultra high vacuum and high vacuum fabricated…
The microwave-driven dynamics of the superconducting phase difference across a Josephson junction is now widely employed in superconducting qubits and quantum circuits. With the typical energy level separation frequency of several GHz,…
We consider a symmetric 0-pi Josephson junction of length $L$, which classically can be in one of two degenerate ground states up or down, corresponding to supercurrents circulating clockwise or counterclockwise around the 0-pi boundary.…
We have realized submicron tunnel ferromagnetic Al/AlO$_x$/Al/Ni$_{80}$Fe$_{20}$/Al Josephson junctions (JJs) in Manhattan-style configuration for qubit applications. These junctions have been designed to lie within the energy range of…