Related papers: Dispersive magnetometry with a quantum limited SQU…
Under negative feedback, the quality factor Q of a radio-frequency magnetometer can be decreased by more than two orders of magnitude, so that any initial perturbation of the polarized spin system can be rapidly damped, preparing the…
Broadband quantum-limited amplifiers are essential for quantum information processing, yet challenges in design and fabrication continue to hinder their widespread applications. Here, we introduce the broadband merged-element Josephson…
While single-photon counting is routinely achieved in the optical domain, operational single microwave photon detectors (SMPDs) have only recently been demonstrated. SMPDs are critical for sensing weak signals from incoherent emitters, with…
We realize a nondegenerate parametric amplifier in an ultrahigh $Q$ mechanical membrane resonator and demonstrate two-mode thermomechanical noise squeezing. Our measurements are accurately described by a two-mode model that attributes this…
An amplifier combining noise performances as close as possible to the quantum limit with large bandwidth and high saturation power is highly desirable for many solid state quantum technologies such as high fidelity qubit readout or high…
One of the major challenges in performing SQUID-detected Magnetic Resonance Force Microscopy (MRFM) at milliKelvin temperatures is the crosstalk between the radiofrequency (RF) pulses used for the spin manipulation and the SQUID-based…
We have developed a new type of magnetometer consisting of a Hybrid Quantum Interference Device (HyQUID) that is set in a bi-stable state. We demonstrate its operation in a latching mode that can be employed to measure small changes in the…
A conventional resonant detector is often subject to a trade-off between bandwidth and peak sensitivity that can be traced back to quantum Cramer-Rao Bound. Anomalous dispersion has been shown to improve it by signal amplification and is…
We report a generic scheme to implement transmission-type quantum gates for propagating microwave photons, based on a sequence of lumped-element components on transmission lines. By choosing three equidistant superconducting quantum…
The deployment of large cryogenic detector arrays, comprising hundreds to thousands of individual detectors, is highly beneficial for various cutting-edge applications, requiring large statistics, angular resolution or imaging capabilities.…
High precision interferometers are the building blocks of precision metrology and the ultimate interferometric sensitivity is limited by the quantum noise. Here we propose and experimentally demonstrate a compact quantum interferometer…
The performance of a wide range of quantum computing algorithms and protocols depends critically on the fidelity and speed of the employed qubit readout. Examples include gate sequences benefiting from mid-circuit, real-time,…
Precise detection of spin resonance is of paramount importance to achieve coherent spin control in quantum computing. We present a novel setup for spin resonance measurements, which uses a dc-SQUID flux detector coupled to an antenna from a…
Designing quantum systems with the measurement speed and accuracy needed for quantum error correction using superconducting qubits requires iterative design and test informed by accurate models and characterization tools. We introduce a…
High-fidelity qubit measurement is a critical element of all quantum computing architectures. In superconducting systems, qubits are typically measured by probing a readout resonator with a weak microwave tone that must be amplified before…
Superconducting Quantum Interference Devices (SQUIDs), formed by incorporating Josephson junctions into loops of superconducting material, are the backbone of many modern quantum sensing systems. It has been demonstrated that, by combining…
We report a detailed theoretical study of a coherent macroscopic quantum-mechanical phenomenon - quantum beats of a single magnetic fluxon trapped in a two-cell SQUID of high kinetic inductance. We calculate numerically and analytically the…
We analyze the dispersive readout of superconducting charge and flux qubits as a quantum measurement process. The measurement oscillator frequency is considered much lower than the qubit frequency. This regime is interesting because large…
Scanning-probe magnetometry is a valuable experimental tool to investigate magnetic phenomena at the micro- and nanoscale. We theoretically analyze the possibility of measuring magnetic fields via the electrical current flowing through…
The microwave SQUID multiplexer (umux) has enabled higher bandwidth or higher channel counts across a wide range of experiments in particle physics, astronomy, and spectroscopy. The large multiplexing factor coupled with recent commercial…