Research Areas - (15) Quantum-Limited Microwave Amplification

Full path: Physics > Quantum Optics > Squeezed Light / Quantum Noise > Quantum-Limited Microwave Amplification

Department(s)/lab(s): Physics & Astronomy – Biophysics | Nguyen Lab (Nanomaterials for Biosensing) @ UCL
Summary:

Nguyen's group at UCL (based at Royal Institution) focuses on magnetic and fluorescent nanoparticles for biomedical sensing and therapy. Research directions: (1) Magnetic nanoparticle synthesis β€” iron oxide (SPION) and other magnetic nanoparticles with controlled size, shape, and surface chemistry for MRI contrast and magnetic hyperthermia; (2) Biosensing platforms β€” functionalized nanoparticles as MRI-detectable sensors for specific biomolecular targets; magnetic particle imaging (MPI) for real-time tracking; (3) Plasmonic nanoparticles β€” gold nanoparticles for optical biosensing and photothermal therapy; (4) Fluorescent nanoparticles β€” QD- and dye-conjugated probes for live-cell imaging. Relevant to quantum sensing through magnetic nanoparticle platforms.

Department(s)/lab(s): School of Electrical Engineering and Telecommunications | Pla Quantum Spin Control and Sensing Laboratory @ UNSW
Summary:

Pla is the strongest single match in this cohort for a candidate whose background is sensitivity-limited spin detection. His laboratory does inductively-detected electron spin resonance at millikelvin using high-quality-factor superconducting microresonators, read out through Josephson and travelling-wave parametric amplifiers operating at the quantum limit of added noise. The result is ESR sensitivity improved by many orders of magnitude over commercial spectrometers β€” the group's stated target is single-spin inductive detection β€” and, in parallel, the development of near-ideal degenerate parametric amplifiers and squeezed microwave states as the readout resource that makes it possible. Applications explicitly include chemistry and biology, where the goal is to do EPR on samples far too small for a conventional spectrometer. Positioned against the established body of NV-ensemble quantum sensing work β€” DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity β€” this is the microwave-inductive route to the same destination: where an NV ensemble reaches pT/sqrt(Hz) by optical readout of many spins, Pla reaches comparable or better spin sensitivity by making the microwave detection chain quantum-limited, and the DEER and dynamical-decoupling sequences are shared verbatim. Preferred attribute present in the strongest form: cutting-edge sensitivity, not device fabrication, is the object.

Department(s)/lab(s): Department of Physics, 1st Institute of Physics | Pop Group - Superconducting Quantum Circuits (1. Physikalisches Institut) @ Stuttgart
Summary:

Pop's group builds superconducting quantum circuits from high-kinetic-inductance materials, above all granular aluminium, and uses them as detectors. The distinctive capability is single-microwave-photon detection and QND photon counting with superinductor-based devices -- an extremely low dark-count, quantum-limited receiver in the GHz band -- plus fluxonium-type qubits, quantum-limited and travelling-wave parametric amplification, and studies of quasiparticle and noise mechanisms that set coherence limits. The direct sensing payoff is dark-matter search: a photon counter that beats the standard quantum limit lets a haloscope integrate far faster than an amplifier-based readout. Relative to the established NV-ensemble quantum-sensing playbook (DEER, nanoscale NMR, T1 relaxometry at pT/sqrt(Hz) ensemble sensitivity), this is the microwave/superconducting counterpart to an NV ensemble -- same objective (detect an absurdly weak field), different physical platform and roughly opposite temperature regime. A recent addition to Stuttgart's 1st Institute of Physics, so the lab is being built out now, which usually means unusual latitude for a postdoc.

Department(s)/lab(s): Physics and Electrical Engineering & Computer Sciences | Siddiqi Quantum Nanoelectronics Laboratory (QNL) @ UCB
Summary:

Siddiqi's Quantum Nanoelectronics Laboratory develops superconducting quantum circuits and near-quantum-limited parametric amplifiers for qubit readout, quantum feedback, and quantum-enhanced sensing, and directs cross-campus quantum information efforts at Berkeley and LBNL.

Department(s)/lab(s): Physics – Institute for Quantum Electronics / PSI | Experimental Quantum Engineering Group (Xu) @ ETH Zurich
Summary:

Xu leads the Experimental Quantum Engineering group with a joint ETH–PSI appointment. Research directions: (1) Superconducting circuit quantum sensing β€” using qubits-as-sensors for detecting weak microwave signals beyond standard quantum limits, quantum non-demolition readout of photon fields; (2) Quantum error correction enabled sensing β€” integrating bosonic codes (cat qubits, binomial codes) into sensing protocols; (3) Quantum acoustics β€” coupling superconducting qubits to surface acoustic wave (SAW) resonators for hybrid quantum sensing; (4) Novel quantum hardware at PSI β€” leveraging PSI's infrastructure for cryogenic device fabrication and testing. Connected to the ETH–PSI Quantum Computing Hub.