Description: Coupling of qubits or spins to microwave resonators for readout and quantum control.
Kolthammer works on quantum photonics with an emphasis on nonclassical states of light and their applications to quantum information and sensing. Research highlights: (1) Gaussian Boson Sampling — first time-bin encoded GBS experiment using a loop-based interferometer with superconducting TES photon-number-resolving detectors, demonstrated enhancement in dense-subgraph search over classical methods (PRX 2022); (2) Squeezed state characterisation — nonclassicality certification using multiplexing layouts with superconducting TES detectors, sub-Poisson and sub-binomial statistics (PRA 2017); (3) Frequency-multiplexed photon pair sources — electro-optic frequency shifting for indistinguishable single-photon multiplexing without added multi-photon events; (4) Photonic quantum sensing — developing time-bin encoded platforms for quantum-enhanced sensing and quantum advantage demonstrations.
Develops superconducting qubits and QND microwave single-photon detectors, applying them both to scalable quantum computing architectures and to axion/dark-photon dark-matter search experiments as ultra-sensitive quantum sensors.
Murch studies continuous quantum measurement and feedback control in superconducting circuit QED systems, including some of the earliest experiments resolving quantum backaction and weak-value amplification, work directly relevant to the quantum limits of continuous sensing and metrology.
Studies quantum optics and quantum information with superconducting and hybrid quantum circuits, focusing on modular quantum computing architectures, microwave-to-optical photon transduction, and quantum error mitigation.
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 — the group's stated target is single-spin inductive detection — 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 — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — 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.
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.
Reilly's Quantum Nanoscience Laboratory works on the interface between quantum devices and the classical control hardware needed to run them at scale — custom VLSI CMOS operating below 100 mK, high-bandwidth dispersive readout, and cryogenic microwave engineering — a programme built up during his long association with Microsoft's quantum effort. A distinct and directly relevant second thread is the manipulation of spin states in nanoparticles for new imaging modalities in medicine: hyperpolarisation and spin-state engineering of nanoparticle contrast agents, which is quantum control applied to MRI. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — the cryo-CMOS readout chain he builds is exactly the enabling technology that would let a pT/sqrt(Hz) spin-ensemble sensor be multiplexed into an array rather than run one channel at a time; and the nanoparticle-MRI thread is an independent route into biological spin sensing. Large group, strong engineering culture, significant industry entanglement.
A pioneer of circuit quantum electrodynamics, Schuster's group uses superconducting qubits and microwave resonators both as quantum-information platforms and as ultra-sensitive quantum-limited sensors/spectrometers, extending qubit-based readout to precision spectroscopy of otherwise inaccessible microwave-frequency phenomena.
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.
Gary Steele's lab works on quantum circuits and mechanical quantum systems, exploring quantum phenomena in nanoelectromechanical (NEMS) and superconducting circuit systems. Research includes: (1) superconducting qubit-membrane optomechanics and electromechanics; (2) circuit quantum acoustodynamics (cQAD) — coupling superconducting qubits to phonons; (3) analog quantum simulation with quantum circuits; (4) probing quantum materials (graphene, 2D materials) with superconducting circuits. The group develops novel quantum sensors for mechanical forces and electromagnetic fields.