Description: Pulsed and continuous-wave microwave measurements of spin-wave (magnon) propagation and dynamics in YIG waveguides at dilution-refrigerator temperatures.
Devlin is a Royal Society URF at the Centre for Cold Matter building a new experiment to detect axion and dark matter particles. His prior work at CERN's BASE collaboration (Penning trap antiproton experiment) used the ultra-sensitive superconducting detection circuit of a cryogenic Penning trap to set new constraints on axion-like particle couplings to photons (~2.79 neV/c² range; PRL 2021). At Imperial he is developing a Penning trap single-photon counter concept using a single trapped electron to detect 30–60 GHz photons from axion-photon conversion in a strong magnetic field (arXiv 2601.05472, March 2026), targeting axion masses of 124–248 μeV. This approach could overcome the standard quantum noise limit that hampers conventional haloscope searches at high mass. Active PDRA posting open May 2025.
Karenowska leads the Quantum Magnonics group, which develops low-temperature microwave magnonic circuits to probe magnon physics at the quantum level. Core experiments are conducted at millikelvin temperatures in a dilution refrigerator. Research foci include: (1) propagating magnon dynamics in YIG waveguides at mK temperatures — measuring spin-wave pulse propagation and characterising the low-temperature ferromagnetic resonance frequency shift; (2) magnon-phonon (phonon-to-magnon) interconversion via magnetoelastic coupling and symmetry breaking in YIG; (3) spin-cat state generation in ferromagnetic insulators — theoretical and experimental work toward macroscopic quantum superposition states of magnons; and (4) magnon spintronics — spin-charge interconversion in YIG/metal heterostructures. These systems are relevant for microwave quantum information processing and quantum-limited magnetic-frequency-band sensing.