Ultrafast viscosity measurement

In our latest article, Lars Madsen, Catxere CasacioAlex Terrasson, Warwick Bowen and collaborators measure the viscosity of a fluid within twenty microseconds and extreme precision—up to the point where the remnant uncertainty stems from its thermal molecular collisions. Read on in Nature Photonics!

A bead trapped in optical tweezers performs thermally driven motion.
From: Madsen, Lars S. et al. Ultrafast viscosity measurement with ballistic optical tweezers. Nat. Photonics (2021)

Making mechanical qubits

Yasmine Sfendla, Chris Baker, Glen Harris, Ray Harrison, Warwick Bowen and collaborating professor Lin Tian from UC Merced have set a step towards developing the elusive all-mechanical qubit. All you need is some superfluid and a slab of silicon! Get the recipe at npj Quantum Information.

Computer-simulated image of a thin film of fluid covering a periodically perforated slab. In the middle, a hole is missing. There, the fluid is moving up and down like water in a pond.
Superfluid wave trapped in a phononic crystal (or “acoustic metamaterial”).
From: Sfendla, Yasmine L., et al. Extreme quantum nonlinearity in superfluid thin-film surface waves. npj Quantum Inf 7, 62 (2021)

How vortex clusters expand

Call us spin doctors if you must, but we’re here with more vortex news to wrap your head around: Warwick Bowen and colleagues studied how vortices in a superfluid spread out over time from an initial arrangement. They found that each and every initial configuration results in a top-hat shaped velocity-position profile. Hat tip to our friends and colleagues at FLEET!

Quantum waves travel in a slot-waveguide

In our latest publication, Glen Harris, Andreas Sawadsky, Yasmine Sfendla, Walter Wasserman, Warwick Bowen and Chris Baker suggest filling a slot waveguide with superfluid to create an ultralow-dissipation resonator for travelling acoustic and optical waves. If you are familiar with our work, that suggestion should not come as a surprise. What can we say? A layer of superfluid does make everything better. Superfluid, some might say, is the mayonnaise of quantum optics.

A very small, not very cold, magnetosensor

Any scientist knows the importance of taking data with a grain of salt. Here at the QO Lab, Beibei Li, George Brawley,  Hamish Greenall, Stefan Forstner and Warwick Bowen went a step further and developed a sensitive on-chip room-temperature magnetometer by embedding a grain of magnetorestrictive material in an optical cavity. Read on in Photonics Research.