Welcome to Wes Campbell's Reseach Group at UCLA Physics & Astronomy

Our research uses ultra-cold atoms and molecules to learn about the physical processes that permeate our world.

We are specifically focused on the physics of quantum information, which includes advanced sensing, simulation, and computing applications.

We use gas and liquid phase atoms and molecules as tiny computers to perform tasks that cannot be simulated on classical computers. Our approach is to focus on novel species and novel ways to control them to leverage the built-in "quantumness" of these molecules for higher performance in these applications.

Latest News

Quantum Functional Groups

July 25, 2022: Spontaneous emission can be used for state preparation and readout of individual atoms and molecules so long as it can be repeated enough times for the detector to "click" before the molecules get bleached to another state. In collaboration with the groups of Eric Hudson, Anastassia Alexandrova, Justin Caram, and John Doyle, we have recently demonstrated (in a recent paper in Nature Chemistry) a class of large molecules that appears to have this property, thereby extending the reach of this technique to species large enough to contain carbon rings.

Photon Spin Molasses

March 2, 2022: The mechanical damping of the translational momentum of gas-phase molecules known as Doppler cooling can trace its origins to a classic experiment by Otto Robert Frisch. There is, however, also an angular counterpart of Frisch's experiment that was performed only a couple of years later by Richard Beth. We have recently found that there is accordingly an associated Doppler laser cooling process that can cool the rotation of gas-phase molecules using photon spin. In fact, both cooling methods are the same when described with the right framework, and we show that it may be possible to laser cool molecular rotation to sub-milikelvin temperatures.

SPAM surges ahead

Dec 29, 2021: Hot on the heels of last year's demonstration of record-setting fidelity for qubit state preparation and measurement (SPAM) in 133Ba+, graduate student Tony Ransford's novel scheme for achieving high fidelity SPAM in 171Yb+ has achieved even lower inaccuracy. Taken together, these two SPAM maps (try saying that backwards) show how to prepare and read out qubits better than ever.

Composite Pulse Sqeuences for Time Depenent Amplitude Errors

Nov 30, 2021: Composite pulse sequences can be used to perform high fidelity qubit rotations with imperfect hardware. Typically, the imperfections (whether in the area/amplitude or frequency of the pulsed classical fields applied to effect the gate) are assumed to be static for the duration of the pulse sequence. Undergraduate David Su's recent paper shows how to generalize to time-dependent imperfections, and shows that Wimperis' F1 sequence is a member of a collection of power-law amplitdue (PLA) pulse sequences.