Presenters and Abstracts:
Bryce Bullock: Mode Resolved Protocol for Measuring the In-Plane Mode Temperatures in a 2D Ion Crystal in a Penning Trap
Two dimensional crystals of 100's of ions in a Penning trap have demonstrated numerous promising results in quantum simulation and sensing. One recent result was the demonstration of electric field sensing of 240 ± 10 nV/m in 1 second, with sensitivity to motional displacements 8.8 ± 0.4 dB below the standard quantum limit. A fundamental limitation was 40 Hz fluctuations of the center of mass mode, believed to be in part caused by elevated in-plane mode temperatures of order 10 mK. We present a new experimental protocol to directly measure the in-plane temperature in the rotating frame of the crystal in a mode resolved way. Finally, we summarize ideas for improving the cooling of the in-plane modes.
Alexander Kwiatkowski: Protocols for optical-microwave quantum transduction with quantum dots and surface-acoustic-wave cavities
We present analysis of protocols for optical-microwave quantum transduction mediated by an optical-frequency two-level-system and a microwave-frequency bosonic mode that are weakly coupled by a \sigma_z \hat{x} term. We focus on parameter regimes where the coupling rate is much smaller than the optical emission rate of the two-level-system, which is in turn smaller than the frequency of the bosonic mode. We demonstrate that quantum transduction is possible in this parameter regime, and investigate the dependence of the success rate on the device parameters. Our results will inform the design of quantum transduction devices consisting of, for example, a quantum dot located in a mechanical resonator.
Emma Nelson: Deep-ultraviolet transient grating for characterizing nanoscale thermal, elastic, and interfacial properties in high-bandgap materials
The functional properties of complex or nanostructured materials deviate from bulk, due to the increased influence of surfaces and interfaces. Characterizing these properties is crucial to designing new, efficient nanoelectronics, energy materials, and quantum technologies. In this work, we demonstrate a deep-ultraviolet (DUV) transient grating to characterize a more general set of materials at smaller length scales than visible-based methods allow. We generate <200nm ultrafast DUV pulses to excite a sample in a transient grating modality. A transient grating is created by interfering two beams to form a spatially-modulated pattern on the sample surface. The resultant heating causes thermal expansion which launches acoustic waves into the sample, allowing us to study its elastic and thermal properties. The visible transient grating periodicity is limited by the wavelength of the light; however, by using DUV light, we are able to create a smaller period interference pattern down to a few hundred nanometers. Moreover, the DUV pulses are above the bandgap for many visibly-transparent samples, extending our technique to more materials, including diamond and next-generation battery technologies.
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Lunch provided.