Kiosk 2

Abstract

Quantum control of phonons is achieved by coupling superconducting qubits to mechanical oscillators, promising a compact hardware platform for quantum information processing.  However, these hybrid systems suffer short coherence times due to spontaneous qubit emission into lossy phononic modes. In my thesis defense, I will describe how crystalline quartz can be used to suppress loss mechanisms in hybrid circuit quantum acoustic devices by over an order of magnitude. This will include demonstrations of crystallographic orientation optimization and engineering of the acoustic mode spectrum. Additionally, I will present a new flip-chip architecture for hybrid devices, the `acoustic trampoline’. 

Abstract: Non-equilibrium physical processes remain one of the major open challenges in physics. At the macroscale, our understanding of these systems relies heavily on empirical laws derived from observation rather than fundamental universal principles. However, at the nanoscale, these laws break down, giving rise to novel exotic phenomena that open new opportunities for designing materials with unprecedented properties. In this talk, we focus on two key non-equilibrium processes – friction and nanoscale heat transport – which together account for over 30% [1,2] of global energy consumption. Using  atomistic simulations in synergy with experiments, we explore how the breakdown of their empirical macroscale laws reveals new emergent physics, linking the "wiggling and jiggling" of atoms [3] to novel mechanisms. Specifically, we demonstrate how a surprising violation of the first law of friction enables the control of ultra-low friction states (superlubricity)[4]. Likewise, we show how the breakdown of Fourier’s law[5] gives rise to superdiffusive heat transport in micrometer-long wires. Finally, we highlight an intimate, yet largely unexplored, connection between these two processes – friction and heat transport – at the nanoscale.

[1] Holmberg et al. Friction 5, 263 (2017); [2] Cooper et al. Nature Energy 8, pp. 1328 (2023); [3] Feynman, R. Engineering & Science 23, 22–36 (1960); [4] Vilhena et al. Physical Review Letters 128 , 216102 (2022) ; Nano Letters 23, pp 4693 (2023); Physical Review X 9 , 041045 (2019); ACS Nano https://doi.org/10.1021/acsnano.4c16645 (2025); [5] Nature Materials, In Press (2025);

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Abstract: 

Two-dimensional electronic spectroscopy (2DES) resolves energy and charge transfer dynamics with femtosecond temporal resolution along multiple spectral dimensions – excitation, emission and coherence axes. Salient features such as 2D cross-peaks (CPs) between coherently coupled transitions and quantum beat maps can, in principle, reveal complex energy transfer pathways and the vibrational-electronic couplings that may be responsible for driving these processes. However, 2DES methods relying on detection of coherently radiated electric field are largely inapplicable to complex light harvesting systems such as intact photosynthetic cells and nanotubes due to overwhelming scatter. I will describe our recent efforts towards introducing 2DES methods that can circumvent the above challenges and demonstrate their applications on intact photosynthetic cells and light harvesting nanotubes that closely mimic naturally occurring chlorosome nanotubes.

I will introduce a repetition-rate scalable approach1 to conventional 2DES that relies on purely conventional optics and electronics with shot-to-shot detection at any repetition rate, only limited by the camera speed. I will demonstrate how the additional knob of polarization-control2 allows us to decipher the presence of strong intraband couplings within the overlapping vibrational-electronic (vibronic) bands of light harvesting nanotubes. These observations suggest that vibronic couplings may indeed survive at room temperature in large aggregates to drive ultrafast internal conversion.

I will then show3 how incoherent detection of the 2D signal through non-linear fluorescence, relying not on coherently radiated electric field but rather on signal generation through incoherent exciton-exciton annihilation, allows for first such observations of exciton diffusion inside cyanobacterial cells across the intact photosynthetic machinery, thereby bypassing the significant complications that are inevitably introduced upon isolating proteins from the native cell environment. Together these suites of white-light 2DES approaches provide a powerful platform to characterize a variety of complex systems with future avenues for introducing spatial resolution as well.

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Dear JILAns,

With everything happening in the world, building a strong scientific community seems more important than ever. Posterfest is a chance to come together, celebrate JILA’s research, and support each other’s work.

We hope you’ll join us for JILA Posterfest 2025, happening at 3 pm on Thursday, May 1, in the X-Wing.

Posterfest is a fantastic opportunity to share your research, connect with fellow JILAns, and learn about the amazing science happening across our community—all while enjoying delicious pizza (including veggie, vegan, and gluten-free options) and your choice of alcoholic or non-alcoholic beverages.

For those new to Posterfest or who may not remember, this event brings together graduate students, postdocs, and researchers to present their work in a casual, interactive setting.

Last year, we saw presentations on everything from high harmonic generation to ultrafast electron dynamics, squeezed-light optical imaging, and fundamental symmetry violations in the universe. This is a great time to highlight your research, get feedback, and engage with the JILA community.

This year, we're making a few changes to enhance the experience:

Instead of three short sessions, we'll have two 45-minute presentation slots, giving you more time to listen, ask questions, and discuss science.

We’re looking for volunteers to help with setup, IDing, and cleanup—if you’re interested, please email kenna.castleberry@colorado.edu or hannah.douglas@colorado.edu.

Want to present your research? Sign up at this link (the deadline to apply is Monday, April 14th)

We hope to see you there!

Best,
Kenna Hughes-Castleberry, Hannah Douglas, and Krista Beck

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