The OMQ Fall Research Symposium 2022 is scheduled for September 12th-13th, and will be held this year at the Civic Winery and Wines in Eugene, Oregon.
The event will feature talks from OMQ faculty and students as well as guest speakers Wei Xiong (UCSD) and Andrei Faraon (Caltech). We have a busy program planned, with engaging talks, a Monday night banquet catered by Carte Blanche highlighting our student poster session, as well as recreation break options, including a downtown brewery stroll, butte hike, or a tasting tour with the Civic Winery staff.
Schedule of Events:
September 12 - Day 1
9:00-9:30 Registration
9:30-9:40 Opening remarks (Brian Smith, Director)
9:40-10:10 Faculty speaker (Jeff Cina) "Electronic coherence-tracking in energy-transfer dimers, and multi-path interference and geometric-phase effects in trimers"
10:15-10:35 Student speaker (Kevin Randles, van Enk group) "Quantum state transfer using input-output theory with time-reversal"
10:40-11:10 Break (The Daily Bagel)
11:10-11:30 Student speaker (T Nicole Nieves, Widom group) "Employing an emissive adenine analog to probe conformations of a Class II NAD+-sensing riboswitch"
11:35-11:55 Student speaker (Peter Zheng, Steck group) "Casimir Energies as Worldline Path Integrals"
12:00-1:00 Lunch (Cafe Yumm!)
1:00-1:20 Student speaker (Jesse Hall, Guenza group) "Incorporating Coupling between Shape, Rotation, and Translation in Coarse-Grained Models of Macromolecules in Dilute Solution"
1:25-1:45 Student speaker (Xinzhu Li, Wang group) "Spin-phonon coupling of ultracoherent mechanical resonators with color centers in diamond"
2:00-3:00 Keynote speaker (Andrei Faraon, Caltech) "Single rare-earth ions and nuclear spin wave registers for quantum networking"
3:00-5:00 Recreation break
5:00-8:00 Poster session
6:00-7:30 Banquet
September 13 - Day 2
9:00-10:00 Keynote speaker (Wei Xiong, UCSD) "Ultrafast Dynamics of Molecular Vibrational Polaritons for Chemistry and Quantum Technology"
10:00-10:30 Break (The Daily Bagel)
10:30-10:50 Student speaker (Jack Maurer, Marcus group) "Using single molecule polarization-sweep spectroscopy to monitor and interpret site-specific fluctuations of (Cy3)2 dimer-labeled DNA constructs at and near ss-ds DNA junctions"
10:55-11:15 Student speaker (Tiemo Landes, Raymer group) "Nonlinear Interactions Driven by Spontaneous Parametric Down-Conversion"
11:20-11:40 Student speaker (Jeremy Metzner, Allcock/Wineland group) "Controlling trapped-ion motional modes for precision measurement and CVQC"
11:45-12:45 Lunch (Mucho Gusto)
12:45-1:15 Faculty speaker (Brian Smith) Director's Talk
1:20-1:40 Student speaker (Zachary Walbrun, Wong group) "Influence of thermal annealing on aggregation and charge transfer in organic thin films"
1:45-2:00 Closing remarks
Abstracts:
Faculty speaker:
Jeff Cina, Cina group
“Electronic coherence-tracking in energy-transfer dimers, and multi-path interference and geometric-phase effects in trimers”
Jeffrey A. Cina, Alexis J. Kiessling, and Eoghan Gormley
A strategy is described and illustrated numerically for quantitatively monitoring the evolution of inter-site or inter-exciton electronic coherence in weakly or strongly coupled excitation-transfer dimers, respectively, using ultrafast two-dimensional wave-packet interferometry. The proposed measurements would use odd polarization combinations and require a spatially oriented dimer with non-parallel transition dipole moments. They could therefore be performed on a macromolecular single crystal or via fluorescence-detected single-molecule spectroscopy on an individual dimer in a solid medium. Turning to an equilateral trimer with mutually perpendicular site transition dipoles, we examine interference effects in excitation transfer to a third site from symmetric and antisymmetric singly excited superposition states on the other two monomers and their quenching by electronic-vibrational coupling. Finally, we consider both electronic geometric phase development and the stabilization against internal conversion which may accompany coherent pseudo-rotational motion in the Jahn-Teller active manifold comprising two of the three singly electronically excited states.
Kevin Randles, van Enk group
“Quantum state transfer using input-output theory with time-reversal”
Achieving quantum state transfer between separate nodes of a quantum network is a topical problem in developing quantum computing and quantum communication systems. Input-output theory can be used to manage a wide class of field states driving cascaded quantum systems to achieve quantum state transfer. We show how the standard input-output theory is modified if the photon is manipulated while propagating between two nodes, from system 1 to system 2. We present a unitary transformation, U, that time-reverses, frequency translates, and stretches the photon wave packet emitted by system 1. U can be tuned to match the different resonance frequencies and decay rates of the systems so that the wave packet is absorbed by system 2. We find that system 2 effectively responds to the time-reversed dynamics of system 1, which can be understood in terms of a change to the state’s time argument, rho(t) = rho_1(t’) tensor rho_2(t), where t’ is a fictitious time for system 1 that runs backwards. For three-level Lambda-systems we numerically illustrate that performing a faultless unitary transformation results in ideal quantum state transfer.
T Nicole Nieves, Widom group
“Employing an emissive adenine analog to probe conformations of a Class II NAD+-s sensing riboswitch”
This work focuses on the application of emissive adenine analogs as tools to study riboswitch folding and ligand binding. In this talk, I will present single-molecule fluorescence resonance energy transfer (smFRET) data on a recently reported class II nicotinamide adenine dinucleotide (NAD+)-sensing riboswitch. Biochemical data have shown the potential for the formation of a pseudoknot within the aptamer domain upon ligand binding. I am using smFRET measurements to test this hypothesis by placing fluorophores in locations that are expected to come into close proximity upon pseudoknot formation. Preliminary smFRET data indicate that a tightly folded pseudoknot structure is the preffered conformation of this riboswitch except, interestingly, in the presence of NAD+ (without Mg2+). We also seek to elucidate changes to ligand structure in the presence of RNA. Fluorescence quenching is commonly observed upon stacking of emissive base analogues in oligonucleotides. Applying the same logic to NtzAD+, we aim to determine whether the ligand adopts a tightly stacked, loosely stacked or an alternate conformation upon binding to the riboswitch. Our results reveal details of the ligand-binding mechanism of the NAD+ riboswitch and will bolster the toolkit for measuring structural dynamics of RNA with minimal perturbation.
Peter Zheng, Steck group
“Casimir Energies as Worldline Path Integrals”
The Casimir effect is a major consequence of the quantized electromagnetic vacuum. It leads to a typically attractive force acting on material bodies due to zero-point fluctuations in photon fields. The advancement of experiments has spurred the development of reliable and efficient methods for computations of Casimir effects. I will describe a worldline approach, which is a geometry-independent numerical method based on the path-integral formalism and provides an intuitive framework for computing Casimir energies. In particular, I will discuss applications of the method in calculating the Casimir-Polder potential, computational techniques for the two decoupled polarizations, and the prospects of generalization to arbitrary configurations.
Jesse Hall, Guenza group
“Incorporating Coupling between Shape, Rotation, and Translation in Coarse-Grained Models of Macromolecules in Dilute Solution”
We present a body-fixed Langevin formalism to describe the motion of a diffusing molecule, including explicit inertial and viscous coupling terms between the internal shape changes and the global diffusion of the molecule. We show that the combination of bound and unbound coordinates in a freely diffusing molecule must be treated carefully in order to accurately estimate the internal potential and friction coefficients from the trajectory. We demonstrate these methods on a toy model, for which we accurately reproduce time correlation functions and identify dynamical features associated with global-internal coupling. Finally we discuss possible implications for biological macromolecules.
Xinzhu Li, Wang group
“Spin-phonon coupling of ultracoherent mechanical resonators with color centers in diamond”
Ultra-coherent nanomechanical resonators play an essential role in optomechanics, spin-mechanics, sensitive measurements and phonon-mediated hybrid quantum systems. Progress has been made for high Q-factor silicon and silicon nitride resonators, but difficulties in fabrication have limited the Q-factor of diamond-based resonators, which are the host for color centers with excellent spin and optical properties. Phononic structures have been used to prevent the coupling of a mechanical mode to its surrounding environment and therefore reduce the clamping loss of the resonator. In this talk, we show the design, fabrication and characterization of out-of-plane mechanical modes with Q>10^6 at frequencies as large as 100MHz. We also demonstrate strong spin-mechanical coupling through an interference experiment where the sensitivity is capable of characterizing single-phonon coupling rate.
Keynote speaker:
Andrei Faraon, Caltech
“Single rare-earth ions and nuclear spin wave registers for quantum networking”
Quantum optical networks will enable distribution of quantum entanglement at long distances, with applications including interconnects between future quantum computers and secure quantum communications. In this talk I will give an overview of the state of the art in solid state quantum networks based on single optically addressable spins, followed by a more in-depth discussion of implementations based on single rare-earth ions. I will focus on ytterbium 171 in yttrium orthovanadate which exhibits long spin coherence times and stable optical transitions. The nearby vanadium nuclear spins can be utilized as nuclear spin wave quantum memory registers. The advantages and disadvantages compared to other systems will be discussed.
Keynote speaker:
Wei Xiong, UCSD
“Ultrafast Dynamics of Molecular Vibrational Polaritons for Chemistry and Quantum Technology”
Molecular vibrational polaritons are hybrid half-light, half-matter quasiparticle under vibrational strong coupling. These hybrid quasiparticles not only inherit properties of both photons and matter, but also processes unique new photonic and molecular phenomena, including tilting chemical potential landscapes of reactions, adding new energy transfer pathways and strong photonic interactions. Many of these developments hinge on the fundamental understanding of the physical properties of molecular vibrational polaritons. Pump-probe and 2D IR spectroscopy provide unique insights to this emerging research area by resolving the dynamics of various states. In this talk, I will first cover the concept of vibrational strong coupling and the current understanding of polaritonic 2D IR spectra. Then I will discuss how polariton could influence inter and intramolecular interactions, including energy transfer between molecules and barrier crossing events. Lastly, I will show some exciting opportunities of using vibrational polaritons as quantum bits for quantum information technology, including coherent transfer among polaritons and confinement effects in polaritons, visualized by 2D IR imaging technique.
Jack Maurer, Marcus group
“Using single molecule polarization-sweep spectroscopy to monitor and interpret site-specific fluctuations of (Cy3)2 dimer-labeled DNA constructs at and near ss-ds DNA junctions”
Local fluctuations of the sugar-phosphate backbones of DNA (a form of DNA ‘breathing’) play key roles in protein-DNA assembly and enzymatic function. Here we present an experimental single-molecule spectroscopic method, recently developed in our laboratory, to monitor the local fluctuations of (iCy3)2 dimer-labeled DNA constructs in which the cyanine probes internally label the sugar-phosphate backbones at varying positions at and near a single-stranded (ss)-double-stranded (ds) DNA junction. The method combines single-molecule total internal reflection fluorescence (TIRF) microscopy with polarized, phase-modulated optical excitation to detect linear optical signals that are sensitive to the (iCy3)2 dimer probe conformation. Our results indicate that the local conformation of (iCy3)2 dimer-labeled DNA at positions at and near ss-dsDNA junctions adopts four topologically-relevant macrostates, which interconvert over a broad range of time scales spanning tens-of-microseconds to hundreds-of-milliseconds. We apply a kinetic network model approach to interpret our observations of the local DNA backbone fluctuations, and we assign structural parameters to the observed macrostates based on exciton-coupling models of the (iCy3)2 dimer probes. This experimental method and analysis can be applied to study protein-DNA interactions for a number of biophysically relevant problems.
Tiemo Landes, Raymer group
“Nonlinear Interactions Driven by Spontaneous Parametric Down-Conversion”
Tiemo Landes, Markus Allgaier, Sofiane Merkouche, Brian J. Smith, and Michael G. Raymer
We investigate the transition from spontaneous parametric down-conversion to bright squeezed vacuum. The transition is characterized via joint spectral intensity measurements alongside spectrally resolved sum frequency generation. Delay and dispersion dependence highlight the role of temporal and spectral correlations in nonlinear interactions with bright squeezed vacuum.
Jeremy Metzner, Allcock/Wineland group
“Controlling trapped-ion motional modes for precision measurement and CVQC”
Motional modes of trapped ions have been shown to be a useful tool for quantum sensing as well as a platform for performing continuous variable quantum computing (CVQC). Both applications require the ability to prepare well-defined motional states with high fidelity. Many of these states can be generated from motional ground states without the use of laser fields. We report our progress towards generation of one-mode [1] and two-mode squeezed states by means of parametric excitation. These operations comprise part of the tool box to create motional state interferometers (such as SU(1,1) interferometers [2]) and can be used to achieve Heisenberg-limited phase sensitivities. We present a preliminary implementation of an SU(1,1) interferometer using two motional modes of a 40Ca+ ion in a Paul trap. In order to characterize motional states, the ions’ motion are coupled to internal ‘spin’ states, which are distinguishable through spin-dependent fluorescence. Photon scattering, giving rise to fluorescence, causes the ion to recoil, which generally decoheres the ions’ motional modes. This decoherence prevents mid-algorithm measurements, which are necessary for processes that require classical feedback. To address this issue, we describe progress towards the use of ‘protected’ [3] modes within chains consisting of an odd number of ions, where the center ion has zero displacement (3(N _ 1)/2 protected modes with N ions). The protection offered by these ions is measured by analysis of the heating rates and coherence time of the protected mode during scattering events. This research was supported by the U.S. Army Research Office through grant W911NF-19-1-0481 as well as support from NSF through the Q-SEnSE Quantum Leap Challenge Institute, Award 2016244.
Director’s Talk:
Brian Smith, Smith/Raymer group
Zachary Walbrun, Wong group
“Influence of thermal annealing on aggregation and charge transfer in organic thin films”
Understanding charge transfer (CT) in electron donor-acceptor systems is critical for the development of more efficient organic photovoltaics (OPVs). Donor-acceptor systems are what compose the active layer in OPVs, and when light is absorbed in the active layer, an electron-hole pair, or exciton, is generated. CT takes place at a donor-acceptor interface, resulting in the electron and hole residing in the acceptor and donor materials, respectively. If these charges can overcome their binding energy, they are able to move further apart, and the result is a charge separated state. CT character can be increased within individual molecules in donor-acceptor-donor (D-A-D) systems, wherein moieties within a single molecule can act as electron donors or acceptors. When organic molecules such as these are cast into films, a variety of molecular orientations are formed due to weak intermolecular forces. Molecules in orientations that yield lower energy excitonic states can act as exciton traps that may decrease the tendency for charge transfer or separation to occur. In this study, we aim to investigate the effects of thermal annealing on the prototypical electron donor-acceptor system, poly(3-hexylthiophene) (P3HT): phenyl C61 butyric acid methyl ester (PCBM). Films composing these molecules are often thermally annealed to change the morphology to form larger, more stable aggregates. Although spectroscopy can be used to characterize films before and after thermal annealing, this does not reveal the evolution of morphology or excited state dynamics during annealing. We performed in situ characterization during thermal annealing with a combination of linear and transient absorption measurements. A kinetic model and global fitting were applied to the transient absorption data for further interpretation of the excited state dynamics. Here we report on the evolution of exciton dynamics during thermal annealing of electron donor-acceptor systems to gain insight into how thermal annealing affects morphology and charge separation.
Student Posters:
Alexander Quinn “One- and two-qubit gates in metastable trapped-ion qubits”
Daniel Moore “Raman scattering errors in trapped-ion qubits”
Sean Brudney “Light Induced Atomic Desorption for Trapped Ions
Claire Albrecht “Determining local nucleic acid base conformations by fluorescence-detected two-photon Fourier transform spectroscopy of 6-methyl isoxanthopterin (6-MI) substituted DNA constructs”
Winston Goldthwaite “The effects of strong coupling on singlet fission in organic semiconductor microcavities”
Mostafa El Demery “Characterization of a temporal-mode sorter using multiple-delay crossed-beam spectral interferometry”
Matthew Brown “Quantum advantage in interferometric imaging”
Janson Hoeher “Investigating stacking/unstacking of a fluorescent base analog - 2-AP dinucleotide through Fluorescence Detected Circular Dichroism”
Paul Andreini “The Kalman Filter”
Gabriel Gregory “Precision laser spectroscopy of Iodine Monobromine towards a frequency reference in the 700-875 nm region”
Andrew Ducharme “Electron Interferometry with 4DSTEM”
Jack Lichtman “Improved Free-Space Entanglement Distribution with Time-Bins in the Presence of Noise”
Amy Soudachanh “Photonic Cluster States for Quantum Networks”
Nathan Swiericzuk “Stabilizing Volume Holographic Grating (VGH) Diode Lasers for Ion Qubit Control”
Ellis Ainley “Frequency locking of RF and laser sources to high-Q resonators”
David Lefevre “Pulse Broadening and Photon-counting Laser Altimetry”
Shuhao Wu “Real-time magnetometry with coherent population trapping in a nitrogen-vacancy center”