PNNL

Session A06: Non-Equilibrium Thermodynamics: From Natural Selection to Chemical Reaction Networks I

8:00 a.m.–10:24 a.m. PT | Room 129

PNNL Organizer: William Cannon

From Metabolites to Cells: A Perspective on Non-Equilibrium Thermodynamics

Session A06: Non-Equilibrium Thermodynamics: From Natural Selection to Chemical Reaction Networks I | Room 129
8:36 a.m.–9:12 a.m. PT
PNNL author: Connah G Johnson

Cells may be seen as chemical factories, processing a fuel source taken from the environment and producing the chemical building blocks vital for life. However, cells are rarely found in isolation with many biological systems being spatially organised. Understanding the non-equilibrium thermodynamics behind cell growth, cell death, and self-organisation is of great importance for when we want to program bio-systems for "useful" work such as biofuel production or industrial chemical synthesis. In this talk, we will provide an overview of field from the perspective of cells as chemical factories and discuss a selection of methods used to study cell systems. READ MORE.

Revealing the Flexibility of Hydrogen Bond Networks in Hexagonal Ice by Frozen Liquid-Cell Electron Microscopy

Session A03: Disorder and Fluctuations in Chemical Physics I | Room 126
8:48 a.m.–9:00 a.m. PT
PNNL authors: Jingshan Du, James De Yoreo

Ice crystals are formed by directional hydrogen bonds between water molecules and are thus considerably more flexible than typical inorganic structures based on covalent or ionic bonds. However, it is challenging to visualize such a crystalline network with atomic resolution in real space due to the weak bond strength and the resulting instability of ice under electron irradiation in vacuo. In this presentation, we report high-resolution transmission electron microscopy (HRTEM) of ice sections encapsulated between amorphous carbon membranes. READ MORE.

Symmetry Breaking with the SCAN Density Functional Describes Strong Correlation in the Singlet Carbon Dimer

Session A17: Density Functional Theory in Chemical Physics I | Room 209
9:00 a.m.–9:12 a.m. PT
PNNL authors: Duo Song, Eric Bylaska

The SCAN (strongly constrained and appropriately normed) meta-generalized gradient approximation (meta-GGA), which satisfies all 17 exact constraints that a meta-GGA can satisfy, accurately describes equilibrium bonds that are normally correlated. With symmetry breaking, it also accurately describes some sd equilibrium bonds that are strongly correlated. This work shows that spin symmetry breaking in singlet C₂, the appearance of net up- and down-spin densities on opposite sides (not ends) of the bond, corrects that under-binding, with a small SCAN atomization-energy error more like that of the other three molecules, suggesting that symmetry-breaking with an advanced density functional might reliably describe strong correlation. READ MORE.

Epitaxial SrTiO₃ Films with Dielectric Constants Exceeding 25,000

Session A38: Novel Synthesis Approaches for Complex Oxide Films and Heterostructures I | Room 230
10:12 a.m.–10:24 a.m. PT
PNNL author: Scott Chambers

SrTiO₃ (STO) is an incipient ferroelectric perovskite oxide for which the onset of ferroelectric order is suppressed by quantum fluctuations. This property results in a very large increase in static dielectric constant from ~300 at room temperature to ~20,000 at liquid He temperature in bulk single crystals. However, the low-temperature dielectric constant of epitaxial STO films is typically a few hundred to a few thousand. In this talk, we will resolve this long-standing issue. READ MORE.

Understanding regulation of CaCO₃ crystallization by de novo designed proteins through in situ imaging and spectroscopy

Session D17: Disorder and Fluctuations in Chemical Physics II | Room 209
3:00 p.m.–3:36 p.m. PT
PNNL authors: James De Yoreo, Biao Jin, Ying Chen, Marcel Baer, Zheming Wang, Nancy Washton, Karl Mueller, Gregory Schenter, Chris Mundy

We investigate CaCO₃ nucleation in the presence of designed proteins presenting arrays of carboxylate groups in patterns expected to mimic the patterns of calcium sites on various faces of the CaCO₃ polymorphs. We combine liquid-phase TEM, liquid and solid state NMR, in situ ATR-FTIR, and molecular modeling to follow the structural and chemical evolution. READ MORE.

Interpolation of Trotter data for eigenvalue and expectation value estimation

Session D64: Quantum Simulation I: Speedups, Improvements, and Beyond | Room 415
3:00 p.m.–3:12 p.m. PT
PNNL author: Nathan Wiebe

In this work, we provide a paradigm-shifting approach in which we achieve a Õ(log 1/ε) cost scaling when estimating observables with a single ancillary qubit, where ε is the error on the observable from approximating the Hamiltonian dynamics. This method relies on interpolating the observable estimated where Hamiltonian dynamics are simulated at different Trotter-step sizes. With these methods, we avoid having to simulate the Hamiltonian evolution with high precision in situ which incurs in extra quantum cost and qubits. READ MORE.

Efficient calculation of nuclear forces on noisy intermediate-scale quantum computers

Session D64: Quantum Simulation I: Speedups, Improvements, and Beyond | Room 415
3:12 p.m.–3:24 p.m. PT
PNNL author: Nathan Wiebe

Accurate nuclear forces are required to simulate the movement of atoms and molecules over time, an essential computational tool for drug discovery. However, most current quantum computing algorithms only focus on determining an accurate estimate of the ground state energy. In this talk, we show how to use noisy intermediate-scale quantum (NISQ) computers to extract nuclear forces and optimize the number of required samples from the quantum computer by using basis rotation groupings, importance sampling and fermionic shadows. READ MORE.

Session F13: Emerging Principles and New Developments in Non-Equilibrium Thermodynamics, Natural Selection and Chemical Reaction Networks

8:00 a.m.–10:24 a.m. PT | Room 238

PNNL Organizer: William Cannon

Predicting Cellular Regulation by Combining Statistical Thermodynamics, Control Theory, and Optimization

Session F13: Emerging Principles and New Developments in Non-Equilibrium Thermodynamics, Natural Selection and Chemical Reaction Networks | Room 238
9:12 a.m.–9:48 a.m. PT
PNNL author: Ethan King

Metabolic networks of biological cells can be viewed as dissipative structures. In particular, metabolic networks operate far from thermodynamic equilibrium, and are typically assumed to be near steady state. In that light, we present methods for inference of the distribution of flux through metabolic networks using the principle of maximum entropy production. READ MORE.

ChemChaste: A hybrid continuum-discrete modelling software suite for simulating bacterial communities

Session G00: Poster Session I | Exhibit Hall (Forum Ballroom)
2:00 p.m.–5:00 p.m. PT
PNNL author: Connah Johnson

Bacterial communities, such as those contained within biofilms, are found in a wide range of industrial and clinical scenarios. They can be composed of multiple cell types which complicate the task of tackling film build up, such as in infections or marine biofouling. We seek to understand the biofilm wide dynamics through developing a hybrid continuum-discrete software library to complement experimentation and improve data informed biological modelling. READ MORE.

Filament sliding in simulations of CaMKII-actin bundles

Session K11: Physics of the Cytoskeleton II | Room 203
5:00 p.m.–5:12 p.m. PT
PNNL author: Margaret Cheung

During synapse formation, small protrusions form on the dendrites of the presynaptic neurons, called dendritic spines, after stimulation with high-frequency electric signals in a process known as long-term potentiation. Calcium/calmodulin-dependent protein kinase II (CaMKII) is crucial in long-term potentiation because it can decode signals, initiate phosphorylation cascades, and interact with actin filaments to form blunt-ended bundles. We modeled CaMKII-actin bundles using a coarse-grained model of four particles per actin promoter and a docking simulation performed in our group. READ MORE.

Tuning crystal symmetries by out-of-plane shear deformation

Session M38: Tools and Techniques for Exploring Materials Physics at the Frontier of Time and Length Scales | Room 230
8:36 a.m.–8:48 a.m. PT
PNNL author: Patrick El Khoury

Crystal structure plays a critical role in how emergent electronic states form in quantum materials, and this has motivated a growing interest in deforming crystals while measuring their electronic properties. The most straightforward way of accomplishing this is via mechanical strain—by mechanically deforming a crystallite, crystal parameters and symmetries can be tuned and their impact on material properties can be observed. Here I will discuss our efforts to perform out-of-plane shear-based measurements. READ MORE.

Spin defects in hexagonal boron nitride for proximity quantum sensing

Session M39: Solid-state Quantum Defects | Room 231
8:48 a.m.–9:00 a.m. PT
PNNL author: Di Xiao

Defects in hexagonal boron nitride (hBN), a 2D Van der Waals (vdW) material, have raised wide range interest for its potential in various quantum applications such as qubits and quantum sensors. In this talk, we will focus on using first-principle calculation along with model Hamiltonians to discuss properties of hBN defect in stacked heterostructure system for quantum applications. READ MORE.

Modulation of Atom Stacking Hierarchy Leads to New Intermetallic Nanocrystal Structures

Session N00: Poster Session II | Exhibit Hall (Forum Ballroom)
11:00 a.m.–2:00 p.m. PT
PNNL author: Jingshan Du

A library of compositionally and structurally well-defined Au-Cu alloy nanocrystals has been prepared via scanning probe block copolymer lithography. These libraries not only allow one to map compositional and structure space but also the conditions (e.g., cooling rate) required to access specific structures. This approach enabled the realization of a previously unobserved architecture, an intermetallic nanoprism, that is a consequence of hierarchical atom stacking. READ MORE.

Thursday, March 9, 2023

Temperature dependence of nuclear quadrupole resonances in ²³⁵U-depleted Cs₂UO₂Cl₄

Session T04: Surfaces, Interfaces & Materials | Room 127
12:18 p.m.–12:30 p.m. PT
PNNL authors: Sejun Park, Eric Walter, Robert Gian Surbella, Chuck Soderquist, Gabriel Hall, Sergey Sinkov, Herman Cho

In this work, we report zero field ³⁵Cl nuclear quadrupole resonance (NQR) for ²³⁵U-depleted Cs₂UO₂Cl₄. A single peak indicates that all Cl ions are at an equivalent site. A good agreement between electric field gradients obtained from the spectrum and a DFT calculation confirms partial charge transfer between Cl and U. READ MORE.

Using measurements to reduce circuit depth: Deterministic preparation of the AKLT state in constant-time on an IBM Quantum processor

Session T64: Noisy Hardware Applications II | Room 415
12:54 p.m.–1:06 p.m. PT
PNNL author: Nathan Wiebe

The ground state of the spin-1 AKLT model is a paradigmatic example of both a matrix product state and a symmetry protected topological phase, and additionally holds promise as a resource state for measurement-based quantum computation. However, because the AKLT state has a nonzero correlation length, its exact unitary preparation requires a circuit whose depth scales linearly with system size. In this talk, we show how to overcome this limitation by augmenting a finite-depth circuit with measurements, and ultimately present a recipe to prepare the spin-1 AKLT state in constant-time. READ MORE.

Reduced-order modeling of Arctic Amplification feedbacks

Session W53: Data Science for Climate | Room 307
4:36 p.m.–4:48 p.m. PT
PNNL authors: Adam Rupe, Craig Bakker, Jian Lu

High latitude regions are warming at an accelerated rate compared to other regions of the Earth. This Arctic Amplification (AA) has significant impacts within and outside the arctic. While it is known from observations and Earth system models that multi-component feedbacks contribute to AA, disentangling the full effects of these complex nonlinear interactions is a major challenge. Here we present initial work on data-driven reduced-order models to analyze the key feedback between ice albedo and surface temperature. Our preliminary analysis utilizes best-fit linear models based on the Dynamic Mode Decomposition with control (DMDc). READ MORE.

Efficient quantum time dynamics using the Yang-Baxter equation

Session Y72: Time Evolution Quantum Algorithms | Room 406
8:24 a.m.–8:36 a.m. PT
PNNL authors: Bo Peng, Niri Govind

This study demonstrates how the Yang-Baxter equation (YBE) can be efficiently utilized to compress and produce a constant depth quantum circuit for efficient time dynamics of 1D lattice spin chains with nearest-neighbor interactions on real quantum devices. We show that the depth of quantum circuits for each time step is independent of time and step size and depends only on the number of spins. READ MORE.

Experimental realization of linearly polarized X-ray detected ferromagnetic resonance

Session Y57: Magnetization and Spin Dynamics II | Room 303
8:48 a.m.–9:00 a.m. PT
PNNL author: Elke Arenholz

We present the first theoretical and experimental evidence of time-resolved dynamic X-ray magnetic linear dichroism (XMLD) measurements of GHz magnetic precessions driven by ferromagnetic resonance in both metallic and insulating thin films. Our findings show a dynamic XMLD in both ferromagnetic Ni₈₀Fe₂₀ and ferrimagnetic Ni_0.65Zn_0.35Al_0.8Fe_1.2O₄ (NZAFO) for different measurement geometries and linear polarizations. READ MORE.

Quantum time dynamics of qudit Hamiltonians employing the Yang-Baxter equation for circuit compression

Session Y72: Time Evolution Quantum Algorithms | Room 406
9:00 a.m.–9:12 a.m. PT
PNNL authors: Bo Peng, Niri Govind

Quantum time dynamics is considered a promising problem for quantum advantage. It has been shown that employing Yang-Baxter symmetry can improve quantum simulations by circuit compression. Generalizing the results to qudits is of great interest since even shallower circuits can be produced by exploiting higher levels. We derive the compressed circuit representations for different special cases of qudit Hamiltonians. READ MORE.

Generating in-situ Heterostrain of Moiré Superlattice Heterostructures

Session Y23: Electronic Effects of Twisted 2D Heterostructures | Room 215
9:12 a.m.–9:24 a.m. PT
PNNL author: James De Yoreo

Moiré superlattices of van der Waals semiconductors have emerged as a highly tunable material platform to study strong electron correlations and simulate Hubbard model physics in two dimensions. Electrostatic gating enables a high degree of control over electron density and interlayer coupling; however, much of the physics of moiré superlattices is set by the geometric properties of lattice mismatch and relative twist angle, which are selected during device fabrication and cannot generally be altered in situ. In this talk, I will discuss a technique for generating and tuning in situ heterostrain, which enables dramatically altering the moiré wavelength and symmetry by applying different amounts of uniaxial strain to each layer in a transition metal dichalcogenide moiré superlattice. READ MORE.

Graph identification of proteins in tomograms (GRIP-Tomo)

Session Z10: Emergent Behavior in Biological Systems | Room 202
1:42 p.m.–1:54 p.m. PT
PNNL authors: Margaret Cheung, Doonam Kim, Trevor Moser, James Evans, Ian Gildea

In this study, we present a method of pattern mining based on network theory that enables the identification of protein structures or complexes from synthetic volume densities, without the knowledge of predefined templates or human biases for refinement. We hypothesized that the topological connectivity of protein structures is invariant, and they are distinctive for the purpose of protein identification from distorted data presented in volume densities. READ MORE.

Recent Developments in the Implementation of the RT-EOM-CC Green's Function Approach

Session AAA04: V: Spectroscopy and Experiment in Chemical Physics | Virtual Room 4
1:42 p.m.–1:54 p.m. PT
PNNL authors: Himadri Pathak, Ajay Panyala, Bo Peng, Nicholas Bauman, Erdal Mutlu, Karol Kowalski

Many-body excitations in X-ray photoemission spectra (XPS) are difficult to simulate from first principles. We have recently developed a non-linear cumulant real-time equation-of-motion coupled-cluster (RT-EOM-CC) Green's function method that provides a non-perturbative framework for treating these problems in molecular systems. READ MORE.