Peter Scherpelz

Implementation and Validation of Fully Relativistic GW Calculations: Spin–Orbit Coupling in Molecules, Nanocrystals, and Solids

We present an implementation of G0W0 calculations including spin-orbit coupling (SOC) enabling investigations of large systems, with thousands of electrons, and we discuss results for molecules, solids, and nanocrystals. Using a newly developed set of molecules with heavy elements (called GW-SOC81), we find that, when based upon hybrid density functional calculations, fully relativistic (FR) and scalar-relativistic (SR) G0W0 calculations of vertical ionization potentials both yield excellent performance compared to experiment, with errors below 1.9%. We demonstrate that while SR calculations have higher random errors, FR calculations systematically underestimate the VIP by 0.1 to 0.2 eV. We further verify that SOC effects may be well approximated at the FR density functional level and then added to SR G0W0 results for a broad class of systems. We also address the use of different root-finding algorithms for the G0W0 quasiparticle equation and the significant influence of including d electrons in the valence partition of the pseudopotential for G0W0 calculations. Finally, we present statistical analyses of our data, highlighting the importance of separating definitive improvements from those that may occur by chance due to a limited number of samples. We suggest the statistical analyses used here will be useful in the assessment of the accuracy of a large variety of electronic structure methods.

Phase Imprinting in Equilibrating Fermi Gases: The Transience of Vortex Rings and Other Defects

We present numerical simulations of phase imprinting experiments in ultracold trapped Fermi gases, which were obtained independently and are in good agreement with recent experimental results. Our focus is on the sequence and evolution of defects using the fermionic time-dependent Ginzburg-Landau equation, which contains dissipation necessary for equilibration. In contrast to other simulations, we introduce small, experimentally unavoidable symmetry breaking, particularly that associated with thermal fluctuations and with the phase-imprinting tilt angle, and we illustrate their dramatic effects. As appears consistent with experiment, the former causes vortex rings in confined geometries to move to the trap surface and rapidly decay into more stable vortex lines. The latter aligns the precessing and relatively long-lived vortex filaments, rendering them difficult to distinguish from solitons.

Theory of fluctuating charge ordering in the pseudogap phase of cuprates via a preformed pair approach

We study the static and dynamic behavior of charge ordering within a d-wave pair pseudogap (pg) scenario. This is addressed using a density-density correlation function derived from the standard pg self energy,

Optimizing surface defects for atomic-scale electronics: Si dangling bonds

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Exact correlation functions in the cuprate pseudogap phase: Combined effects of charge order and pairing

and compatible with the longitudinal and transverse sum rules. The broadening factor

Unified treatment of Fermi pockets and arcs scenarios for the cuprates: Sum-rule-consistent response functions of the pseudogap

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Approximation Algorithms for Traffic Grooming in WDM Rings

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Entanglement-secured single-qubit quantum secret sharing

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Microscopic Approach to Viscosities in Superfluid Fermi Gases: From BCS to BEC

reflects the breaking of pairs into constituent fermions. We apply this form for

Direct Lattice Shaking of Bose Condensates: Finite Momentum Superfluids

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