Scalable codes for precision calculations of properties of complex atomic systems

Abstract

High precision atomic data is indispensable for experiments involving studies of fundamental interactions, astrophysics, atomic clocks, plasma science, and others. We develop new parallel atomic structure codes and explore the difficulties of load-balancing in these codes. Efficient load-balancing of matrix elements for many-electron systems is very difficult due to the intrinsic nature of the computational methods used to compute them. By arithmetically selecting determinants for each core, we achieve very even workload distribution, and attain near-perfect linear scalability and efficiency with the number of cores. We also implement dynamic memory allocation to minimize memory usage and remove the need for users to set certain array parameters. Our newly developed codes enable computations that were not possible before due to lack of memory or prohibitive computation times, and allow a broader range of correlations to be investigated in a shorter period of time. This includes calculations correlating all 60 electrons in the highly charged Ir${}^{17+}$ ion and calculations predicting the $3C/3D$ line intensity ratio in Fe${}^{16+}$. Our new code package will also be used to produce large volumes of high precision atomic data for a new online portal being developed at the University of Delaware.

References in corpus (17)

• Search for New Physics with Atoms and Molecules
• Highly charged ions: optical clocks and applications in fundamental physics
• Optical clock comparison test of Lorentz symmetry
• Precision determination of electroweak coupling from atomic parity violation and implications for particle physics
• Enhanced laboratory sensitivity to variation of the fine-structure constant using highly-charged ions
• Development of a configuration-interaction + all-order method for atomic calculations
• Observation of a Large Atomic Parity Violation Effect in Ytterbium
• Highly-charged ions as a basis of optical atomic clockwork of exceptional accuracy
• Precision determination of weak charge of ${}^{133}$Cs from atomic parity violation
• Hole transitions in multiply-charged ions for precision laser spectroscopy and searching for alpha-variation
• Optical transitions in highly-charged californium ions with high sensitivity to variation of the fine-structure constant
• Electric dipole moment enhancement factor of thallium
• High-precision atomic clocks with highly charged ions: nuclear spin-zero $f^{12}$-shell ions
• High Resolution Photoexcitation Measurements Exacerbate the Long-Standing Fe XVII Oscillator Strength Problem
• Accurate prediction of clock transitions in a highly charged ion with complex electronic structure
• Transitions between the $4f$-core-excited states in Ir${}^{16+}$, Ir${}^{17+}$, and Ir${}^{18+}$ ions for clock applications
• Towards a new measurement of parity violation in dysprosium