Quantum Dissipative Dynamics (QDD): A real-time real-space approach to far-off-equilibrium dynamics in finite electron systems
Bibliographic record
Abstract
In this paper, we present “QDD” (Quantum Dissipative Dynamics), a code package for simulating the dynamics of electrons and ions in finite electron systems (atoms, molecules, clusters) under the influence of external electromagnetic fields. Electron emission is properly accounted for. The novel feature of the present code is that it also covers the description of dissipative dynamics induced by dynamical correlations generated by electron-electron collisions. The paper reviews the underlying theoretical as well as numerical methods and demonstrates the code's capabilities on a selection of typical examples. Program Title: QDD CPC Library link to program files: https://doi.org/10.17632/jpwzm9knmb.1 Licensing provisions: GPLv3 Programming language: Fortran 90 (with Fortran 2008 standard) Supplementary material: User Manual, input and output files Nature of problem: The QDD code serves to simulate the dynamics of finite electron systems (atoms, molecules, clusters) excited by strong electromagnetic fields as delivered by lasers or highly charged ions. Basis of the description is Time-Dependent Density Functional Theory (TDDFT) at the level of the Time-Dependent Local-Density Approximation (TDLDA) augmented by an approximate Self-Interaction Correction (SIC), the latter being crucial for proper description of electron emission. The novel feature of the present code is that it allows one to track the dissipative dynamics induced by dynamical correlations from the earliest times of excitation on. This is done here at a fully quantum mechanical level within the Relaxation-Time Approximation (RTA). Electron dynamics is also coupled to ionic motion treated by classical molecular dynamics. Solution method: The numerical representation uses a 3D coordinate-space grid for electronic wave functions and fields. The kinetic energy operator is evaluated in momentum space connected by a Fast Fourier Transform (FFT). Standard schemes for electronic ground state, ionic ground state, and propagation of TDLDA in real time as well as ionic dynamics are used. Electron emission is enabled by absorbing boundary conditions using a mask function near the boundaries. The time evolution of dissipation (by RTA) is evaluated in a large space of occupied and unoccupied single-electron states. Additional comments including restrictions and unusual features: Only the actual computing hardware (RAM, number of nodes on board) limits the system size which can be treated. The code package allows sequential and parallel (OpenMP) computation. The simulation can be continued from a previously saved dynamical configuration.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".