Large-Scale Electron Correlation Calculations: Rank-Reduced Full Configuration Interaction

Rank-Restricted Full Configuration Interaction

which is a linear combination of n-electron configurations, or determinants, with coefficients equal to c!. The components |Φ! form an orthonormal basis of the wavefunction. The determinants are the set of features that comprise the wavefunction, so we can optimize them by minimizing the electronic energy. To determine the energy of the wavefunction c, the Schrödinger equation in matrix form reads

Benchmark Full Configuration Interaction Calculations for the Ground State of Three- Electron Harmonium Atoms

Accelerating Full Configuration Interaction Calculations for Nuclear Structure∗

One of the emerging computational approaches in nuclear physics is the full configuration interaction (FCI) method for solving the many-body nuclear Hamiltonian in a sufficiently large single-particle basis space to obtain exact answers either directly or by extrapolation. The lowest eigenvalues and corresponding eigenvectors for very large, sparse and unstructured nuclear Hamiltonian matrices ...

Large-scale first principles configuration interaction calculations of optical absorption in aluminum clusters.

We report the linear optical absorption spectra of aluminum clusters Aln (n = 2-5) involving valence transitions, computed using the large-scale all-electron configuration interaction (CI) methodology. Several low-lying isomers of each cluster were considered, and their geometries were optimized at the coupled-cluster singles-doubles (CCSD) level of theory. With these optimized ground-state geo...

Reduced-Rank Channel Estimation for Large-Scale MIMO Systems

We present two reduced-rank channel estimators for large-scale multiple-input, multiple-output (MIMO) systems and analyze their mean square error (MSE) performance. Taking advantage of the channel’s transform domain sparseness, the estimators yield outstanding performance and may offer additional mean angle-of-arrival (AoA) information. It is shown that, for the estimators to be effective, one ...