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Ab initio study of 40Ca with an importance-truncated no-core shell model
1Institut für Kernphysik, TU Darmstadt, Schlossgartenstr. 9, 64289 Darmstadt, Germany. robert.roth@physik.tu-darmstadt.de
Physical Review Letters
|October 13, 2007
Summary
We developed a new importance truncation scheme for nuclear structure calculations. This method significantly reduces computational complexity, enabling accurate studies of heavier nuclei.
Area of Science:
- Nuclear Physics
- Computational Quantum Many-Body Physics
Background:
- No-core shell model (NCSM) calculations are computationally intensive.
- Basis spaces grow rapidly with the number of nucleons and excitations.
Purpose of the Study:
- To develop an efficient truncation scheme for NCSM and configuration interaction (CI) methods.
- To enable converged nuclear structure calculations for systems beyond the p shell.
Main Methods:
- An importance truncation scheme based on many-body perturbation theory.
- A priori measure of basis state importance to select physically relevant states.
- Application to realistic nucleon-nucleon interactions and low-momentum interactions.
Main Results:
- Dramatic reduction in basis dimension for NCSM/CI calculations.
- Validated scheme with calculations for 4He and 16O, comparing to conventional methods.
- Achieved first converged calculations for 40Ca ground state with up to 16 harmonic oscillator excitations.
Conclusions:
- The proposed importance truncation scheme is efficient and accurate.
- It enables converged calculations for heavier nuclei previously inaccessible.
- The universal nature of the scheme allows application to other quantum many-body problems.
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