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T. Dytrych

Publications and source records attributed to T. Dytrych.

22 records · Page 2Linked to original sources
arXiv2013

Symplectic No-core Shell-model Approach to Intermediate-mass Nuclei

We present a microscopic description of nuclei in an intermediate-mass region, including the proximity to the proton drip line, based on a no-core shell model with a schematic many-nucleon long-range interaction with no parameter adjustments. The outcome confirms the essential role played by the symplectic symmetry to inform the interaction and the winnowing of shell-model spaces. We show that it is imperative that model spaces be expanded well beyond the current limits up through fifteen major shells to accommodate particle excitations that appear critical to highly-deformed spatial structures and the convergence of associated observables.

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arXiv2013

Program in C for studying characteristic properties of two-body interactions in the framework of spectral distribution theory

We present a program in C that employs spectral distribution theory for studies of characteristic properties of a many-particle quantum-mechanical system and the underlying few-body interaction. In particular, the program focuses on two-body nuclear interactions given in a JT-coupled harmonic oscillator basis and calculates correlation coefficients, a measure of similarity of any two interactions, as well as Hilbert-Schmidt norms specifying interaction strengths. An important feature of the program is its ability to identify the monopole part (centroid) of a 2-body interaction, as well as its 'density-dependent' one-body and two-body part, thereby providing key information on the evolution of shell gaps and binding energies for larger nuclear systems. As additional features, we provide statistical measures for 'density-dependent' interactions, as well as a mechanism to express an interaction in terms of two other interactions. This, in turn, allows one to identify, e.g., established features of the nuclear interaction (such as pairing correlations) within a general Hamiltonian. The program handles the radial degeneracy for 'density-dependent' one-body interactions and together with an efficient linked list data structure, facilitates studies of nuclear interactions in large model spaces that go beyond valence-shell applications.

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arXiv2012

Construction of the center-of-mass free space for the SU(3) no-core shell model

We address the removal of states with center-of-mass excitation from the SU(3) no-core shell model [SU(3)-NCSM] space, i.e., construction of the nonspurious subspace. A procedure is formulated based on solution of the null-space problem for the center-of-mass harmonic oscillator lowering operator Bcm, operating at the level of SU(3) irreducible representations. Isolation of the center-of-mass free subspace for the SU(3)-NCSM provides the foundation for exact removal of center-of-mass dynamics in the proposed Sp(3,R) symplectic no-core shell model. We outline the construction process for the matrix representation of Bcm, present the algorithm for obtaining the nonspurious space, and examine the dimensions obtained for center-of-mass free SU(3) subspaces in representative light nuclei.

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