Bulletin of the American Physical Society
2021 Fall Meeting of the APS Division of Nuclear Physics
Volume 66, Number 8
Monday–Thursday, October 11–14, 2021; Virtual; Eastern Daylight Time
Session JM: Nuclear Theory IV |
Hide Abstracts |
Chair: Thomas Papenbrock, University of Tennessee Room: White Hill |
Wednesday, October 13, 2021 9:30AM - 9:42AM |
JM.00001: Angular momentum projection in coupled-cluster theory Gaute Hagen, Zhonghao Sun, Thomas Papenbrock, Samuel J Novario, Thomas Duguet, Alex Tichai Atomic nuclei have good spin, parity, and third component of the isospin. Yet for many nuclei, symmetry unrestricted mean-field calculations find it advantageous to break rotational invariance and particle number conservation such that the vacuum states accurately reflect the emergent symmetry breaking of intrinsically deformed and superfluid nuclei, respectively. Starting from such symmetry-breaking mean-field states in nuclear structure computations has the advantage that less effort needs to be spent in including correlations beyond the mean field; the disadvantage consists in the need to perform symmetry projections. In this talk I will present the first implementation and application of symmetry restoration in axially deformed coupled-cluster calculations. I will show results for the prototypical deformed nuclei 8Be and 20Ne and compare with data and other existing calculations. |
Wednesday, October 13, 2021 9:42AM - 9:54AM |
JM.00002: Optimized reference ensembles for the in-medium similarity renormalization group Jacob Davison, Heiko Hergert The in-medium similarity renormalization group (IMSRG) is an ab-initio method for computing the properties of medium mass and heavy nuclei. The IMSRG flow is a continuous unitary transformation of the Hamiltonian that decouples a chosen reference state from all excitations in a given many-body basis, thereby mapping it to the true ground state. In general, this transformation induces three-, four- and higher many-body interactions that cannot be tracked explicitly due to a prohibitive computational cost. We must truncate the induced operators at a certain point, which introduces error into the wavefunction solutions. |
Wednesday, October 13, 2021 9:54AM - 10:06AM |
JM.00003: Importance truncation for the symplectic no-core configuration interaction framework Jakub Herko, Mark A Caprio, Patrick J Fasano, Anna E McCoy, Tomas Dytrych, Pieter Maris, Chao Yang, Brandon G Cook The \textit{ab initio} no-core configuration interaction (NCCI), or no-core shell model (NCSM), approach predicts properties of light nuclei from the underlying internucleon interaction. However, the dimension of the NCCI model space rapidly increases with the maximal number of allowed excitation oscillator quanta and the number of nucleons, which limits the convergence of calculated observables that can be achieved in practice. In the symplectic NCCI (SpNCCI) framework, the basis is organized according to the Sp(3,\textit{R}) symmetry giving us the opportunity to truncate the basis by symmetry properties. In this work we apply a truncation scheme based on the ideas of the importance-truncated NCSM (IT-NCSM), where the basis is truncated by an importance measure derived from first-order perturbation theory. We explore the effect of the importance truncation on the dimension of the SpNCCI model space and the convergence of calculated observables. |
Wednesday, October 13, 2021 10:06AM - 10:18AM |
JM.00004: Generic properties of bosonic systems with random interactions. Charles M White, Declan Mulhall, Alexander S Volya, Vladimir G Zelevinsky Quantum many-body dynamics is of paramount importance in many branches of science. The emergence of mean-fields, formation of effective degrees of freedom, and appearance of dynamical symmetries are often generic results of two-body interactions. While the fermionic systems driven by random two-body interactions have been extensively discussed in the past, the physics of bosonic systems is less understood. In this work we study systems of bosons driven by random two-body interactions. We find that there are some statistical and collective limits that resemble the corresponding fermionic cases, however we also find that condensation and clusterization, which for fermions would be blocked by the Pauli principle, play a significant role in shaping many-boson structures. We present numerical studies and explore special analytic limits to support our findings. |
Wednesday, October 13, 2021 10:18AM - 10:30AM |
JM.00005: Factorization Methods and the Similarity Renormalization Group Boyao Zhu, Roland Wirth, Heiko Hergert We perform Singular Value Decompositions of modern nucleon-nucleon inter- actions and implement their Similarity Renormalization Group (SRG) evolution directly in terms of the relevant singular vectors. We study the behavior of the singular value spectrum as a function of the resolution scales, and demon- strate that low-resolution interactions allow accurate low-rank approximations, using two-nucleon scattering phase shifts and the deuteron binding energies as benchmark observables. |
Wednesday, October 13, 2021 10:30AM - 10:42AM |
JM.00006: Symmetries as a framework for understanding signatures of collectivity and shape coexistence Anna E McCoy, Mark A Caprio, Patrick J Fasano, Pieter Maris Ab initio nuclear theory provides not only a microscopic framework for quantitative description of the nuclear many-body system, but also a foundation for deeper understanding of collective behavior. To gain insight into the structure and correlations which give rise to emergent collective behavior in no-core shell model (NCSM) predictions of p-shell nuclei, we decompose the calculated wave functions by symmetries. In particular, we consider the Elliott's SU(3) and Sp(3,R) symmetries, which are tied to nuclear rotation, deformation and giant resonances. These decompositions demonstrate that Elliott's SU(3) rotational model provides a natural framework for understanding the emergence of rotational bands throughout the p-shell. In some nuclei, rotational bands with vastly different structure appear within the low lying spectrum of the same nucleus hinting at shape coexistence. |
Wednesday, October 13, 2021 10:42AM - 10:54AM |
JM.00007: Non-Abelian electric field correlator for quarkonium transport and thermal dark matter relic abundance Bruno Scheihing, Tobias Binder, Kyohei Mukaida, Xiaojun Yao Quantifying the transport properties of heavy particles traveling through thermal non-abelian plasmas is of paramount importance to interpret measurements on those particles conducted after the freezeout. One such example is quarkonium suppression in heavy-ion collisions (HIC). Depending on the nature of dark matter (DM), another example is the thermal DM relic abundance. |
Wednesday, October 13, 2021 10:54AM - 11:06AM |
JM.00008: A new explanation for the nature of the superstring and the manner of its creation Gh. Saleh, M. J. Faraji, Reza Alizadeh In 1971 a mathematical transformation between bosons and fermions was the first attempt to the invention of supersymmetry. So the String theories that include fermionic vibrations were known as "superstring theories". In other words, Superstring theory is a theory that attempts to explain all fundamental forces of nature in one theory. It also tries to form the particles by using the supersymmetric strings that require 11 dimensions. Since its beginnings, superstring theory has developed into a broad and varied subject with connections to quantum gravity, particle and condensed matter physics, cosmology, and pure mathematics. Although Superstring theory is based on supersymmetry, but no supersymmetric particles have been discovered yet. |
Wednesday, October 13, 2021 11:06AM - 11:18AM |
JM.00009: All Masses When Created Will Exhibit No Motion, Linear, Rotational and/or Vibrational Motion in some combination DueTo Excess Energy of Creation Which May Later Be Modified By External Forces.A Natural Law. and Universal Equation Of State For All Masses Is E=mc2 + 1/2mv2 + 1/2Iω2 + 1/2kx2 . Stewart Brekke, Charles Nissim -Sabat, PhD Before 1950-60 it was thought all matter, from the smallest to the largest mass, exhibited only linear motion. By 1950-60's it was found that all types of matter as elementary ;particles, protons, nuclei, stars and planets are rotating and vibrating as well Every form of matter may exhibit not only linear motion, but also rortational and vibrational motion as well. In 1905 Einstein proposed that at slow speeds the total energy for a mass is given by E = mc2 + 1/2mv2. The equation for the total energy of a mass at slow speeds must be updated slightly to include rotation and vibration kinetic energy factors : E = mc2 + 1/2mv2 + 1/2Iω2 + 1/2kx2 + Gm1m2/r + kq1q2/r + ...+ also including all the various potential energies as gravitational and electrostatic .Every mass when created, |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700