3,161 research outputs found
Quantum Monte Carlo calculations of symmetric nuclear matter
We present an accurate numerical study of the equation of state of nuclear
matter based on realistic nucleon--nucleon interactions by means of Auxiliary
Field Diffusion Monte Carlo (AFDMC) calculations. The AFDMC method samples the
spin and isospin degrees of freedom allowing for quantum simulations of large
nucleonic systems and can provide quantitative understanding of problems in
nuclear structure and astrophysics.Comment: Final version published in the Phys. Rev. Let
Path Integral Quantum Monte Carlo Calculations of Light Nuclei
We describe a path-integral ground-state quantum Monte Carlo method for light
nuclei in continuous space. We show how to efficiently update and sample the
paths with spin-isospin dependent and spin-orbit interactions. We apply the
method to the triton and alpha particle using both local chiral interactions
with next-to-next-to-leading-order %(NLO) and the Argonne interactions. For
operators, like the total energy, that commute with the Hamiltonian, our
results agree with Green's function Monte Carlo and auxiliary field diffusion
Monte Carlo calculations. For operators that do not commute with the
Hamiltonian and for Euclidean response functions, the path-integral formulation
allows straightforward calculation without forward walking or the increased
variance typical of diffusion methods. We demonstrate this by calculating
density distributions, root mean square radii, and Euclidean response functions
for single-nucleon couplings.Comment: 15 pages, 9 figures, 6 tables. Accepted by Physical Review C on
2022-9-28; published on 2022-10-2
Structure, rotational dynamics, and superfluidity of small OCS-doped He clusters
The structural and dynamical properties of OCS molecules solvated in Helium
clusters are studied using reptation quantum Monte Carlo, for cluster sizes
n=3-20 He atoms. Computer simulations allow us to establish a relation between
the rotational spectrum of the solvated molecule and the structure of the He
solvent, and of both with the onset of superfluidity. Our results agree with a
recent spectroscopic study of this system, and provide a more complex and
detailed microscopic picture of this system than inferred from experiments.Comment: 4 pages. TeX (requires revtex4) + 3 ps figures (1 color
Second-Order Perturbation Theory in Continuum Quantum Monte Carlo Calculations
We report on the first results for the second-order perturbation theory
correction to the ground-state energy of a nuclear many-body system in a
continuum quantum Monte Carlo calculation. Second-order (and higher)
perturbative corrections are notoriously difficult to compute in most
\textit{ab~initio} many-body methods, where the focus is usually on obtaining
the ground-state energy. By mapping our calculation of the second-order energy
correction to an evolution in imaginary time using the diffusion Monte Carlo
method, we are able to calculate these corrections for the first time. After
benchmarking our method in the few-body sector, we explore the effect of
charge-independence breaking terms in the nuclear Hamiltonian. We then employ
the new approach to investigate the many-body, perturbative, order-by-order
convergence that is fundamental in modern theories of the nucleon-nucleon
interaction derived from chiral effective field theory. Our approach is quite
general and promises to be of wide applicability.Comment: 6 pages, 3 figures, 1 tabl
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