Physicists use numerical 'tweezers' to study nuclear interactions

June 9, 2017 by Tracey Peake, North Carolina State University
Numerical tweezers used to measure the effective potential between two quantum states. Credit: North Carolina State University

Researchers from North Carolina State University and the Ruhr-Universität Bochum have developed numerical "tweezers" that can pin a nucleus in place, enabling them to study how interactions between protons and neutrons produce forces between nuclei. They found that the strength of local interactions determines whether or not these nuclei attract or repel each other, shedding light on the parameters that control attraction or repulsion in quantum bound states.

"Ultimately we want to understand how nuclear forces determine nuclear structure by studying how attract or repel one another," says Dean Lee, professor of physics at NC State and corresponding author of a paper describing the work. "So we needed a way to hold in place and move them around relative to one another in order to measure attraction or repulsion."

Lee, along with Ruhr-Universität Bochum colleagues Evgeny Epelbaum and Hermann Krebs and graduate student Alexander Rokash, utilized a numerical lattice with attractive potentials in order to isolate the particles they wanted to study. The attractive potentials created a way for a particle to get "stuck" in one place - like a hole in the ground that a marble could roll into. These were the numerical tweezers.

The team began simulations with two single particles held in different positions, then with particle pairs. They looked at two types of interactions between the groups of particles: local interactions, where the particles' positions relative to one another don't change; and non-local interactions, where the positions do change.

"We found that the local interactions had a much bigger effect on determining whether nuclei would stick together, or become bound," Lee says. "Specifically, the strength and range of the local interactions determined whether or not the nuclei would bind to each other. In non-local interactions, on the other hand, the nuclei sometimes repelled each other.

"We're interested in finding out why nuclei bind together to form new elements," Lee continues. "Numerical tweezers allow us to do simple simulations using just a few particles, giving us insight into the most basic particle interactions and the ways in which inform ."

The findings appear in Physical Review Letters. Rokash is first author of the paper.

Explore further: Nucleon interactions key to quantum phase transition

More information: "Effective Forces Between Quantum Bound States" Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.118.232502

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7 comments

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bschott
3 / 5 (2) Jun 09, 2017
This research is 20 times more useful than anything that can come of annihilating nuclei. I hope they find what they are looking for..
Lischyn
4 / 5 (2) Jun 09, 2017
There has to be a more intelligent way of probing than building a $10billion ring. This at least looks like a start
billpress11
not rated yet Jun 10, 2017
Quote from article"
"Ultimately we want to understand how nuclear forces determine nuclear structure by studying how nuclei attract or repel one another,"

Doesn't anyone else find it strange that there is a repulsive inside nuclei? I thought there was only an attractive force inside the nucleus.
billpress11
not rated yet Jun 10, 2017
Could the explanation of the strong nuclear force on pages 30 and 31 from the link below be an explanation for the repulsive force inside the nucleus?

http://www.scribd...-Physics

HocusLocus
not rated yet Jun 12, 2017
> Doesn't anyone else find it strange that there is a repulsive inside nuclei? I thought there was only an attractive force inside the nucleus.

Space keeps everything everywhere and elsewhere
Nucleonic repulsion iswhyitsallnot nothing nowhere over there
You are here
Grab a painted pony
let the spinning wheel spin
Hyperfuzzy
not rated yet Jun 13, 2017
Since radiation is produced by charge, a simple model, duh.
Hyperfuzzy
not rated yet Jun 13, 2017
However, the time changing nuclear field and the time changing orbitals fields may also be simulated with a stationary nucleus, this defines the set of allowed states for orbitals with the maximum instability before nuclear interaction. and possibly most isotopes.

Hence, sensitivity to all radiation, or specific, dynamic? With software?

Best if each memory location is an object, ...

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