Image source: Jingchen | Chalms University of Technology | Yan Strandquist
When a star dies, the violent ending will lead to the birth of neutron star . Neutron stars are the real heavyweight substance in the universe - a teaspoon of celestial bodies that are several kilometers long weighs a billion tons. There is an unimaginable size difference between the nucleus and the neutron star of the isotope lead-208, but the physics describing its properties is largely the same. Now, Chalmes' researchers have developed a new computational model to study the nucleus of lead. The 126 neutrons (red) in the nucleus form an outer envelope, which can be described as skin. How thick the skin is, it is related to strength. By predicting the thickness of neutron skin, you can add knowledge about how powerful works - whether in a nucleus or in a neutron star.
Massive neutron stars collide in space are believed to be able to produce precious metals such as gold and platinum. While the nature of these stars remains a mystery, the answer may be under the skin of one of the smallest building blocks on Earth - the lead nucleus. It turns out that it is difficult to let the nucleus reveal the secrets of controlling the powerful forces inside neutron stars. Now, a new computer model from Chalms University of Technology in Sweden can provide the answer.
Chalmes researchers proposed a breakthrough in calculating the nucleus of heavy and stable element lead in a recent article published in the scientific journal "Natural Physics" .
plays a major role in strength
Although there are huge size differences between microscopic nuclei and neutron stars of several kilometers in size, essentially controlling its properties is the same physics. The common point is to keep particles (protons and neutrons) in the nucleus of strong . The same force also prevents the neutron star from collapse. Although power is the fundamental force of the universe, it is difficult to include it in a computational model. This is especially true when it comes to heavy neutron-rich nuclei such as lead. Therefore, scientists have been working hard to solve many unanswered problems in challenging calculations.
Andreas Ekstrom, Associate Professor, Department of Physics, Charms University of Technology, Sweden. Image source: Charms Polytechnic University | Anna-Lena Lundquist
Reliable calculations
"To understand how powerful works in neutron-rich substances, we need to make meaningful comparisons between theory and experiments. So, in addition to observations made in laboratories and telescopes, reliable theoretical simulations are needed. Our breakthrough means we can do such calculations on the heaviest stable element - lead," said Andreas Ekström, associate professor in the Department of Physics, one of the lead authors of this article.
The new computer model developed by Charms with colleagues in North America and the United Kingdom now points out the way forward. It can predict the properties of isotope*lead-208 and its so-called "neutron skin" with high accuracy.
Christian Fousen is a professor in the Department of Physics, Charms University of Technology, Sweden. Image source: Charms Polytechnic University | Anna-Lena Lundquist
The thickness of the skin is important
It is the 126 neutrons in the nucleus that form an outer layer, which can be described as a skin. How thick the skin is is related to its strong nature. By predicting the thickness of neutron skin, you can increase your knowledge about how powerful forces work - whether in a nucleus or in a neutron star.
"We predict that the neutron skin is surprisingly thin, which can provide new insights into the forces between neutrons. A breakthrough aspect of our model is that it not only provides predictions, but also evaluates the theoretical error range. This is crucial to being able to make scientific progress," said Christian Fousen, professor and head of research in Charles' Department of Physics.
Model for Coronavirus transmission
To develop a new computational model, researchers combined theory with existing data from experimental studies. The complex calculations are then combined with statistical methods previously used to simulate the possible spread of coronavirus.
uses a new model of lead and can now evaluate different assumptions about strength. The model can also predict other nuclei, from lightest to heaviest.
This breakthrough could lead to more precise models, such as neutron stars, and increase understanding of how these stars form.
"Our goal is to better understand the behavior of power in neutron stars and nuclei. It brings research closer to understanding, for example, how gold and other elements are produced in neutron stars - ultimately it's about understanding the universe," said Christian Forsen.
