Thread by @nuclearIdini

New paper out📝!

Let’s explain how we take the impractical high energy-short range nuclear interactions or functionals out there and make up something that can be used for nuclei w. strange shapes🥔

a🧵
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Today @PhysRevC:
journals.aps.org/prc/abstract/1…
#nuclear #physics #paper

The big problem in nuclear physics is that the nucleus is composed of many neutrons and protons, making it a quantum many-body system. Furthermore, the interaction between them is unknown and extremely complicated.

This kind of complicated 👇

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There is always this tension in nuclear physics on how much detailed you want to be with your interaction, or precise with the description of the many-body dynamics. You have to settle the tradeoff according to your computational power (thnx @LUNARC_LU ) and interests.

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The main idea is to reduce the complexity of an interaction based on scheme that reproduces and expands around general physical properties, such as the shape (collective coordinates). Having a simple interaction that emulates the stiffness of popular models when deformed as a🏉
>

With this simple interaction, we can afford to be very detailed exploring all the ways the nucleus can couple and move neutrons and protons around while stretched in the shape of🏉 or🥞 or irregular🥔. Each point👇represents a shape, and the color the cost to deform to that.
5/n

In each of the above points we “heat up” the nucleus, to bookkeep all the ways that it can be excited in each of the shapes.
This method that we introduced is very fun for practitioners (it shows how excitations and ground states are related, i.e. through Thouless HFB vacua)

6/n

Results are imho stunning! Without any direct information on excitations we nail the rotations w. ~10 keV precision (parts per 10k+)!
We can also have a lot of fun, looking at famous behaviors of nuclei & understanding them from a microscopic, fully quantum, description.
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One cool feature are the terminating states. At some point it will be spherical and the angular momentum will be provided by disjointed particles. At that point, to rotate even more it will have to drastically change!
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Another one is backbanding, where the rotation affects the structure to the point of dramatically and suddenly change the inertia of rotation. Indicating either a breaking of nuclear pairs, or a change in the shape or axis of rotation. Look at our model go! 👇

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This precision and avenues of investigations are true also for nuclei with odd number of particles, traditionally the black sheep of nuclear modeling.
I care because being precise and predictive opens to nuclear reactions: no model has brought these effects in that field!

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There are a lot of ways forward for us now, from strengthening the link with fundamental interactions, trying other collective coordinates to explore the ways nuclei move around, to simply use it in other contexts, e.g. heavier and more exotic nuclei.

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I’m happy about how this model came about, considering a bit of a rethinking from scratch around old and new ideas we did something that will keep us busy and excited for quite a while.
Shoot all the questions you want!

The paper here:
journals.aps.org/prc/abstract/1…

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