scholarly journals Nuclear Physics and Astrophysics Constraints on the High Density Matter Equation of State

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 257
Author(s):  
Jirina R. Stone

(1) This review has been written in memory of Steven Moszkowski who unexpectedly passed away in December 2020. It has been inspired by our many years of discussions. Steven’s enthusiasm, drive and determination to understand atomic nuclei in simple terms of basic laws of physics was infectious. He sought the fundamental origin of nuclear forces in free space, and their saturation and modification in nuclear medium. His untimely departure left our job unfinished but his legacy lives on. (2) Focusing on the nuclear force acting in nuclear matter of astrophysical interest and its equation of state (EoS), we take several typical snapshots of evolution of the theory of nuclear forces. We start from original ideas in the 1930s moving through to its overwhelming diversity today. The development is supported by modern observational and terrestrial data and their inference in the multimessenger era, as well as by novel mathematical techniques and computer power. (3) We find that, despite the admirable effort both in theory and measurement, we are facing multiple models dependent on a large number of variable correlated parameters which cannot be constrained by data, which are not yet accurate, nor sensitive enough, to identify the theory closest to reality. The role of microphysics in the theories is severely limited or neglected, mostly deemed to be too difficult to tackle. (4) Taking the EoS of high-density matter as an example, we propose to develop models, based, as much as currently possible, on the microphysics of the nuclear force, with a minimal set of parameters, chosen under clear physical guidance. Still somewhat phenomenological, such models could pave the way to realistic predictions, not tracing the measurement, but leading it.

1971 ◽  
Vol 46 ◽  
pp. 356-363
Author(s):  
M. R. McNaughton

The conditions for superfluidity or ferromagnetism in neutron stars are presented and discussed (but not derived). It is suggested that present estimates relating to these are in error and that the predictions made contradict at least one of three sets of nuclear physics data cited in the text. This is due to neglecting the action of the exclusion principle.A comparatively simple method for calculating the strength of nuclear forces in the presence of many-body effects is outlined. Some preliminary results are presented together with projected future developments.


2017 ◽  
Vol 26 (11) ◽  
pp. 1730005 ◽  
Author(s):  
R. Machleidt

The nuclear force is the heart of nuclear physics and, thus, the significance of this force for all of nuclear physics can hardly be overstated. Research on this crucial force has by now spanned eight decades and we are still not done. I will first review the rich history of hope and desperation, which had spin-off far beyond just nuclear physics. Next, I will present the current status in the field which is characterized by the application of an effective field theory (EFT) that is believed to represent QCD in the low energy regime typical for nuclear physics. During the past two decades, this EFT has become the favorite vehicle to derive nuclear two- and many-body forces. Finally, I will take a look into the future: What developments can we expect from the next decades? Will the 30-year cycles of new and “better” ideas for efficiently describing nuclear forces go on for ever, or is there hope for closure?


Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 100 ◽  
Author(s):  
M. Coleman Miller

Astronomical data about neutron stars can be combined with laboratory nuclear data to give us a strong base from which to infer the equation of state of cold catalyzed matter beyond nuclear density. However, the nuclear and astrophysical communities are largely distinct; each has their own methods, which means that there is often imperfect communication between the communities regarding caveats about claimed measurements and constraints. Here we present a brief summary from one astronomer’s perspective of relevant observations of neutron stars, with warnings as appropriate, followed by a set of questions that are intended to help enhance the dialog between nuclear physicists and astrophysicists.


1966 ◽  
Vol 21 (12) ◽  
pp. 2009-2012
Author(s):  
P. Gombás ◽  
D. Kisdi

Using a semi-empirical theory of interaction between neutrons in atomic nuclei, the average energy of a neutron, the equation of state, and the pressure-compressibility relation is computed for a neutron gas of very high density (n ≈ 1015 gcm-3). The results are applied to the computation of the mass and the radius of a neutron star as a function of the central density. For the critical mass, above which a neutron star cannot exist, a value of 0.96 solar masses is found.


Medicines ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 38
Author(s):  
Kyung-Hyun Cho

The composition and properties of apolipoprotein (apo) A-I and apoA-II in high-density lipoproteins (HDL) might be critical to SARS-CoV-2 infection via SR-BI and antiviral activity against COVID-19. HDL containing native apoA-I showed potent antiviral activity, while HDL containing glycated apoA-I or other apolipoproteins did not. However, there has been no report to elucidate the putative role of apoA-II in the antiviral activity of HDL.


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