Pairing in excited nuclei a review năm 2024

The present review summarizes the recent studies on the thermodynamic properties of pairing in many-body systems including superconductors, metallic nanosized clusters and/or grains, solid-state materials, focusing on the excited nuclei, that is nuclei at finite temperature and/or angular momentum formed via heavy-ion fusion, [Formula: see text]-induced fusion reactions, or inelastic scattering of light particles on heavy targets. Because of the finiteness of the systems, several interesting effects of pairing such as nonvanishing pairing gap, smoothing of superfluid-normal phase transition, first and second order phase transitions, pairing reentrance, etc, will be discussed in detail. Influences of exact and approximate thermal pairing on some nuclear properties such as temperature-dependent width of the giant dipole resonance, total level density, and radiative strength function of the [Formula: see text]-rays emission will be also analyzed. Finally, the first experimental evidence of the pairing reentrance phenomenon in a 104Pd nucleus as well as its solid-state counterpart of ferromagnets under strong magnetic field will be presented.

本综述总结了最近关于多体系统配对热力学性质的研究，包括超导体、金属纳米簇和/或晶粒、固态材料，重点是受激核，即有限温度和/或角的核。通过重离子聚变形成的动量，[公式：见正文]诱导的聚变反应，或轻粒子在重目标上的非弹性散射。由于系统的有限性，将详细讨论配对的几个有趣的影响，例如非零配对间隙、超流体-法向相变的平滑、一阶和二阶相变、配对重入等。精确和近似热配对对一些核特性的影响，例如巨偶极共振的温度相关宽度，还将分析[公式：见正文]-射线发射的总能级密度和辐射强度函数。最后，将展示强磁场下 104Pd 核及其固态铁磁体配对重入现象的第一个实验证据。

The nucleus is considered as a Fermi gas with pairs of degenerate single particle states and a coupling energy DELTA between the two states of a pair. A statistical treatment gives expressions for the density of excited states and the expected value of the total angular momentum. Suitable approximations for purposes of calculation are indicated. All the formulas become equivalent to those of a simple Fermi gas at high enough excitations. (auth)

Authors: Le Couteur, K J Publication Date: Tue Dec 01 00:00:00 EST 1959 Research Org.: Australian National Univ., Canberra OSTI Identifier: 4189590 NSA Number: NSA-14-006960 Resource Type: Journal Article Journal Name: Nuclear Phys. Additional Journal Information: Journal Volume: Vol: 14; Other Information: Orig. Receipt Date: 31-DEC-60 Country of Publication: Country unknown/Code not available Language: English Subject: PHYSICS; BINDING ENERGY; DENSITY; ENERGY; ENERGY LEVELS; EQUATIONS; EXCITATION; FERMI GAS; FERMIONS; NUCLEAR MODELS; NUCLEAR THEORY; NUCLEI; PAIRING ENERGY; SPIN; STATISTICS

Citation Formats

Lang, D W, and Le Couteur, K J. PAIRING ENERGY EFFECTS IN EXCITED NUCLEI. Country unknown/Code not available: N. p., 1959. Web. doi:10.1016/0029-5582(59)90067-7.

Lang, D W, & Le Couteur, K J. PAIRING ENERGY EFFECTS IN EXCITED NUCLEI. Country unknown/Code not available. https://doi.org/10.1016/0029-5582(59)90067-7

Lang, D W, and Le Couteur, K J. 1959. "PAIRING ENERGY EFFECTS IN EXCITED NUCLEI". Country unknown/Code not available. https://doi.org/10.1016/0029-5582(59)90067-7.

@article{osti_4189590, title = {PAIRING ENERGY EFFECTS IN EXCITED NUCLEI}, author = {Lang, D W and Le Couteur, K J}, abstractNote = {The nucleus is considered as a Fermi gas with pairs of degenerate single particle states and a coupling energy DELTA between the two states of a pair. A statistical treatment gives expressions for the density of excited states and the expected value of the total angular momentum. Suitable approximations for purposes of calculation are indicated. All the formulas become equivalent to those of a simple Fermi gas at high enough excitations. (auth)}, doi = {10.1016/0029-5582(59)90067-7}, url = {https://www.osti.gov/biblio/4189590}, journal = {Nuclear Phys.}, number = , volume = Vol: 14, place = {Country unknown/Code not available}, year = {Tue Dec 01 00:00:00 EST 1959}, month = {Tue Dec 01 00:00:00 EST 1959} }

What is the pairing energy of the nucleus?

The pairing energy is of the order of magnitude of 1–3 MeV and the difference for different angular momentum exceeds in some cases 1 MeV. Therefore it is nearly as important for the discussion of shell effects as the spacing of single particle levels, and for the magic number 28 it appears to be dominant.

What does it mean for a nucleus to be excited?

In an excited state, one or more of the protons or neutrons in a nucleus occupy a nuclear orbital of higher energy than an available nuclear orbital. These states are analogous to excited states of electrons in atoms. When excited atomic states decay, energy is released by fluorescence.

What is the spin pairing of nucleons?

A major factor in what holds a nucleus together is the formation of nucleonic spin pairs; neutron-neutron, neutron-proton, and proton-proton. These spin pairs form whenever possible but they are exclusive in the sense that a neutron may pair with one other neutron and with one proton but no more.

What are the properties of the nuclei in nuclear structure?

The important static properties of the nuclei include their electric charge , mass, binding energy, size ,shape, angular momentum , magnetic dipole moment, electric quadruple moment, statistics, parity, and iso- spin.