4.23-4.27 学术活动预告
2018/4/23 15:58:48 中科院理论物理所
Title
On the Stability of Super-Heavy Nuclei
Speaker
Professor K. Pomorski
Affiliation
Marie Curie-Sklodowska University, Lublin, Poland
Date & Venue
15:00, Apr 24 (Tuesday), 2018
Conference room 6620 New Building
Abstract
The potential-energy surfaces of an extended set of heavy and super-heavy even-even nuclei with 92 ≤ Z ≤ 126 and isospin 40 ≤ N - Z ≤ 74 are evaluated within the recently developed Fourier shape parametrization. Ground-state and decay properties are studied for 324 different even-even isotopes in a four-dimensional deformation space, de fined by non-axiality, quadrupole, octupole, and hexadecapole degrees of freedom. Nuclear deformation energies are evaluated in the framework of the macroscopic-microscopic approach, with the Lublin-Strasbourg-Drop model and a Yukawa-folded mean- field potential. The evolution of the ground-state equilibrium shape and possible shape-isomeric states is studied as a function of Z and N. Alpha-decay Q-values and half-lives, as well as fission-barrier heights, are deduced. In order to understand the transition from asymmetric to symmetric fission along the Fm isotopic chain, the properties of all identified fission paths are investigated. Good agreement is found with experimental data wherever available. New interesting features about the population of different fission modes for nuclei beyond Fm are predicted.
Title
人类社会的集群智能
Speaker
陶勇
Affiliation
苏黎世联邦理工学院
Date & Venue
15:00, Apr 24 (Tuesday), 2018
Conference room 6420 New Building
Abstract
尽管许多生物个体的行为非常简单，但在其数量达到某个阈值时，就展现出群体的智能行为，这是生物学中一种非常有趣的现象。比如，研究蚂蚁习性的专家Nigel R. Franks就发现：单个蚂蚁可能是已知的行为最简单的生物，将100只蚂蚁放在一个平面上，它们会不断往外绕圈直到体力耗尽死去；但是，如果将上百万只蚂蚁放到一起，群体就会组成一个整体，从而形成具有集群智能的“超级生物”。人类的大脑也具有与蚂蚁群相类似的特性，单个神经元并不具有智能，但是由数百亿神经元组成的大脑却呈现高度的智能。同样道理，蚂蚁群、神经网络以及其他生物群落所表现出的集群智能行为，也应当出现在拥有更高智能等级的物种之中。我们的研究显示人类社会作为一个生物群落，也呈现出高度的集群智能行为(技术进步)，而社会熵恰好是人类群体智能大小的度量。我们的研究还进一步显示，不同于物理熵，社会熵呈现出“自我指涉”的特征。Douglas Hofstadter曾在其名著《哥德尔、艾舍尔、巴赫—集异璧之大成》中将“自我指涉”联系到“自我意识”的形成，因此我们猜测人类社会的群体行为类似于一个“社会脑”。
Title
“自指”玻尔兹曼机：人类集群智能的一个应用
Speaker
陶勇
Affiliation
苏黎世联邦理工学院
Date & Venue
15:00, Apr 25 (Wed), 2018
Conference room 6420 New Building
Abstract
物理系统中的玻尔兹曼分布被用于构造人工神经网络，俗称“玻尔兹曼机”，该工作导致了目前非常热的深度学习系统。我们的研究发现：人类社会作为一个生物系统，其收入分布也服从玻尔兹曼分布，但不同于物理系统的是，该生物系统的社会熵具有“自我指涉”的特征。我们将具有“自我指涉”熵的玻尔兹曼分布称为“自指玻尔兹曼分布”。在更早的工作中我们发现，由于社会熵的“自我指涉”特性，人类社会可能类似于一个“社会脑”。因此，我们尝试利用“自指玻尔兹曼分布”来构造具有“自我指涉”特性的人工神经网络，并称之为：“自指”玻尔兹曼机。相比于物理系统的玻尔兹曼机，我们期待基于生物系统的“自指”玻尔兹曼机可以改进目前的深度学习系统。
Title
Lectures on Strong Interactions
Speaker
Prof. Ulf-G. Mei?ner
Affiliation
University of Bonn / Jülich Research Center
Date
10:00, Apr 26 (Thur.), 2018
Conference Room 6620
Abstract
I) Short Introduction
II) Effective Field Theories
III) Chiral QCD Dynamics
IV) Testing Chiral Dynamics in Hadron-Hadron Scattering
V) Nuclear Forces from EFT
VI) Chiral Dynamics in Nuclei
More emphasis will be put on the foundations rather than on specific calculations.
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