报告题目 (Title)：Chirality, Relativity and The Standard Model of Particle physics（手性，相对论效应与粒子物理的标准模型）

报告人 (Speaker)：Prof. Gustavo Aucar（Northeastern University, Argentina）

报告时间 (Time)：2024年6月21日（周五）14:30-16:30

报告地点 (Place)：校本部 D413

邀请人 (Inviter)：任伟 教授

主办部门：理学院物理系

报告摘要：

My lecture will start with a general introduction to the concept of chirality, together with some examples of chiral arrangements in different areas of Natural Science. I want to go on a bit deeply here about the previous inquiry raised in the workshop on why it is exciting to learn about chirality and chiral effects. Then I shall introduce the basic symmetry operations in physics and specially the symmetries that are involved in the well-known CPT theorem of quantum physics. Afterwards, some basic aspect of the Standard Model of the Particle physics, together with its still incomplete use in lowenergy physics, will be introduced. This will permit us to highlight the interplay of chirality, light and magnetism. Which physical processes could originate the chirality at different scales? The easiest way to try a first answer is considering the basic forces that could be involved for each situation. Parity-violation only appears in weak interactions.

These interactions could then underlie, for example, the biological homochirality; a hypothesis that is still under debate and could explain the fact that mostly L-amino-acids and D-sugars are involved in the biochemistry of living organisms. Answering this inquire requires the use of measures of chirality. Recently we have worked with a chiral measure, the electron chiral measure or ECM, that is in addition of the ones presented by professor Avnir. Before showing some of the new results we have obtained applying ECM, I shall introduce the fundamental concepts of relativistic quantum physics and chemistry in order to show what can be learned on the fundamental physics when working within a relativistic framework. Briefly, I will show some of the newest theories and models which consider in one way or another the relativistic effects (i.e. spin-orbit effects and others); specially those related with magnetic response molecular properties. It is known that relativistic effects must be introduced when heavy-atom containing molecules are involved.

In the last (third) part of the lecture I will try to turn to a bridge among what is known within quantum chemistry on chirality to those studies that are typical in solid state physics and material science. In this sense, I will focus on some of the new phenomena that requires to be explained, like the chirality-induce spin selectivity, and also have high potential to introduce new technologies.