RUI: Photons Acting Like Fermions: Search for Violations of the Spin Statistics Theorem Using Sr Atoms

RUI：光子的行为像费米子：使用 Sr 原子搜索自旋统计定理的违反情况

• 批准号: 1607762
• 负责人: Jennie Guzman
• 金额: $ 32.07万
• 依托单位: California State University, East Bay Foundation, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607762&HistoricalAwards=false
• 关键词: RUI; Photons; Acting; Like; Fermions

Fundamental particles of nature can be characterized by their individual properties such as electric charge, mass, and spin. This last property, spin angular momentum, appears to determine whether a particle falls into one of two general categories. Particles with integer valued spin are called "bosons", and those with half-integer valued spin are called "fermions." The boson or fermion distinction has a remarkable effect on the statistical behavior of particle groups. For example, an unlimited number of bosons (such as photons) can occupy the same quantum state, but only a single fermion (such as an electron) can occupy a specific state.  These differences in properties result in vastly different macroscopic behaviors. The distinction between a boson an a fermion is important for the structure of the periodic table of the elements, the degree to which atoms interact with each other during collisions, and even the stability of matter in everyday objects. This research aims to answer the question: are there exceptions to the general rule which links spin to the characterization of a particle as a boson or fermion?  Researchers at California State University East Bay will probe the fundamental properties of light (a spin-1 particle) and explore whether it, a boson, ever exhibits any fermion-like behavior.  Such a discovery would provide a new direction for the theoretical development of the basic axioms of physics and supply an essential ingredient to a more fundamental view of the world.Experimental searches for violations of the spin statistics theorem (SST) test fundamental assumptions of quantum field theory, such as local Lorentz invariance.  For this research, researachers will constrain the SST-forbidden two-photon transition rate between the ground J=0 and excited J'=1 states in atomic strontium.  A two-photon transition between these two states would possess total angular momentum J=1, which is an exchange-antisymmetric (fermionic) state forbidden by the SST.  This new experimental search is motivated by an expected three orders of magnitude increase in sensitivity over previous searches.  This increase is made possible by using laser-cooled strontium atoms and separate detection and excitation regions, reducing the leading systematic effect, scattered light. This work will take place at an undergraduate institution and will directly engage undergraduate students in hands-on research.  This research program will especially benefit the diverse student body at California State University East Bay, where nearly two-thirds of students are women, over sixty percent are first-generation college students, and over seventy-five percent are underrepresented minorities.

自然界的基本粒子可以通过其各自的属性来表征，例如电荷、质量和自旋，最后一个属性（自旋角动量）似乎决定了粒子是否属于两个一般类别之一。具有整数值自旋的粒子被称为。 “玻色子”，具有半整数值的自旋称为“费米子”。玻色子或费米子的区别对粒子群的统计行为有显着影响。​例如，无限数量的玻色子（例如光子）可以占据相同的量子态，但只有单个费米子（例如电子）可以占据特定的状态。这些性质的差异导致了玻色子和费米子之间截然不同的宏观行为。这项研究旨在回答以下问题：将自旋与自旋联系起来的一般规则是否存在例外。表征一个加州州立大学东湾分校的研究人员将探索光（一种自旋 1 粒子）的基本特性，并探索它作为玻色子是否表现出任何类似费米子的行为。物理学基本公理理论发展的新方向，并为更基本的世界观提供了重要组成部分。对自旋统计定理 (SST) 违反情况的实验搜索测试了量子场论的基本假设，例如局域在这项研究中，研究人员将限制锶原子中基态 J=0 和激发态 J'=1 之间的 SST 禁止双光子跃迁速率。这两种状态之间的双光子跃迁将具有总角动量。 J=1，这是 SST 禁止的交换反对称（费米子）态。这种新的实验搜索的动机是预期灵敏度比以前的搜索提高了三个数量级。通过使用激光冷却的锶原子以及分离的检测和激发区域，减少了散射光的主导系统效应，这项工作将在本科机构进行，并将直接让本科生参与该研究项目。尤其有利于加州州立大学东湾分校的多元化学生群体，该校近三分之二的学生是女性，百分之六十以上是第一代大学生，百分之七十五以上是代表性不足的少数族裔。