Climate Change Physics; Precision Laser Spectroscopy; and Ultracold Atom Microtrap Arrays

气候变化物理学；

• 批准号: RGPIN-2017-03717
• 负责人: vanWijngaarden, William
• 金额: $ 1.53万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710407
• 关键词: Climate; Change; Physics; Precision; Laser

Our research in the broad area of General Physics focuses on 3 distinct areas. 1) Climate Change Physics: The 2014 Intergovernmental Panel on climate Change report warns the last 3 decades have been the warmest since 1850 due to the highest levels of greenhouse gases in the past 800,000 years. Our work first checks archival climate records for inhomogeneities due to abrupt changes in instruments or procedure. Next, the statistical significance of trends is examined. The Earth's surface temperature has increased by about 1^o C in the last century. However, decadal temperature fluctuations such as the recently termed global warming hiatus since 2000 are poorly understood. Our objective is to examine discrepancies between observations and theory to better understand the anthropogenic contribution to climate change. We also plan to examine the perturbation of spectral lineshapes from a characteristic Voigt profile due to line mixing of closely spaced CO2 infrared transition caused by atmospheric collisions. This is critical to estimate radiative forcing used by global climate models. 2) Precision Laser Spectroscopy: This encompasses the precise laser spectroscopic measurement of fine and hyperfine structure of neutral and single ionized Li. Recent advances in theory enable very precise computation of wavefunctions of few electrons atoms. This enabled us to determine the 6,7Li relative nuclear charge radius to a few parts times 10^-18 meters. We are doing an optical double resonance experiment to measure the hyperfine splitting of the 6Li+ 1s2p 3P state. Each ion is first laser excited and then proceeds through a cavity resonant with the microwave transition. The longer term objective is to measure the fine structure interval separating the 6Li+ 1s2p 3P (J=0,1,2) levels to determine the fine structure constant with an uncertainty of approximately one part per billion. 3) Atom Microtrap Arrays: Ultracold atoms are ideal for precision measurements as their Doppler shifts are negligible. We created Canada's first Bose Einstein Condensate at temperatures below 100 nanoKelvins. We invented a microtrap consisting of 2 concentric loops having radii 60 and 132 microns carrying oppositely oriented currents. This generates a 3 dimensional trap whose position relative to the chip surface can be adjusted by applying a bias magnetic field perpendicular to the chip surface which is important for developing surface sensors. The microtraps can be daisy chained together to create a one or two dimensional microtrap array. We plan to demonstrate our proposed atom conveyor that transports atoms among a two dimensional microtrap lattice and also study interactions between atoms at neighbouring lattice sites. Eventually we would like to generate a 2 dimensional array of microtraps, each containing a single ultracold atom, where the atoms are entangled with each other to study quantum information.

我们在广泛的普通物理领域的研究主要集中在三个不同的领域。