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

我们在普通物理学的广泛领域的研究集中在三个不同的领域。*1)气候变化物理学：2014年政府间气候变化专门委员会的报告警告称，由于过去80万年来温室气体水平最高，过去30年是自1850年以来最热的。我们的工作首先检查由于仪器或程序的突然变化而导致的不均匀的档案气候记录。接下来，我们考察了趋势的统计意义。上个世纪，地球表面温度上升了约1摄氏度。然而，人们对年代际温度波动，如最近被称为2000年以来的全球变暖间歇期知之甚少。我们的目标是检查观测和理论之间的差异，以更好地理解人为因素对气候变化的影响。我们还计划研究由于大气碰撞引起的近距离二氧化碳红外跃迁的谱线混合，来自特征Voigt剖面的谱线形状的扰动。这对于估计全球气候模式所使用的辐射强迫是至关重要的。*2)精密激光光谱学：这包括对中性和单一电离锂的精细和超精细结构的精确激光光谱测量。理论上的最新进展使极少电子原子的波函数能够非常精确地计算。这使我们能够确定6，7Li的相对核电荷半径为10^-18米的几个部分。我们正在进行光学双共振实验，测量6Li+1s2p3P态的超精细分裂。每个离子首先被激光激发，然后通过与微波跃迁共振的腔进行。较长期的目标是测量分离6Li+1s2p 3P(J=0，1，2)能级的精细结构间隔，以确定精细结构常数，不确定度约为十亿分之一。*3)原子微陷阱阵列：超冷原子是精确测量的理想选择，因为它们的多普勒频移可以忽略不计。我们在低于100纳米开尔文的温度下创造了加拿大第一个玻色爱因斯坦凝聚体。我们发明了一种由两个半径为60微米和132微米的同心环组成的微捕捉器，携带相反方向的电流。这产生了一个三维陷阱，其相对于芯片表面的位置可以通过施加垂直于芯片表面的偏置磁场来调整，这对于开发表面传感器是重要的。微捕获器可以菊花链连接在一起以形成一维或二维微捕获器阵列。我们计划演示我们提出的原子传输器，该传输器可以在二维微陷阱晶格中传输原子，并研究相邻晶格点上原子之间的相互作用。最终，我们想要产生一个二维的微陷阱阵列，每个微陷阱包含一个超冷原子，在那里原子相互纠缠，以研究量子信息。

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.