Collaborative Research: Science Observation with BICEP3 CMB Polarization Experiment

越来越多的证据表明，整个可见宇宙是在亚核体积的戏剧性超光速“膨胀”中产生的。物质的这种剧烈加速会产生宇宙引力波背景(CGB)，其幅度测量的是膨胀的能量尺度。CGB在宇宙微波背景(CMB)的偏振中留下了一个微弱的信号，其幅度由张量与标量模之比r=T/S参数表示，许多慢卷膨胀模型产生了r~0.01？0.1，对应于CMB在度角尺度上30？100nKRMS的峰值波动。探测CGB的偏振信号可以说是当今宇宙学最重要的目标。Astro2010年十年调查将寻找CGB描述为“最激动人心的探索”，并强调“需要对旨在探测CMB(B模式)极化的系统进行中期投资”。2005年，CMB研究工作队确定这是该领域的最高优先事项，并将目标敏感度确定为r=0.02。正在进行的BICEP/BICEP2/SPUD系列实验致力于实现这一科学目标。他们于2006年开始在南极站(南极洲)作业，并坚持不懈地绘制着一片800°2的天空区域，这是银河系前景中独一无二的低空--即所谓的南洞。150 GHz的综合灵敏度(现在大于普朗克航天器的灵敏度)集中在南洞，大大提高了探测CGB的能力。该奖项将在三年内支持CMB使用名为BICEP3的新型偏振仪进行科学观测和分析，这是一种第三代紧凑型折射仪，将代表着每接收器灵敏度的又一突破。与单一的BICEP2/SPUD接收器相比，BICEP3的光吞吐量又增加了十倍。经过三年的观测，在95 GHz下填充了2560个TESS，BICEP3将在任何当前或计划的实验中产生最灵敏的95 GHz的CMB偏振图。BICEP3的观测与SPUD的150 GHz和220 GHz深度覆盖相结合，将在CMB偏振和银河系前景之间提供明显更强大的区分。发现CGB之于通胀，就像发现CMB之于大爆炸一样。事实上，它的影响可能会更广泛，因为通胀直接影响到当前基础物理学的前沿。该项目将继续为本科生和研究生以及在这方面有出色记录的实验室的博士后研究员(包括来自任职人数不足的群体)提供出色的培训。宇宙学和南极洲的研究都吸引了公众的想象力，使这种结合成为激发人们对科学感兴趣的非常有效的工具。

Evidence is mounting that the entire observable Universe was spawned in a dramatic superluminal "Inflation" of a sub-nuclear volume. This violent acceleration of matter would have produced a cosmic gravitational-wave background (CGB), the amplitude of which measures the energy scale of Inflation. The CGB imprints a faint signature in the polarization of the Cosmic Microwave Background (CMB) with an amplitude parameterized by the ratio of tensor to scalar modes, r = T/S. Many slow-roll models of Inflation produce r ~ 0.01?0.1, corresponding to peak CMB fluctuations of 30?100 nK rms on degree angular scales. Detecting the polarization signature of the CGB is arguably the most important goal in cosmology today. The Astro2010 Decadal Survey described the search for the CGB as "the most exciting quest of all", and emphasized that "mid-term investment is needed for systems aimed at detecting the (B-mode) polarization of the CMB". In 2005, the Task Force on CMB Research identified this as the highest priority for the field and established a target sensitivity of r = 0.02. The ongoing BICEP/BICEP2/SPUD series of experiments is dedicated to this science goal. They began operating at the South Pole Station (Antarctica) in 2006 and are relentlessly mapping an 800-deg2 region of the sky that uniquely low in Galactic foregrounds - the so-called Southern Hole. The combined sensitivity at 150 GHz (now greater than that of the Planck spacecraft) is concentrated on the Southern Hole increasing the ability to detect the CGB significantly. This award will support for three years the science observations and analysis with a new CMB polarimeter called BICEP3 - a third-generation compact refractor that will represent another breakthrough in per-receiver sensitivity. BICEP3 provides a further ten-fold increase in optical throughput compared to a single BICEP2/SPUD receiver. Populated with 2560 TESs at 95 GHz over three years of observing, BICEP3 will produce the most sensitive degree-scale CMB polarization maps of 95 GHz of any current or planned experiment. BICEP3 observations, when combined with SPUD's deep 150 GHz and 220 GHz coverage, will provide significantly more powerful discrimination between CMB polarization and Galactic foregrounds. Detection of the CGB would be to Inflation what the discovery of the CMB was to the Big Bang. Indeed its impact might be even broader, as Inflation directly bears on the current frontiers of fundamental physics. The project will continue to provide excellent training for undergraduate and graduate students, as well as postdoctoral fellows (including those from underrepresented groups) in laboratories that have exceptional track records in this regard. Cosmology and research in Antarctica both capture the public imagination, making this combination a remarkably effective vehicle for stimulating interest in science.