Radio Experimental Cosmology at Oxford

就在大爆炸之后，天文学家认为宇宙在一个被称为“宇宙膨胀”的时期迅速膨胀。经过一个更长、更温和的时期，在此期间，物质的引力开始逐渐减缓膨胀，宇宙现在似乎已经开始了第二个加速膨胀时期。这种最近的膨胀是由天文学家所说的“暗能量”驱动的。虽然天文学家相信所有这些事情，但地球上没有人理解“宇宙膨胀”或“暗能量”。这是一个有点尴尬。一些著名的科学家认为，这些神秘的概念是全新物理学的标志，甚至是额外维度存在的标志！我们的研究旨在设计，建造和使用望远镜来观测宇宙，这将告诉我们更多关于宇宙膨胀和暗能量的信息。宇宙暴胀的大多数解释都预测，无论是什么引起了它，都应该以时空涟漪的形式留下它的活动的“指纹”，称为引力波。这些涟漪的影响可以通过观察来自大爆炸的残余辐射的偏振来看到，宇宙微波背景。我们研究的一个主要目标是在智利和南极洲建造望远镜，这将是第一个发现这些指纹的望远镜。这些望远镜将被称为安静和三叶草。不幸的是，这些指纹必须在一个非常混乱的宇宙中找到。在我们能够“看穿它”并找到指纹之前，我们必须非常好地理解来自我们自己星系的偏振无线电发射。我们将建造一个新的仪器，我们将把它带到南半球和北方半球的射电望远镜上，帮助我们找到银河系中最干净的一点，用安静和三叶草来窥视。这种仪器将被称为C-BASS。我们还将继续致力于使我们的望远镜和仪器尽可能灵敏的技术。我们将测试使用各种巧妙的量子物理学和数字处理技术的新设备，以尽可能干净和有效地测量来自宇宙的信号。我们希望有一天能利用这些技术来设计实验，告诉我们暗能量是什么。

Just after the Big Bang, astronomers believe the Universe expanded rapidly during a period known as `cosmic inflation'. After a longer, gentler period, during which the gravitational pull of matter began gradually to slow down the expansion, the Universe now appears to have begun a second period of accelerated expansion. This recent expansion is driven by what astronomers call `dark energy'. Although astronomers believe all these things, no person on Earth understands either `cosmic inflation' or `dark energy'. This is a bit embarassing. Some reputable scientists believe that these mysterious concepts are signatures of totally new physics, or even of the presence of extra dimensions! Our research is aimed at designing, building and using telescopes to make observations of the Universe which will tell us more about both cosmic inflation and dark energy. Most explanations of cosmic inflation predict that whatever caused it should have left `fingerprints' of its activity in the form of ripples in space-time called gravitational waves. The effects of these ripples can be seen by looking at the polarization of the relic radiation from the Big Bang, the Cosmic Microwave Background. A major goal of our research is to build telescopes in Chile and Antartica which will be the first to find these fingerprints. These telescopes will be called QUIET and CLOVER. Unfortunately, these fingerprints must be found in a very messy Universe. Polarized radio emission from our own galaxy has to be understood incredibly well before we can `see through it', and find the fingerprints. We will be building a new instrument which we will take to radio telescopes in both the southern and northern hemispheres to help us find the cleanest bit of the galaxy to peer through with QUIET and CLOVER. This instrument will be called C-BASS. We will also keep working on the technologies that make our telescopes and instruments as sensitive as possible. We will be testing out new devices that use all sorts of clever quantum physics and digital processing techniques to measure signals from the Universe as cleanly and efficiently as possible. We hope one day to use these technologies to devise experiments that will tell us what dark energy is.