New Physics on the Brane

像大多数亚原子理论家一样，我的主要目标是理解自然的基本规律。目前，我们有一个非常成功的理论，即广义相对论的标准模型，直到最近，它还描述了所有已经完成的实验。最近的三个例外是中微子振荡的地球和天体物理证据，以及揭示原始密度波动存在的宇宙学观测，以及两种未知的引力来源：所谓的暗物质和暗能量。这表明标准模型是失败的；亚原子理论家寻求它的替代品。******现在很多证据都来自太空，这就是为什么宇宙学一直是我的主要关注点。在过去，我提出了一些暗物质、暗能量和原始波动起源的主要模型。这些模型的动机是简单性，并且认识到我们所看到的可能是更基本的东西的低能量极限（这对候选理论施加了“自然性”限制，特别是对暗能量）。但是，随着大型强子对撞机（LHC）在2015年中期开始其期待已久的全能量运行，我们也站在了许多新的地球信息的门槛上。******我的建议分为两部分。在宇宙学方面，我建议根据正在进行的新观测继续探索宇宙学对基础物理的影响，例如备受期待的普朗克和BICEP合作的更新。这本身包括两个部分：通过对原始波动的观察来推断高能物理，以及寻找涉及更“近代”宇宙学（如暗物质和暗能量）的谜题的解决方案。在粒子物理方面，我寻求在对撞机实验中看到的现象（反之亦然），特别是当这些现象是由宇宙学问题引起的时候。我在过去已经确定了几个这样的联系，并继续寻找它们，因为从大型强子对撞机获得了更多的信息。***当我这样做的时候，我试图使用的一个线索是从弦理论中获取想法，弦理论是唯一一个将引力与量子力学相协调的候选基本理论，它的预测足够精确，可以系统地利用。弦理论预言，自然界的一切都是由微观的弦构成的，这些弦可以在超维时空中沿着巨大的宏观表面（膜）移动。我研究的一条发展路线是，通过改变我们在低能理论中所看到的自然现象，弦理论如何影响宇宙学和粒子物理学的思想。特别是，膜的潜在存在可以强烈地改变低能世界可能显示的各种特征。对加拿大来说，我的产品是人：基础物理吸引优秀的年轻人学习可转移的数学、计算和沟通技能，他们可以将这些技能带到更广泛的经济领域。**

Like most subatomic theorists my broad objective is to understand the fundamental laws of nature. At present we have a very successful theory, the Standard Model with General Relativity, that until recently described all experiments that had been done. The three recent exceptions are terrestrial and astrophysical evidence for neutrino oscillations, together with cosmological observations revealing the existence of primordial density fluctuations as well as two unknown sources of gravitation: the so-called dark matter and dark energy. These show that the Standard Model fails; subatomic theorists seek its replacement.******Much of this evidence now comes from space, which is why cosmology has been my main focus. In the past I have proposed some of the leading models for dark matter, for dark energy and for the origins of primordial fluctuations. These models are motivated by simplicity and by the recognition that what we see is likely the low-energy limit of something more fundamental (which imposes 'naturalness' restrictions on candidate theories, particularly for dark energy). But we stand at the threshold of much new terrestrial information too, with the Large Hadron Collider (LHC) beginning its long-awaited full-energy run in the middle 2015.******My proposal comes in two parts. On the cosmology side I propose to continue exploring the implications of cosmology for fundamental physics in light of the on-going new observations, such as the much-anticipated updates from the Planck and BICEP collaborations. This itself comes in two parts: inferences about physics at very high energies coming from observations of primordial fluctuations, and searches for solutions to puzzles involving more 'recent' cosmology (like dark matter and dark energy). On the particle physics side I seek phenomena to be seen in collider experiments (and vice versa), particularly when these are motivated by problems in cosmology. I have identified several such connections in the past, and continue to seek them as more information arrives from the LHC.***One clue I try to use when doing so is to take ideas from string theory, which is the only candidate fundamental theory reconciling gravity with quantum mechanics for which predictions are precise enough to exploit systematically. String theory predicts that all of Nature is built from microscopic strings that can move along large, macroscopic surfaces (branes) within extra-dimensional space-time. One line of development on which I work examines how string theory impacts ideas for cosmology and particle physics, by changing what we see as natural in a low-energy theory. In particular, the potential existence of branes can strongly modify the kinds of features that the low-energy world might display.***For Canada my product is people: Fundamental physics draws fine young minds to learn transferable mathematical, computing and communications skills, which they can bring to the wider economy. **