The Gravity of New Phenomena in Particle Physics

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Like most subatomic theorists my objective is to understand the fundamental laws of nature. Our current most successful theory is the Standard Model (with General Relativity), which until recently accounted for all experiments. It now fails to describe a few observations: evidence for neutrino oscillations; for cosmological observations revealing the existence of primordial density fluctuations; and for the discovery in cosmology of two unknown sources of gravitation - the so-called dark matter and dark energy. Because these show that the Standard Model fails, we seek its replacement (whose discovery would revolutionize our understanding of nature). Much of the evidence against the Standard Model now comes from space, which is why cosmology and gravity have been my recent focus. In the past I proposed the simplest successful model for dark matter, and leading approaches to dark energy and for the origins of primordial fluctuations. These models were motivated both 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). Besides continuing these directions I wish also to exploit the recent discovery of gravitational waves and high-resolution black-hole images to see whether they contain signs of the Standard Model's demise. This involves developing new theoretical tools, since the strong-gravity regime they probe does not easily lend itself to standard perturbative methods. These new tools involve exploring different aspects of gravitational fields with event horizons (surfaces through which objects can only travel in one direction if they at most move at the speed of light - as they must). One tool classifies new near-horizon phenomena by exploiting the simplicity that comes from proximity to the horizon (relative to a problem's other scales). A second tool - Open EFTs - explores late-time evolution, where interesting phenomena (like black-hole information loss) occur, but for which perturbative methods also generically fail. Open EFTs nonetheless make headway by adopting similar tools used elsewhere in physics (eg optics) to solve similar problems with late-time predictions. Some of these tools also are useful more widely: one class explores how very small objects (nuclei, for example) influence their much larger surroundings (atoms). This proposal tests the new tools by using them to simplify calculations of nuclear structure on atomic energy levels. A spinoff identifies observables that are independent of nuclear properties (and the large errors that come with them). Similar tools are also applied to simplify calculations of monopole catalysis of baryon-number violation. For Canada my product is people: The excitement of fundamental physics draws the finest young minds to learn mathematical problem-solving skills, which they then can (and do) bring to the rest of the economy.