Beyond LambdaCDM: Theoretical Predictions & Observational Constraints

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The two deepest mysteries in our understanding of nature are: the selection of the initial conditions (IC) of our universe, and the recent acceleration of the universe, attributed to dark energy (DE). The PI proposes to study both of these outstanding problems, within a new framework that extends the conventional approach and which uses observational analysis for guidance on these phenomena and for the testable predictions of the program. The radical departure of the PI's approach from the conventional approach is that it proposes to use the quantum dynamics of the gravitational and matter fields degrees of, in a multiverse framework, for selecting the IC and for extracting the cosmological implications of the landscape. The PI advocates that the only way to address the problem meaningfully is by extending our investigation to a multiverse framework. This proposal is one way resolving the puzzle of why our universe had to start with High Energy Big Bang, while avoiding paradoxes born out of previous attempts. This approach also offers a multitude of testable predictions, tracked down by superhorizon entanglement modes, thereby placing it as a strong candidate for a scientific theory of IC. Three of these predictions are already successfully tested, with the most recent test being the NASA discovery of a "dark flow" in Sept.2008. Another topic of research concerns the puzzle: what is Dark Energy? Currently, the best way to tell is by observationally finding ways to measure its pressure and equation of state w[z]. Although ranked among the highest priorities in the community, this measurement has proven difficult so far. The PI proposes a complementary method, namely the use of Gravitational Waves from SBH binaries for pinning down w. This method can be quite powerful since it avoids the noise in the signal that is inherited from the vastness of structure through which the signal propagates. Besides complementing current large-scale surveys, the benefit of this method is that we can start taking data immediately and make use of existing and planned LIGO and LISA experiments. The project has many broader impacts. The PI shares the excitement of her research by giving a series of talks nationally and internationally, and by talking to media in order to help make cutting edge research accessible to a wider audience. Together with Brian Greene and J.Khoury, the PI has initiated and is co-organizing a series of conferences, "A Debate in Cosmology", on these outstanding topics, meant not only to stimulate progress and breakthroughs by bringing together authorities in the field, but also for disseminating knowledge by having online video-cams of the talks. She is also co-editing a book on Time's Arrow (NYAS) and co-authoring invited chapters for Springer's "Frontier" collection meant to disseminate cutting edge research to the general public.