Quantum Simulation and Chemistry with Ultracold Mixtures and Molecules

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One of the most exciting, and challenging, frontiers in quantum physics is strongly interacting systems. Strong interactions lie at the heart of poorly understood materials from unconventional superconductors to the cores of neutron stars and the quark-gluon plasma that filled the universe a tiny fraction of a second after the big bang. In such materials, many particles become inextricably linked to an extent that is impossible in classical physics. This connection, called entanglement, makes calculations of their structure and behavior extremely difficult. Entanglement is also the key resource that gives quantum computers the power to outperform classical computers. In quantum simulations, sometimes called analog quantum computers, experiments are built to obey specifically chosen rules that lead to strong interactions. In ultracold quantum simulations, we can manipulate and measure the system atom by atom, developing a deep understanding of how exotic properties emerge from seemingly simple rules. First, we will use cesium atoms to cool lithium atoms to record low temperatures in a simulation of a simple model believed to explain the behavior of high-temperature superconductors. Our quantum simulations will search for sets of parameters pointing to new materials that superconduct at higher temperatures. Second, we will use mixtures of cesium and lithium atoms to simulate lattice gauge theories. The most fundamental description of our universe, The Standard Model, is a collection of quantum field theories called gauge theories. The gauge theory describing nuclear matter has strong interactions that thwart attempts to understand nuclear physics from first principles. Our quantum simulations of related strongly interacting gauge theories will allow us to build intuitions that can then be applied back to The Standard Model and potentially point to new physics beyond it. The dynamics of chemical reactions are also determined by strong interactions. Even in simple reactions the large number of degrees of freedom couple strongly to one another. While these dynamics are innately quantum mechanical, room temperature chemistry experiments average over many quantum states, obscuring the fundamental dynamics. At ultracold temperatures we can completely control the quantum states of atoms and molecules to observe chemical dynamics with quantum state resolution. Since complex reactions can often be analyzed as a collection of simpler reactions, we will be able to apply what we learn from simple reactions to industrially important reactions. In addition to advancing our knowledge of technologically important physics, this research teaches students technical skills in electronics, optics, systems engineering, and programming. They also build analytical and quantitative skills valued by many industries. This training prepares students who will help drive Canada's high-tech economy in industry or independent research careers of their own.