Laser-cooled mercury to search for physics beyond the standard model

This thesis explores the development and application of laser-cooled mercury atoms for precision measurements relevant to fundamental physics. A primary motivation is the search for a permanent electric dipole moment in mercury, that could shed light on the baryon asymmetry of the universe. We present the design and construction of a custom experimental apparatus for producing and trapping cold mercury atoms, detailing challenges associated with working with mercury in an ultra-high vacuum environment and considering deep-ultraviolet optics. A magneto-optical trap operating on the ¹<em>S</em>₀-³<em>P</em>₁ intercombination line at 254 nm is realized for all seven stable isotopes, achieving atom numbers up to 5x10⁷ and phase-space densities up to 1x10^-6 suitable for optical dipole trap loading. Cooling efficiency for all bosonic and fermionic isotopes are characterized over a wide parameter space, and we show sub-Doppler cooling in ¹⁹⁹Hg and ²⁰¹Hg. The successful loading of mercury into a high-power optical dipole trap is demonstrated, forming the basis for future electric dipole moment experiments of laser cooled mercury atoms. Prospects of evaporatively cooling mercury down to quantum degeneracy could allow for a quantum-enhanced metrology tool kit for the planned measurements. Apart from this, we are exploring the use of ultracold fermionic gases made of mercury as a quantum simulator for impurity physics. As a promising versatile and tunable platform for studying impurity-bath interactions, we are assessing the feasibility of observing Friedel oscillations in ultracold quantum gases.Further, we perform precision isotope shift spectroscopy on several dipole-allowed atomic transitions in mercury. Via King plot analysis this allows investigations of the mercury nuclear structure – also relevant for electric dipole moment bounds – and lays the foundation for probing a potential fifth force carrier coupling electrons to neutrons. We also propose upgrades to the machine for improvements in laser cooling, extensions of the spectroscopy search and a proposed experimental setup for probing the atomic electric dipole moment in an optical dipole trap of cold mercury atoms.