Precision measurements using atoms and molecules

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Humankind has observed the sky for centuries, but an entire universe of phenomena is invisible to our electromagnetic eyes and telescopes. Every massive object in the universe radiates gravitational waves, which can carry information to us from the far corners of the universe. Yet, this gravitational universe remains hidden from view, and awaits the development of instruments precise enough to detect the feeble spacetime fluctuations caused by gravitational waves. The proposed research program aims to construct precise atomic tools to enable the development of gravitational wave telescopes and other precision instruments. ******Atoms and molecules are the most precise physical tools available to us. Their quantum states can be exquisitely controlled, which allows them to be used as oscillators with extremely regular frequencies – such atomic frequency references are electromagnetic “tuning forks”. Just as a humble set of tuning forks is vital to the performance of a complex orchestral symphony, electromagnetic frequency references are essential for the performance of many modern technological tasks, including communication, radio ranging and navigation. These stable oscillators provide sets of evenly spaced ticks, which can also be used to measure the distortions of spacetime caused by passing gravitational waves. Our research program aims to construct novel frequency references that are robust and portable, and can be used as the building blocks of precision instruments. The frequency references developed in this research program will provide stable markers at optical and terahertz frequencies, which can be used for improved time-keeping, accurate satellite ranging, and in the next generation of communications technologies. The research program will train undergraduates, graduate students, and postdocs for leadership positions in the high-technology industry, where they will be able to leverage their experience with precision measurements.******To gravitationally observe the most distant objects in the universe, ever more precise atomic frequency references are needed. The path to improved precision is through the use of quantum entanglement, where an entire ensemble of thousands of atoms can behave as one correlated quantum system. Measurements with improved precision can be made using such entangled ensembles, without the noise that arises from uncorrelated fluctuations of individual atoms and molecules. Our long-term goal is to investigate the use of quantum entanglement to build atomic and molecular frequency references with enhanced performance. This will also open up ways to use atoms and molecules for stringent tests of fundamental physical theories such as quantum electrodynamics, probing for cracks in the structure of these theories that would signal the onset of new and unknown physics.