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Principal Investigators Science

Eric Cornell and Peter Engels “Few body studies in microgravity"

The  goal of this project is to make use of CALs unique capabilities to explore the quantum mechanics of few- and many-body interacting systems. Quantum mechanics is the science of the very small, and is thus of extreme technological relevance. Future quantum technologies promise a high pay off but require a detailed understanding of quantum mechanical principles.

Ultracold atomic gases, such as the one available with CAL, provide an exquisite system for studying quantum physics in a controlled environment. Of particular interest is the capability to tune the interaction strength between atoms over several orders of magnitude, which allows for the creation and exploration of exotic few-body states as well as intriguing strongly correlated quantum many-body states of matter. An experimental realization of the exotic quantum states that are the subject of our investigation will provide highly valuable insights for the development of atomic few-body theories. However, these states are also very fragile and require ultralow temperatures and ultralow densities to be studied in their purest form. By operating in a microgravity environment, CAL is uniquely positioned to provide the necessary conditions. In addition to studying exotic three-body states such as Efimov trimers, we will also explore effects that go beyond few-body physics by probing dependencies of the few-body states on the temperature and density of the gas.

Cass Sackett “Extreme Adiabatic Cooling”

Professor Cass Sackett hopes to take advantage of the microgravity environment on CAL to cool atoms to temperatures lower than can be achieved on earth. The Cold Atom Laboratory will already produce atoms with extremely low temperatures, on the order of billionths of a degree of above absolute zero. It does this using techniques known as laser cooling and evaporative cooling. These were developed in terrestrial experiments, where similar temperatures are reached. New methods will be needed to cool further yet. Sackett and his collaborators at the University of Virginia and the Air Force Research Laboratory will explore one such method, known as expansion cooling.

This is similar to how an aerosol can cools down when it is sprayed, or how the expansion valve works in an ordinary air conditioner. In the case of atomic gases, the atoms are confined by a magnetic field, and they can be expanded by reducing the strength of the magnetic field. On Earth, this is limited because when the field becomes too weak, the atoms fall in gravity. On CAL no such limit exists, so it should be possible to expand to much lower temperatures. Sackett and his colleagues will investigate this process and discover how low a temperature can be reached. If successful, these experiments will reach temperatures of trillionths of a degree above absolute zero, and set a new record for low-temperature matter.

The extremely cold atom samples produced by this work will be useful for many other experiments on CAL. Sackett's group plans to explore one application as an inertial navigation system. Any residual gravity or acceleration of the ISS will cause the cold atoms to "fall" relative to the station. This apparent motion can be observed and used to measure the acceleration. The motion can be observed directly with a camera, or by using more sensitive techniques such as atom interferometry. These experiments may eventually lead to high-performance navigation systems to assist with deep space travel.

Nathan Lundlad “Microgravity dynamics of bubble-geometry Bose-Einstein condensates”

We are seeking to explore a quantum state of matter inaccessible to terrestrial researchers: a Bose-Einstein condensate in the shape of a bubble or shell. Such bubbles, which would sag and pool into a puddle in terrestrial traps, can give us clues as to how quantum mechanics works in curved geometries (like a bubble) through the study of collective sound-wave-like modes of this "quantum bubble."   Additionally, work aboard CAL with bubble-BECs could point the way to understanding how quantum vortices behave in a topology where, as the vortices move in one direction around a bubble, they eventually find their way back to where they started. Finally, bubbles of quantum gas like this proposed work aboard CAL could lead to a better understanding of just how large we can make BECs while preserving their inherently strange quantum properties.

Jason Williams and Jose’ D’Incao “Controlled interactions for mitigating systematics in space-based atom interferometers”

Precision atom interferometers (AI) in space promise exciting technical capabilities with diverse applications of interest to NASA. These quantum sensors are particularly relevant for fundamental physics research, with proposals including using them for unprecedented tests of the validity of the weak equivalence principle, precision measurements of the fine structure and gravitational constants, and detection of gravity waves and dark matter/dark energy. Our studies will utilize NASA’s Cold Atom Laboratory (CAL), in the microgravity environment of the International Space Station, to study mitigation schemes for the leading-order systematics expected to corrupt future high-precision measurements of fundamental physics with AIs in microgravity. The flight experiments, supported by theoretical investigations and ground studies at our facilities at JPL, will concentrate on the physics of pairwise interactions and molecular dynamics in ultracold quantum gases as a means to overcome uncontrolled AI shifts associated with the gravity gradient and few-particle collisions. We will further help develop and use a space-based dual-species AI, which is planned as an on-orbit upgrade to the CAL science module after approximately a year of science investigations, for proof-of-principle tests of systematic mitigations and phase-readout techniques for use in the next-generation of precision metrology experiments based on AIs in microgravity. Our proposed studies require the effective position invariance, long free fall times, and extremely low temperature samples uniquely available with the CAL apparatus. It is anticipated that our studies can lead to the unprecedented level of control and accuracy necessary for AIs to explore some of the most fundamental physical concepts in nature.