Cryogenic ion trap system for precision measurements and quantum control
Abstract
We propose to acquire an ion trap system operating at cryogenic temperature (< ?263 ?C) to improve the performance of state-of-the-art optical atomic clocks as well as precision measurements and manipulation of charged molecules (molecular ions). The Ion Storage group at NIST develops optical atomic clocks based on precision spectroscopy of a single aluminum ion (Al+). By carefully controlling and characterizing all the known physical factors influencing an oscillation frequency unique to Al+, that frequency, which is employed as the rate of ticking of the clocks, currently can be held constant to within one part per quintillion error. Some of those factors, such as Doppler shifts due to the motion of the Al+ ion and shifts caused by environmental electromagnetic fields, could be greatly suppressed with the proposed system. Our group also develops innovative precision spectroscopy protocols for molecules. We prepare the molecular ions under study in a single quantum mechanical state, providing the best starting point for precision measurements and molecular control. We can thus extract the most possible amount of information about the molecular ions and use this to study their properties. Both of the aforementioned research efforts are hindered by the adverse effects caused by the room temperature environment of the apparatus currently employed. Collisions between the subject ions and background gas molecules shorten the time over which the ions can be studied and thus lead to a limit on the measurement precision. At cryogenic temperature, most gaseous molecules will condense and/or freeze, leading to a vacuum environment virtually free of particles and the associated collision events. This will lead to better control of the ion motion and long un-interrupted interrogation of ion properties. One of the environmental electromagnetic fields in the apparatus will also be nearly eliminated, suppressing a significant shift on the oscillation frequency of the Al+ optical clocks and leading to a prolonged lifetime of the quantum mechanical states of the molecular ions and higher precision in our measurements. The proposed cryogenic ion trap system consists of a vacuum chamber housing an ion trap cooled to cryogenic temperature by a refrigerator circulating liquid helium. The closed-cycle refrigerator will enable long-term experiments free of interruptions. Vibration detrimental to precision measurements is carefully shielded from the ion trap to ensure that the setup is compatible with precision measurements. The temperature of the ion trap is held at about 4 K (?269 ?C) by a thermally conducting, but mechanically isolating, link to the refrigerator. Vibrations of the ground are actively damped by active vibration isolation legs that support the vacuum system. Cryogenic systems have a profound impact on quantum-enabled technologies, which are expected to play a pivotal role in the tech industry in the US. The proposed cryogenic ion trap system will be operated by students and postdoctoral researchers in the early stages of their scientific and engineering careers, under the advisement of career NIST physicists with extensive experience and expertise. Thus, this system will both make a significant contribution to the training of a next-generation workforce in science and technology and advance the state-of-the-art in metrology and quantum-enabled technology.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 18, 2019
- Source ID
- W911NF1910151
Entities
People
- David Leibrandt
Organizations
- Army Contracting Command
- United States Army
- University of Colorado Boulder