Menu

 

The NASA Task Book
Advanced Search     

Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2022 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 09/27/2024  
Task Last Updated: 06/13/2022 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Key Personnel Changes / Previous PI: March 2018 report: Our Co-Principal Investigator (Co-PI) John Burke has left Air Force Research Laboratory (AFRL) to take a program management job at DARPA (Defense Advanced Research Projects Agency). Our points of contact at AFRL are now Brian Kasch and Gordon Lott.
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Flight Assignment/Project Notes: NOTE: End date changed to 9/27/2024 per U. Israelsson/JPL (Ed., 1/6/22)

NOTE: Extended to 9/30/2022 per U. Israelsson/JPL (Ed., 3/9/21)

NOTE: Extended to 10/28/2020 per PI (Ed., 2/28/2020)

NOTE: Extended to 10/30/2019 per U. Israelsson/JPL (Ed., 12/14/17)

Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station (ISS).

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2022 
Task Progress: Efforts on the Cold Atom Laboratory (CAL) during the performance period were centered on developing and demonstrating atom interferometer capability. In the first part of the year, we completed a set of CAL runs that provided a measurement of the recoil frequency of the rubidium atoms used. The recoil frequency characterizes the energy delivered to an atom when it absorbs a single photon, and high-precision measurements of the recoil frequency are important for determining the fine-structure constant accurately. The demonstrations on CAL were not of high precision, but they showed that the atom interferometry capabilities could be used for a physically interesting measurement. These measurements will be documented in a joint paper with the CAL team on atom interferometry, which is currently under development.

CAL suffered technical issues later in the year, and after these were repaired, the facility was focused on implementing cooling of potassium atoms. This limited time available for other experiments. However, the adiabatic expansion techniques that we previously developed proved highly useful in bringing the CAL system back online with a new trapping configuration, and for working with potassium after cooling was successful.

In our ground-based work, we made substantial progress in our gyroscope progress, where we rebuilt the apparatus to improve reliability and stability. In the new apparatus, we demonstrated a Sagnac interferometer with an enclose area about ten times larger than our previous results, and we were able to maintain the interference signal after the atoms completed two orbits through the Sagnac path. Furthermore, with the improved stability we demonstrated continuous operation for approximately 36 hours, which was a sufficient time to obtain quantitative data on the stability of the Sagnac signal. Although the signal exhibited more noise than expected, it did not exhibit long term drifts. We believe that the anomalous noise is due to instability of our trap magnetic fields and we have developed a remediation plan.

Our other ground experiment uses atom interferometry to characterize tune-out wavelengths in rubidium, optical wavelengths where the dynamic polarizability of the atom is zero. Last year a new student started on this apparatus, and was able to complete an analysis of earlier data. Those results were written up and published in January 2022.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
Abstracts for Journals and Proceedings Sackett CA, Sen B. "An atom interferometric measurement of the photon recoil frequency aboard the International Space Station." 52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Virtual, May 31- June 4, 2021.

Bulletin of the American Physical Society. 2021;66(6):Abstract: C05.00001. https://meetings.aps.org/Meeting/DAMOP21/Session/C05.1 , May-2021

Abstracts for Journals and Proceedings Beydler M, Sackett CA, Moan ER. "A compact atom-chip apparatus for Sagnac interferometry." 52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Virtual, May 31- June 4, 2021.

Bulletin of the American Physical Society. 2021 May;66(6):Abstract: H09.00010. https://meetings.aps.org/Meeting/DAMOP21/Session/H09.10 , May-2021

Articles in Other Journals or Periodicals Williams J, Aveline D, Bigelow N, Chiow S, Elliott E, Engels P, Gaaloul N, Kohel J, Krutzik M, Lundblad N, Meister M, Rasel E, Roura A, Sackett C, Sbroscia M, Schleich W, Thompson R, Worner L, Yu N. "Quantum test of the universality of free fall in Earth’s orbit." White Paper for the Decadal Survey on Life and Physical Sciences Research in Space 2023-3032, National Academies of Sciences, Engineering, and Medicine. Cleveland, Ohio : NASA Glenn Research Center, 2021. , Nov-2021
Articles in Peer-reviewed Journals Luo Z, Moan ER, Sackett CA. "Semiclassical phase analysis for a trapped-atom Sagnac interferometer." Atoms. 2021 Mar 27;9(2):21. https://doi.org/10.3390/atoms9020021 , Mar-2021
NASA Technical Documents Urban DL, Kim J, Paul AL, Sackett CA, Suman SR, Weislogel M, . "High Throughput Ground-based Reduced Gravity Testing." White Paper for the Decadal Survey on Biological and Physical Sciences Research in Space 2023-2032, National Academies of Sciences, Engineering, and Medicine. Cleveland, Ohio : NASA Glenn Research Center, 2021. NASA/Document ID# 20210023623. https://www.nationalacademies.org/our-work/decadal-survey-on-life-and-physical-sciences-research-in-space-2023-2032 , Nov-2021
Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2021 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 09/27/2024  
Task Last Updated: 03/10/2021 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Key Personnel Changes / Previous PI: March 2018 report: Our Co-Principal Investigator (Co-PI) John Burke has left Air Force Research Laboratory (AFRL) to take a program management job at DARPA (Defense Advanced Research Projects Agency). Our points of contact at AFRL are now Brian Kasch and Gordon Lott.
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Flight Assignment/Project Notes: NOTE: End date changed to 9/27/2024 per U. Israelsson/JPL (Ed., 1/6/22)

NOTE: Extended to 9/30/2022 per U. Israelsson/JPL (Ed., 3/9/21)

NOTE: Extended to 10/28/2020 per PI (Ed., 2/28/2020)

NOTE: Extended to 10/30/2019 per U. Israelsson/JPL (Ed., 12/14/17)

Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station (ISS).

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2021 
Task Progress: The CAL SM1 system ended operations in November 2019. As detailed in our previous reports, we were able to demonstrate adiabatic expansion in the SM1 system, with some limitations. During the current period we analyzed this data set and published the results. The key conclusion was that the adiabatic expansion method could be used to prepare a sample of cold atoms for atom interferometry experiments, but that the performance was limited by a background magnetic field that was considerably larger than expected. This prevented us from reaching some of our goals, such as setting a low-temperature record. From our data, we ere able to precisely characterize this background field. For future work, it will be important to prepare atoms in the non-magnetic m=0 spin state so that the effects of the background field can be eliminated.

Some additional work remains to be done with the SM1 dataset. In our time of flight expansions, the Bose condensates can be observed to expand and twist under the influence of the background field. It should be possible to use this data to confirm our field model, but the calculations are challenging. We have initiated a theoretical collaboration with the group of Mark Edwards at Georgia Southern University, with whom we hope to develop tools for this type of analysis. These tools will be useful for many of the experiments to be performed on CAL and eventually Bose-Einstein Condensate/Cold Atom Laboratory (BECAL).

The SM3 system was installed in December 2019 and the first Bose-Einstein condensates were quickly achieved in February 2020. The new system features a more complex atom chip geometry than SM1. This allows for atom interferometry experiments, but also makes sample preparation more complex. We have developed and implemented an adiabatic expansion sequence which positions atoms near the center of the atom interferometry beam. The confinement strength is reduced enough to avoid rapid expansion of the released atoms. The residual ‘sloshing’ motion of the atoms is small. The performance obtained so far, in terms of both confinement and sloshing, is not yet as good as we achieved in SM1. This can be improved with further work but we expect the initial results are sufficient for the atom interferometry experiments being performed.

We have also carried out atom interferometry experiments using atoms prepared with a sequence developed by the Jet Propulsion Laboratory (JPL) team. (This preparation leads to larger release velocities than ours, but so far this is not a limitation.) As a demonstration of the atom interferometer capability, we have demonstrated a simple low-precision measurement of the atomic recoil velocity. We expect to publish the results in 2021.

We also continue work on improving our ground-based trapped-atom Sagnac interferometer. Although the COVID shutdowns had some impact on our progress, we have rebuilt our condensate apparatus to use an atom chip which was developed by our collaborators at Air Force Research Laboratory (AFRL). We have achieved Bose-Einstein condensation in the new apparatus and, significantly, we have demonstrated that the atom trapping potential is at least an order of magnitude more stable than in our previous trap. We will take advantage of this stability to improve our rotation measurements.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
Abstracts for Journals and Proceedings Pollard A, Sackett C. "Cooling Rubidium 87 Atoms Using Adiabatic Expansion in Microgravity." Presented at 51st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Portland, OR, June 1-5, 2020.

Bulletin of the American Physical Society. 2020 Jun;65:4:abstract E01.00115. https://meetings.aps.org/Meeting/DAMOP20/Session/E01.115 , Jun-2020

Articles in Peer-reviewed Journals Luo Z, Moan ER, Sackett CA. "Semiclassical phase analysis for a trapped-atom Sagnac interferometer." Atoms. 2021 Jun;9(2):21. Online March 27, 2021. https://doi.org/10.3390/atoms9020021 , Jun-2021
Articles in Peer-reviewed Journals Moan ER, Horne RA, Arpornthip T, Luo Z, Fallon AJ, Berl SJ, Sackett CA. "Quantum rotation sensing with dual Sagnac interferometers in an atom-optical waveguide," Phys Rev Lett. 2020 Mar 27;124(12):120403. https://doi.org/10.1103/PhysRevLett.124.120403 , Mar-2020
Articles in Peer-reviewed Journals Pollard AR, Moan ER, Sackett CA, Elliott ER, Thompson RJ. "Quasi-adiabatic external state preparation of ultracold atoms in microgravity." Microgravity Science & Technology. 2020 Dec;32:1175-84. https://doi.org/10.1007/s12217-020-09840-w , Oct-2020
Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2020 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 10/28/2020  
Task Last Updated: 03/03/2020 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Key Personnel Changes / Previous PI: March 2018 report: Our Co-Principal Investigator (Co-PI) John Burke has left Air Force Research Laboratory (AFRL) to take a program management job at DARPA (Defense Advanced Research Projects Agency). Our points of contact at AFRL are now Brian Kasch and Gordon Lott.
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Flight Assignment/Project Notes: NOTE: Extended to 10/28/2020 per PI (Ed., 2/28/2020)

NOTE: Extended to 10/30/2019 per U. Israelsson/JPL (Ed., 12/14/17)

Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station (ISS).

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2020 
Task Progress: We are pleased to report progress on the project, for both ground-based and flight-based efforts.

In the flight effort, we took data through 2019 and demonstrated adiabatic cooling. As mentioned in the previous report, we observed unexpected heating and loss of the atoms during the cooling process. The effect seemed intermittent, making it difficult to study systematically. We ultimately found an experimental procedure that usually provided enough atoms to continue cooling, but we were not able to conclusively explain the source of the losses. We were able to successfully expand atoms into a trap with a mean frequency of about 3 Hz, corresponding to a temperature of about 1 nK. While this remains above our ultimate goal of 0.1 nK, it is an important milestone because it corresponds to residual velocities low enough to enable atom interferometry.

We were unable to reach lower temperatures because the apparatus featured a background magnetic field gradient that was somewhat larger than expected. We measured the field gradient to be about 50 mG/cm, compared to a specification of 10 mG/cm. This field distorts the trap and causes the atoms to be lost when the trap is too weak.

We were able to release the atoms from the 3 Hz trap and observe their subsequent behavior. Because of the large background gradient, the atoms were accelerated relatively quickly, but they could be observed for about 0.5 s. To avoid this acceleration, we hope to transfer the atoms the m = 0 Zeeman state where they do not interact with the magnetic field. This has been previously demonstrated in the CAL apparatus.

At the end of 2019, the apparatus stopped functioning well, but at the same time the new SM2 module was launched as replacement unit. SM2 has now been installed and is operating well. It offers the capability to perform atom interferometry, which will be the focus of the next year’s operation.

In our ground efforts, we have successfully implemented an atom interferometer gyroscope with Earth-rate sensitivity. A Bose-Einstein condensate is produced in our specially-designed magnetic trap. Off-resonant lasers are used to coherently split the condensate into wave packets, which are then driven into circular trajectories orbiting the trap with a diameter of about 0.5 mm. When the packets are subsequently recombined they exhibit interference, and the phase of the interference is related to the rotation rate of the experimental platform. We observe interference signals with a visibility of about 60%. We have verified the rotation sensitivity by slightly rotating the optical table holding the apparatus, and the measured interference shift agrees with expectations. This work has been written up and submitted to Physical Review Letters.

We have also carried out a theoretical study of the interferometer performance and limitations. This turns out to depend sensitively on the anharmonicity of the trapping potential. We developed a method to experimentally characterize the anharmonicity and were able to determine the anharmonic terms with an accuracy of 10% to 30%.

A major effort over the past year has been upgrading the apparatus to improve its stability and speed of operation. This will enable more careful studies of its performance and extension to higher sensitivities. The new trap features additional shimming coils to allow adjustment of the anharmonicity. The new apparatus is nearly complete. We have collaborated with our partners at Air Force Research Laboratory (AFRL) to produce a unique atom chip that the trap will use.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
 None in FY 2020
Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2019 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 10/30/2019  
Task Last Updated: 02/01/2019 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Key Personnel Changes / Previous PI: March 2018 report: Our Co-Principal Investigator (Co-PI) John Burke has left Air Force Research Laboratory (AFRL) to take a program management job at DARPA (Defense Advanced Research Projects Agency). Our points of contact at AFRL are now Brian Kasch and Gordon Lott.
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Flight Assignment/Project Notes: NOTE: Extended to 10/30/2019 per U. Israelsson/JPL (Ed., 12/14/17)

Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station (ISS).

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2019 
Task Progress: We are pleased to report significant progress on the project, for both ground-based and flight-based efforts.

In the flight effort, the CAL system launched in spring 2018 and PI operations commenced in November 2018. We have run about 500 successful sequences on the apparatus, pursuant to our effort to implement adiabatic cooling to very low temperatures, on the order of 100 pK or lower. This will be achieved by gradually relaxing the magnetic trap in which the atoms are confined. Initially, the atoms are held about 150 um from the atom chip that produces the trap magnetic fields, with an atom oscillation frequency of about 1200 Hz. Our goal is to move the atoms to about 1 mm from the chip, and reduce the trap frequency to 1 Hz or lower, while minimizing any motional excitation or sloshing of the atoms.

We have successfully implemented a protocol for the first stage of this process, displacing the atom to the desired final location and reducing the trap frequency to 100 Hz, with no measureable motion excitation. We are presently working on reducing the trap frequency to about 2 Hz. We have observed atoms in a trap with this frequency, but accompanied by an unexpected source of heating or atom loss. We are investigating this loss process. If this can be resolved, it should be possible to attain temperatures below 1 nK in this trap. We expect to resolve this issue within the next few weeks. The final stage of expansion will require careful adjustment of the trapping fields to produce a stable but very weak trap. The effort required is not yet easy to predict, but there is a good chance this project will be completed by the end of the current period. Follow-up projects include testing the use of supercooled atoms as an inertial reference mass, and support of the CAL upgrade to permit atom interferometry.

In our ground efforts, we have successfully implemented an atom interferometer gyroscope with Earth-rate sensitivity. A Bose-Einstein condensate is produced in our specially-designed magnetic trap. Off-resonant lasers are used to coherently split the condensate into wave packets, which are then driven into circular trajectories orbiting the trap with a diameter of about 0.5 mm. When the packets are subsequently recombined they exhibit interference, and the phase of the interference is related to the rotation rate of the experimental platform. We observe interference signals with a visibility of about 60%. We have verified the rotation sensitivity by slightly rotating the optical table holding the apparatus, and the measured interference shift agrees with expectations.

We are presently preparing a manuscript on these results for publication, which will certainly be completed by the end of the reporting period. Future efforts include increasing the size of the atom orbit, and allowing the atoms to make multiple orbits before measurement. Both of these techniques will enable further improvements to the rotation sensitivity.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
Abstracts for Journals and Proceedings Moan E, Sackett C, Luo Z. "A trapped-atom Sagnac interferometer using reciprocal circular trajectories." 49th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics (DAMOP) Meeting, Ft. Lauderdale, Florida, May 28–June 1 2018.

Bulletin of the American Physical Society. 2018 May;62(8):Abstract ID: Q06.00010. http://meetings.aps.org/Meeting/DAMOP18/Session/Q06.10 , May-2018

Papers from Meeting Proceedings Moan E, Luo Z, Sackett CA. "A large-area Sagnac interferometer using atoms in a time-orbiting potential." Presented at SPIE Photonics West (OPTO), Conference on Optical, Opto-Atomic and Entanglement-Enhanced Precision Metrology XII: OE120, San Francisco, CA, February 2-7 2019.

Proceedings of SPIE Optical, Opto-Atomic and Entanglement-Enhanced Precision Metrology; 109341X, 2019. https://doi.org/10.1117/12.2515457 , Feb-2019

Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2018 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 10/30/2019  
Task Last Updated: 02/28/2018 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Key Personnel Changes / Previous PI: March 2018 report: Our Co-Principal Investigator (Co-PI) John Burke has left Air Force Research Laboratory (AFRL) to take a program management job at DARPA (Defense Advanced Research Projects Agency). Our points of contact at AFRL are now Brian Kasch and Gordon Lott.
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Flight Assignment/Project Notes: NOTE: Extended to 10/30/2019 per U. Israelsson/JPL (Ed., 12/14/17)

Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station (ISS).

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2018 
Task Progress: I. Preparations for flight missions

We have concluded our initial preparations for our proposed adiabatic cooling experiments. We had previously implemented a model of the original CAL atom chip, but we were required to revise this calculation to reflect the final chip geometry that was implemented. The new geometry is slightly less effective for these experiments, but should still permit cooling to a three-dimensional temperature below 150 pK. We re-optimized our dynamical expansion model, and also corrected a small source of heating we discovered in the way that we had originally transitioned between the various current ramps involved. This work has now been published in Microgravity Science and Technology.

We have also assisted the Jet Propulsion Laboratory (JPL) staff with their own efforts to model cooling methods, in particular delta-kick cooling. It seems at this time that the adiabatic expansion technique will be favorable for reaching ultralow three-dimensional temperatures.

II. Ground Investigations

Our ground efforts are directed at developing a rotation-sensing atom interferometer using atoms confined in a cylindrically symmetric magnetic trap. We have made considerable progress in this regard. We can now drive atoms into a circular trajectory with a diameter of about 0.6 mm. A total of four packets of atoms undergo this trajectory, forming two independent interferometer measurements. Most technical noise sources will be common to both interferometers, but the rotation phase from the Sagnac effect will be differential. For this, it is necessary for two pairs of trajectories to close upon themselves at the same time, since the atomic wave packets must overlap with each other to exhibit interference. So far we have achieved a closed trajectory for one pair, and we expect the tools we have developed will allow us to close the second pair as well. The interferometer configuration we are using should have sufficient rotational sensitivity to detect the rotation of the Earth.

We have also made several technical improvements to the apparatus that have improved the reliability of its operation.

Finally, we have initiated planning for the next stage of this experiment, where we hope to transition a working interferometer to a more compact chip-based apparatus. We have designed an atom chip that will provide magnetic field comparable to our current trap, and the chip is now being microfabricated by our collaborators at AFRL.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
Abstracts for Journals and Proceedings Moan E, Arpornthip T, Sackett C. "Characterizing the potential profile of an atom trap using tomographic fluorescence imaging." Presented at 48th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics (DAMOP), Sacramento, CA, June 5–9, 2017.

Bulletin of the American Physical Society. 2017 May;62(8):Abstract ID:BAPS.2017.DAMOP.K1.12. http://meetings.aps.org/link/BAPS.2017.DAMOP.K1.12 , May-2017

Articles in Peer-reviewed Journals Sackett CA, Lam TC, Stickney JC, Burke JH. "Extreme adiabatic expansion in micro-gravity: Modeling for the Cold Atomic Laboratory." Microgravity Science and Technology. 2018 May;30(3):155-63. First Online: 15 December 2017. https://doi.org/10.1007/s12217-017-9584-3 , May-2018
Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2017 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 10/30/2019  
Task Last Updated: 06/14/2017 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
Burke, John  Ph.D. Air Force Research Laboratory 
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Flight Assignment/Project Notes: NOTE: Extended to 10/30/2019 per U. Israelsson/JPL (Ed., 12/14/17)

Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station.

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2017 
Task Progress: In regards to our proposed flight experiments, we report the following progress:

We have performed extensive modelling and analysis for the adiabatic cooling experiments. Using the original CAL1 chip trap, we developed a set of parameters that produces a very weak trap as an endpoint for expansion. We maintain a relatively large bias magnetic field in the trap to help reduce sensitivity to stray background fields. We expect that stray backgrounds will likely be the limiting factor in the expansion, but we have also modeled techniques to compensate for backgrounds using available current elements in the apparatus. The trap configuration we found will allow adiabatic cooling to a temperature of about 100 pK.

We also investigated the dynamics of adiabatic expansion. We find that an expansion time of 10 s should be sufficient to maintain non-adiabatic heating effects below the 100 pK level. The dominant limitation here will again probably be background field gradients, since these cause the trap to shift in an uncontrolled way. This generally leads to motional excitation.

We have documented these efforts in a paper recently submitted to Microgravity Science and Technology.

We have also performed analysis relevant to our proposed inertial sensing flight experiments. The removal of the Bragg beam from the apparatus has required some changes to this project. We find that an accelerometer measurement should still be possible, with a measurement sensitivity of about 0.1 micro-g. We are exploring methods to recover a rotation measurement, at the 1 micro-rad/s level of accuracy.

For our ground experiments, we continue development of an atom-interferometer gyroscope. It is essential to have a well-characterized trapping potential for the atoms to move in. We have developed a powerful and rapid method to measure the potential energy function, and we are exploring a new method to impose small adjustments to the potential in order to correct for any observed imperfections.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
Abstracts for Journals and Proceedings Fallon A, Leonard R, Sackett C. "High-precision measurements of the 87Rb D-line tune-out wavelength." 47th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Providence, Rhode Island, May 23-27, 2016.

Bulletin of the American Physical Society. 2016 May;61(8):BAPS.2016.DAMOP.N5.9. http://meetings.aps.org/link/BAPS.2016.DAMOP.N5.9 , May-2016

Abstracts for Journals and Proceedings Fallon AJ, Berl S, Sackett CA. "High-precision measurements of the 87-Rb vector polarizability." 83rd Annual Meeting of the APS Southeastern Section, Charlottesville, VA, November 10-12, 2016.

Bulletin of the American Physical Society. 2016 Nov;61(19):BAPS.2016.SES.G4.7. http://meetings.aps.org/link/BAPS.2016.SES.G4.7 , Nov-2016

Abstracts for Journals and Proceedings Moan E, Arpornthip T, Sackett CA. "Tomographic characterization of an atom trapping potential." 83rd Annual Meeting of the APS Southeastern Section, Charlottesville, VA, November 10-12, 2016.

Bulletin of the American Physical Society. 2016 Nov;61(19):BAPS.2016.SES.G4.8. http://meetings.aps.org/link/BAPS.2016.SES.G4.8 , Nov-2016

Articles in Peer-reviewed Journals Horne RA, Sackett CA. "A cylindrically symmetric magnetic trap for compact Bose-Einstein condensate atom interferometer gyroscopes." Rev Sci Instrum. 2017 Jan;88(1):013102. https://doi.org/10.1063/1.4973123 ; PubMed PMID: 28147663 , Jan-2017
Articles in Peer-reviewed Journals Oh E, Horne RA, Sackett CA. "Fast phase stabilization of a low frequency beat note for atom interferometry." Rev Sci Instrum. 2016 Jun;87(6):063105. https://doi.org/10.1063/1.4953338 ; PubMed PMID: 27370424 , Jun-2016
Articles in Peer-reviewed Journals Fallon AJ, Sackett CA. "Obtaining atomic matrix elements from vector tune-out wavelengths using atom interferometry." Atoms. 2016;4(2):12. Published online: 30 March 2016. https://doi.org/10.3390/atoms4020012 , Mar-2016
Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2016 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 10/30/2017  
Task Last Updated: 02/16/2016 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
Burke, John  Ph.D. Air Force Research Laboratory 
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

Ground and flight based efforts are proceeding in three broad areas. First, we are performing ground studies and developing a flight mission for the Cold Atom Laboratory (CAL) to study atomic techniques for inertial sensing in microgravity. Ground efforts include development of new rotation-sensing techniques and implementation of an optically suspended atom source for gravimetry. Flight efforts involve implementation and characterization of atom interferometry techniques using the CAL apparatus on the International Space Station.

Second, we are investigating methods to produce an ultra-low temperature atom source in free space using the CAL apparatus. The apparatus produces atoms confined in a magnetic trap, but inertial measurements require free atoms. We will investigate releasing the atoms by gradually turning off the trapping fields, allowing the atoms to adiabatically expand and cool off. This can produce a relatively dense and very low-velocity sample that is ideal for atom interferometry methods.

Third, we will continue ground-based studies to develop novel precision measurement techniques for use with atom interferometry, such as tune-out spectroscopy. Techniques like this are useful for advancing scientific knowledge and would be good candidates for future flight studies.

Research Impact/Earth Benefits: The development of precision inertial sensing techniques is useful for Earth-based as well as space-based navigation. Besides using direct sensing for inertial navigation, rotation sensing can also be useful for north-finding while gravity sensing can be used to tabulate local gravity variations and form a type of three-dimensional map for navigating.

These techniques also have many applications in geophysics. Gravity sensing can be used for oil and mineral exploration, while rotation sensing can detect dynamics in the Earth's core. Gravity sensing also has defense applications such as locating underground tunnels and potential screening cargo for high-density contraband or weapons.

Other precision measurement applications have less direct impact, but advance scientific knowledge. For instance, precision tune-out spectroscopy measurements of atomic matrix elements can be used to improve the interpretation of atomic parity violation experiments. These in turn impact our understanding of the standard model of particle physics and thus the nature of our universe. Direct benefits of such understanding can be hard to trace, but in general the continued advance of technological applications builds on advances in our fundamental knowledge.

Task Progress & Bibliography Information FY2016 
Task Progress: Progress in this reporting period can be separated into three tasks: planning for flight operations on the Cold Atom Laboratory (CAL), development of new atom-based inertial sensing methods, and development of new precision measurement techniques based on atom interferometry.

For flight planning, we have developed and analyzed three related experiments. The first is adiabatic cooling and release, in which Bose-condensed atoms are released from a magnetic trap into free space by slowly reducing the magnetic field amplitude. When the trap field is suitably low, the atoms are transferred to a magnetically insensitive state to avoid degradation of subsequent measurements from environmental fields. When performed correctly, this method can produce extremely cold atoms, with temperatures on the order of 100 picoKelvin (pK). This corresponds to extremely low atomic velocities, which prevents the atom sample from expanding or drifting out of the interaction region in subsequent experiments. Adiabatic expansion also provides the minimum possible size expansion for a given amount of cooling, so the final sample is relatively compact.

Successful implementation of adiabatic expansion requires careful control of the magnetic fields. We have imported the CAL field design into a numerical simulation tool and developed a set of control trajectories for the fields. The expansion method is limited by uncontrolled environmental fields and gradients. We developed an expansion to an estimated temperature of 200 pK which is robust against the expected level of stray fields. We plan to continue investigating the field geometry to determine if further cooling is possible.

We have also developed experiments to implement atom interferometry using a Bose-Einstein condensate that has been released from the trap. A set of experiments will be used to optimize parameters and test the performance of atom interferometry. A culminating experiment will be a measurement of the atomic recoil frequency using a contrast interferometer.

We also developed a method to implement simultaneous interferometers using both rubidium and potassium atoms. This requires careful control of the laser beams used to manipulate the atoms to ensure that both species respond correctly. Using this technique we can measure the ratio of the atomic recoil frequencies, which could ultimately provide improved knowledge of the mass ratio of the species.

Finally we have proposed and developed an alternative inertial measurement technique in which the atomic sample is used as a "proof mass" reference for rotation sensing. A set of three atom clouds can be prepared in a line that is aligned to the controlling laser beam. After a delay time the atom clouds can be imaged, and any rotation of the system will appear as a deviation in the apparent orientation of the line. This method is readily sensitive enough to detect the orbital motion of the International Space Station.

These experiments have been presented for our Science Concept Review, and were approved by the advisory board for CAL.

On the ground, we are also developing the "proof mass" rotation sensing technique. This is more challenging since it is not possible to observe the atoms for a long time without supporting them against gravity. However, we have implemented a magnetic trap with excellent cylindrical symmetry such that atoms can be set to oscillating along one axis, and over time the Coriolis force causes the axis to precess. We have observed sensitivity at the level of 1 mrad/s, and expect to be able to reach Earth rate sensitivity with further optimization.

Also on the ground, we have developed a high-precision method for tune-out spectroscopy. This is the determination of a light frequency for which an atom has zero response. Using light at this frequency can be useful for some applications like dual species atom trapping. It also allows a precise characterization of the quantum state of the electrons in an atom. Our technique is based on atom interferometry and is about one hundred times more precise than previous methods. The resulting improvements in our understanding of electrons in atoms will be useful for many applications. A notable example is interpreting parity violation experiments in atoms, where the quantum state is needed in order to relate the measured parity violation in the atom to the fundamental properties of the electron-nucleon interaction. Understanding these properties better will improve our understanding of fundamental particle physics.

These types of experiments would benefit greatly from a microgravity environment, since that would allow long interaction times without needing to support the atoms against gravity. The magnetic fields we use to support the atoms introduce a number of perturbations that must be controlled for and limit our precision.

Articles have been submitted to the following peer-reviewed journals:

Fallon AG, Sackett CA. "Obtaining atomic matrix elements from vector tune-out wavelengths using atom interferometry." Atoms, in press, expected publication July 2016.

Oh E, Horne RA, Sackett CA. "Fast phase stabilization of a low frequency beat note for atom interferometry." Rev Sci Instrum, in press, expected publication July 2016.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
Abstracts for Journals and Proceedings Horne R, Sackett C. "Magnetic Waveguide for Atom Interferometry and Inertial Navigation Applications." Presented at the 45th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Madison, Wisconsin, June 2–6, 2014.

Bulletin of the American Physical Society. 2014;59(8):Abstract ID: BAPS.2014.DAMOP.D1.70. http://meetings.aps.org/link/BAPS.2014.DAMOP.D1.70 , Jun-2014

Abstracts for Journals and Proceedings Sackett C. "Atom Interferometry using Bose-Einstein condensates on Earth and in Space." 81st Annual Meeting of the APS Southeastern Section, Columbia, SC, November 12-15, 2014.

Bulletin of the American Physical Society. 2014;59(18):Abstract ID: BAPS.2014.SES.DB.1. https://meetings.aps.org/link/BAPS.2014.SES.DB.1 , Nov-2014

Abstracts for Journals and Proceedings Sackett CA, Arpornthip T, Fallon A, Burke JHT. "Atom Interferometry Aboard the ISS." Presented at the 30th Annual Meeting of the American Society for Gravitational and Space Research, Pasadena, California, October 22-26, 2014.

30th Annual Meeting of the American Society for Gravitational and Space Research, Pasadena, California, October 22-26, 2014. https://www.asgsr.org/index.php/presentation-abstracts-10-25-2014 ; accessed 2/16/2016. , Oct-2014

Articles in Peer-reviewed Journals Leonard RH, Fallon AJ, Sackett CA, Safronova MS. "High-precision measurements of the 87Rb D-line tuneout wavelength." Phys Rev A. 2015 Nov; 92(5):052501. http://dx.doi.org/10.1103/PhysRevA.92.052501 , Nov-2015
Papers from Meeting Proceedings Sackett C, Leonard RH, Fallon A. "Atom interferometry using Bose-Einstein condensates on Earth and in space." Presented at SPIE Photonics West (OPTO): Slow Light, Fast Light, and Opto-Atomic Precision Metrology VIII, San Francisco, California, February 7-12, 2015.

Proceedings of SPIE. Vol. 9378, Slow Light, Fast Light, and Opto-Atomic Precision Metrology VIII:93781Y, 2015. http://dx.doi.org/10.1117/12.2086847 , Mar-2015

Papers from Meeting Proceedings Burke JH. "Magnetically guided cold atom gyroscopes and their photonic requirements." Presented at SPIE Photonics West (OPTO): Slow Light, Fast Light, and Opto-Atomic Precision Metrology VIII, San Francisco, California, February 7-12, 2015.

Proceedings of SPIE. Volume 9378, Slow Light, Fast Light, and Opto-Atomic Precision Metrology VIII:93781Z, 2015. http://dx.doi.org/10.1117/12.2087490 , Mar-2015

Project Title:  Development of Atom Interferometry Experiments for the International Space Station's Cold Atom Laboratory Reduce
Fiscal Year: FY 2014 
Division: Physical Sciences 
Research Discipline/Element:
Physical Sciences: FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 10/30/2017  
Task Last Updated: 07/25/2014 
Download report in PDF pdf
Principal Investigator/Affiliation:   Sackett, Cass  Ph.D. / University of Virginia 
Address:  Physics 
382 McCormick Rd 
Charlottesville , VA 22904-1000 
Email: sackett@virginia.edu 
Phone: 434-924-6795  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Virginia 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
Burke, John  Ph.D. Air Force Research Laboratory 
Project Information: Grant/Contract No. JPL 1502012 
Responsible Center: NASA JPL 
Grant Monitor: Callas, John  
Center Contact:  
john.l.callas@jpl.nasa.gov 
Unique ID: 9883 
Solicitation / Funding Source: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: JPL 1502012 
Project Type: FLIGHT,GROUND 
Flight Program: ISS 
No. of Post Docs:  
No. of PhD Candidates:  
No. of Master's Candidates:  
No. of Bachelor's Candidates:  
No. of PhD Degrees:  
No. of Master's Degrees:  
No. of Bachelor's Degrees:  
Program--Element: FUNDAMENTAL PHYSICS--Fundamental physics 
Task Description: The ultimate objective of this proposal is to develop an ultra-high sensitivity atom interferometer capable of operating in and benefiting from a microgravity environment. The interferometer would be specifically suited for measurements of rotations, but it would be broadly applicable to a variety of precision measurements.

The interferometer will use a low-density Bose-Einstein condensate, as this form of matter has the lowest possible velocity spread and thus allows for the longest possible measurement times. Many of the required components have already been demonstrated in our terrestrial experiments, including long-duration interferometry, high fidelity control of atomic motion using optical pulses, expansion of condensates to extremely low density, and rotation-sensitive interferometer geometries. We will combine these components and investigate their optimization for microgravity performance.

We have also demonstrated an optical levitation technique that permits the table-top simulation of microgravity, up to times of about one second. We will use this approach to test the interferometer performance in a terrestrial experiment without the expense and complexity of a drop tower apparatus. The work will be carried in collaboration between the University of Virginia and the AFRL Space Vehicles Directorate at Kirtland Air Force Base.

This work is highly relevant to the objectives of the solicitation, which specifically calls for the development of atom interferometer experiments. The precise measurement of rotations is of immediate utility for space-based navigation systems and testing of general relativistic predictions. However, the techniques developed would be readily applicable to other interferometric measurements, such as acceleration.

The program solicitation indicates that atom interferometry experiments would be projected for future upgrades to the CAL facility. Besides ground based preparatory work, we propose a preliminary flight experiment to investigate the adiabatic release of a trapped condensate. This will test the critical ability to attain samples with very low relative and mean velocities. It also would likely produce the lowest-temperature matter yet attained. This experiment would be important for future interferometry development, and also other potential experiments that require ultra-low atomic velocity.

Research Impact/Earth Benefits: 0

Task Progress & Bibliography Information FY2014 
Task Progress: New project for FY2014.

Bibliography: Description: (Last Updated: 07/06/2022) 

Show Cumulative Bibliography
 
 None in FY 2014