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Project Title:  Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment Reduce
Images: icon  Fiscal Year: FY 2019 
Division: Physical Sciences 
Research Discipline/Element:
FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 05/03/2021  
Task Last Updated: 05/02/2019 
Download report in PDF pdf
Principal Investigator/Affiliation:   Williams, Jason  Ph.D. / NASA Jet Propulsion Laboratory 
Address:  Quantum Sciences & Technology Group 
4800 Oak Grove Dr 298-103B 
Pasadena , CA 91109-8001 
Email: Jason.R.Williams.Dr@jpl.nasa.gov 
Phone: 303-725-1580  
Congressional District: 27 
Web:  
Organization Type: NASA CENTER 
Organization Name: NASA Jet Propulsion Laboratory 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
D'Incao, Jose  Ph.D. University of Colorado 
Elliott, Ethan  Ph.D. Jet Propulsion Lab 
Project Information: Grant/Contract No. Internal Project 
Responsible Center: NASA JPL 
Grant Monitor: Israelsson, Ulf  
Center Contact:  
ulf.e.israelsson@jpl.nasa.gov 
Solicitation: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: Internal Project 
Project Type: FLIGHT 
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: ISS

NOTE: End date changed to 5/3/2021 per PI information (Ed., 5/6/19)

Task Description: 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 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 the capabilities of NASA's multi-user Cold Atom Laboratory (CAL), in the microgravity environment onboard the International Space Station (ISS), to study mitigation schemes for the leading-order systematics expected to limit 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 Jet Propulsion Laboratory (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 utilize the dual-species AI 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.

Research Impact/Earth Benefits: Our studies are designed to achieve technological advances in precision metrology that can only be realized in the microgravity environment of the Cold Atom Laboratory. We utilize the tools of ultracold atomic and molecular physics (namely Feshbach resonances) for exquisite control of the differential center-of-mass distributions of the dual-species quantum gases and on methods to use the fundamentals of few-body interactions to maintain coherence in atomic ensembles for enhanced precision sensor capabilities. Subsequent proof-of-principle studies with the dual-species atom interferometer on CAL will further advance the state of the art for precision interferometry with ultracold matter waves. The impact of such research to the field of metrology can be seen through its potential to increase precision for atom-interferometry and also the possibility of engineering highly efficient system-specific devices based on the fundamental nature of few-body interactions. The microgravity environment of the CAL facility will strongly favor such explorations and allow for the possibility of uncovering novel effects and quantum phases of matter, a major goal in ultracold quantum gases and other disciplines of fundamental physics. These studies can benefit life on Earth by providing both fundamental understanding of nature in previously inaccessible environments and energy regimes, and by enhancing the tools available for scientific exploration at the highest precision.

Task Progress & Bibliography Information FY2019 
Task Progress: The flight experiments, supported by theoretical investigations and measurements using the ground test bed facilities at JPL, will concentrate on the physics of pairwise interactions and low-energy s-wave Feshbach molecules in ultracold quantum gases as a means to overcome uncontrolled AI shifts associated with the differential center of mass of two atomic species influenced by gravity gradients and rotations. We will further utilize the dual-species AI, already in build at JPL and expected to be integrated into CAL by early 2020, for proof-of-principle demonstrations of unprecedented atom-photon coherence times, phase-readout techniques, and characterizations of the rotational noise on the ISS for use in the next-generation of precision metrology experiments based on AIs in microgravity. Our proposed experiments require the effective position invariance, long free fall times, and extremely low temperature samples uniquely available with the CAL apparatus. It is anticipated that these studies can lead to the unprecedented level of control and accuracy necessary for future space missions, based on precision AIs, to test some of the most fundamental questions of modern physics.

In this fifth year of performance, we have focused on the studies of molecular association using magnetic field ramps; this analysis has been finalized. This represents an alternative method to the one we have previously proposed (within this program) using RF fields and a manuscript covering such methodology is in preparation. We ultimately want to determine which of the methods for association and dissociation is more efficient in the microgravity environment. Our main finding is that a simple ramp scheme might not be sufficient to create a substantial number of molecules in the CAL's microgravity environment. We, however, further propose a scheme to fix this deficiency and verify that a much better molecular association efficiency can be expected.

Although the theoretical studies are nearly complete, experimental efforts have been hampered during this year due to required efforts by key group members to assist the CAL project in the Engineering Testbed (EMTB), Ground Test Bed (GTB), and Flight System throughout the first year of CAL's operation onboard the ISS. Significant milestones of the team that will help enable our flight project include: Leading the efforts that demonstrated CAL's minimum mission success criteria during the three-month commissioning phase after flight, demonstrated laser-cooling of 39-K using flight-hardware in the flight system and loading of potassium onto the atom-chip using flight-like hardware in the EMTB, and development of a new AI capable science module that will enable dual-species atom interferometry in the flight system in 2020.

During the sixth year, our ongoing work on this project will concentrate on working with the CAL Ground Test Bed (GTB), Engineering Testbed (EMTB), and CAL Flight Systems towards a) validating the flight hardware and b) proving all of the functionality of CAL for proof of principle and characterization studies to support our flight science projects. Due to the technical innovations required in our project and the sensitivity to numerous experimental/environmental parameters, access to the GTB has and will be enabling to mature our studies and to optimize our utilization of CAL.

Bibliography Type: Description: (Last Updated: 05/02/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings D'Incao J, Williams J. "Formation of heteronuclear Feshabch molecules in microgravity." Quantum Gases forum. Presented at 49th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics (DAMOP) APS Meeting, Ft Lauderdale, FL, May 28-June 1, 2018.

Bulletin of the American Physical Society. 2018 Jun;63(5): Abstract T01.00102. http://meetings.aps.org/Meeting/DAMOP18/Session/T01.102 , Jun-2018

Abstracts for Journals and Proceedings Williams J, D'Incao J. "Opportunities for Maturing Precision Metrology with Ultracold Gas Studies Aboard the ISS." Precision Measurements and Atom Interferometers forum. Presented at 49th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics (DAMOP) APS Meeting, Ft Lauderdale, FL, May 28-June 1, 2018.

Bulletin of the American Physical Society. 2018 Jun;63(5): Abstract Q06.00002. http://meetings.aps.org/Meeting/DAMOP18/Session/Q06.2 , Jun-2018

Abstracts for Journals and Proceedings Williams J, D'Incao J. "Maturing Space-Based Precision Metrology with Quantum Gas Studies Aboard the ISS." Atom Interferometers. Presented at NASA Fundamental Physics Workshop, La Jolla, CA, April 9-11, 2018.

NASA Fundamental Physics Workshop, La Jolla, CA, April 9-11, 2018. , Apr-2018

Abstracts for Journals and Proceedings Williams J. "Maturing Space-Based Precision Metrology with Quantum Gas Studies Aboard the ISS." H0.6. Presented at Committee on Space Research (COSPAR) 2018 42nd Scientific Assembly, Pasadena, CA, July 14-22, 2018.

Committee on Space Research (COSPAR) 2018 42nd Scientific Assembly, Pasadena, CA, July 14-22, 2018. , Jul-2018

Project Title:  Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment Reduce
Images: icon  Fiscal Year: FY 2018 
Division: Physical Sciences 
Research Discipline/Element:
FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 05/03/2019  
Task Last Updated: 07/08/2018 
Download report in PDF pdf
Principal Investigator/Affiliation:   Williams, Jason  Ph.D. / NASA Jet Propulsion Laboratory 
Address:  Quantum Sciences & Technology Group 
4800 Oak Grove Dr 298-103B 
Pasadena , CA 91109-8001 
Email: Jason.R.Williams.Dr@jpl.nasa.gov 
Phone: 303-725-1580  
Congressional District: 27 
Web:  
Organization Type: NASA CENTER 
Organization Name: NASA Jet Propulsion Laboratory 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
D'Incao, Jose  Ph.D. University of Colorado 
Elliott, Ethan  Ph.D. Jet Propulsion Lab 
Key Personnel Changes / Previous PI: February 2017 report: Dr. Ethan Elliott, Jet Propulsion Laboratory, is a world expert in the development of leading edge quantum gas facilities for ground and space-based fundamental physics experiments. Notably, he continues to play a leading role in the development, integrating, and testing of numerous subsystems of NASA’s multiuser Cold Atom Lab facility. Dr. Elliott joins the project as a Co-Investigator to provide expertise to essentially all aspects of the project. His specific efforts will include leading the planned ground testbed studies, cooperating in the experimental sequence development, and analysis and dissemination of the results to the scientific community.
Project Information: Grant/Contract No. Internal Project 
Responsible Center: NASA JPL 
Grant Monitor: Israelsson, Ulf  
Center Contact:  
ulf.e.israelsson@jpl.nasa.gov 
Solicitation: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: Internal Project 
Project Type: FLIGHT 
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: ISS

Task Description: 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 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 the capabilities of NASA's multi-user Cold Atom Laboratory (CAL), in the microgravity environment onboard the International Space Station (ISS), to study mitigation schemes for the leading-order systematics expected to limit 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 Jet Propulsion Laboratory (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 utilize the dual-species AI 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.

Research Impact/Earth Benefits: Our studies are designed to achieve technological advances in precision metrology that can only be realized in the microgravity environment of the Cold Atom Laboratory. We utilize the tools of ultracold atomic and molecular physics (namely Feshbach resonances) for exquisite control of the differential center-of-mass distributions of the dual-species quantum gases and on methods to use the fundamentals of few-body interactions to maintain coherence in atomic ensembles for enhanced precision sensor capabilities. Subsequent proof-of-principle studies with the dual-species atom interferometer on CAL will further advance the state of the art for precision interferometry with ultracold matter waves. The impact of such research to the field of metrology can be seen through its potential to increase precision for atom-interferometry and also the possibility of engineering highly efficient system-specific devices based on the fundamental nature of few-body interactions. The microgravity environment of the CAL facility will strongly favor such explorations and allow for the possibility of uncovering novel effects and quantum phases of matter, a major goal in ultracold quantum gases and other disciplines of fundamental physics. These studies can benefit life on Earth by providing both fundamental understanding of nature in previously inaccessible environments and energy regimes, and by enhancing the tools available for scientific exploration at the highest precision.

Task Progress & Bibliography Information FY2018 
Task Progress: 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 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 onboard the International Space Station, to study the leading-order systematics expected to limit future high-precision measurements of Einstein's weak equivalence principle with dual atomic-species AIs in microgravity.

The flight experiments, supported by theoretical investigations and measurements using the ground test bed facilities at JPL, will concentrate on the physics of pairwise interactions and low-energy s-wave Feshbach molecules in ultracold quantum gases as a means to overcome uncontrolled AI shifts associated with the differential center of mass of two atomic species influenced by gravity gradients and rotations. We will further utilize the dual-species AI, expected to be integrated into CAL, for proof-of-principle demonstrations of unprecedented atom-photon coherence times, phase-readout techniques, and characterizations of the rotational noise on the ISS for use in the next-generation of precision metrology experiments based on AIs in microgravity. Our proposed experiments require the effective position invariance, long free fall times, and extremely low temperature samples uniquely available with the CAL apparatus. It is anticipated that these studies can lead to the unprecedented level of control and accuracy necessary for future space missions, based on precision AIs, to test some of the most fundamental questions of modern physics.

In the fourth year of the project, we have finished our theoretical studies relevant for molecular delta-kick cooling, a possible cooling technique that can allow us to obtain much colder molecular samples for our interferometry studies as well as enable optimized collimation for two, initially co-trapped, atomic species. The differential ballistic expansion for two species is a limitation for achieving ultra-low temperatures for these dual-species gas studies in microgravity. In applying delta-kick cooling for molecules we found that the molecular internal degree of freedom can generate torques during the cooling process depending on the strength and duration of the delta-kick pulse. Such effects, although interesting from the fundamental point of view, are detrimental to our precision interferometry studies. Our analysis, therefore, focuses in determining the parameter regime in which such effects can be mitigated. We have developed a novel theoretical approach that accounts for the effects of the center-of-mass and relative motion of the molecules and additional studies are currently been performed in order to determine the final cooling efficiency. We are currently on the stage of developing other numerical tools to extract all the information necessary for qualitatively describing the delta-kick cooling technique for heteronuclear molecules in the microgravity environment.

We have also pursued during this year preliminary theoretical studies relevant for molecular association using magnetic field ramps. This represents an alternative method to the one we have previously proposed (within this program) using RF fields. We ultimately want to determine which of the methods for association and dissociation is more efficient in the microgravity environment. In order to qualitatively explore this problem, we developed a theoretical model in which a few atoms are subjected to an artificial trapping potential whose trap frequency is adjusted to reproduce the average interatomic distance in the ultracold gas. This model has been successfully used to analyze previous experiments in molecular formation and we will extend such an approach to include various quantitative aspects related to the few-body physics in the problem. In particular, processes that can lead to molecular losses during the magnetic field ramp and the possible formation of Efimov states. At this point, our studies were focused on a system with only two atoms. As a running test, this has all the ingredients relevant for our future experiments with dual species atomic gases (87Rb and 41K), a study to be performed in the next step of our program.

Although the theoretical studies are nearly complete, experimental efforts have been hampered during this year due to required efforts by key group members to build and test the CAL flight system. These efforts lead to the successful launch of CAL to the ISS on May 21, 2018. Therefore, during the fourth year, our ongoing work on this project has concentrated on working with the CAL Ground Test Bed (GTB) and CAL flight systems towards a) validating the flight hardware and b) providing all of the functionality of CAL for proof of principle and characterization studies to support the flight science projects. Due to the technical innovations required in our project and the sensitivity to numerous experimental/environmental parameters, access to the GTB has and will be enabling to mature our studies and to optimize our utilization of CAL.

Bibliography Type: Description: (Last Updated: 05/02/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings D'Incao J, Williams J. "Theoretical studies of association and dissociation of Feshbach molecules in a microgravity environment." Presented at the 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;62(8):abstract Q1.00085. http://meetings.aps.org/link/BAPS.2017.DAMOP.Q1.85 , Jun-2017

Abstracts for Journals and Proceedings Williams J, D'Incao J. "Opportunities for Maturing Precision Metrology with Ultracold Gas Studies Aboard the ISS." Presented at the 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;62(8):abstract P9.00007. http://meetings.aps.org/link/BAPS.2017.DAMOP.P9.7 , Jun-2017

Abstracts for Journals and Proceedings Williams J, D'Incao J. "Maturing Space-Based Precision Metrology with Quantum Gas Studies Aboard the ISS." Presented at the 2017 NASA Fundamental Physics Workshop, Santa Barbara, CA, May 31-June 2, 2017.

2017 NASA Fundamental Physics Workshop, Santa Barbara, CA, May 31-June 2, 2017. , May-2017

Abstracts for Journals and Proceedings D'Incao J, Williams J. "Theoretical studies of association and dissociation of Feshbach molecules in a microgravity environment." Presented at the 2017 NASA Fundamental Physics Workshop, Santa Barbara, CA, May 31-June 2, 2017.

2017 NASA Fundamental Physics Workshop, Santa Barbara, CA, May 31-June 2, 2017. , May-2017

Abstracts for Journals and Proceedings Williams J. "The Cold Atom Laboratory (CAL): A facility for ultracold atom experiments aboard the ISS." Presented at the 2017 Sacramento State Physics Colloquium Series, Sacramento, CA, November 9, 2017.

2017 Sacramento State Physics Colloquium Series, Sacramento, CA, November 9, 2017. https://www.csus.edu/physics/events/colloquiaarchive.html#spring17 , Nov-2017

Project Title:  Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment Reduce
Images: icon  Fiscal Year: FY 2017 
Division: Physical Sciences 
Research Discipline/Element:
FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 05/03/2019  
Task Last Updated: 02/10/2017 
Download report in PDF pdf
Principal Investigator/Affiliation:   Williams, Jason  Ph.D. / NASA Jet Propulsion Laboratory 
Address:  Quantum Sciences & Technology Group 
4800 Oak Grove Dr 298-103B 
Pasadena , CA 91109-8001 
Email: Jason.R.Williams.Dr@jpl.nasa.gov 
Phone: 303-725-1580  
Congressional District: 27 
Web:  
Organization Type: NASA CENTER 
Organization Name: NASA Jet Propulsion Laboratory 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
D'Incao, Jose  Ph.D. University of Colorado 
Elliott, Ethan  Ph.D. Jet Propulsion Lab 
Key Personnel Changes / Previous PI: February 2017 report: Dr. Ethan Elliott, Jet Propulsion Laboratory, is a world expert in the development of leading edge quantum gas facilities for ground and space-based fundamental physics experiments. Notably, he continues to play a leading role in the development, integrating, and testing of numerous subsystems of NASA’s multiuser Cold Atom Lab facility. Dr. Elliott joins the project as a Co-Investigator to provide expertise to essentially all aspects of the project. His specific efforts will include leading the planned ground testbed studies, cooperating in the experimental sequence development, and analysis and dissemination of the results to the scientific community.
Project Information: Grant/Contract No. Internal Project 
Responsible Center: NASA JPL 
Grant Monitor: Israelsson, Ulf  
Center Contact:  
ulf.e.israelsson@jpl.nasa.gov 
Solicitation: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: Internal Project 
Project Type: FLIGHT 
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: 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 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 the capabilities of NASA's multi-user Cold Atom Laboratory (CAL), in the microgravity environment onboard the International Space Station (ISS), to study mitigation schemes for the leading-order systematics expected to limit 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 Jet Propulsion Laboratory (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 utilize the dual-species AI 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.

Research Impact/Earth Benefits: Our studies are designed to achieve technological advances in precision metrology that can only be realized in the microgravity environment of the Cold Atom Laboratory. We utilize the tools of ultracold atomic and molecular physics (namely Feshbach resonances) for exquisite control of the differential center-of-mass distributions of the dual-species quantum gases and on methods to use the fundamentals of few-body interactions to maintain coherence in atomic ensembles for enhanced precision sensor capabilities. Subsequent proof-of-principle studies with the dual-species atom interferometer on CAL will further advance the state of the art for precision interferometry with ultracold matter waves. The impact of such research to the field of metrology can be seen through its potential to increase precision for atom-interferometry and also the possibility of engineering highly efficient system-specific devices based on the fundamental nature of few-body interactions. The microgravity environment of the CAL facility will strongly favor such explorations and allow for the possibility of uncovering novel effects and quantum phases of matter, a major goal in ultracold quantum gases and other disciplines of fundamental physics. These studies can benefit life on Earth by providing both fundamental understanding of nature in previously inaccessible environments and energy regimes, and by enhancing the tools available for scientific exploration at the highest precision.

Task Progress & Bibliography Information FY2017 
Task Progress: 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 unprecedented tests of the validity of the weak equivalence principle, precision measurem9ents 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 onboard the International Space Station, to study the leading-order systematics expected to limit future high-precision measurements of Einstein's weak equivalence principle with dual atomic-species AIs in microgravity.

The flight experiments, supported by theoretical investigations and measurements using the ground test bed facilities at JPL, will concentrate on the physics of pairwise interactions and low-energy s-wave Feshbach molecules in ultracold quantum gases as a means to overcome uncontrolled AI shifts associated with the differential center of mass of two atomic species influenced by gravity gradients and rotations. We will further utilize the dual-species AI, expected to be integrated into CAL, for proof-of-principle demonstrations of unprecedented atom-photon coherence times, phase-readout techniques, and characterizations of the rotational noise on the ISS for use in the next-generation of precision metrology experiments based on AIs in microgravity. Our proposed experiments require the effective position invariance, long free fall times, and extremely low temperature samples uniquely available with the CAL apparatus. It is anticipated that these studies can lead to the unprecedented level of control and accuracy necessary for future space missions, based on precision AIs, to test some of the most fundamental questions of modern physics.

In the third year of this project, we have finished the analysis of the conditions for efficient molecular association and dissociation, crucial for our goal of producing a dual specie ultracold quantum gas that mitigates systematic errors in differential AI related to the center-of-mass displacement of the two clouds. These studies were accepted for publication in Physical Review A. Our findings indicate that the microgravity environment of CAL provides an ideal scenario for such studies.

We also initiated a theoretical study relevant for molecular delta-kick cooling, a possible cooling technique that can allow us to obtain much colder molecular samples for our interferometry studies as well as enable optimized collimation for two, initially co-trapped, atomic species. The differential ballistic expansion for two species is a limitation for achieving ultra-low temperatures for these dual-species gas studies in microgravity. In applying delta-kick cooling for molecules we found that the molecular internal degree of freedom can generate torques during the cooling process, depending on the strength and duration of the delta-kick pulse. Such effects, although interesting from the fundamental point of view, are detrimental to our precision interferometry studies. Our analyses, therefore, focus on determining the parameter regime in which such effects can be mitigated. We have developed a novel theoretical approach that accounts for the effects of the center-of-mass and relative motion of the molecules and additional studies are currently being performed in order to determine the final cooling efficiency.

Still during this period of performance, we have also developed other numerical techniques in which molecular association and dissociation can be studies, e.g., during magnetic field ramps. We are also moving towards the elaboration of novel numerical techniques in which we will be able to study, in more detail, the effects of atomic and molecular losses during the association and dissociation processes. These studies, therefore, partially define our goals for the next funding year.

Recent and ongoing work on this project has also concentrated on working with the CAL Ground Test Bed (GTB) and Science teams in maturing the GTB to a) validate the flight hardware and b) provide all of the functionality of CAL in a ground-based lab system for proof of principle and characterization studies to support the flight science projects. Due to the technical innovations required in our project and the sensitivity to numerous experimental/environmental parameters, access to the GTB has and will be enabling to mature our studies and to optimize our utilization of CAL. This work will progress through the remaining two months of this third-year effort.

Bibliography Type: Description: (Last Updated: 05/02/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings D'Incao JP, Williams JR. "Association and dissociation of Feshbach molecules in a microgravity environment." Presented at the 47th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics (DAMOP), Providence, Rhode Island, May 23–27, 2016.

Bulletin of the American Physical Society. 2016;61(8):abstract D1.00183. http://meetings.aps.org/Meeting/DAMOP16/Session/D1.183 , May-2016

Abstracts for Journals and Proceedings Williams J, D'Incao J. "Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at the 2016 NASA Fundamental Physics Workshop, Dana Point, CA, April 2016.

2016 NASA Fundamental Physics Workshop, Dana Point, CA, April 2016. , Apr-2016

Abstracts for Journals and Proceedings Williams J. "Utilizing NASA's Cold Atom Lab for Technology Maturation of Precision Atom Interferometry in Space." Presented at the Workshop on Atom Interferometry, General Relativity and Space Technologies at the Occasion of Claus Lammerzahl's 60th Birthday, Hannover, Germany, August 08, 2016.

Workshop on Atom Interferometry, General Relativity and Space Technologies at the Occasion of Claus Lammerzahl's 60th Birthday, Hannover, Germany, August 08, 2016. , Aug-2016

Abstracts for Journals and Proceedings Williams J. "Opportunities for Maturing Precision Metrology with Ultracold Gas Studies Aboard the ISS." Presented at the US-German Programmatic Meeting for the NASA/DLR collaboration on the Bose-Einstein Condensate/Cold Atom Laboratory (BECAL), Bremen, Germany, December 15, 2016.

US-German Programmatic Meeting for the NASA/DLR collaboration on the Bose-Einstein Condensate/Cold Atom Laboratory (BECAL), Bremen, Germany, December 15, 2016. , Dec-2016

Articles in Peer-reviewed Journals D'Incao JP, Krutzik M, Elliott E, Williams JR. "Enhanced association and dissociation of heteronuclear Feshbach molecules in a microgravity environment." Physical Review A. 2017 Jan;95:012701. https://doi.org/10.1103/PhysRevA.95.012701 , Jan-2017
Project Title:  Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment Reduce
Images: icon  Fiscal Year: FY 2016 
Division: Physical Sciences 
Research Discipline/Element:
FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 05/03/2019  
Task Last Updated: 02/01/2016 
Download report in PDF pdf
Principal Investigator/Affiliation:   Williams, Jason  Ph.D. / NASA Jet Propulsion Laboratory 
Address:  Quantum Sciences & Technology Group 
4800 Oak Grove Dr 298-103B 
Pasadena , CA 91109-8001 
Email: Jason.R.Williams.Dr@jpl.nasa.gov 
Phone: 303-725-1580  
Congressional District: 27 
Web:  
Organization Type: NASA CENTER 
Organization Name: NASA Jet Propulsion Laboratory 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
D'Incao, Jose  Ph.D. University of Colorado 
Project Information: Grant/Contract No. Internal Project 
Responsible Center: NASA JPL 
Grant Monitor: Israelsson, Ulf  
Center Contact:  
ulf.e.israelsson@jpl.nasa.gov 
Solicitation: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: Internal Project 
Project Type: FLIGHT 
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: 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 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 the capabilities of NASA's multi-user Cold Atom Laboratory (CAL), in the microgravity environment onboard the International Space Station (ISS), to study mitigation schemes for the leading-order systematics expected to limit 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 Jet Propulsion Laboratory (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 utilize the dual-species AI 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.

Research Impact/Earth Benefits: Our studies are designed to achieve technological advances in precision metrology that can only be realized in the microgravity environment of the Cold Atom Laboratory. We utilize the tools of ultracold atomic and molecular physics (namely Feshbach resonances) for exquisite control of the differential center-of-mass distributions of the dual-species quantum gases and on methods to use the fundamentals of few-body interactions to maintain coherence in atomic ensembles for enhanced precision sensor capabilities. Subsequent proof-of-principle studies with the dual-species atom interferometer on CAL will further advance the state of the art for precision interferometry with ultracold matter waves. The impact of such research to the field of metrology can be seen through its potential to increase precision for atom-interferometry and also the possibility of engineering highly efficient system-specific devices based on the fundamental nature of few-body interactions. The microgravity environment of the CAL facility will strongly favor such explorations and allow for the possibility of uncovering novel effects and quantum phases of matter, a major goal in ultracold quantum gases and other disciplines of fundamental physics. These studies can benefit life on Earth by providing both fundamental understanding of nature in previously inaccessible environments and energy regimes, and by enhancing the tools available for scientific exploration at the highest precision.

Task Progress & Bibliography Information FY2016 
Task Progress: 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 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 onboard the International Space Station, to study the leading-order systematics expected to limit future high-precision measurements of Einstein's weak equivalence principle with dual atomic-species AIs in microgravity.

The flight experiments, supported by theoretical investigations and measurements using the ground test bed facilities at JPL, will concentrate on the physics of pairwise interactions and low-energy s-wave Feshbach molecules in ultracold quantum gases as a means to overcome uncontrolled AI shifts associated with the differential center of mass of two atomic species influenced by gravity gradients and rotations. We will further utilize the dual-species AI, recently integrated into CAL, for proof-of-principle demonstrations of unprecedented atom-photon coherence times, phase-readout techniques, and characterizations of the rotational noise on the ISS for use in the next-generation of precision metrology experiments based on AIs in microgravity. Our proposed experiments require the effective position invariance, long free fall times, and extremely low temperature samples uniquely available with the CAL apparatus. It is anticipated that these studies can lead to the unprecedented level of control and accuracy necessary for future space missions, based on precision AIs, to test some of the most fundamental questions of modern physics.

In the second year of this project, we finalized the science concepts, requirements, and feasibility studies for both the originally proposed flight project, studying Feshbach molecules as a tool to enhance high-precision AI-based experiments in space, as well as for the flight experiments to use the CAL dual-species AI to further mature the technology of high-precision AI for enabling future space-based fundamental physics missions. For each proposed study, the approach, science management and data analysis plans, generalized experimental sequences, science requirements, and all other relevant experimental considerations were compiled into a Science Requirements Document that was submitted for review in October, 2015. At the same time, our group presented and conditionally passed the Science Concept Review to the CAL Science Review Board, allowing the project to continue in its flight status.

As part of the Feshbach molecule filtering study we 1) Developed the specific sets of experimental sequences required to associate and dissociate the heteronuclear molecules with minimal heating and loss. 2) Characterized the expected efficiency for removing unpaired atoms while minimally perturbing the Feshbach molecules. 3) Developed the dual-species imaging routine, error budgets, and analyses for optimally measuring the differential density distributions for the dissociated clouds and estimated the total averaging time required to achieve differential center-of-mass accuracy on the nanometer scale. 4) Identified the ground tests required to sufficiently characterize the atomic and molecular loss rates, heating rates, and all potential ground tests to optimally utilize the experimental time with the CAL apparatus on the ISS, and 5) Identified potential shortfalls and mitigations for this study.

For the dual-species AI studies, our tasks over the year included: 1) Calculated the expected contrast and systematic shifts based on the Bragg-beam design. 2) Developed the experimental sequences for demonstrating extended atom-photon coherence in a 3-pulse AI in free fall. 3) Developed the experimental sequences for observing rotational phase-fringes on the ISS. 4) Quantified the expected SNR and optimum sensitivity for the dual-species AI, leading to the required interrogation times and expected precision of each measurement. 5) Identified the possible AI-based ground tests to optimally utilize the experimental time with the CAL apparatus on the ISS, and 6) Identified potential shortfalls, mitigations, and applications of the CAL AI, including the feasibility of using the CAL AI during the anticipated down time as a high-precision sensor for local accelerations and rotations.

Recent work on this project has concentrated on assisting the CAL Ground Test Bed (GTB) and Science teams in maturing the GTB to a) validate the flight hardware and b) provide all of the functionality of CAL in a ground-based lab system for proof of principle and characterization studies to support the flight science projects. Due to the technical innovations required in our project and the sensitivity to numerous experimental/environmental parameters, access to the GTB will be enabling to mature our studies and to optimize our utilization of CAL. This work will progress through the remaining two months of this second-year effort.

Bibliography Type: Description: (Last Updated: 05/02/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings Williams J, D'Incao J, Chiow S-W, Yu N. "Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at the 6th International Symposium on Physical Sciences in Space and the 10th International Conference on Two-Phase Systems for Space and Ground Applications, Kyoto, Japan, September 14-18, 2015.

6th International Symposium on Physical Sciences in Space and the 10th International Conference on Two-Phase Systems for Space and Ground Applications, Kyoto, Japan, September 14-18, 2015. , Sep-2015

Abstracts for Journals and Proceedings Williams J, D'Incao J, Chiow S-W, Yu N. "Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at 46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Columbus, OH, June 8-12, 2015.

46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Columbus, OH, June 8-12, 2015. Abstract #C2.004. http://adsabs.harvard.edu/abs/2015APS..DMP.C2004W , Jun-2015

Abstracts for Journals and Proceedings Williams J, Chiow S-W, Kellogg J, Kohel J, Yu N. "Atom Interferometer Technologies in Space for Gravity Mapping and Gravity Science." Presented at the 46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Columbus, OH, June 8-12, 2015.

46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Columbus, OH, June 8-12, 2015. Abstract ##K1.064. http://adsabs.harvard.edu/abs/2015APS..DMP.K1064W , Jun-2015

Abstracts for Journals and Proceedings D'Incao JP, Williams JR. "Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at 46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Columbus, OH, June 8-12, 2015.

46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics, Columbus, OH, June 8-12, 2015. Abstract #D1.036. http://adsabs.harvard.edu/abs/2015APS..DMP.D1036D , Jun-2015

Project Title:  Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment Reduce
Images: icon  Fiscal Year: FY 2015 
Division: Physical Sciences 
Research Discipline/Element:
FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 05/03/2019  
Task Last Updated: 02/09/2015 
Download report in PDF pdf
Principal Investigator/Affiliation:   Williams, Jason  Ph.D. / NASA Jet Propulsion Laboratory 
Address:  Quantum Sciences & Technology Group 
4800 Oak Grove Dr 298-103B 
Pasadena , CA 91109-8001 
Email: Jason.R.Williams.Dr@jpl.nasa.gov 
Phone: 303-725-1580  
Congressional District: 27 
Web:  
Organization Type: NASA CENTER 
Organization Name: NASA Jet Propulsion Laboratory 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
D'Incao, Jose  Ph.D. University of Colorado 
Project Information: Grant/Contract No. Internal Project 
Responsible Center: NASA JPL 
Grant Monitor: Israelsson, Ulf  
Center Contact:  
ulf.e.israelsson@jpl.nasa.gov 
Solicitation: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: Internal Project 
Project Type: FLIGHT 
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: 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 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 the capabilities of NASA's multi-user Cold Atom Laboratory (CAL), in the microgravity environment onboard the International Space Station (ISS), 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 utilize the dual-species AI, recently integrated into CAL, 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.

Research Impact/Earth Benefits: Our studies are designed to achieve technological advances in precision metrology that can only be realized in the microgravity environment of the Cold Atom Laboratory. We utilize the tools of ultracold atomic and molecular physics (namely Feshbach resonances) for exquisite control of the differential center-of-mass distributions of the dual-species quantum gases and on methods to use the fundamentals of few-body interactions to maintain coherence in atomic ensembles for enhanced precision sensor capabilities. Subsequent proof-of-principle studies with the dual-species atom interferometer on CAL will further advance the state of the art for precision interferometry with ultracold matter waves. The impact of such research to the field of metrology can be seen through its potential to increase precision for atom-interferometry and also the possibility of engineering highly efficient system-specific devices based on the fundamental nature of few-body interactions. The microgravity environment of the CAL facility will strongly favor such explorations and allow for the possibility of uncovering novel effects and quantum phases of matter, a major goal in ultracold quantum gases and other disciplines of fundamental physics. These studies can benefit life on Earth by providing both fundamental understanding of nature in previously inaccessible environments and energy regimes, and by enhancing the tools available for exploring a wide variety of nature at the highest precision.

Task Progress & Bibliography Information FY2015 
Task Progress: During this first year of the project, we concentrated on further developing our science concepts and on design studies of the CAL facility, in addition to theoretical modeling of the physics of ultra-low energy Feshbach molecules in microgravity to better predict the outcomes of the study. The driving goals were to assist in maturing the flight projects, to understand the relevant design constraints of CAL, to predict the CAL performance and our science deliverables, and to understand the implications of the project for follow on precision-AI-based studies of fundamental physics in space. Our work during the year is summarized in the following.

The effects of low-frequency ISS vibrations on the performance of CAL and on our experiments requiring high-stability dual-species imaging capabilities were a significant concern at the beginning of the task. To address these issues, we developed a general algorithm to collect and analyze the raw accelerometer data from the Principal Investigator Microgravity Services (PIMS) website for the 121F04 SAMS sensor located nearest the projected CAL location. A representative acceleration record for the entire day of January 01, 2015 was analyzed, from which we determined that the displacements between the ultracold atoms in free fall and the CAL apparatus, from ISS vibrations, are on the order of 10s of microns, negligible in comparison to the distance from the atoms to the surfaces of the Science Chamber and also as compared to the diameter of the AI Bragg beam. Further, we considered the effects of ISS vibrations on the ability to determine the overlap of two clouds that are sequentially imaged. Assuming that the images of the two clouds are taken within 100 microseconds of each other, and assuming that vibrations at all frequencies above 200 Hz is negligible, the displacement extrapolates to a root-mean-square displacement between the two images on the order of 10 nanometers along all directions, well-below the camera resolution. Vibrations from hardware on the CAL apparatus and the related effects still need to be characterized and similar analyses will be required when that data becomes available.

Our main project explores a unique energy regime for studying the dynamics and adiabaticity in associating/dissociating long-lived, heteronuclear Feshbach molecules from low-density, dual-species gases at 100s of pK. During this year, we completed many of the theoretical investigations that were required to understand the lifetime and heating rates/mechanisms in these ultra-low energy gas studies on CAL. It is well known that at large scattering lengths (a), three-body collisions can lead to the formation of deeply bound states with large enough kinetic energy to make them escape from typical traps. Therefore, three-body losses set an important time scale within which our experiments have to be performed, i.e., before losses start drastically affecting the atomic and molecular densities. We used our previously calculated semi-analytical results and those from K. Helfrich et al., Phys. Rev. A 81, 042715 (2010) in order to estimate the importance of three-body losses for the experimental scenario described in our proposal.

The free-atom lifetimes are found to be long for small values of a, and they reach a minimum value for a << 1/(2uT)^(1/2), where u is the three-body reduced mass. As the temperature decreases [implying the decrease of the atomic densities for a given phase-space density and interparticle interaction strength], the lifetime increases for all values of a. Temperatures of about 100pK and densities of the order of 10^8 /cm^3 are expected to be accessible at CAL, which would allow for lifetimes greater than 1s for values of a<10^5 a0, where a0 is the Bohr radius. For inelastic atom-molecule collisions, similar temperatures and densities correspond to lifetimes in excess of 100s of milliseconds. It should be stressed that the presence of three-body (Efimov) and atom-molecule resonances are expected in the range of scattering lengths accessible on CAL, in the close-vicinity of which, the lifetime can be reduced significantly. Ground studies are planned to map out the Efimov resonances in our system to optimize the flight studies and avoid anomalous loss due to these resonant loss channels. More detailed analyses of three-body, atom-molecule, and molecule-molecule losses will be performed as results from the ground studies become available.

One other collisional effect that can lead to systematic errors in preparing our initial state for interferometry (two perfectly overlapping clouds of Rb and K) are elastic atom-molecule collisions. In this case, elastic collision can introduce additional momentum to the molecules, which in turn can affect the molecular dissociation rates. Therefore, we also estimated the typical collision time in which elastic atom-molecule collisions are important. We found that the collision times are considerably shorter than the lifetime corresponding to inelastic atom-molecule for large values of a, by an order of magnitude or greater. This indicates that some attention will be required to understand the effects of elastic atom-molecule collisions in our system. We note, however, that since elastic rates can vanish for some specific values of the scattering lengths, it is possible to minimize the atom-molecule collisional effects. The actual position of such zeros, however, can only be determined from ground experiments or through full numerical simulations.

The CAL AI is developed as a technology demonstration to perform experiments related to atom interferometry in microgravity on a “best effort” basis. The great majority of the work developing the dual-species AI and incorporating it into the already-mature CAL system design was carried out before the start of this NRA. However, on April 28, 2014, the atom interferometer was peer-reviewed as a delta PDR (preliminary design review) for this subsystem. I supported this review by developing the AI performance budget and as a consultant for required hardware developments for the AI upgrade. I was also a reviewer at the PMR2/TIM of ColdQuanta's chip trap and atom interferometer designs on November 3, 2014. My findings and recommendations for the CAL AI system are summarized below.

The pointing of the Bragg beam must be constrained to (a) maintain the optical lattice-depth and (b) maintain overlap with the atomic clouds throughout the AI sequence. After delta-kick cooling, the 87Rb (39K) atoms have a Gaussian width on the order of 200 (400) microns, whereas the Bragg beam diameter is designed to be 1 mm. Lateral translations of the Bragg beam should be made as stable as possible to preserve contrast and to minimize wavefront-related systematic shifts for precision measurements; however, vibrations of the ISS, discussed previously, practically limit the overlap of the Bragg beam and the free-fall atoms to 10s of microns with no benefit for lateral pointing stability beyond this level. Further, if the atoms travel a maximum of two inches from the chip in the science cell, the mirror must be normal to the Bragg beam to within 2 mRad at all timescales! This level of pointing-accuracy is also required to assure that the atoms don't drift out of the Bragg beam during interferometry. This is a requirement on the overlap of the incident and reflected beams so absolute pointing accuracy is required.

The curvature of the coated chip surface and the mode of the beam out of the GRIN lens are also a concern, with different constraints for beam-overlap and for controlling systematic shifts for precision measurements. I proposed that the ColdQuanta team characterize the beam wavefront out of the GRIN lens and also after reflection from the entire AI beam path (including the coated chip during operation and through the vacuum cells). I recommend using a Shack-Hartmann wavefront sensor camera that will provide unambiguous pictures of the wavefronts for a quick measurement of the curvature.

The contrast of the CAL AI and the loss of atoms from the interferometer are calculated with a simple model that we developed, taking into account the temperature-dependent density profile of the atomic gases in freefall and the spatially dependent Rabi frequency for the two-photon Bragg pulses in a Mach-Zehnder AI. We find that there is a complicated tradeoff between the initial temperature, cloud size, and Bragg pulse-width for achieving the optimum contrast and population in the AI. These constraints arise due to the significant initial atom size in comparison to the Bragg beam waist for the coldest delta-kick-cooled samples (100 pK), the faster rate of ballistic expansion at higher (1 nK) temperatures, and the Doppler width of the transitions for the ultracold clouds. The model allows us to optimize the interferometer interrogation time, the time-dependent cloud density, and the temperature and pulse times depending on the sensitivity and temperature requirements of the AI experiments planned. Further, we calculated the noise requirements on the retro-reflecting mirror fluctuations and the Bragg laser noise to demonstrate that these effects will negligibly affect the performance of the CAL AI based on the known ISS vibration environment and the laser system performance already characterized for CAL.

In the final two months of our first-year effort, we will concentrate on preparing for the Science Concept Review (SCR) that is expected to be held sometime in May, 2015. It is expected that in March, a CAL performance package will be sent out to the NASA Research Announcement (NRA) PIs highlighting the expected CAL system performance and noise characteristics, and hopefully information about the imaging system, SNR, and software or PI interface. This information will then guide the following tasks that will be among the subjects reviewed at the SCR:

For the Feshbach molecule filtering study we anticipate to 1) Develop the specific sets of experimental sequences required to associate and dissociate the heteronuclear molecules with minimal heating and loss. 2) Characterize the expected efficiency for removing unpaired atoms while minimally perturbing the Feshbach molecules. 3) Develop the dual-species imaging routine and analyses for optimally measuring the differential density distributions for the dissociated clouds and estimate the total averaging time required to achieve ~nanometer level differential center-of-mass accuracy. 4) Identify the ground tests required to sufficiently characterize the atomic and molecular loss rates, heating rates, and all potential ground tests to optimally utilize the experimental time with the CAL apparatus on the ISS and 5) Identify potential shortfalls and mitigations for the study.

For the dual-species AI studies, our tasks over the next two months include: 1) Calculate the expected contrast and systematic shifts based on the measured Bragg-beam characteristics. 2) Develop the experimental sequences for demonstrating extended AI time by refocusing the 87Rb atomic clouds with a near-resonance dipole trap. 3) Develop the experimental sequences for observing rotational phase-fringes on the ISS. 4) Quantify the expected SNR and optimum sensitivity for the dual-species AI, leading to the required interrogation times and expected precision of each measurement. 5) Identify the possible AI-based ground tests to optimally utilize the experimental time with the CAL apparatus on the ISS. and 6) Identify potential shortfalls, mitigations, and applications of the CAL AI, including the feasibility of using the CAL AI during the anticipated down time as a high-precision sensor for local accelerations and rotations.

Bibliography Type: Description: (Last Updated: 05/02/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings Williams J, D'Incao J, Chiow S-W, Botter T, Kellogg J, Yu N. "Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at the 30th Annual Meeting of the American Society for Gravitational and Space Research, Pasadena, CA, October 22-26, 2014.

30th Annual Meeting of the American Society for Gravitational and Space Research, Pasadena, CA, October 22-26, 2014. https://asgsr.org/index.php/presentation-abstracts-10-25-2014 ; accessed 2/10/15. , Oct-2014

Abstracts for Journals and Proceedings Williams J, D'Incao J, Chiow S-W, Mueller H, Yu N. "Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at the NASA Fundamental Physics PI Workshop, Pasadena, CA, November 17-18, 2014.

NASA Fundamental Physics PI Workshop, Pasadena, CA, November 17-18, 2014. https://custom.cvent.com/216E523D934443CA9F514B796474A210/files/50fef62c4e944bcf8f8436bc538c17a4.pdf ; accessed 2/10/15. , Nov-2014

Abstracts for Journals and Proceedings D'Incao J, Williams J. "Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment." Presented at the NASA Fundamental Physics PI Workshop, Pasadena, CA, November 17-18, 2014.

NASA Fundamental Physics PI Workshop, Pasadena, CA, November 17-18, 2014. https://custom.cvent.com/216E523D934443CA9F514B796474A210/files/50fef62c4e944bcf8f8436bc538c17a4.pdf ; accessed 2/10/15. , Nov-2014

Project Title:  Fundamental Interactions for Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment Reduce
Images: icon  Fiscal Year: FY 2014 
Division: Physical Sciences 
Research Discipline/Element:
FUNDAMENTAL PHYSICS--Fundamental physics 
Start Date: 04/01/2014  
End Date: 05/03/2019  
Task Last Updated: 07/29/2014 
Download report in PDF pdf
Principal Investigator/Affiliation:   Williams, Jason  Ph.D. / NASA Jet Propulsion Laboratory 
Address:  Quantum Sciences & Technology Group 
4800 Oak Grove Dr 298-103B 
Pasadena , CA 91109-8001 
Email: Jason.R.Williams.Dr@jpl.nasa.gov 
Phone: 303-725-1580  
Congressional District: 27 
Web:  
Organization Type: NASA CENTER 
Organization Name: NASA Jet Propulsion Laboratory 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
D'Incao, Jose  Ph.D. University of Colorado 
Project Information: Grant/Contract No. Internal Project 
Responsible Center: NASA JPL 
Grant Monitor: Israelsson, Ulf  
Center Contact:  
ulf.e.israelsson@jpl.nasa.gov 
Solicitation: 2013 Fundamental Physics NNH13ZTT002N (Cold Atom Laboratory--CAL) 
Grant/Contract No.: Internal Project 
Project Type: FLIGHT 
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: Understanding of the effects of interatomic interactions is becoming increasingly important for the broad range of studies with ultracold quantum gases. Rapid progress in these studies is attributed to the unprecedented level of control over the interatomic interactions, which has been translated into development of the next-level instruments for precision metrology as well as triggered the creation of novel quantum phases and the deeper understanding and control of chemical reactions. Our proposed studies explore fundamental aspects of the interactions that, perhaps, can only be accessible in the microgravity environment of the NASA's multi-user Cold Atom Laboratory. In the first part of our proposed flight experiment, we will investigate the association/dissociation dynamics of weakly bound heteronuclear diatomic molecules in microgravity to produce dual-species gases with unprecedented overlap in both position and momentum space. This technology would overcome one of the greatest sources of systematic uncertainty in future precision tests of the Weak Equivalence Principle with atom interferometry. We also plan to study a novel method of canceling nonlinear effects due to few-body interactions that can extend the coherence times of dense atomic gases for even more precise metrology applications, enabling next-generation tests of the principles of Einstein's Theory of General Relativity with atomic clocks and atom interferometers. In the second part of our proposal, we plan to explore the physics of Boson-mediated interactions allowing for fundamental studies of the pairing mechanisms affecting both few- and many-body nature of the system. Our proposed studies require the effective position invariance and/or the extremely low temperature samples generated by the CAL apparatus. We believe that our proposed studies can lead to an unprecedented level of control and accuracy necessary to explore some of the most fundamental physical concepts in nature and open up venues for exploration of novel quantum phases in exotic dynamical regimes.

Research Impact/Earth Benefits: 0

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

Bibliography Type: Description: (Last Updated: 05/02/2019)  Show Cumulative Bibliography Listing
 
 None in FY 2014