Summary

From navigation and time-keeping to health and medical care, the field of atomic, molecular, and optical (AMO) physics has provided numerous important scientific and technological advances that have transformed human society in the past several decades. Harnessing the exquisite quantum properties of atoms and their interaction with light underpins many everyday technologies—from the lasers in consumer electronics, medical technologies such as laser therapies, and magnetic resonance imaging (MRI), to the most precise atomic clocks, which maintain the accuracy of the global positioning system. Within the past decade alone, the techniques of AMO physics played a pivotal role in the discovery of gravitational waves and the new era of multimessenger astrophysics that is ensuing, and in the explosive development of quantum information and sensing technologies.

AMO physics studies the fundamental building blocks of matter to help advance the understanding of the universe. It is a foundational discipline within the physical sciences, relating to atoms and their constituents, to molecules, and to light at the quantum level. AMO physics combines fundamental research with practical application, coupling fundamental scientific discovery to rapidly evolving technological advances, innovation, and commercialization.

Because of the wide-reaching intellectual, societal, and economical impact of AMO, agencies within the federal government have deemed it worthwhile to conduct a survey of the recent advances in AMO physics, and to review what may be on the horizon for the field. This report reflects on the successes of AMO science and identifies the most pressing current challenges, as well as the most promising future opportunities presented by AMO science. The U.S. research community

has long enjoyed global leadership in AMO physics, thanks to sustained, strong support from the federal government and the unique AMO culture that fosters collaboration and open research. At the same time, the broader international scientific community has recognized the importance of AMO research, and over the past decade the U.S. global leadership position has begun to erode, as funding has not kept up with growth in the field, and other countries have increased investments in this field. As such, this report also considers federal funding trends and practices, trends in education and workforce participation, and ways to ensure the continued health of AMO science in the United States and globally.

The committee’s advice is summarized into 10 broad and high-level recommendations, which are directed at the entire AMO research enterprise and are highlighted at the end of this summary and in the Overview of Chapter 1. The committee provides another 16 more focused, subfield-specific recommendations, embedded within the relevant chapters, which are also summarized in Chapter 1.

FUNDING

Considering the breadth and depth of AMO physics described above, the committee strongly urges continued national investment in AMO science; as a curiosity-driven research enterprise it has been the driving force behind many scientific discoveries and innovative technologies. Given the central role of AMO science to other disciplines in physical sciences, and considering the increasingly large investments in AMO-related quantum information science and technology in European countries and China, coordinated interagency support is needed for continued development and leadership of AMO science in the United States. Within the United States, data collected from three agencies that fund AMO science—the National Science Foundation (NSF), the Department of Defense (DoD), and the Department of Energy (DOE)—shows that aggregate funding over the past decade for AMO science has not kept up with the growth of the field, showing large annual variations for certain programs, and essentially flat budgets for others.

Key Recommendation: The U.S. government should vigorously continue investment in curiosity-driven atomic, molecular, and optical (AMO) science to enable exploration of a diverse set of scientific ideas and approaches. AMO is a critical investment in our economic and national security interests.

Noting important discovery potentials, current funding situations, and international competitiveness, the committee finds specific opportunities in certain research areas and for certain funding agencies, many of which are discussed in the findings presented in Chapter 1. AMO and quantum science continues to

improve necessary precision measurement concerning fundamental physics, and has produced significant discoveries in the area traditionally the realm of particle physics. Thus, AMO-based projects on quantum sensing and addressing beyond-the-standard-model fundamental physics questions will be key in meeting emerging opportunities in quantum science.

The development of quantum technologies brings important new opportunities in sensing and precision measurement that can have applications ranging from quantum computation and simulation, enhanced communication and navigation, to fundamental probes of the universe. With quantum information technology still at a very early stage, there is an increasing number of potential new systems and platforms one can exploit for the construction of quantum machines. Therefore, it is urgent that the research community develop platform-independent metrics to measure and characterize the performance of quantum technologies. Nurturing research into quantum information systems, work that will provide critical tools and insights for other areas of science, will require long-term investments that cross traditional disciplinary boundaries.

Key Recommendation: Basic research in science, engineering, and applications underlying both existing and emerging new platforms needs to be broadly supported, including research on techniques for cross-verification of quantum machines across different platforms for various applications. Specifically, the committee recommends that the National Science Foundation, Department of Energy, National Institute of Standards and Technology, and Department of Defense should provide coordinated support for scientific development, engineering, and early applications of AMO-based quantum information systems.

Rapid advances in the precision and capabilities of AMO technologies have dramatically increased the potential of AMO-based techniques to discover new physics beyond the standard model. The present lack of a federal funding program dedicated specifically to supporting such research at the intersection of high-energy physics and AMO is a limiting factor in fully utilizing the plethora of opportunities for new discoveries.

Key Recommendation: The Department of Energy’s High-Energy Physics, Nuclear Physics, and Basic Energy Sciences programs should fund research on quantum sensing and pursue beyond-the-Standard-Model fundamental physics questions through AMO-based projects.

Armed with emerging AMO technologies, both space- and laboratory-based fundamental AMO science is needed to address key questions in astronomy,

astrophysics, and cosmology. Likewise, the committee finds that the time is ripe for recently developed AMO tools and technologies to be deployed in space missions.

Key Recommendation: The National Aeronautics and Space Administration, in coordination with other federal agencies, should increase investments in theory and experiment for both space- and laboratory-based fundamental atomic, molecular, and optical science that are needed to address key questions in astronomy, astrophysics, and cosmology.

Creative science carried out by single principal investigator (PI) groups is the heart of AMO science. The field has done well building on the innovative, imaginative efforts of these individual investigators, but it is entering a new phase for which collaborations with flexible-sized teams would enable exciting new discoveries that may call for focused efforts. Advances in ultrafast light sources will be key to microscopic understanding of dynamics in complex systems, such as the motion of electrons in a material. Therefore, it is important to continue investment in a broad range of science, including at ultrafast X-ray light source facilities, while maintaining a strong single PI funding model. The 2018 National Academies report Opportunities in Intense Ultrafast Lasers: Reaching for the Brightest Light recommended that the DOE lead the development of a comprehensive interagency strategy for high-intensity lasers that includes the development and operation of both large-scale national laboratory projects and mid-scale university-hosted projects. A good balance between facilities and single-investigator programs in the context of emerging quantum centers is particularly important.

Key Recommendation: U.S. federal agencies should invest in a broad range of science that takes advantage of ultrafast X-ray light source facilities, while maintaining a strong single principal investigator funding model. This includes the establishment of open user facilities in mid-scale university-hosted settings.

EDUCATION AND WORKFORCE DEVELOPMENT

Academia needs to evolve to encourage cross-disciplinary hiring of both theorists and experimentalists at the rapidly growing interfaces between AMO and quantum information science, computer science, mathematics, chemistry, biology, astrophysics, engineering, and industry. Overall, education in preparation for a research career, measured by the number of Ph.D.s granted, remains robust. In order for other fields to be able to take advantage of critical AMO advances, it is important to improve educational programs and funding mechanisms that encourage interdisciplinary work/collaboration to translate AMO work across fields.

Strong collaboration between theorists and experimentalists has been important for maintaining the health of AMO science. However, the number of faculty positions in AMO theory has been limited. Additionally, experimental AMO science has become very expensive, and the starting cost of a new experimental program has become a deterrent for young AMO scientists being appointed as faculty in academia. The translation from AMO science to technology and engineering and a strong partnership between AMO academia and industry are particularly important now with the national emphasis on the development of quantum technologies and a corresponding new generation of workforce.

AMO technologies are not being transferred into other fields for use as rapidly as AMO science itself develops. The committee finds that it is increasingly important to improve the visibility of AMO. The breakneck pace of AMO breakthroughs leads the committee to believe that other communities would benefit from knowing more about AMO. Furthermore, departmental boundaries create barriers for young AMO-trained post-docs to move into related disciplines and departments, such as quantum information science and computer science, where their AMO training would play key roles in advancing those fields. In particular, quantum technology cuts across scientific fields and technologies beyond AMO, and so encounters barriers with traditional funding mechanisms. Recent Quantum Leap Initiatives at NSF are based on a stewardship model that starts to break the traditional barriers between disciplines.

Traditional AMO training focuses on physics; however, the development of quantum technology requires reaching across both academic disciplines and to industry to leverage the impact of AMO. There are existing successful portable funding models in the United States and Europe, such as the National Institutes of Health (NIH)-K99 and European Research Council (ERC) grants, that could be used as models to assist faculty appointment and early career development. In designing such portable funding models, it will be important to ensure that the level of research effort is compatible with teaching expectations that are standard in the physical sciences academic community. Other AMO funding agencies should develop similar models that support the transition of AMO theorists and experimentalists into faculty positions.

Key Recommendation: AMO funding agencies should develop portable fellowship grant models that support the transition of AMO science theorists and experimentalists into faculty positions.

Key Recommendation: To maximize the effectiveness of federal investment, academia should enable and encourage cross-disciplinary hiring of theorists and experimentalists at the rapidly growing interface between AMO science fields and computer science, mathematics, chemistry, biology, engineering, as well as industry.

Key Recommendation: The National Science Foundation, Department of Energy, National Institute of Standards and Technology, and Department of Defense should increase opportunities for translating atomic, molecular, and optical science advances to other fields by fostering collaboration with scientists and engineers from other disciplines through, for example, support of workshops and similar mechanisms for cross-disciplinary interactions.

AMO science, like other physics disciplines, continues to have difficulty in attracting women and underrepresented minorities at all levels. It is clear that education and workforce development in AMO is not keeping up with the demographics in the nation, and that this is a lost opportunity. There is a growing untapped national talent pool of women and underrepresented minorities.

Key Recommendation: The entire AMO science enterprise should find ways to tap into the growing national talent pool of women and underrepresented minorities. The committee therefore endorses the relevant recommendations in the National Academies reports Graduate STEM Education for the 21st Century and Expanding Underrepresented Minority Participation, for example.

INTERNATIONAL CONNECTIONS OF ATOMIC, MOLECULAR, AND OPTICAL SCIENCE

The health of AMO science relies heavily on strong international collaborations, and this report identifies regulatory impediments to fostering international collaborations and maintaining U.S. leadership in research, education, and innovation globally (see Chapter 8). Yearly trends of research publications provide a good indicator that the United States maintains a strong position in AMO science globally, although many European nations, China, South Korea, Japan, and Australia are rapidly catching up or already leading in certain subfields of AMO. Mechanisms for co-funding research that is carried out with international collaboration fuels collective progress in AMO science. However, the committee finds that the U.S. position in terms of investment and commercialization in this area has weakened compared to Europe and Asia. There are a number of technical and regulatory impediments including major differences in effort certification, intellectual property ownership policies, and conflict-of-interest rules, as well as unfunded external audit requirements and unreasonable currency exchange requirements, all of which make it difficult for U.S. universities to accept and administer grants from, for example, the European Union (EU).

The committee recognizes the real security concerns in open, international collaboration, but there is great national benefit in having intellectual leaders visiting the United States. This benefit is at risk due to continuing significant issues with

access to national research facilities, and visa denials and excessive delays for international students, collaborators, and speakers at conferences. Open collaborations have been vital for the health of AMO physics, and the nation’s reputation as a welcoming place for the best international students and researchers has been key to attract future leaders to the United States. The Office of Science and Technology Policy and federal funding agencies need to work collaboratively with the Department of State and an academic consortium such as the Council on Governmental Relations to remove impediments to international cooperation.

Key Recommendation: The committee recognizes the real security concerns in open, international collaboration. However, because open collaborations have been so vital for the health of atomic, molecular, and optical physics, the Office of Science and Technology Policy and federal funding agencies should work collaboratively with the Department of State and an academic consortium such as the Council on Governmental Relations to remove impediments to international cooperation. There is a critical need for

IMPORTANT TOPICS IN AMO PHYSICS

This report highlights major scientific themes that are of strong current interest and have substantial growth potentials for AMO science, presenting them in Chapters 2 to 7. These grand challenge themes are closely related, and their interconnections highlight the richness and expansiveness of AMO science.

• Chapter 2: Tools Made of Light. The strong tradition in advancing the frontiers of light properties and creating new platforms with light will be a key part of AMO to enable future progress in fundamental discoveries and novel technologies. Generating light with precisely controlled properties has enabled novel tools for probing and controlling matter, providing greater reach into the unique phenomena underlying fundamental physics.
• Chapter 3: Emerging Phenomena from Few- to Many-Body Systems. Microscopic control of a diverse set of atoms and molecules at the quantum level is a critical foundation of AMO from which new scientific understandings emerge and new toolboxes are created. The committee explores atomic and

• molecular systems where scaling from a few particles to many reveals new phenomena that emerge due to the quantum interactions between atoms.
• Chapter 4: Foundations of Quantum Information Science and Technology. As AMO provides one of the most precisely controlled quantum systems that form the basis for quantum information processing, AMO will play a central role in delivering the most promising approaches in this increasingly active field. The production, transmission, storage, and use of quantum bits (qubits) are the building blocks of quantum information systems that promise computational and encryption advantages exceeding the capabilities of current classical computing.
• Chapter 5: Harnessing Quantum Dynamics in the Time and Frequency Domains. Novel tools of light and matter are providing unprecedented clarity in the observation and understanding of how systems evolve at vastly different time scales and across a large range of energies, creating new opportunities for controlling matter. Studying the dynamics and transformations of quantum systems on varying time scales provides extraordinary opportunities to create, manipulate, and understand quantum matter.
• Chapter 6: Precision Frontier and Fundamental Nature of the Universe. AMO-based technologies are being deployed to solve some of the outstanding scientific puzzles of our time, including the study of fundamental symmetries, testing physics postulates, searches for dark matter, and the detection of gravitational waves. Through the precise control of light, atoms, and molecules, the tools of AMO science have become integral to the exploration of fundamental phenomena in nature. The precision achievable by AMO techniques, coupled to and cross-fertilized by different disciplines of physics, will play a leading role in understanding nature at the deepest and most fundamental level.
• Chapter 7: Broader Impact of AMO Science. Because of its deep connections to other scientific disciplines and to advanced engineering and industrial innovations, the impact of AMO on scientific discovery and technological progress extends over a wide swath of human society—from life and health sciences to material engineering. A natural consequence of the sheer breadth and diversity of AMO tools and techniques is their applicability to many scientific endeavors outside the traditional boundaries of AMO science. These connections in turn fuel creative ideas and new developments within AMO.