|FAS Public Interest Report
The Journal of the Federation of American Scientists
Volume 56, Number 2
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21st Century Physics: Grand Challengesby C. Kumar N. Patel and Izzat Jarudi
The course of twentieth-century history was deeply shaped by advances in physics that enabled everything from the nuclear to computer revolutions. The advent of nuclear weapons, for example, revolutionized international politics after 1945 as the foundation for the new doctrine of mutual assured destruction. Half a century later, the advent of al Qaeda combined with the existence of weapons of mass destruction like nuclear weapons have again revolutionized international politics as the basis for the new Bush Doctrine of preemptive war.
At the beginning of a new century, the field of physics continues to have the potential to transform the rest of science and society. Our work can lead to tremendous gains in terms of scientific progress and societal welfare if we effectively confront a number of grand challenges that lie before the physics community in the coming decades.
Of course, the claim that there is a well-defined set of challenges for future research is more difficult to defend today than it would have been fifty years ago. The field of contemporary physics is more complex and fuzzy than it used to be. Each physicist has his own definition(s) of his profession. Moreover, the field itself has branched out into a myriad of subfields with interdisciplinary links to formerly distinct sciences like biology. There are few science and engineering departments at universities today that do not include physicists on their payroll. Despite all these difficulties in bounding the question, however, I believe the following nine grand challenges for 21st century physics should capture the essence of future research.
Grand Challenge #1: Quantum Science and Technologies
In the coming decades, research at the quantum level will continue to benefit from the manipulation of single atoms and molecules through devices like optical traps. The necessary technological developments for that manipulation will allow physicists to treat atoms as "bits" of information for the purposes of quantum computing.
On the other hand, quantum technologies will probably also lead to the observation of novel physical phenomena. The Bose-Einstein Condensate was one such phenomenon, which arose from many atoms of ultra-cold gas being in the same quantum mechanical state with a high probability of spatial overlap.
All of this future physics research will hinge on the development of highly sensitive instrumentation, but the measurement and sensor technologies based on working at the quantum level could fuel progress in other areas of science and engineering through applications like quantum-controlled chemistry, quantum cryptography and highly precise clocks.
Grand Challenge #2: Nanosciences
Like quantum science and technologies, the progress of the nanosciences will be constrained by the current state of the art in nanotechnology. In particular, it will depend on the invention of novel ways of making materials and devices at the nano level like the new techniques that can create "black" silicon.
And once again, the advances in technology will have unanticipated and beneficial consequences elsewhere. In medicine and health, nanotechnology might enable doctors to conduct molecular level surgery and implant nanodevices like atomic magnets in lungs. This important advancement would refine current medical diagnostic and treatment techniques. It could also be applied to energy production and environmental remediation, nanoscale electronics, and nanoparticle based fuels for space propulsion.
Grand Challenge #3: Complex systems
Physicists are often derided for the simplifying assumptions in their models of physical systems (e.g. the famous "spherical cow" joke); however, theoretical advances in physics that relax some of those assumptions could be our best hope for improving our understanding of complex systems. On the more practical side of physics research, large-scale computer modeling and the simulation of linear and nonlinear phenomena such as turbulence and chaos could illuminate complexity at a number of levels and in a variety of domains. For physical systems, modeling and simulation could yield important insight into the properties of real materials under extreme conditions and the explosive deaths of stars. For biological systems, they could move us closer to understanding the human body, social systems, and the economy and perhaps even the stock market.
Grand Challenge #4: Applying Physics to Biology and Medicine
Physics underpins biology, which, in turn, underpins medicine; therefore, the potential for applications of physics to biology and medicine is enormous. In biology, more physicists should be employed to model molecular processes rigorously such as protein folding. Electrical activity at the cellular level could also be used to understand the functioning of the nervous, circulatory, and respiratory systems. Furthermore, both mechanics and electromagnetism could be integrated in using the electromechanical properties of DNA and enzymes to understand cellular processes.
In medicine, physics could inform the design of novel non-invasive diagnostics of the human body such as the use of analysis of breath for understanding biochemistry within the body. Other domains for the application of physics to the medical sciences include the biomechanics of motion and the biophysics of neurons in the brain.
Grand Challenge #5: New Materials
Physicists themselves should also draw on the knowledge of a variety of disciplines, including the natural sciences, to enhance the discovery, development and deployment of new materials. For example, analogies from biological systems could illuminate the self-assembly of complex physical structures and the role of molecular geometry and motion in restricted dimensions. The synthesis, processing and understanding of complex multi-component materials such as a blue laser depend on interdisciplinary research among physicists, materials scientists, and engineers.
Grand Challenge #6: Exploring the Universe
One of the grandest challenges of all physics continues to be seeking to understand the origin and destiny of the universe. New generations of tools to explore earlier and earlier moments of the beginning such as the Hubble Telescope could yield the measurements necessary to test the foundations of cosmology. Other engineering marvels could illuminate the nature of the dark matter and energy that constitutes 95% of the mass-energy of the universe or more generally, explore the connections between basic forces of nature and the structure and evolution of the universe. For example, the Laser Interferometer Gravitational-wave Observatory (LIGO) is currently addressing the unsolved theoretical mystery of gravitational waves by trying to directly detect them.
Grand Challenge #7: Unifying the Forces of Nature
Perhaps an even more fundamental challenge than understanding the origin of the universe is integrating the micro and macro levels of nature in a theory of everything that links physics at the tiniest distances to that of the cosmos. Drawing on tools such as increasingly powerful particle colliders, the next generation of experiments should provide a sound footing for the theory to understand the basic constituents of matter. In addition, they could enable us to arrive at a unified description of all the fundamental forces of nature-the strong nuclear force, the electroweak forces, and gravity.
Grand Challenge #8: Physics in Support of Homeland and National Security
A very different kind of challenge arises from the evolving role of our discipline in homeland and national security. Physics promises to support our physical and cyber security by being applied to a variety of areas, including sensors and screening needs, reliable and accurate detection of chemical, biological and explosive agents, and unbreakable quantum cryptographic protocols.
Grand Challenge #9: A Meta-Challenge
The grandest of all challenges for 21st century physics is a meta-challenge above the other research questions: who will be the next generation of physicists doing this research? More specifically, will they be Americans or foreigners, men or women, and how do we motivate them? Perhaps more importantly, who will pay for doing physics and how will that affect how we evaluate the relative importance of all these "grand challenges"? Throughout the coming decades, we need to keep reminding ourselves as well as others that the achievements of physics can and should be brought into harmony with the expectations of the society that we ourselves have helped to nurture because the "physical sciences are sciences for creating wealth."
Authors' Note: Dr. Patel, professor of physics, chemistry, and electrical engineering at UCLA, is a new board member at FAS. He has made numerous seminal contributions in several fields, including gas lasers, nonlinear optics, molecular spectroscopy, pollution detection and laser surgery. Named one of "85 innovations that changed the way we live" by Forbes Magazine, his invention of the high power carbon dioxide laser at Bell Labs in 1964 ultimately enabled surgeons to perform highly intricate surgery using photons instead of scalpels. He is also a former president of the American Physical Society and Sigma Xi, the Scientific Research Society. This article was adapted from a talk Dr. Patel gave to the Council of Scientific Society Presidents on May 4th by Izzat Jarudi who is entering his final year of undergraduate study at MIT in the Department of Brain and Cognitive Sciences.