Showing papers in "Physics Today in 2004"
1,487 citations
[...]
TL;DR: The fuel cell is to become the modern steam engine, and basic research must provide breakthroughs in understanding, materials, and design to make a hydrogen-based energy system a vibrant and competitive force as mentioned in this paper.
Abstract: If the fuel cell is to become the modern steam engine, basic research must provide breakthroughs in understanding, materials, and design to make a hydrogen-based energy system a vibrant and competitive force
1,329 citations
TL;DR: In this article, the application of probability theory to a wide variety of problems in physics, mathematics, economics, chemistry and biology is discussed, along with its application in a wider context.
Abstract: This book goes beyond the conventional mathematics of probability theory, viewing the subject in a wider context. Now results are discussed, along with the application of probability theory to a wide variety of problems in physics, mathematics, economics, chemistry and biology. It contains many exercises and problems, and is suitable for use as a textbook on graduate level courses involving data analysis. The material is aimed at readers who are already familiar with applied mathematics at an advanced undergraduate level or higher. The book is not restricted to one particular discipline but rather will be of interest to scientists working in any area where inference from incomplete information is necessary.
1,268 citations
TL;DR: In this article, a new theoretical framework is proposed to calculate the electronic structure of correlated electrons, which can exist in a rich variety of phases and can exhibit some of the most intriguing phenomena in condensed matter physics.
Abstract: Materials with correlated electrons exhibit some of the most intriguing phenomena in condensed matter physics. A new theoretical framework is now allowing theorists to calculate the electronic structure of these materials, which can exist in a rich variety of phases.
639 citations
TL;DR: The realization that light beams can have quantized orbital angular momentum in addition to spin angular momentum has led, in recent years, to novel experiments in quantum mechanics and new methods for manipulating microparticles.
Abstract: The realization that light beams can have quantized orbital angular momentum in addition to spin angular momentum has led, in recent years, to novel experiments in quantum mechanics and new methods for manipulating microparticles
568 citations
TL;DR: After certain cellular polymers are internally charged, they behave like soft and sensitive piezoelectrics that can be used to interconvert acoustical or mechanical signals and electrical signals.
Abstract: After certain cellular polymers are internally charged, they behave like soft and sensitive piezoelectrics that can be used to interconvert acoustical or mechanical signals and electrical signals.
508 citations
TL;DR: The authors showed that materials engineered to have negative permittivity and permeability demonstrate exotic behavior, from a negative refractive index to subwavelength focusing, demonstrating exotic behavior from negative to positive refractive indices.
Abstract: Materials engineered to have negative permittivity and permeability demonstrate exotic behavior, from a negative refractive index to subwavelength focusing.
465 citations
TL;DR: Locally localized modes have been theoretical constructs for more than a decade and have been observed in physical systems as distinct as charge transfer solids, Josephson junctions, photonic structures, and micromechanical oscillator arrays.
Abstract: Intrinsic localized modes have been theoretical constructs for more than a decade. Only recently have they been observed in physical systems as distinct as charge-transfer solids, Josephson junctions, photonic structures, and micromechanical oscillator arrays.
390 citations
TL;DR: In this paper, the authors discuss the history of the notion of globe normalism and its application in the field theory of intersectionality, and propose methods for using it in the use of the GLOBAL FORMALISM.
Abstract: I: CLASSICAL DYNAMICAL THEORY II: THE HEURISTIC ROAD TO QUANTIZATION. THE QUANTUM FORMALISM AND ITS INTERPRETATION III: EVALUATION AND APPROXIMATION OF FEYNMAN FUNCTIONAL INTEGRALS IV: LINEAR SYSTEMS V: NONLINEAR FIELDS VI: TOOLS FOR QUANTUM FIELD THEORY. APPLICATIONS VII: SPECIAL TOPICS VIII: EXAMPLES. SIMPLE EXERCISES IN THE USE OF THE GLOBAL FORMALISM
378 citations
TL;DR: In this paper, the authors show that in laboratory plasmas and in space, charged microparticles can be uniquely informative and can be used for fusion energy schemes and semiconductor manufacturing.
Abstract: Charged microparticles are an annoyance in the plasmas of fusion energy schemes and semiconductor manufacturing. But in laboratory plasmas and in space, they can be uniquely informative.
337 citations
TL;DR: It is argued that common properties of those networks allow for a quantitative theory of the structure, organization, and dynamics of living systems.
Abstract: Biological systems have evolved branching networks that transport a variety of resources. We argue that common properties of those networks allow for a quantitative theory of the structure, organization, and dynamics of living systems.
TL;DR: In this article, the Dirac Delta Function has been used to model the relationship between stress and strain in two-dimensional lattices and elasticity relations in a three-dimensional manifold.
Abstract: 1 Introduction: Linear Atomic Chains- 2 Two- and Three-Dimensional Lattices- 3 Properties of the Phonon Gas- 4 Stress and Strain- 5 Elasticity Relations- 6 Static Deformations of Solids- 7 Dynamical Behavior of Solids- 8 Dissipation and Noise in Mechanical Systems- 9 Experimental Nanostructures- 10 Nanostructure Fabrication I- 11 Nanostructure Fabrication II- A Mathematical Tools- A1 Scalars, Vectors, Tensors- A11 Vectors- A12 Tensors- A2 Eigenvectors and Eigenvalues- A3 The Dirac Delta Function- B Compatibility Relations for Stress and Strain- C Notation
TL;DR: In this paper, the authors discuss the need for close international cooperation, peace, and security for sharing natural resources in order to deal with population growth and energy demand, some on the timescale of a single human lifespan.
Abstract: Population growth and energy demand are exhausting the world’s fossil energy supplies, some on the timescale of a single human lifespan. Increasingly, sharing natural resources will require close international cooperation, peace, and security.
TL;DR: The Arctic has warmed by about 1°C in the past two decades as mentioned in this paper, which has seen glaciers retreat, permafrost thaw, snow cover decrease, and ice sheets thin.
Abstract: The Arctic has warmed by about 1°C in the past two decades. That time period has seen glaciers retreat, permafrost thaw, snow cover decrease, and ice sheets thin.
TL;DR: The theory of QCD and Monte Carlo models are discussed in this paper, where the strong coupling constant and the leading-log QCD are compared to the Parton distribution of the QCD.
Abstract: 1 Introduction 2 The development of QCD 3 The theory of QCD 4 Monte Carlo models 5 Experimental setup 6 QCD analyses 7 Structure functions and Parton distributions 8 The strong coupling constant 9 Tests of the structure of QCD 10 Tests of the gauge structure of QCD: Colour factors 11 Leading-log QCD 12 Differences Between Quark and Gluon Jets 13 Fragmentation 14 Summary A Elements of group theory B Building blocks of theoretical predictions C Dimensional Regularization D R(ital) gamma(ital lowercase subset), R(ital)iota(lowercase ital subset) and R(ital)tau(ital lowercase subset) for arbitrary colour factors E Scaling Violations in fragmentation functions F Solutions References
TL;DR: Both the precision control of trapped-ion systems and very large samples of cold neutral atoms are opening important new possibilities for quantum computation and simulation as mentioned in this paper, and both of these possibilities can be found in the literature.
Abstract: Both the precision control of trapped-ion systems and very large samples of cold neutral atoms are opening important new possibilities for quantum computation and simulation.
TL;DR: A Century of Innovation as mentioned in this paper is a collection of the most significant engineering achievements of the last hundred years, from the first flight at Kitty Hawk to the birth of the Internet, with a focus on more commonplace advances that had a profound and widespread effect on all of society.
Abstract: As the world eagerly looked forward to the dawn of a new millennium, the turning of the calendar also represented an opportunity to pause and reflect on the tremendous ingenuity and invention that marked the previous hundred years. Electricity, automobiles, telephones, radio, television, computersa | these are a just a few of the innovations the decades had introduced a " all compliments of the worlda (TM)s engineers. Celebrating a century of innovation, the National Academy of Engineering and a consortium of professional engineering societies present the most significant engineering triumphs of the era. While the achievements encompass many dramatic and highly visible engineering feats, from the first flight at Kitty Hawk to the birth of the Internet, the lineup is largely composed of more commonplace advances that had a truly profound and widespread effect on all of society. Indeed, most of the achievements profiled in this book are so much a part of our lives that we have come to take them for granted. But to learn the stories behind these great achievements is to behold and appreciate them anew. Topping the list is electrification. More than half of the a /Top 20a would not have been possible without it. Abundant and available electric power helped spur Americaa (TM)s economic development and distributed benefits widely, from cities to farms. This achievement clearly shines as an example of how engineering has changed the world. But often we take the likes of air conditioning and refrigeration for granted even though they have significantly improved our sense of comfort and contributed to our physical health, giving us the ability to transport and extend the shelf life of food. Radio and television are so much more than mere entertainment devices. Indeed, they have changed the way we view the world and our place in it. The telephone has made the whole planet a smaller but much more connected place for all of us. And underlying and enabling many of these technologies is the computer a " from room-sized super computers to palm-sized devices. Each chapter tells the life story of a specific engineering achievement. Each chapter also features a personal reflection by a notable engineer involved with the achievement. Among them: Bill Gates, who brought the personal computer into our home; Charles Townes, inventor of the laser; Robert Kahn, one of the originators of the Internet; Bill Anders, the Apollo 8 astronaut who took the famous a /Earthrisea photograph while in lunar orbit; and Wilson Greatbatch, inventor of the pacemaker. The engineersa (TM) commentaries capture the excitement, imagination, vision, and tenacity that ultimately made each achievement a reality. Timelines trace the evolution of the achievements while dramatic illustrations depict how things actually work. Replete with photographs and drawings, the drama of invention and discovery is brought vividly to life. More than a simple tally of engineering achievements, A Century of Innovation is proof positive that the genius and the talent of the worlda (TM)s engineers have truly transformed the way people live.
TL;DR: The heavy elements are made only in cataclysmic events as discussed by the authors, and finding out whether supernovae are cataclysmically enough requires extensive astronomical observation and sophisticated computer modeling. But it is not a trivial task.
Abstract: The heaviest elements are made only in cataclysmic events. Finding out whether supernovae are cataclysmic enough requires extensive astronomical observation and sophisticated computer modeling.
TL;DR: Extracting a signal from noise can be complicated, especially along a coastline filled with marine life, shipping lanes, undersea waves, shelves, and fronts that scatter sound.
Abstract: Extracting a signal from noise can be complicated, especially along a coastline filled with marine life, shipping lanes, undersea waves, shelves, and fronts that scatter sound.
TL;DR: In this article, a number of not-yet-reconciled mathematical approaches can be applied to nonequilibrium systems, and some of them can be found in this paper.
Abstract: Nonequilibrium systems come in many varieties, and a number of not-yet-reconciled mathematical approaches can be applied to them
TL;DR: The second edition of the Introduction to Cosmology as mentioned in this paper is an exciting update of an award-winning textbook aimed primarily at advanced undergraduate students in physics and astronomy, but is also useful as a supplementary text at higher levels.
Abstract: This second edition of Introduction to Cosmology is an exciting update of an award-winning textbook. It is aimed primarily at advanced undergraduate students in physics and astronomy, but is also useful as a supplementary text at higher levels. It explains modern cosmological concepts, such as dark energy, in the context of the Big Bang theory. Its clear, lucid writing style, with a wealth of useful everyday analogies, makes it exceptionally engaging. Emphasis is placed on the links between theoretical concepts of cosmology and the observable properties of the universe, building deeper physical insights in the reader. The second edition includes recent observational results, fuller descriptions of special and general relativity, expanded discussions of dark energy, and a new chapter on baryonic matter that makes up stars and galaxies. It is an ideal textbook for the era of precision cosmology in the accelerating universe.
TL;DR: In this article, the authors argue that if the electric power grid is to meet 21st-century demands, society will need to invest in extensive modernization, which will require massive investment in extensive modernization.
Abstract: If the electric power grid is to meet 21st-century demands, society will need to invest in extensive modernization
TL;DR: The water content of Mars is cold enough that its meager water content appears to exist today simply in frozen and gas phases as mentioned in this paper. But as recent evidence suggests, that may not have always been the case.
Abstract: Mars is cold enough that its meager water content appears to exist today simply in frozen and gas phases. But as recent evidence suggests, that may not have always been the case.
TL;DR: In the 1970s, the publish-or-perish emphasis for some, but not all, institutions has deteriorated into bean counting, and the race is on to publish en masse as discussed by the authors.
Abstract: T recent events, taking place in rapid succession, incited me to write this Opinion. The first was an annual report from a major school of engineering whose dean proudly listed 52 papers that he wrote in the course of the previous year. Such an output is, on average, one idea conceived, executed, written, and published every week. That is an amazing feat for a busy administrator, or anybody else for that matter. The second was a physics professor who was introduced at a meeting as the author of 80 books. This man was not the superhumanly prolific Isaac Asimov, but a professor with a publication rate, over a 20-year career, of one technical book every three months. The straw that broke the camel’s back, at least this Arabian one, was a book on flow control I was asked to review for a journal. The 200-page, camera-ready manuscript was clearly never seen by a copyeditor and was mostly a shoddy cut-and-paste job from the author’s doctoral dissertation—and worse, from the publications of others. The book offered little of value, yet it was priced at 50 cents per page. The three events are a syndrome of what is ailing academic publishing today. Academic institutions in the US have made it imperative for faculty members to publish in order to survive and prosper. The publish-or-perish mantra became a household motto for faculty. There is nothing wrong with that principle if it emphasizes quality rather than quantity. For the most part, that emphasis on publishing has worked for many decades. The number of publications was reasonable, and tenure and promotion decisions in research universities were largely based on the impact of a candidate’s scholarly work, as measured by the number of citations and, less quantitatively, by expert opinions. The number of journals and consequently the number of requests for refereeing were both manageable. Overall, technical books were published when a senior researcher with years of experience had something significant to write about. Unfortunately, today we witness a different environment from that of a generation ago. The publish-or-perish emphasis for some, but not all, institutions has deteriorated into bean counting, and the race is on to publish en masse. Demand spurs supply. Mostly-for-profit publishers of books and journals have mushroomed, and mediocrity has crept into both venues. Journal pages have to be filled, and library shelves have to be stacked with books. The number of periodicals worldwide currently stands at 169 000,1 and the number of books published in the US alone in 2001 is 56 364.2 Of course, not all of these are academic publications, but the sheer numbers are frightening enough. Currently, more journals in a particular research field are published than anyone can reasonably keep up with. The publishing craze has now extended to all-electronic journals. Many articles, both print and electronic, remain without a single citation five or more years after publication. Although more difficult to measure, I presume even more papers remain unread by anyone other than their authors. The way some papers list their authors today, some articles may not even be read by all their respective coauthors.
TL;DR: In fact, the subject that gave me the most trouble was classical mechanics as discussed by the authors, which always struck me as peculiar, because I had no trouble learning more advanced subjects, which were supposed to be harder.
Abstract: Frank Wilczek When I was a student, the subject that gave me the most trouble was classical mechanics. That always struck me as peculiar, because I had no trouble learning more advanced subjects, which were supposed to be harder. Now I think I've figured it out. It was a case of culture shock. Coming from mathematics, I was expecting an algorithm. Instead I encountered something quite different— a sort of culture, in fact. Let me explain.
TL;DR: Precision experiments and astrophysical observations provide complementary tests of Lorentz invariance and may soon open a window onto new physics as discussed by the authors, and they have already constrained models of quantum gravity and cosmology.
Abstract: Precision experiments and astrophysical observations provide complementary tests of Lorentz invariance and may soon open a window onto new physics. They have already constrained models of quantum gravity and cosmology.
TL;DR: In this article, the authors present a framework to study the history of the National Labs and their role in the development of the modern National Laboratory System (NLLS) and its management.
Abstract: * Introduction * Why Study the Labs? * What Were the Labs? * The Approach * I. The Framework *1. Origins * Manhattan Project * Postwar Plans * Postwar Realities *2. Individuality * Contractors * Laboratory Organization * Manpower *3. Interdependence * Security * Organization of the AEC * The Path of Proposals * The Lab Directors' Club * II. The Environment *4. Cold War Winter, 1947--1954 * Drivers * Big Equipment * Small Science *5. False Spring, 1954--1962 * Nationalism and Internationalism * Boundary Disputes * III. Consequences *6. Adaptive Strategies * Specialization * Diversification *7. Exemplary Additions * Biomedicine, 1947--1954 * Solid-State and Materials Science, 1954--1962 * IV. Epilogue and Conclusion *8. Epilogue, 1962--1974 * The Framework * The Environment * The Response *9. Conclusion: Strategy and Structure * The Actors * The System: A New Species * National Labs and National Goals * Appendix 1. Laboratory Operating Budgets, 1948--1966 * Appendix 2. Laboratory Operating Budgets, 1973 * Abbreviations * Notes * Index
TL;DR: For 150 years the Riemann hypothesis has been the holy grail of mathematics as discussed by the authors, and at a moment when mathematicians are finally moving in on a proof, Dartmouth professor Dan Rockmore tells the riveting history of the hunt for a solution.
Abstract: Stalking the Riemann Hypothesis-Dan Rockmore 2007-12-18 For 150 years the Riemann hypothesis has been the holy grail of mathematics. Now, at a moment when mathematicians are finally moving in on a proof, Dartmouth professor Dan Rockmore tells the riveting history of the hunt for a solution.In 1859 German professor Bernhard Riemann postulated a law capable of describing with an amazing degree of accuracy the occurrence of the prime numbers. Rockmore takes us all the way from Euclid to the mysteries of quantum chaos to show how the Riemann hypothesis lies at the very heart of some of the most cutting-edge research going on today in physics and mathematics.