Nonlinear Physics of Ecosystems Physics Today Nonlinear Physics of Ecosystems Hugo Fort Citation: Physics Today 68(10), 46 (2015); doi: 10.1063/PT.3.2949 View online: http://dx.doi.org/10.1063/PT.3.2949 View Table of Contents: http://scitation.aip.org/content/aip/magazine/physicstoday/68/10?ver=pdfcov Published by the AIP Publishing This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. 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When I caught a distracted glimpse of her artwork, I thought she had drawn the baryon decuplet, an often-used dia- gram to depict relations between some of the particles composed of three quarks. The baryon decuplet doesn’t come easy to humans, but the beauty of sym- metry does. And how amazing it is that physicists have found symmetry tightly woven into the fabric of nature itself: Both the standard model of particle physics and general relativity, currently our most fundamental theories, are in essence mathematically precise imple- mentations of symmetry requirements. Next to being instrumental for the accurate description of nature, symme- tries are also universally appealing to humans, as reflected in art and design across cultures. For the physicist, it is second nature to see the equations be- hind the art. Indeed, having that ability may be considered either a curse or a blessing. To Frank Wilczek, it clearly is a bless- ing. In A Beautiful Question: Finding Nature’s Deep Design he highlights the success of symmetries in physics and goes on to answer the question of whether “the world embodies beautiful ideas” with an emphatic “Yes.” Wilczek starts from the discovery of basic math- ematical relationships like Pythagoras’s theorem (and doesn’t shy away from proving it!) and proceeds through the history of physics, stopping to consider such milestone topics as musical har- monies, the nature of light and the basics of optics, Newtonian gravity and its extension to general relativ- ity, quantum mechanics, and ultimately the standard model of particle physics. He touches briefly on condensed-matter physics—graphene in particu- lar—and takes an interesting detour into the human eye’s limited ability to decode visual information. In the last chapters of the book, Wilczek goes into quite some detail about the particle content of the stan- dard model and how, it seems, the model is not as beautiful as one may have hoped. He introduces the reader to extended theories such as grand unification and also supersymmetry, which was invented to remedy some of the supposed shortcomings of the standard model. The reader unfamiliar with the quantum numbers used to classify elementary particles will likely find some parts of that section a bit demanding. But whether or not one makes the effort to follow the details, Wilczek gets his message across clearly: Striving for beauty in natural law has been a useful guide, and he expects it to remain one. He is, however, careful to note that relying on beauty has, on various occa- sions, led to plainly wrong theories, such as an explanation of planetary orbits in terms of Platonic solids or a theory of atoms based on the mathe- matics of knots. A Beautiful Question is a skillfully written reflection, or “meditation,” as Wilczek puts it. It is well structured and accompanied by many figures, includ- ing two inserts with color prints. The book also contains an extensive glos- sary, recommendations for further reading, and a timeline of discoveries mentioned in the text. The content of the book is unique in the genre of popular works. Dave Goldberg’s The Universe in the Rearview Mirror: How Hidden Symmetries Shape Reality (Dutton, 2013), for example, also discusses the role of symmetries in fun- damental physics, but Wilczek gives more space to the connection between aesthetics in art and science. A Beautiful Question picks up and expands on the theme of Steven Weinberg’s book, Dreams of a Final Theory (Pantheon, 1992), which also expounds on the rel- evance of beauty in the development of physical theories. More than 20 years have passed since Weinberg wrote his book, but the dream is still as elusive today as it was back then. For all its elaboration on the beauty of symmetry, Wilczek’s book falls short of spelling out a conundrum physicists face today: We have no reason to be confi- dent that the laws of nature yet to be discovered will conform to the human sense of beauty. Nor does Wilczek spend many words on aspects of beauty beyond symmetry; he only briefly touches on fractals, and never goes into the rich appeal of chaos and complexity. My mother used to say that “sym- metry is the art of the dumb,” a criticism perhaps too harsh to level at the stan- dard model. But seeing that reliance on beauty has not helped us in the past two decades, maybe it is time to consider that a beautiful answer might not reveal itself as effortlessly as does the appeal of plane tilings to a four-year-old. Maybe the inevitable subjectivity in our sense of aesthetic appeal will turn out to be a curse, misleading us as to where the answers lie. Wilczek’s book contains something for every reader, from the physicist who wants to learn how a Nobel Prize win- ner thinks of the connection between ideas and reality to the layman who wants to know more about the structure of fundamental laws. A Beautiful Ques- tion reminds us of the many ways that science connects to the arts, and it in- vites us to marvel at the success our species has had in unraveling the mys- teries of nature. Nonlinear Physics of Ecosystems Ehud Meron CRC Press, 2015. $89.95 (344 pp.). ISBN 978-1-4398-2631-7 Many concepts and methods from non- linear physics have proved to be useful for addressing important problems in ecology. Indeed, a growing number of physicists are working with ecologists and are making significant contribu- tions to ecology. Pattern formation and spatial ecology—how those patterns are related to ecological phenomena—are particular research areas that benefit The allure of the aesthetic Sabine Hossenfelder is an assistant professor of high-energy physics at Nordita, the Nordic Institute for Theoretical Physics, in Stockholm. She works on physics beyond the standard model and on quantum- gravity phenomenology, and she blogs at http://backreaction.blogspot.com. This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 164.73.83.101 On: Thu, 01 Oct 2015 22:06:59 October 2015 Physics Today 49 from the interdisciplinary inter- actions. For example, field ob- servations of vegetation pat- terns in arid and semiarid regions have revealed patterns similar to ones found in fluid dynamics and nonlinear optics. Any book that attempts to bridge ecology and nonlinear physics would be welcomed by scien- tists who work at the intersection of both fields. In my own work, I have col- laborated with ecologists to develop quantitative methods and models to address biodiversity dynamics and spatiotemporal early warning signals of catastrophic shifts in ecosystems. I have also taught courses for mixed audiences of agronomists, ecologists, and physicists. I was greatly impressed by the vari- ety of topics covered in Ehud Meron’s Nonlinear Physics of Ecosystems and by the depth in which they are discussed. The author’s introduction to each topic is clear, and the book’s overall organiza- tion makes it easily readable. At the be- ginning of each chapter is an outline of the major points treated, and at the end, a summary of the key ideas that were developed. The bibliography is exten- sive and comprehensive. I found few omissions. The most significant one would be James Murray’s classic text Mathematical Biology II: Spatial Models and Biomedical Applications (Springer, 2003), which, although it does not focus on spatial ecology, has substantial over- lap with this book. Nonlinear Physics of Ecosystems also contains many figures and photos that help readers to visual- ize spatial patterns in real eco systems. All that makes Meron’s book an im - portant reference, particularly for re- searchers of spatial self-organization and spatial ecology. The book is divided into three parts. The first begins with a quite standard presentation of the basics of self- organization in nonequilibrium sys- tems. It then offers a qualitative review of spatial ecology and presents out- standing problems such as desertifi - cation and biodiversity loss. The con- cluding chapter for that section raises important and broadly relevant ques- tions about ecosystem modeling: Why model? How should a model be set up? What is the significance of qualitative information? Such questions should be considered by anyone who conducts scientific research and uses models. The second part is devoted to pat- tern formation theory, which, according to Meron, is a missing link in ecological research. In fact, the book’s main pur- pose is to fill that gap; in essence, part two is the book’s nucleus. The author presents basic and advanced methods related to the main types of pattern formation mechanisms. Among the plethora of struc- tures are stripe and hexagonal patterns, scale-free patterns, and spiral waves. The third part considers different applications of pattern formation the- ory to spatial ecology. The author ex- plains the significance of self- organized vegetation patchiness to paramount ecological problems presented in the first part, including desertification and biodiversity loss in changing environ- ments. I enjoyed reading the two final chapters—11 and 12—which cover topics I have been working on, namely, regime shifts, desertification, and species coexistence and diversity in plant communities. Particularly well done were the discussions on different early warning signals of regime shifts and their spatial aspects. I enjoyed the explanation of species coexistence in- duced by plants that act as ecosystem engineers by modifying their physical 20+ years serving the scientific & engineering community NEW VERSION Over 100 new features & improvements in Origin 2015! FOR A FREE 60-DAY EVALUATION, GO TO ORIGINLAB.COM/DEMO AND ENTER CODE: 2876 Over 500,000 registered users worldwide in: ◾ 6,000+ Companies including 120+ Fortune Global 500 ◾ 6,500+ Colleges & Universities ◾ 3,000+ Government Agencies & Research Labs This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 164.73.83.101 On: Thu, 01 Oct 2015 22:06:59 50 October 2015 Physics Today www.physicstoday.org books environment and in certain circum- stances facilitating the growth of other species. Nonlinear Physics of Ecosystems surely will contribute to the development of a newly emerging interdisciplinary re- search field at the interface of ecology and pattern formation. I would recom- mend it to graduate students who want to conduct research in mathematical ecology or physics applied to spatial- ecology problems. A minor caveat: I wish the book had included exercises to help students reinforce and test their understanding; maybe it will in the next edition. Nonetheless, it could be used either as a main or supporting textbook in a one-semester course for advanced un- dergraduate or graduate students in physics or ecology or in a course with a mixed audience of students from both disciplines. I also warmly recommend the book for nonlinear physicists, ap- plied mathematicians, and theoretical ecologists working on those cutting- edge environmental interdisciplinary problems. Hugo Fort University of the Republic Montevideo, Uruguay Particle Accelerators From Big Bang Physics to Hadron Therapy Ugo Amaldi Springer, 2015. $34.99 (284 pp.). ISBN 978-3-319-08869-3 Particle Accelerators: From Big Bang Physics to Hadron Therapy takes us on a fascinating odyssey of accelerator history and applications. Author and prominent CERN scientist Ugo Amaldi’s principal aim is to highlight and praise the role of the machine builders. In doing so, he borrows a comparison made by particle theorist Victor Weiss - kopf, CERN director general from 1961 to 1965. Weisskopf likens accelerator builders to the creators and captains of the ships that brought Christopher Columbus and his crew to the Ameri- cas; experimentalists to those who set foot on the new lands and described them; and, somewhat self-mockingly, theorists to those who stayed behind in Europe and made the prediction that Columbus would arrive at India. Amaldi’s book also confirms the view that developments in science are driven by the achievements of many people across many generations, and that we are indeed standing on the shoulders of giants. The first version of Particle Accelerators was published in 2012 and written in Italian. In 2013 it won a science communi- cation award from the Italian Book Association. Following that success, the author consid- erably expanded his text, add - ing many useful details. In its present form, the book contains many recollections of CERN; it would defi- nitely warm the heart of anyone who worked and lived in that wonderful sci- entific mecca. Particle Accelerators, which is aimed at the general public, is filled with intrigu- ing analogies, metaphors, and humor. For example, the author describes the uncertainty principle as the process of taking a “loan of energy” from the “Heisenberg bank,” with the unusual twist that the greater the loan amount, the earlier it matures. He compares the Bevatron at Lawrence Berkeley National Laboratory to a 10 000-ton “cracker of invisible nuts” and electron–positron annihilation to the disappearance of two colliding strawberries giving rise to a flood of bananas or apples. And he suggests what he considers a compact and more meaningful nomenclature for the three neutrinos: neutrino for the electron neutrino, neutretto for the muon neutrino, and neutrotto (or fatter neutrino) for the tau neutrino. After telling the story of the early ac- celerator builders, the book goes on to particle physics, the field that has most benefited from the technology. Topics covered include the standard model and its extensions; dark matter; dark energy; supersymmetry; and string the- ory, which the author believes provides the most likely explanation for symme- try breaking. If a subsequent edition is written, I hope it includes brief and sim- ple descriptions of the many phenom- ena and methods that are mentioned but never explained—for example, syn- chrotron radiation and the supernova standard candles that led to the idea of an accelerating universe. Medical applications are featured in the book’s concluding section, which de- scribes in popular terms the basics of x-ray and particle imaging and tumor treatment. Readers will learn about many technical details and enjoy some intriguing stories along the way. For instance, the first—and for a long time, the only—interest in an early article outlining computerized tomography came from a Swiss center for avalanche research, which wanted to use the technology to find objects—like lost skiers—trapped in snow. Amaldi captures the roman- tic spirit of the early days of par- ticle physics experiments. He also touches on the cooperation and competition between the continents. Surprisingly, at least at the time this edition was pub- lished, all bosons since 1948 had been discovered in Europe and all fermions in America—a peculiar sort of symmetry breaking. The author also occasionally makes what some readers may consider as frank and provocative remarks. For example, he states that the Large Electron–Positron Collider could have discovered the Higgs more than a decade ago had he and his colleagues convinced the CERN directorate to invest substantially in upgrading the superconducting RF cavities. Amaldi also laments that Bruno Touschek and Gersh Budker were not rewarded with the Nobel Prize for their role in the de- velopment of electron–positron collid- ers; he suggests that had the scientists been working in the US—where the main action was—they would have re- ceived the honor. In any case, such com- ments are nicely balanced by wonderful stories of cooperation, such as between Brookhaven National Laboratory and CERN during the building of the CERN Proton Synchrotron. Particle Accelerators culminates with an inspiring story of the development and creation of the Italian National Center for Oncological Hadron Ther- apy, a great achievement for Amaldi, who put an enormous amount of effort and energy into its creation. He is now working to develop a novel linac for proton therapy. These initiatives prove the author’s own maxim that “physics is beautiful and useful.” Andrei Seryi University of Oxford Oxford, UK Gravity Newtonian, Post-Newtonian, Relativistic Eric Poisson and Clifford M. Will Cambridge U. Press, 2014. $80.00 (780 pp.). ISBN 978-1-107-03286-6 Gravity: Newtonian, Post-Newtonian, Rel- ativistic is not the usual relativity text. But it’s the one you need if you actually want to calculate something astrophysi- cal without a supercomputer. I know of no other text that compares with this compendium of tricks for calculating ob- servables in the large fraction of the uni- verse that is not near an event horizon. This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 164.73.83.101 On: Thu, 01 Oct 2015 22:06:59