Praxis Archives – Page 81 of 181

Henri Poincaré: A Biography Through the Daily Papers

By Jean-Marc Ginoux and Christian Gerini
World Scientific
Hardback: £19
E-book: £14

Henri Poincaré: A Biography Through the Daily Papers – where papers clearly include letters, because many are included – has caused some confusion in my mind. Turning the pages, it is hard to know where I am in time, and the events that are described seem to be of sub-relevance to what I was keen to read about. Two towering examples concern Poincaré’s relation to politics and relativity.

I note that despite extensive discussion of his interaction with the daily press, there is only the briefest mention that Henri Poincaré had an influential cousin, Raymond Poincaré, who was president of France during the years 1913–1920 (and so covered the First World War), and before that a member of the French parliament, and on several occasions minister or prime minister. I had been hoping to learn how close Henri was to Raymond and how this impacted on the opinion of the French public on both of them – a genius mathematician and a powerful politician from the same family.

I also hoped for a discussion of the relation of Henri Poincaré to Hendrik Antoon Lorentz and Albert Einstein. There is only one phrase, on page 212 at the end of the subsection on an “old quarrel” with Einstein – and in my view this is inaccurate. What I know from having read some of Poincaré’s research papers is that it was Lorentz who was castigated by Poincaré for “needing five pages where five words suffice” (I paraphrase). The situation with Einstein seemed more complex. Here I was seeking clarity. Everybody “knows”, and therefore in accord with diplomatic traditions, this book avoids any explicit mention of what is, in my opinion, the historical-context issue of importance.

A search on the web reveals a recommendation letter from Poincaré regarding the appointment of Einstein at ETH-Zurich written in November 1911. In this letter, Poincaré the mathematician, who died in 1912, characterizes Einstein the young physicist, who became noticed around 1907–1912, as an oddity among scientists, deserving a mention for this reason: “Mr Einstein is one of the most original thinkers I have ever met,” and going on to say, “Since he seeks in all directions one must…expect most of the trails which he pursues to be blind alleys.” This shows that Poincaré died in ignorance of the fact that Einstein had already created several new paradigms of science, of which (special) relativity was directly related to Poincaré’s own work. I wonder if there is any other evidence in the press or in letters about what Poincaré knew and thought about Einstein?

Having seen this letter, I believe that in November 1911 Poincaré had no appreciation of the subtle nature of Einstein’s revolutionary work. Poincaré, who worked on the generalized Lorentz transformations, does not mention E = mc², arguably the most famous equation, published six years previously. By 1911 Poincaré had created the tools that were needed to prove E = mc² in more abstract mathematical terms, and yet he showed no interest in following Einstein’s footsteps. Why?

With the two pivotal issues – Henri Poincare’s relation to the family’s political power and his competition with the young and most-important scientist of the epoch – not addressed, I wonder what priorities led to selection of the material that is presented. There is the “Dreyfus affair”, which is discussed amply and where Poincaré played an honourable role. This was clearly of contemporary importance, but historically, looking at Poincaré the pre-eminent mathematician, this is a footnote at best. On the other hand, the presentation of his involvement in Ernst Mach’s thinking and the Earth’s rotation is the high point of this small book, and might yet justify its presence in the history of science literature.

Cosmic Cartoon Collection: Cartoons on Astronomy, Cosmology, Quarks, and other Physical Matters

By Claus Grupen
Universitätsverlag Siegen
Paperback: €5

Cartoons about science often take on a life of their own, as people copy them to add interest to their presentations, hand them on, add them to their websites, blogs and so on. I once found an excellent one about neutrinos left on a photocopier, which later became a key part of some of my talks. What often happens is that the name of the cartoonist becomes lost as the cartoons become widely spread – especially if the signature is small and becomes blurred with multiple copying. That seems to be the case with some of Claus Grupen’s work. Indeed, I was recently asked to identify the source of a familiar cartoon about the Higgs boson. Only after failing to find the answer via Google, did I remember that Grupen draws cartoons – and, yes, it was one of his.

Probably better known as a physicist and author of a number of textbooks, for example, on astroparticle physics, he also has a talent for sketching, and so could create his own amusing visuals to accompany his lectures. He has now assembled a range of his output in this small book published by Siegen University, where he has been professor of physics for many years.

As advertised in the subtitle, the cartoons cover a variety of topics in physics, but mainly focus on phenomena at the largest and smallest scales. Some are decidedly whimsical, while others are more didactic, and some seem to hark back to an earlier age in terms of the representation of women. This said, there is enough variety to bring a smile to most physicists, and at least now when people use one of Grupen’s cartoons, they might know whom to credit.

Particle Fever

“He was ALWAYS there!” This was the reaction of CERN scientists who spent years being followed by film-maker Mark Levinson. The result is Particle Fever – a feature-length documentary about CERN, which has been touring cinemas and festivals, reaching audiences far beyond particle physics. Why? Because Levinson manages to capture, through his narrative and character-driven piece, a compelling story of passion, disaster, loss and then triumph. It is not “boy meets girl”, but scientists build accelerator, scientists lose accelerator (in the September 2008 incident), scientists get accelerator running again and find elusive particle – cue thunderous applause.

The film focuses on a handful of CERN characters, from the ATLAS experiment mainly: Fabiola Gianotti, Martin Aleksa and Monica Dunford, together with Mike Lamont from the accelerator side. While this skews the film away from the reality of thousands of collaborating physicists, it enables a picture to form through the eyes of these protagonists of passionate people working together towards a common goal. Levinson weaves in US-based theorists David Kaplan, Nima Arkani-Hamed and Savas Dimopoulos to stitch together a dramatic narrative of a mighty quest for the Higgs boson. In being swept along by the action, the audience is also taught a fair amount of physics with the help of beautifully designed graphics. My most memorable scene is the moment of the first LHC collisions, where Levinson’s use of music and kaleidoscopic imagery leaves the audience captivated by the almost spiritual exaltation of this scientific achievement.

This US film-maker aiming at a US audience has, inevitably, made an American film, with gutsy postdoc Monica and self-assured theorists. A great deal of the film is dominated by American accents, so much so that I felt that the international spirit of CERN became somewhat neglected. Nonetheless, Monica delivers a spectacular performance and was by far my favourite “character”, with her candid pieces to camera and analogies: “The entire control room is like a group of six-year-olds whose birthday is next week…and there’ll be cake.”

There is something incredibly heart-warming about watching your place of work portrayed dramatically on the big screen. Goosebumps came in waves with the film’s twists and turns, and I came away thinking “Wow, I work there.” As a result, I pity my poor family, who will all have to watch this at Christmas, whether they want to or not!

• Particle Fever is currently touring cinemas and festivals, and is available to buy as an HD download worldwide from 15 July. For more details, see http://particlefever.com/.

How Big is Big and How Small is Small: The Sizes of Everything and Why

By Timothy Paul Smith
Oxford University Press
Hardback: £25
Also available as an e-book, and at the CERN bookshop

This book canters through the sizes and lifetimes of things, from the outermost reaches of the universe to the confined locality of quarks, telling us what is found where and why, and is, according to the publisher’s website, suitable for “interested general readers as well as professional scientists” – a broad church.

In scanning 45 orders of magnitude, the author presents a wealth of information on “everything”, from cosmology to string theory, with passing reference to cooking, football, square dancing and more. The narrative is exuberant and many of the facts are little gems, but they are jumbled up, disordered and congested. The book reads like a series of digressions and there are enough typos and mistakes – bacteria and criteria are plural not singular, the shadow on a sundial is not cast by a gnome – to irritate anyone trying to stay the course.

Concepts seemingly pop up out of nowhere, reappearing again (and again and again) when the plot is all but lost. Much of the material is erudite, abstruse and irrelevant, such as “The delta particles Δ^–– Δ^– Δ⁰ Δ⁺ are like neutrons and protons but with complex spin.” Spin, complex or not, is not in the too-brief index, so the reader cannot check whether it has been defined earlier, or indeed anywhere, and the doubly charged member of this quartet is actually the Δ⁺⁺, although by now – page 123 – it is debatable whether even the most interested readers care. And why should they?

Some aggressive editing would have been in order, not only to fix imperfections and remove chunks of repeated or unnecessary text, but also to avoid slowing down the observant with infelicitous phrasing, for example, “A number of species in the new world and the old world have the same common name because, at least superficially, they look the same, for example the robin and the buffalo.”

And in a cup of water drawn from an ocean today, how many molecules were in a cupful poured into the oceans long ago? After 10 pages of exhaustive and exhausting accounts of the work of Avogadro, Dalton, Gay-Lussac, Loschmidt and Maxwell, we arrive at the numbers. There are 3.3 × 10²⁴ water molecules in a cup and 1.3 × 10²² cups in the oceans. So, 250 of the original molecules are in today’s cup and, although not stated, the oceans contain 4.3 × 10⁴⁶ water molecules. Yes? No! On the following page, “there are about 8 × 10⁴⁵ molecules of water on Earth.”

I was once told, if lost for affable words when asked for an opinion on something quite extraordinary, to say “astounding!” This book is astounding, which is a pity as it could and should have been excellent.

US particle-physics community sets research priorities

In May, an advisory panel to federal funding agencies in the US approved a proposed plan for the future of the country’s particle physics. Top priorities in the plan – written by the Particle Physics Prioritization Panel (P5) – include continuing to play a major role at the LHC in Europe; building a world-leading neutrino programme hosted in the US; and participating in the development of a proposed future linear collider, if a decision is made in Japan to go forward with construction.

The P5 report culminates a process open to all members of the US particle-physics community that lasted more than a year. It was presented to the High Energy Physics Advisory Panel (HEPAP), a body that formally advises the US Department of Energy Office of Science and the National Science Foundation.

The plan recommends a US particle-physics programme that will pursue research related to the Higgs boson, neutrinos, dark matter, dark energy and inflation, and as-yet-undiscovered particles, interactions and physical principles. It advises increasing investment in the construction of new experimental facilities.

The P5 panel envisions the US as the host of an international programme of neutrino research that will operate the world’s most powerful neutrino beam and, with international partners, build a major long-baseline neutrino facility complemented by multiple small, short-baseline neutrino experiments. Launching this programme will involve a change in direction, because the panel recommends reformulating the currently planned Long-Baseline Neutrino Experiment as an internationally designed, co-ordinated and funded programme called the Long-Baseline Neutrino Facility, or LBNF. The facility would use a neutrino beam at Fermilab, upgraded through the proposed project called the Proton Improvement Plan II, together with a massive liquid-argon neutrino detector placed underground, probably at the Sanford Underground Research Facility in South Dakota, and a smaller detector placed nearer to the source of the beam.

The plan emphasizes the need for the US to begin several planned second-generation dark-matter experiments immediately, with a vision to build at least one large, third-generation experiment in the US near the beginning of the next decade. It also recommends increasing funding for the particle-physics components of cosmic surveys.

The strength of worldwide collaboration

The enthusiasm and motivation to explore particle physics at the high-energy frontier knows no borders between the nations and regions of the planet. It is shared between physicists of widely different cultures and origins. This is evident today when looking around the large but still overcrowded auditoria where the latest results from the LHC are presented, as with the announcements of the Higgs-boson discovery. Such results are, in turn, presented by speakers on behalf of LHC collaborations that span the globe, with physicists from all inhabited continents.

CCvie2_06_14 — Peter Jenni in the ATLAS cavern.
Image credit: Claudia Marcelloni.

Today we take this for granted, but it is worth remembering that it took about two decades to grow and consolidate these worldwide scientific and human projects into the peaceful, creative and efficient networks that are now exploring LHC physics. This process of collaboration building is of course not finished yet, and many challenges remain. CERN and its experiment collaborations at the LHC’s predecessors – the Large Electron–Positron collider and the Super Proton Synchrotron pp collider – have long been a fertile cradle for physicists teaming up from different regions, but with the LHC collaborations, globalization for the experiments has reached a new scale. Roughly speaking, about half of the participants in ATLAS and CMS are from non-member states of CERN.

I consider it a big privilege to have witnessed this evolution from inside CERN and actively from inside the ATLAS collaboration – and to have been able, humbly, to contribute to it a little. For me, the first contacts with far-away countries started with several visits as a junior member of CERN delegations in the late 1980s and early 1990s, presenting the LHC dream to colleagues and decision makers in places such as Russia (still the Soviet Union in the beginning), Eastern Europe and Japan, and later across the world. My “hat” changed quickly from predominantly CERN to ATLAS from the early 1990s, and the focus moved from generic LHC detectors and physics to a concrete experiment project.

A formidable evolution took place during the past 25 years, which was a pleasure to see. Presenting the LHC and ATLAS in the early years could be quite an adventure. There were places where electricity for the slides was not always guaranteed, many colleagues from potential new collaboration partners barely spoke any English, and the local custom could be that only the most senior professor would be expected to speak up. Today one may find, at the same places, the most modern conference installations and – even more enjoyable to see – confident, clever young students and postdocs expressing their curiosity and opinions.

What was also striking in the early times was the great motivation to be part of the experiment collaborations and to contribute – sometimes under difficult conditions – to the building up of the experiments. I often had the impression that colleagues in less privileged countries made extraordinary efforts, with many personal sacrifices, to fulfil their promises for the construction of the detectors. Those of us from richer countries should not forget that!

Of course an experiment like ATLAS could not have been built without the massive and leading contributions from CERN’s member states and other large, highly industrialized countries, and we experimentalists must be grateful for their support in the first place. They are the backbone that made it possible to be open to other countries that have great human talent but little in the way of material resources.

The years immediately following the ATLAS and CMS Letters of Intent in October 1992 were a time when the two collaborations grew most rapidly in terms of people and institutes. The spokespersons made many trips to far-flung, non-European countries to motivate and invite participation and contributions to the experiments, in parallel (and sometimes even in competition) with CERN’s effort to enlist non-member-state contributions to enable the timely construction of the accelerator. It was during this period that the current healthy mix of wealthy and less-wealthy countries was established in the two collaborations, placing value clearly not only on material contributions but also on intellectual ones.

The building up and consolidation of collaboration with continents in the Southern hemisphere is, in general, more recent, and has benefited, for example in the case of Latin America, from European Union exchange programmes, which in particular have brought many bright students to the experiments. Yet, there is a long way to go in Africa, with many talented people eager to join the great LHC adventure. Of course fundamental physics is our mission, but personally I am also convinced that attracting young people into science will help society in all regions, ultimately. So CERN with the LHC, which from the early dreams now spans half of the organization’s 60 years, can also be proud of contributing a seed to building up a peaceful global society. For me personally, besides the physics, the LHC has also brought many friends across the world.

Boundary Conformal Field Theory and the Worldsheet Approach to D-Branes

By Andreas Recknagel and Volker Schomerus
Cambridge University Press
Hardback: £65 $99
Also available as an e-book

Boundary conformal field theory is concerned with a class of 2D quantum field theories, which display a rich mathematical structure and have many applications, ranging from string theory to condensed-matter physics. This comprehensive introduction to the topic reaches from theoretical foundations to recent developments, with an emphasis on the algebraic treatment of string backgrounds.

Une introduction à L’aventure du grand collisionneur LHC: Du big bang au boson de Higgs

By Daniel Denegri, Claude Guyot, Andreas Hoecker and Lydia Roos
EDP Sciences
Paperback: €34
Also available at the CERN bookshop

The authors, leading figures in the CMS and ATLAS experiments, have succeeded in writing a remarkable book, which I enthusiastically recommend to anyone interested in learning about the recent progress, open questions and future perspectives of high-energy physics. Throughout its 300 pages, it offers a broad coverage of the present status of particle physics, adding a few chronological accounts to place things in an historical context.

Despite being published in a collection that targets the general public, the book delves into several topics to a deep level and will be useful reading for many professional physicists. To accommodate different audiences, the authors have organized the book nicely in two “layers”, the standard flow of chapters being complemented by extra boxes giving “further reading”. Still, the reader is often told that some sections might be left aside in a first reading. It seems to me that this is a well-balanced solution for such a book, although I wonder if most readers from the “general public” would agree with the claim that the text is written in a “simple and pedagogical form”. The first chapter, describing the Standard Model, is particularly demanding and long, but these 40 pages should not deter: the rest of the book provides easier reading.

I was impressed particularly by the care with which the authors prepared many figures, which in some cases include details that I have not seen in previous works of this kind – for example, the presence of gluon lines and quark–antiquark loops inside the cartoon representing the pion, besides the standard valence quarks. Such representations are common for the proton, especially when discussing deep-inelastic scattering measurements, but it is rare to point out that any hadron – including the π or the Υ – should equally be characterized by “parton distribution functions”. The profusion of high-quality figures and photographs contributes significantly to making this book well worth reading.

A few things could be improved in a future edition. For instance, the number of footnotes is excessive. While meant as asides not worth including in the main body of the text, they end up disrupting the fluidity of the reading, especially when placed in the middle of a sentence. Most footnotes should be integrated in the text, deleted, or moved to the end of the book, so that the reader can ignore them if preferred. While understanding that this book is addressed to a French audience, I would nevertheless recommend “smoothing out” some French-specific choices. For instance, I was pleased to read that Pierre Fayet, in Paris, had an important role in the development of the MSSM extension to the Standard Model, but I was puzzled to see no other name mentioned in the pages devoted to supersymmetry.

Being one of the “LHC adventurers” myself, I read with particular curiosity the chapters devoted to the construction of the LHC accelerator and experiments, which include many interesting details about sociological aspects. I would have liked this part to have been further expanded, especially knowing by personal experience how fascinating it is to listen to Daniel Denegri, when he tells all sorts of anecdotes about physics and physicists.

All in all, this is a highly recommendable book, which provides an interesting guided tour through present-day high-energy physics while, at the same time, offering opportunities for non-French people to learn some French expressions, such as “se faire coiffer au poteau“. Note, however, that the enjoyable reading comes mixed with harder sections, which require extra effort from the reader: this book, like the LHC data, provides “du pain sur la planche“.

The Physics of Quantum Mechanics

By James Binney and David Skinner
Oxford University Press
Hardback: £49.99
Paperback: £24.99
Also available as an e-book

The aim of this book is to give students a good understanding of how quantum mechanics describes the material world. It shows that the theory follows naturally from the use of probability amplitudes to derive probabilities. It emphasizes that stationary states are unphysical mathematical abstractions that enable solution of the theory’s governing equation – the time-dependent Schrödinger equation. Every opportunity is taken to illustrate the emergence of the familiar classical, dynamical world through the quantum interference of stationary states.

Introduction to Modern Physics: Solutions to Problems

By Paolo Amore and John Dirk Walecka
World Scientific
Paperback: £32

John Dirk Walecka’s Introduction to Modern Physics: Theoretical Foundations, published in 2009 aimed at covering a range of topics in modern physics in sufficient depth that things would “make sense” to students, so that they could achieve an elementary working knowledge of the subjects. To this end, the book contained more than 175 problems. Now, Introduction to Modern Physics: Theoretical Foundations provides solutions to these problems.

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