Praxis Archives – Page 46 of 179

Maxwell’s enduring legacy

In 1871, James Clerk Maxwell undertook the titanic enterprise of planning a new physics laboratory for the University of Cambridge from scratch. To avoid mistakes, he visited the Clarendon Laboratory in Oxford, and the laboratory of William Thomson (Lord Kelvin) in Glasgow – then the best research institutes in the country – to learn all that he could from their experiences. Almost 150 years later, Malcolm Longair, a renowned astrophysicist and the Cavendish laboratory’s head from 1997 to 2005, has written a monumental account of the scientific achievements of those who researched, worked and taught at a laboratory which has become an indispensable part of the machinery of modern science.

The 22 chapters of the book are organised in ten parts corresponding to the inspiring figures who led the laboratory through the years, most famously among them Maxwell himself, Thomson, Rutherford, Bragg, Mott and few others. The numerous Nobel laureates who spent part of their careers at the Cavendish are also nicely characterised, among them Chadwick, Appleton, Kapitsa, Cockcroft and Walton, Blackett, Watson and Crick, Cormack, and, last but not least Didier Queloz, Nobel Laureate in 2019 and professor at the universities of Cambridge and Geneva. You may even read about friends and collaborators as the exposition includes the most recent achievements of the laboratory.

Rutherford and Thomson managed the finances of the laboratory almost from their personal cheque book

Besides the accuracy of the scientific descriptions and the sharpness of the ideas, this book inaugurates a useful compromise that might inspire future science historians. So far it was customary to write biographies (or collected works) of leading scientists and extensive histories of various laboratories: here these two complementary aspects are happily married in a way that may lead to further insights on the genesis of crucial discoveries. Longair elucidates the physics with a competent care that is often difficult to find. His exciting accounts will stimulate an avalanche of thoughts on the development of modern science. By returning to a time when Rutherford and Thomson managed the finances of the laboratory almost from their personal cheque book, this book will stimulate readers to reflect on the interplay between science, management and technology.

History is often instrumental in understanding where we come from, but it cannot reliably predict directions for the future. Nevertheless the history of the Cavendish shows that lasting progress can come from diversity of opinion, the inclusiveness of practices and mutual respect between fundamental sciences. How can we sum up the secret of the scientific successes described in this book? A tentative recipe might be unity in necessary things, freedom in doubtful ones and respect for every honest scientific endeavour.

ATLAS – A 25 Year Insider Story of the LHC Experiment

ATLAS – A 25 Year Insider Story of the LHC Experiment is a comprehensive overview of one of the most complex and successful scientific endeavours ever undertaken. 117 authors collaborated to write on diverse aspects of the ATLAS project, ranging from the early days of the proto-collaboration, to the test-beam studies to verify detector concepts, the design, building and installation of the detector systems, building the event selection and computing environment required, forming the organisation, and finally summarising the harvest of physics gathered thus far. Some of the chapters cover topics that are discussed elsewhere – the description of the detector summarises more extensive journal publications, the major physics achievements have been covered in recent review articles and the organisational structure is discussed on the web – but this volume usefully brings these various aspects together in a single place with a unified treatment.

Despite the many authors who contributed to this book, the style and level of treatment is reasonably coherent. There are many figures and pictures that augment the text. Those showing detector elements that are now buried out of sight are important complements to the text descriptions: the pictures of circuit boards are less helpful, besides demonstrating that these electronics exist. A most engaging feature is the inclusion of one-page “stories” at the ends of the chapters, each giving some insight into the ups and downs of how the enterprise works. Among these vignettes we have such stories as the ATLAS collaboration week that almost no one attended and the spirit of camaraderie among the experimenters and accelerator operators at the daily 08:30 run meetings.

One could imagine several audiences for this book, and I suspect that, apart from ATLAS collaborators themselves, each reader will find different chapters most suited to their interests. The 26-page chapter “The ATLAS Detector Today” offers a more accessible overview for students just joining the collaboration than the 300-page journal publication referenced in most ATLAS publications. Similarly, “Towards the High-Luminosity LHC” gives a helpful brief introduction to the planned upgrades. “Building up the Collaboration” will be useful to historians of science seeking to understand how scientists, institutions and funding agencies engage in a project whose time is ripe. Those interested in project management will find “Detector Construction Around the World” illuminating: this chapter shows how the design and fabrication of detector subsystems is organised with several, often geographically disparate, institutions joining together, each contributing according to its unique talents. “From the LoI to the Detector Construction” and “Installation of the Detectors and Technical Coordination” will appeal to engineers and technical managers. The chapters “Towards the ATLAS Letter of Intent” and “From Test Beams to First Physics” catalogue the steps that were necessary to realise the collaboration and experiment, but whose details are primarily interesting to those who lived through those epochs. Finally, “Highlights of Physics Results (2010 – 2018)” could have offered an exciting story for non-scientists, and indeed the thrill of the chase for the Higgs boson comes through vividly, but with unexplained mentions of leptons, loops and quantum corrections, the treatment is at a more technical level than would be ideal for such readers, and the plots plucked from publications are not best suited to convey what was learned to non-physicists.

What makes a collaboration like this tick?

Given the words in the foreword that the book is “intended to provide an insider story covering all aspects of this global science project,” I looked forward to the final chapter, “ATLAS Collaboration: Life and its Place in Society”, to get a sense of the human dimensions of the collaboration. While some of that discussion is quite interesting – the collaboration’s demographics and the various outreach activities undertaken to engage the public – there is a missing element that I would have appreciated: what makes a collaboration like this tick? How did the large personalities involved manage to come to common decisions and compromises on the detector designs? How do physicists from nations and cultures that are at odds with each other on the world stage manage to work together constructively? How does one account for the distinct personalities that each large scientific collaboration acquires? Why does every eligible author sign all ATLAS papers, rather than just those who did the reported analysis? How does the politics for choosing the collaboration management work? Were there design choices that came to be regretted in the light of subsequent experience? In addition to the numerous successes, were there failures? Although I recognise that discussing these more intimate details runs counter to the spirit of such large collaborations, in which one seeks to damp out as much internal conflict as possible, examining some of them would have made for a more compelling book for the non-specialist.

The authors should be commended for writing a book unlike any other I know of. It brings together a factual account of all aspects of ATLAS’s first 25 years. Perhaps as time passes and the participants mellow, the companion story of the how, in addition to the what and where, will also be written.

Particle physicists challenge EC rebranding

An open letter addressed to the presidents of the European Parliament and the European Commission (EC) demanding better recognition for education and research has closed, having attracted around 13,600 signatories during the past two months.

Published on 17 September by a group of eight prominent particle physicists in Europe – Siegfried Bethke (MPI for Physics), Nora Brambilla (TU-München), Aldo Deandrea (U-Lyon 1), Carlo Guaraldo (INFN Frascati), Luciano Maiani (U-Roma La Sapienza), Antonio Pich (U-València), Alexander Rothkopf (U-Stavanger) and Johanna Stachel (U-Heidelberg) – the letter followed the announcement of a new EC organisational structure on 10 September in which former EC directorates for education, culture, sports and youth, as well as that for research, science and innovation, have been subsumed under a single commissioner with the titular brief “innovation and youth”.

“Words are important,” says Maiani, who was CERN Director-General from 1999–2003. “Omitting ‘research’ from the logo of the EC is reason for concern. The response we received, including from prestigious personalities, reassured us that this concern is widely shared.”

With signatories including hundreds of university and laboratory leaders, 19 Nobel laureates and many institutions including the European, French and German physical societies, the letter demands that the EC revises the title of the brief to “Education, Research, Innovation and Youth”. It states: “We, as members of the scientific community of Europe, wish to address this situation early on and emphasise both to the general public, as well as to relevant politicians on the national and European Union level, that without dedication to education and research there will neither exist a sound basis for innovation in Europe, nor can we fulfill the promise of a high standard of living for the citizens of Europe in a fierce global competition.”

Of course we are disappointed that the voices of more than 13,600 scientists went unheard
Johanna Stachel, University of Heidelberg

The letter closed on 13 November after the EC issued a press release stating that it will rename three commissioner portfolios, but that the title of commissioner designate for innovation and youth, Mariya Gabriel, is not among those three being changed. “Naturally we are disappointed, and even frightened as the decisions about non-renaming prove that the omission of research and education in the title signals how low these fields may be valued by the new commission,” says Bethke.

“We will keep pushing,” adds Stachel. “But of course we are disappointed that the voices of more than 13,600 scientists went unheard, despite many prominent voices and also significant press coverage.”

On 18 November, Rothkopf responded to European parliament president David Sassoli on behalf of the initial signatories with a letter, stating: “It is with great disappointment that we recognize that the voice of science has not reached the ears of the Commission. The intention of the Commission is to stimulate innovation. But we reiterate with force that without research and education there is no future to innovation… We are counting on you, Mr. President, to represent the voice of all European citizens who have signed up as supporter of the open letter and in the interest of European research.”

Update 28th November: Speaking at a plenary session of the European Parliament in Strasbourg on 27 November, European Commission (EC) president-elect Ursula von der Leyen announced that the brief of commissioner Mariya Gabriel would be been renamed “Innovation, research, culture, education and youth”. The addition of “education” and “research” to the initial title of the brief announced on 10 September was met with applause in the chamber.

The Weil conjectures

“I am less interested in mathematics than in mathematicians,” wrote Simone Weil to her brother André, a world-class mathematician who was imprisoned in Rouen at the time. The same might be said about US novelist and onetime mathematics student Karen Olsson. Despite the title, her new book, The Weil Conjectures, stars the extraordinary siblings at the expense of André’s mathematical creation.

First conceived by André in prison, and finally proven three decades later by Pierre Deligne in 1974, the Weil conjectures are foundational pillars of algebraic geometry. Linking the continuous and the discrete, and the realms of topology and number theory, they are pertinent to efforts to unite gravity with the quantum theories of the other forces. Frustratingly, though, mathematical hobbyists hoping for insights into the conjectures will be disappointed by this book, which instead zeroes in on the people in orbit around the maths.

Olsson is particularly fascinated by Simone Weil. An iconoclastic public intellectual in France, and possessed by an intensely authentic humanity that the author presents as quite alien to André, Simone was nevertheless envious of her brother’s mathematical insight, writing that she “preferred to die than to live without that truth”. Olsson is clearly empathetic, and so, one would suspect, will be most readers in a profession where intellect is all. Whether one is a grad student or a foremost expert in the field, there is always someone smarter, whose insights seem inaccessible.

Physicists may also detect echoes of the current existential crisis in theoretical physics (see Redeeming the role of mathematics) in Simone’s thinking. While she feels that “unless one has exercised one’s mind at the gymnastics of mathematics, one is incapable of precise thought, which amounts to saying that one is good for nothing,” she criticises “the absolute dominion that is exercised over science by the most abstract forms of mathematics.”

Peppered with anecdotes about other mathematicians – Girolamo Cardano is described as a “total dick” – and more a succession of scenes than a biography, the book is as much about Olsson herself as the Weils. The prose zig-zags between vignettes from the author’s own life and the Weils without warning, leaving the reader to search for connections. Facts are unsourced, and readers are left to guess what is historical and what is the author’s impressionistic character portrait. Charming and quirky, the text transforms dusty perceptions of the meetings of the secret Bourbaki society of French mathematicians into scenes of lakeside debauchery and translucent camisoles that are almost reminiscent of Pride and Prejudice. Olsson even takes us into Simone’s dreams, with the conjectures only cropping up at the end of the book. If you limit your reading to the maths and the Weils, the resulting slim volume is a page turner.

Ernst-Wilhelm Otten 1934–2019

Ernst Otten initiated the KATRIN neutrino experiment, among many other achievements. Credit: University of Mainz

Ernst-Wilhelm Otten received his doctorate in 1962 at the University of Heidelberg under the supervision of atomic and nuclear physicist Hans Kopfermann. From 1972 until his retirement in 2002, he headed the department of experimental atomic and nuclear physics (EXAKT) at the University of Mainz. Ernst spent numerous research stays abroad, including at CERN and at the Ecole Normale Supérieure in Paris. After his retirement Ernst continued his research activities, especially for the KATRIN neutrino experiment. The hallmark of his work was the extraordinary breadth across almost all disciplines of physics, which earned him a large number of distinctions and prizes.

In Heidelberg, Ernst developed the method of optical pumping for polarising the nuclear spins of radioactive isotopes to determine their nuclear moments. He also recognised, from its start-up in the late 1960s, the opportunities offered by the on-line isotope separator ISOLDE at CERN. He became a pioneer of optical spectroscopy with accelerators. The discovery of unexpected nuclear-shape coexistence and nuclear-size changes in neutron-deficient mercury isotopes is one of the most outstanding results obtained at ISOLDE, as early as 1972. In Mainz, his group developed the high-resolution method of collinear laser spectroscopy – now a workhorse at ISOLDE for the determination of nuclear ground-state properties of short-lived nuclei – and with his collaborators initiated laser-based trace analysis for the detection of radionuclides in the environment.

The electron accelerators at Mainz enabled spectacular experiments: the test of parity non-conservation by neutral currents in polarised–electron nucleon scattering, and the determination of the neutron electric form factor using polarised ³He targets at high density. With hyperpolarised ³He gas, Ernst performed lung diagnostics by magnetic resonance imaging in collaboration with the German Cancer Research Centre in Heidelberg and the department of radiology at the University of Mainz.

In the 1980s, when a group reported a 30 eV mass of the antineutrino, Ernst developed a novel high-resolution beta spectrometer at Mainz to determine the neutrino mass very precisely from tritium decay. Together with his team he succeeded in setting an upper limit of 2 eV. After the discovery of neutrino oscillations in 1998, proving the existence of finite neutrino masses, Ernst initiated the KATRIN experiment at the Karlsruhe Institute of Technology to measure the neutrino mass. The construction of this technically extremely difficult spectrometer started in 2001, and Ernst was very actively involved until his death on 8 July. As such, he was able to witness the first successful result: the setting of a new upper limit on the neutrino mass of 1 eV (see KATRIN sets first limit on neutrino mass).

Ernst leaves deep traces in science and in the physics community. We will remember him as a great scientist, teacher, mentor and friend.

Irish politicians call for associate membership of CERN

A cross-party committee of the legislature of the Republic of Ireland has unanimously recommended joining CERN. In a report published last week, the Joint Committee on Business, Enterprise and Innovation recommended that negotiations to become an Associate Member State begin immediately. The report follows the country’s Innovation 2020 science strategy, published in 2015, which identified CERN as one of four international research bodies which Ireland would benefit from joining. Since then, Ireland has joined the other three organisations, namely the European Southern Observatory, the intergovernmental life-science collaboration ELIXIR, and the LOFAR network of radio-frequency telescopes.

Ireland is one of only three European countries that do not have any formal agreement with CERN, said committee chair Mary Butler. “Innovation 2020’s vision is for Ireland to be a global innovation leader driving a strong sustainable economy and a better society. If Ireland is to deliver on this vision, membership of organisations such as CERN, which are at the forefront of innovation, is critical.” CERN already enjoys a productive relationship with physicists in Ireland, with University College Dublin a longstanding member of the LHCb and CMS collaborations, Dublin City University working on ISOLDE, University College Cork contributing civil engineering expertise, and theorists from several institutions involved in CERN projects. In January 2016, Ireland notified CERN of its intention to initiate deliberations on potential associate membership.

“I welcome this report and endorse its recommendations, which are pragmatic and cost-effective,” says Ronan McNulty, leader of the LHCb group at University College Dublin, and witness to the committee. “Delivery of these recommendations would enormously improve Irish academic links to CERN and create a new landscape for training the next generation of scientists and engineers, as well as developing business opportunities in the technology sector, and beyond.”

Ireland has a strong particle-physics community and CERN would welcome stronger institutional links
Charlotte Warakaulle

The report envisages a “multiplier effect” for return on investment to the Irish economy as a result of joining CERN. Although around 20 Irish companies already have contracts with CERN, it notes that they are at a competitive disadvantage as the laboratory prioritises companies from member countries. Under associate membership, says the report, contracts with Irish companies could rise to one third of the country’s financial contribution to the laboratory, which for Associate Member States must be at least of 10% of the cost of full membership. The cost of full membership, which yields voting rights at the CERN Council and eliminates the investment cap, depends on a country’s GDP, and would currently be estimated to be of the order of €12.5 million per year in Ireland’s case.

“We note the positive report from the committee, which clearly sets out the opportunities that membership or associate membership of CERN would bring to Ireland,” said Charlotte Warakaulle, CERN’s director for international relations. “Ireland has a strong particle-physics community and CERN would welcome stronger institutional links, which we believe would be mutually beneficial.”

The Irish government will now consider the committee’s findings.

The consolations of physics

As someone who lives and breathes physics every day, I have to confess that when I curl up with a book, it’s rarely a popularisation of science. But when I saw that Tim Radford had written such a book, and that it was all about how physics can make you happy, it went straight to the top of my reading list.

Despite Radford’s refusal to be pigeonholed as a science journalist, insisting instead that a good journalist moves from beat to beat, never colonising any individual space, he was science correspondent for The Guardian for a quarter of a century. Now retired, he remains one of the most respected science writers around.

The book is a joy to read. More a celebration of human curiosity than a popular science book, it’s an antidote to the kind of narrow populism so prevalent in popular discourse today: a timely reminder of what we humans are capable of when we put differences aside and work together to achieve common goals.

Boethius, who took consolation in philosophy as he languished in a sixth-century jail is another recurring presence

The Voyager mission, along with LIGO and the LHC, serves as a guiding thread through Radford’s vast and winding exploration of human curiosity. Right from the opening lines, the reader is taken on a breathtaking tour of the full spectrum of human inventiveness, from science to religion, and from art to philosophy. On the way, we encounter thinkers as diverse as St Augustine, Dante and H G Wells. Boethius, who took consolation in philosophy as he languished in a sixth-century jail is another recurring presence, the book’s title being a nod to him.

We’re treated to a concise and clear consideration of the roles of science and religion in human societies. “Religious devotion demands unquestioning faith,” says Radford, whereas “science demands a state of mind that is always open to doubt”. While many can enjoy both, he concludes that it may be easier to enjoy science because it represents truth in a way that can be tested.

No sooner have we dealt with religion than we find ourselves listening to echoes of the great Richard Feynman as Radford considers the beauty of a dew-laden cobweb on an English autumn morning. “Does it make it any less magical a sight to know that this web was spun from a protein inside the spider?”, he asks, bringing to mind Feynman’s wonderful monologue about the beauty of a flower in Christopher Sykes’ equally wonderful 1981 documentary, The Pleasure of Finding Things Out. Both conclude that science can only enhance the aesthetic beauty of the natural world.

The overall effect is a bit like a roller-coaster ride in the dark: you’re never quite sure when the next turn will come, or where it will take you. That’s part of the joy of the book. There are few writers who could pull so many diverse threads together, spanning such a broad spectrum of time and subjects. Radford pulls it off brilliantly.

Someone expecting a popularisation of physics might be disappointed. Indeed, the physics is sometimes a little cursory. Yes, the LHC takes us back to the first unimaginably brief instants of the universe’s life, and that’s indeed something that catches the imagination. But that’s just a part of what the LHC does – it’s also about the here and now, and it’s about the future as well. But to dwell on such things would be to miss the point of this book entirely.

An elegant manifesto for physics is how the publisher describes this book, but it’s more than that. It’s a celebration of the best in humanity, built around the successes of CERN, LIGO and most of all the Voyager mission. What such projects bring us may be intangible and uncertain, but their results are available to all, and they enrich anyone who cares to look. Like any good roller coaster, when you get off, you just want to get right back on again, because if there’s something else that can make you happy, it’s Tim Radford’s writing.

Spiro appointed IUPAP president

Prominent French particle physicist Michel Spiro has been appointed president of the International Union of Pure and Applied Physics (IUPAP), replacing theorist Kennedy Reed of Lawrence Livermore National Laboratory. IUPAP, which aims to stimulate and promote international cooperation in physics, was established in 1922 with 13 member countries and now has close to 60 members. Spiro, who participated in the UA1 experiment, the GALLEX solar-neutrino experiment and the EROS microlensing dark-matter search, among other experiments, has held senior positions in the French CNRS and CEA, and was president of the CERN Council from 2010 to 2013.

Breakthrough Prize for black-hole image

The first direct image of a black hole, obtained by the Event Horizon Telescope (EHT, a network of eight radio dishes that creates an Earth-sized interferometer) earlier this year, has been recognised by the 2020 Breakthrough Prize in Fundamental Physics. The $3 million prize will be shared equally between 347 researchers who were co-authors of the six papers published by the EHT collaboration on 10 April. Also announced were six New Horizons Prizes worth $100,000 each, which recognise early-career achievements. In physics, Jo Dunkley (Princeton), Samaya Nissanke (University of Amsterdam) and Kendrick Smith (Perimeter Institute) were rewarded for the development of novel techniques to extract fundamental physics from astronomical data. Simon Caron-Huot (McGill University) and Pedro Vieira (Perimeter Institute) were recognised for their “profound contributions to the understanding of quantum field theory”.

Flying high after the Higgs

In 2018, Eleni Mountricha’s career in particle physics was taking off. Having completed a master’s thesis at the National Technical University of Athens (NTUA), a PhD jointly with NTUA and Université Paris-Sud, and a postdoc with Brookhaven National Laboratory, she had just secured a fellowship at CERN and was about to select a research topic. A few weeks later, she ditched physics for a career in industry. Having been based at CERN for more than a decade, and as a member of the ATLAS team working on the Higgs boson at the time of its discovery in 2012, leaving academia was one of the toughest decisions she has faced.

“On the one hand I was looking for a more permanent position, which looked quite hard to achieve in research, and on the other, in the years after the Higgs-boson discovery, my excitement and expectation about more new physics had started to fade,” she says. “There was always the hope of staying in academia, conducting research and exploring new fields of physics. But when the idea of possibly leaving kicked in, I decided that I should explore the potential of all alternatives.”

Mountricha had just completed initial discussions about her CERN research project when she received an offer of a permanent contract at Inmarsat – a provider of mobile satellite communications based in the nearby Swiss town of Nyon. It was unexpected, given how few positions she had applied for. “I felt a mixture of happiness and satisfaction at having succeeded in something that I didn’t expect I had many chances for, and frustration at the prospect of leaving something that I had spent many years on with a lot of dedication,” she explains. “What made it even harder was the discussions with other CERN experiments during the first month of the fellowship, which sparked my physics excitement again.”

New pastures

Mountricha’s idea to leave physics first formed after attending, out of curiosity, a career networking event for LHC-experiment physicists in November 2017. “The main benefit I got out of the event was a feeling that, even if I left, this would not be the end of the world; and that, if I searched enough, I could always find exciting things to do.” The networking event now takes place annually.

The Inmarsat job was brought to Mountricha’s attention by a fellow CERN alumnus and it was the only job that she had applied for outside physics. “I believe that I was lucky but I also had invested a lot of personal time to polish my skills, prepare for the interview and, in the end, it all came together,” she says.

People should not feel disappointed for having to move outside physics

Today, Mountricha’s official job title is “aero-service performance manager”. She works in the data-science team of the company’s aviation department collecting and reporting on data about aircraft connectivity and usage. This involves the use of Python to develop custom applications, analysing data using Python and SQL, and developing reporting and monitoring tools such as web applications. Her daily tasks vary from data analysis to developing new products. “Much of the work that I do, I had no clue about in the past and I had to learn. Some other pieces of work, like the data analytics, I used to do in a research context. However, the level at which I was doing it at CERN was much more sophisticated and complex. Many people in my team are physicists, all of them from CERN. Besides the technical aspects though, it is really at CERN that I learned how to collaborate, discuss with people, bring and collect ideas, solve problems, present arguments, and all those soft skills that are very important in my current job.”

As for advice to others who are considering taking the leap, Mountricha thinks that people should not feel disappointed for having to move outside physics. “Fundamental research is a lot of fun and does equip us with much sought-after skills and experience. On the other hand, there are many exciting projects out there, where we can apply everything that we have learned and develop much further.”

Higgs nostalgia

While happy to be on a new career path at the age of 37, working on the search for the Higgs boson will take some beating. “The announcement of the discovery was made in July, the papers were published in August and I defended my PhD thesis in September, so there was much pressure to finalise my work for all of those deadlines,” recalls Mountricha. “Even the times when I was sleeping on top of my PC, exhausted, I still remember them with love and nostalgia. In particular, I remember the day of the announcement of the discovery, there were people sleeping outside the main auditorium the night before in order to make it to the presentation. As a result, I ended up watching it remotely from building 40 together with the whole analysis team. I was slightly disappointed not to be physically present in the packed auditorium, but this nevertheless remains such an important moment of my life.”

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