Nuclear fusion: Creating artificial stars

Too little does the public hear about nuclear fusion — a process in which two light nuclei collide at high speed and fuse into a heavier nucleus — which is surprising considering the need for alternative energy sources and fusion’s promise to deliver limitless clean and safe energy. If the word fusion brings anything to the mind of the wider public, this is likely related to ITER, a research reactor under construction in France that has repeatedly made the news by over blowing its budget and being substantially behind schedule. Is this all there is to know about fusion? By all means, no. “Let there be light – the 100 years journey to fusion” brings the audience on a fascinating journey across time and ideas into the complex landscape of past and present fusion research.

The documentary, directed by Mila Aung-Thwin and Van Ryoko, was released in March 2017, and explores the world of fusion mainly through the eyes of four of its protagonists, each bringing a different point of view.

Credit: Heath Cairns

Mark Henderson works at ITER, a reactor based on a tokamak design, in which a powerful magnetic field confines the plasma in a toroidal shape. ITER is poised to become the biggest fusion reactor in the world, and its goal is to demonstrate that fusion at the power-plant scale is feasible. At ITER, Henderson is in charge of the systems heating the plasma.

Eric Lerner develops a fusion concept called dense plasma focus, in which large electrical currents run through the plasma, harnessing its natural instabilities to confine and compress it; this type of reactor has the advantage of being much smaller and cheaper than other designs, but technologically is not as advanced. “The first error of the governments in the 1970s was to put all their eggs in the tokamak basket”, he comments. “But actually we still don’t know which route will lead to practical and economical fusion: you should invest not in ideas you think will work, but in all ideas you can’t prove won’t work”.

Michel Laberge is the founder of General Fusion, a private company developing a fusion power device that, instead of employing magnetic fields, uses pistons to compress liquid metal surrounding the plasma to create fusion conditions. “It’s pistons and its’ rings, it’s metal and pipes, it’s plumbing,” he explains. “Turning that into a power plant would actually be not that complicated. I have a saying, I tell my engineers: if you can’t find it at Home Depot it doesn’t go in the machine.”

Finally, Sibylle Gunter is the scientific director of Wendelstein 7-X, an experimental reactor in Germany that is the largest stellarator device in the world. Stellarators, which have worst plasma confinement than tokamaks but can run continuously — an important advantage for future power plants — are based on complicated coils optimized to generate a specific magnetic field configuration. Although stellarators are technologically behind tokamaks, some believe it is stellarators that will eventually deliver fusion on the grid.

The documentary takes the audience right at the beginning of the history of fusion, to the time when, in 1939, Hans Bethe understood the proton–proton reaction that powers stars. A decade later, in the USSR, a self-educated Red Army sergeant posted to a remote island suggested a concept that would become the tokamak; physicist Andrei Sakharov completed the projects for the first reactor in 1950. That same year, the claim (then proven fraudulent) that fusion had been achieved in Argentina inspired Lyman Spitzer, an American physicist, to develop the stellarator. The importance of international collaboration to achieve fusion was recognized already during the cold war (it helped that fusion has no military applications), and in 1985 Gorbachev and Reagan agreed to start a collaborative international project to develop fusion energy, laying the basis for the ITER project.

Among scientists, a period of tremendous enthusiasm in the 1960s was followed by a decade of doubt and skepticism when it was realized that the problem was more complex than initially thought. In the 1980s, on the wake of a new wave of enthusiasm, it was believed that fusion would be on the grid within 50 years, and indeed until 2000 advances were fast. But to take the next step a new machine was needed, bigger, more complex: ITER, which is likely the most complex machine ever built.  I know I will be retired by the time ITER is successful” says Henderson, “so I’m like the guy building a cathedral, who knows he is gonna […] spend his entire career putting bricks together, but he will never see the end piece.

Indeed, ITER is more than a decade behind schedule — first plasma was originally planned for 2016 — and several billion dollars over budget. In a management assessment back in 2013 the problem was pinned down as poor management, ill-defined decision-making processes and poor communications within the project. In 2015 a new Director General was appointed, Bernard Bigot. ITER now has a new date for first plasma, Christmas 2025. “I think ITER will probably work; it will demonstrate that fusion is doable,” says Laberge. “They are gonna blow their budget and their schedule big time, it will burn money at twice the rate you need to, but it will get built and it will work, and this will give a big shot in the arm of fusion.”

One point everybody seems to agree on is that more funding is needed to develop fusion. “The more money you put in, the faster the return. And we have really being putting in peanuts,” comments Henderson. “Fusion is about 20 billions for 20 years. One billion a year. One fancy bridge a year. Peanuts! Let’s do it!” says Laberge. “How long it will take to achieve fusion? At current levels of financing, it will take approximately the age of the universe,” concludes Lerner.

With its beautiful images, helpful animations and an engaging soundtrack, the documentary, which is all narrated through interviews and original clips, is informative and enjoyable. It does not shy away from the challenges and doubts about the feasibility of a complex project such as ITER, but keeps a positive outlook.  It is a welcome reminder that achieving fusion is an extremely important goal, and all potential avenues need to be explored. Whether expert on fusion or curious onlooker, in “Let there be light” there is something for everyone.

Interactions: John Hammersley

After a PhD in theoretical physics (specifically, holography and the ADS/CFT correspondence), John left academia and later co-founded Overleaf in 2012. He has been developing Overleaf ever since to bring it to more and more users.

What did you train in? What are you doing now?

My background is in mathematics and physics; I completed an MPhys at Warwick in 2004, before heading up to Durham for my PhD, which I completed in 2008. I then moved out of academia into industry, working for Ultra PRT, the company behind the world’s first driverless taxi system. I joined the company as a research scientist, and my role later broadened out to be bid manager for the various projects the company was involved in.

How did Overleaf start?

When joining Ultra PRT, I was lucky enough to be mentored by Prof. Martin Lowson, a former rocket scientist and aeronautical engineer. He founded Ultra PRT out of Bristol University in the mid-nineties, and always maintained a strong link with academia, encouraging us to write up and share our research into large scale driverless taxi systems with the wider community. This involved collaborations both internally and with others at partner universities/organizations, and it was whilst collaborating on these research papers that we discovered Etherpad, a new browser-based collaboration tool. This made it easy for us to share and collaborate on notes, but because we typically use LaTeX for our papers, it wasn’t quite what we needed.

So one weekend, my co-founder Dr John Lees-Miller built the prototype for Overleaf (then called WriteLaTeX), which allowed us all to collaborate in the browser on LaTeX documents, and would generate a PDF output by compiling the LaTeX on a server. We also found that this greatly lowered the barriers to collaborating with others who were new to LaTeX, as there was nothing to install — all that’s needed is a web browser. Usage of the site continued to grow through word-of-mouth and being featured on sites such as HackerNews, and in late 2012 we decided to found our own company and work on Overleaf full time!

Who is using Overleaf today?

Today over four million people worldwide are using Overleaf! These range from students taking their first steps with LaTeX, through to large scale collaborations between hundreds of the world’s leading scientists. I’m always amazed at the wide range of uses people find for LaTeX and Overleaf. For example, one of the first projects on Overleaf that wasn’t one of our research papers was a set of wedding invitations!

We also see Overleaf helping to extend LaTeX out into fields where it’s less common, such as in the humanities and social sciences (for example, see this a short interview with Brian Lucey, Professor of Finance at Trinity College, Dublin, who started using LaTeX through Overleaf and is now part of our Advisor programme).

We’re also collaborating with partners in the publishing industry to try to help streamline the authoring, submission and publication workflows for journals and preprint servers, by providing updated templates and simple submission links. Overleaf is the natural place for authors and editors to be able to check that all the files for a submission are present, and that there are no compilation errors within a manuscript. Because of the built-in error reporting, and friendly interface, it also helps when there are any problems to resolve!

What I personally find most exciting is that Overleaf is helping students create and share their work in ways not easily possibly before. For example, the ‘Nano Ninjas’ — a group of 7th and 8th Graders in the US — used Overleaf to write up the engineering notebook from their school Robotics challenge! They won an award for their notebook, and have shared it in full on Overleaf as a template for future students to see and take inspiration from!

You can read more about the Nano Ninjas here, and some of their members also went on to form ‘The Three Musketeers’. It’s amazing to see, and hopefully provides an inspiration to future researchers and scientists everywhere 🙂

 What are the main challenges when starting a company? Do you have any advice to share?

There’s a lot I could talk about here! Although, I’m a bit reluctant to start by listing out challenges; you have to be somewhat naively optimistic to start a company, and focusing too much on any perceived challenges can be (wrongly) off-putting. So I’ll focus on advice instead.

If four points is too many, just read point four: don’t run out of money!

  1. Take everyone’s advice with a pinch of salt: we all give advice based on our own experiences, and in the early days it’s easy to get side-tracked by advice that’s well-meaning, but not relevant for you.
  2. Talk to people about your idea as early as you can, but don’t be put off if the first people you talk to seem a bit confused as to what you’re proposing. It’s natural, as you’re still developing the idea, and it’ll help highlight where you need to be able to explain your idea more clearly. Early on, you’ll need positive reaction for motivation, early adoption for validation, and any critical feedback for development. But remember to take any advice they give you with a pinch of salt 🙂
  3. Focus on solving the immediate problems that you need to get done to get yourself to the next stage (whether that’s finding a co-founder, building the MVP, or getting feedback from your first users), and don’t worry too much about things beyond that. At the start this is focusing one week or one month at a time, and certainly no more than six months ahead. If you focus too much on the long term, you’ll find it takes you too long to get the important stuff done now, and you’ll run out of time/money.
  4. Finally, and most importantly, it’s the CEO’s main job to make sure you don’t run out of money — whoever the CEO is in your founding team needs know how long you have with initial money you’ve saved/raised to get started, and needs to focus on getting the next funding secured before this runs out. If you run out of money, it doesn’t matter how close you are to solving any of the other problems; that’s usually game over.

I also wrote on a similar topic in a blog for ErrantScience, and in my Reddit AMA from a few years ago. If you’re interested in my longer thoughts on this, those are both good follow-on reads.

If you are starting a company, good luck, and feel free to reach out to me directly if you think I can help! If it’s in the #TechForGood space, I’d also recommend talking to the Bethnal Green Ventures team; they’re very friendly, and have a lot of experience helping start-ups develop in the very early stages. We were part of their summer cohort in 2013, and I still help out as a mentor and alumni!

Do you have a favourite Overleaf tip(s)?

If you’re at a university, check if your institution has a site license for Overleaf! You can see the list of institutions here, and if they do, you’ll be able to get a free upgrade to an Overleaf Professional account through that license!

My other top tip isn’t for Overleaf specifically, but can greatly help if you can’t remember the LaTeX command for a symbol — you can use detexify to find it! Simply draw the symbol, and it’ll give you the corresponding LaTeX command!

Finally, if you’re new to LaTeX itself, we’ve put together this short introduction which can be completed in about 30 minutes, to help you get started. Good luck, and if you do use Overleaf, we’d love to hear from you!


Rivalry, crystal structure prediction and discovery of new materials

Post by Artem Oganov.

The review in Nature Reviews Materials can be read here.

The story of our review started in 2006 when my group and the duo of Chris Pickard and Richard Needs published papers that changed the view of the scientific community in an important way. Prior to this, it was widely believed that crystal structures are, in general, not predictable: the number of possible structures is just way too large, and going through all of them is impossible. Our works showed that this problem can be handled, and this opens a way for computational materials discovery. I developed an evolutionary approach, while Pickard and Needs used random sampling. Within a few years we found ourselves in an increasingly intense competition which drove us to develop our methods and explore new applications for them, which, of course, is good for science.

At some point it became clear that if the intensity of this competition was allowed to develop further it could slip into bitterness, and potentially outright hostility. Did I need to win such a fight, if it brought me nothing positive in the end? The question was how to change this. I knew two things: first, that every problem has a solution. Second, I knew that with the right approach every problem can be turned into an advantage. At some point Qiang Zhu, my former PhD student and now Assistant Professor, found a brilliant solution: to write together a review. First, we felt that the community really needed such a review of many years of hard work, now not just of two groups, but also of many others who joined this field later. Second, writing a review with your rivals makes the review actually better: reviews have to be balanced, and rivals are the best people for ensuring this balance! Third, working on something together helps to build bridges. So, with this in mind, after a thorough discussion with Qiang Zhu, Chris Pickard and Richard Needs, I talked to Giulia Pacchioni, an editor at Nature Reviews Materials, and convinced her that we could write something important for the community.

We began working on the review from a position of low trust. We had countless debates, and the writing initially went very slowly. This delay risked us losing the invitation. However, the editors were very patient and encouraging. However, the editors were very patient and encouraging. The first skeleton, basically, a set of bullet points, was sketched by Richard Needs, and then each of us expanded these points, transforming them into a more or less coherent text (I think I took the most bullet points, Chris Pickard took many as well). We tried different ways of co-writing, experimenting with Google-docs and Overleaf, but there was not one technical solution that everyone liked, so eventually we just created our own versions of the review and let Qiang Zhu merge and edit them all. Much later he told me that he quietly cut a lot of text which had a potential for igniting arguments; funny that at the time no one noticed this, which I guess shows that our differences of opinion are actually of little importance. Once we had a complete draft, everyone started editing the text written by everyone else. By the end of this process we were all on the same wavelength. After submission we had one round of peer review and quite a bit of proofreading, mostly handled by me. The end result is one we can be proud of: a nice review of a field that we were fortunate to catalyze. But also a human victory. Rivals becoming friends and gaining a shared understanding is so much more important than winning a competition.

Artem Oganov
Center for Energy Science and Technology
Skolkovo Institute of Science and Technology, Moscow, Russia.

Escape into the wonders of physics

Post by Giulia Pacchioni

LabEscape is an escape room based on physics – I got the opportunity to explore it during the APS March meeting in Boston, where it was set up for one week away from its usual site in Urbana, Illinois.

Prof. Schrödenberg went missing, and an important grant needs to be submitted. As her new interns we need to log into the computer and hit the submit button. Easy… well, we need to figure out the password, but luckily the professor left hints around the lab in case she forgot it!

Together with a team of five other physicists (the other interns in the lab), before entering the room I was handled information sheets covering some essential physics concepts laid out in a very digestible way. Indeed, the room, which is the brainchild of Paul Kwiat, a physics professor at the University of Illinois, is by all means not designed for physicists (even though it’s an absolute delight for them). It was created to provide an experience that demonstrates to the general public that physics is useful, permeates everyday objects and is, yes, fun.

Peter recommended we read the material carefully no matter how well we thought we knew it already, as knowing which concepts are illustrated in the room can help understanding how to crack the puzzles inside. Apparently, a group of physicists who refused to go through the material couldn’t escape in the set time, whereas a family with no scientific background who did their reading (as any good intern should do!) aced the challenge.

The main suggestion from Paul was to work as a team, with two or three people looking at each hint or object to combine different points of view, and to share all information with the others. He had to help us a bit, reminding us to work together each time we went our separate ways exploring the fascinating bits and pieces scattered around the lab.

The room contains a clever mix of challenges ranging from the usual looking around for hints and tools to actual small experiments using lab equipment that needs to be manipulated and sometimes completed with missing pieces. As in any good lab, instructions on how to use the instruments are provided, accompanied by extra explanations about how each experience works for the curious explorer. I don’t want to give too much away, but we got to play with an oscilloscope and a laser, polarizing glasses and, of course, a dead/alive cat in a box!

The riddles are generally simple, but require some lateral thinking and careful observation, which makes the experience fun and varied without it ever getting boring or frustrating. The experiments use scientific instruments in very creative ways, the type that stimulates a wow reaction both in science novices who think ‘how is this even possible!’ and physicists who think ‘I never thought of using it like THIS!’ Marveling at the various tricks was so fun that escaping the room became a bit of a secondary focus. Even after we did work out the password and could have escaped, my fellow interns had plenty of questions for Paul about how everything worked and how they could use some of the ideas in their own outreach activities.

For me, the take home message is that that working on a problem together and listening to each team member’s ideas is essential for overcoming challenges in the lab. Also in real life.

Interactions: Chen Fang and the Materiae database

Post by Anastasiia Novikova.

In theory, many ordinary materials can have exotic topological phases. But how can we find them? In 2018 a research group from the National Laboratory for Condensed Matter Physics in Beijing scanned 39519 materials to predict which phases of the already-known compounds might exhibit topological properties. These materials were summarised into an interactive database Materiae, where you can browse compounds containing particular elements, check if they have any topological phases and visualise their band structure.

We asked Prof. Chen Fang — one of the team members who worked on Materiae along with Prof. Hongming Weng —  to give us more details of the project, which has now been published in Nature.

When did the database start? What were the main challenges of this project? What goals do you have for the future?

The database has been online since 23 July 2018; it appeared simultaneously with the posting of the corresponding paper on arXiv. By now there have been over 10000 unique visitors (1=ip*day). The most difficult part is, naturally, the calculation that was done to obtain the topological properties of about 30000 materials. The theory, the underlying work was accomplished back in late 2017 (arXiv:1711.11049 and 1711.11050), but even so, it was an effort to implement the fully automated algorithm shown in the flowchart. Currently we have the band structures plotted for topological materials only, and in the future we will add the band structure plots for all materials, topological and non-topological.

Using your algorithm, you scanned 39519 materials. How much time did the whole calculation process take?

We didn’t track the CPU hours used on this, but if we count the time spent on debugging small bugs now and then, it took us about three to four months in total for the bulk results to come out.

You mention that 8056 materials from your database are actually topological. How many of these materials were experimentally studied?

All materials have been reportedly synthesized in literature, but most of them were not studied from a “topological perspective”, but were studied for superconductivity or ferroelectricity, for example. I think at most few hundreds of these materials have been studied for potential topological properties.

What is the most “underestimated” material?

One example is Tl2Nb2O7. Oxides are seldom considered as topological materials in literature, yet our database registers it as a topological semi-metal. Surprised by this result, we further looked into this material, and realized that the mixed-valence nature of Tl ion is the origin of the nontrivial topology.

Another is Ba3Cd2As4. The layered structure made us expect it to be a weak topological insulator, but our database shows it to be a new type of topological crystalline insulator (having so-called C2-anomalous surface states). Shortly after the prediction, experimental groups have started synthesizing this material.

We expect the study of certain materials, like the ones above, may be “revived” by what we show in the database.

The database contains only non-magnetic materials. Is it possible to envision a similar type of database for magnetic materials?

The entire prediction is based on first-principle calculation, but magnetism is notoriously difficult to predict/include in any first-principle calculations. Therefore, while some theoretical work on the mapping between symmetry data and topological data has been out there for a while (arXiv:1707.01903), I do not think a similar material database can be obtained in near future because of the inherent difficulty of DFT mentioned above.

Interactions: Luke Fleet

Luke Fleet is a Senior Editor & Team Leader at Nature. He joined Nature Research in 2013 as an editor at Nature Communications, before moving to Nature Physics in 2014, and then to Nature in 2017. He’s responsible for selecting the research papers that are published across a range of fields, including applied physics and electronics, and also assists in devising and delivering the goals for the physics team.

 What made you want to be a physicist?

It was more chance than an active decision, so let’s go with luck and curiosity. Like many people, I didn’t really know what I wanted to do when I was younger and so I decided to carry on in education to basically avoid having to choose. In doing so, I pursued something that I found interesting. Luckily for me, that was physics!

If you weren’t a physicist, what would you like to be (and why)?

If I could choose anything, then I’d want to be a musician or a footballer, as these are my hobbies, but I think people have already said these so I’m going to go with joiner. I actually worked for several years when I was a teenager building things like rabbit hutches and dog kennels, and there are lots of things about working outside crafting something that are satisfying so that’s my back-up if this career goes south.

Which historical figure would you most like to have dinner with — and why?

There are so many to choose from but let’s go with Leonardo Pisano (Fibonacci). He convinced Europeans to switch from Roman numerals to Hindu-Arabic numbers and if you ever have the pleasure of visiting Pisa you’ll see that he also inspired the Church to put a Fibonacci sequence-based artwork above the main entrance to the church of San Nicola. Relatively little is known about Fibonacci so I’d love to know how he managed to convince so many people to embrace arithmetic mathematics during the Middle Ages.

What would be your (physics) superpower?

When I was a researcher I worked with magnets and if they were big enough then then I liked to think that I was like Magneto from the X-men, so that’s the superpower I want: mastery of electromagentism, without trying to instigate a civil war.

What’s your favourite (quasi-)particle?

I’m really a condensed matter physicist at heart, so is has to be a quasiparticle. And whilst there are so many to choose, I’d have to say Weyl fermions. Physicists had been searching for these particles for decades but they were discovered not long after I started working as an editor. It was pretty exciting covering these advances at the time, so I think I’m always going to have a Weyl soft spot.

If you could have an effect or equation named after you, what would it be?

I love playing football and like to think I have some mastery over the Magnussen effect. I know that already exists but I’d like to discover a new effect related to spinning objects so that I can improve my shooting, which is definitely getting worse with age.

Interactions: Federico Levi

Federico Levi is a Senior Editor at Nature Physics.

What made you want to be a physicist? 

I was a rather curious kid — the annoying kind that asks a lot of ‘why’ questions. But I never found my interests to be limited to the natural world. The adolescent me somehow decided that good learning opportunities would come from a degree in physics or history or English literature. While I like to think that some natural inclination towards analytical thinking nudged me in the direction of physics, the reality is that my parents were pretty persuasive in their case against a career in the humanities. But once I started learning physics for real, I was hooked. When I got to quantum mechanics, I was totally sold.

If you weren’t a physicist, what would you like to be (and why)?

I would like to write novels, I think. Too bad I’m not very good at it.

Which historical figure would you most like to have dinner with — and why?

Thomas Kuhn, to thank him for having written a great book.

What is the development that you would really like to see in the next 10 years?

Understanding so much better the foundations of quantum mechanics, cosmology or the interplay between quantum physics and general relativity to realize that what we all assumed was clearly right is actually rather wrong.

What would be your (physics) superpower?

Skipping stones for hundreds of meters.

What Sci-Fi gadget / technology would you most like to have / see come true (and why)?

A time machine to undo stupid mistakes. Could probably have other uses too.

Interactions: David Abergel

David Abergel is an Associate Editor at Nature PhysicsBefore joining Nature Physics in 2017, David carried out theoretical research on graphene and other two-dimensional crystals, and quantum topological materials. 

What made you want to be a physicist? 

When I was a kid, I was really into astronomy, so I guess I’ve always had an inclination towards science. Then, as a teenager, I read John Gribbin’s In Search of Schödinger’s Cat. I loved it. The vivid picture he painted of how quantum mechanics works, how it’s so different from the classical world that we experience, and most importantly how we can use maths to understand it had me hooked. From that point on I never wanted to be anything else.

If you weren’t a physicist, what would you like to be (and why)?

I would probably have ended up as a forensic scientist working for the police. I’m sure it’s nowhere near as cool as it looks on TV, but the idea of trying to piece together a lot of small clues to provide evidence for case seems like a really interesting type of problem solving.

What would be your (physics) superpower?

Getting code to compile first time!

What’s your favourite (quasi-)particle?

Undoubtedly the Cooper pair. I find it counterintuitive that the jiggling of an atomic lattice can make two negatively-charged electrons ‘stick’ together. And the fact that there is most likely a completely different mechanism that we don’t understand going on in high-Tc superconductors is a fascinating mystery.

What Sci-Fi gadget / technology would you most like to have / see come true (and why)?

Apart from the obvious ones like time travel and teleportation, I want someone to come up with a material that is soundproof, but allows cool air through. It would be the perfect window covering for warm summer nights.

Which physicist would you like to see interviewed on Interactions — and why?

Is this like one of those facebook things where you have to nominate five of your friends to keep the game going??!! But more seriously, seeing as he kind-of came up with the idea, I want to hear what Lev Landau’s favourite quasiparticle is.

Interactions: Elena Belsole

Elena Belsole is the Chief Editor of Communications Physics. An astrophysicist by training, Elena was the executive editor of New Journal of Physics, before joining Nature Research.

What made you want to be a physicist? 

Since the age of 8 I wanted to be a medical doctor. I have always been a very inquisitive person and I would have pursued any direction that was giving me as many answers as possible on what the world is all about. But the truly determining factor was meeting my physics teacher in high school. He was so inspirational and made things look so fascinating; he even introduced the Schrödinger equation to the class. I could not leave it at that. I had to learn more.

If you weren’t a physicist, what would you like to be (and why)?

An herbalist I think. I love how you can forage and use herbs for medicinal use and being able to find a remedy for any minor ailments.  I also considered theatre acting for a short time.

Which historical figure would you most like to have dinner with — and why?

Since I started University I had Richard Feynman lecture notes on my bedside table and always found the simplicity of his explanations fascinating, but I would probably not want to go for dinner with him. If I have to choose one person to take out for dinner I would go for `the queen of carbon’, Millie Dresselhaus. She has guided and inspired so many people and she was a great physicist in an environment that was (and to some extent still is) quite adverse to women, while also having a family. I would like to know how she did it all.

Which is the development that you would really like to see in the next 10 years?

I would like to see physical methods effectively used for controlling and stopping cancer and other diseases in a way that is not intrusive and not damaging for the patient.

What would be your (physics) superpower?

Definitely teleportation. I cannot even imagine how many places on Earth and beyond I could visit if that was true.

What’s your favourite particle?

The neutrino. It is such a versatile particle. Perhaps it is because of my fascination with cosmic rays from astrophysical objects, perhaps because it can be used to probe the Standard Model, or maybe just because thousands of them cross our body every second and are impossible to see and difficult to detect. Regardless, they are fascinating and may be a key to solve the mysteries of the Universe.



Interactions: Vittoria Colizza

Vittoria Colizza is Research Director of the EPIcx lab at INSERM and Sorbonne Université.

What did you train in? What are you working on now?

My formal training is in theoretical physics, but already during my PhD my work was at the interface with biology. Since then, I’ve been working on the characterization, modelling and surveillance of infectious disease epidemics, moving progressively from theoretical approaches to increasingly applied research informing public health. If I have to use a single tag to describe my research it would be ‘Computational and digital epidemiology’, integrating statistical physics, mathematical epidemiology, computer science, statistics, medicine, public health, complex systems approaches, network science, data science, surveillance, numerical thinking and geographic information systems.

My research focuses on real epidemic outbreaks to gather context epidemic awareness and provide risk assessment analyses for preparedness, mitigation, and control. Applications range from human epidemics (e.g. 2009 H1N1 pandemic influenza, MERS-CoV epidemic, Ebola virus disease epidemic, childhood infections, antimicrobial resistance spread in hospital settings) to animal epidemics (e.g. bovine brucellosis, bovine tuberculosis, foot-and-mouth disease, rabies).

In 2011 I joined the French National Institute of Health and Medical Research (INSERM), after several years spent in interdisciplinary departments/institutions (my only affiliation to a Physics Dept. was during my education at Sapienza University in Rome).

How do you introduce yourself (e.g. I am a physicist/biologist/…) ?

It depends on the audience.

In front of an epidemic/medicine/public health community I’d just state that I’m a modeler, as this is the key information they would need about my profile, e.g. to distinguish my expertise from the one of field epidemiologists, biostatisticians, public health professionals, MDs, and others. But a few exchanges about my approaches would often identify me as a ‘stranger’ and force me to reveal I’m a physicist by training. I tend not to state that upfront as it may induce an unneeded distance that is not beneficial for the interaction.

Talking to physicists, I would introduce myself as ‘originally a physicist’ to establish a common ground facilitating the communication, but I would specify that my work is fully framed in the context of infectious disease epidemics (and therefore, it’s not physics anymore – at least most of the times).

In all circumstances, I try to introduce myself in a way that could avoid misunderstandings, assumptions, cross-disciplinary suspicion, and would allow putting my audience more at ease to have a comfortable and fruitful dialogue.

What did you find most difficult when you first had contact with other disciplines?

Definitely a long list of painful aspects that all interdisciplinary scientists experience – lack of shared language/notation/methods/practices, huge investment of time, confusion, need for uninterrupted nurturing of the interdisciplinary dialogue, mutual suspicion. These aspects are more or less foreseeable before embarking in an interdisciplinary endeavor (though experiencing them directly is unforeseeably painful).

What caught me completely by surprise was realizing that the very same reason behind interdisciplinary research – mindset diversity bringing additional richness – was also its biggest obstacle. Mindsets are mainly rooted in the disciplines of training of each scientist, thus shaping their ability to frame and interpret concepts. While each offers a different perspective to a given problem, they all need to be reconciled and synthesized in something new to achieve the knowledge advancement that interdisciplinary research aims to produce. And reconciling different mindsets, under varying conditions of rigidity, may be extremely challenging.

And what did you find most helpful to familiarize yourself with new concepts and jargon?

For me there was no other shortcut than reading reading reading out-of-my-field papers and books, attending Schools to complete my training, and discussing infinite times and for infinite hours with experts from other fields. And clearly I learnt a lot through the collaborations, as I still do.

Tell us about your experience the first time you went to a conference outside the field you trained in.

It was a rollercoaster of highs and lows. On the low points there was definitely the intimidating feeling of being an outsider along with the depressing realization that the community didn’t feel any need for outsiders… Up to the moment I realized that my just-developed model was able to answer the questions left open by the keynote speaker – so after all, the community didn’t have all the solutions within the boundaries of its discipline. This was a very powerful impulse for a young post-doc starting interdisciplinary science.

What would be your advice to a PI leading an interdisciplinary group?

I don’t think there is a single recipe for success. But I learnt that there are many important skills –beyond scientific expertise –  that are crucial to a successful and effective interdisciplinary dialogue. Among them, respect for other disciplines, for other points of view, as well as tolerance for ambiguity. These are not taught in courses and should be fostered and practiced in the everyday lab life. The aim is for young researchers to learn how to establish comfortable, engaging and unassuming scientific interactions, lowering cross-disciplinary barriers and removing perceived hierarchies of discipline importance.

Is there any anecdote you would like to share?

Oh yes, I have so many! Are you coming to the Nature Reviews Physics event in London on Feb 26? 😉

Interactions: Athene Donald

Athene Donald is a professor of soft matter and biological physics at the Cavendish Laboratory, University of Cambridge.

What did you train in? What are you working on now?

I was educated in Cambridge in the so-called Natural Sciences Tripos, ultimately specialising in Theoretical Physics. That meant a broad course in the first year – physics, chemistry, materials science and maths – that narrowed down by the third year. I could easily have studied some biology in the first year, but as I had been so put off it at school by the fact it seemed to consist simply of memorising facts, it never crossed my mind to do so. So my formal biology education simply consists of two years at school, not even an O Level.

Although I specialised in Theoretical Physics I soon realised I did not want to spend my life only doing theory and went on to do an experimental PhD (‘Electron Microscopy of Grain Boundary Embrittled Systems’). Although electron microscopy – as well as other microscopies – has formed the core of my research, I have switched the kinds of materials I look at considerably during my career. After a first post-doc continuing on metals I switched to polymers and, over time, moved to biopolymers (first polysaccharides and much later proteins) and ultimately cellular biophysics.

How do you introduce yourself (e.g. I am a physicist/biologist/…) ?

A physicist working at the interface with biology. For my postdoctoral years, however, I was working, not in a physics department but in materials science and, in the USA for four years, that was within the Engineering Faculty.

What motivated you to move away from active research?

It was not a conscious decision! Back in the 1990s I was invited to serve on one of the very first government-organised so-called Foresight panels, looking at the future of the Food and Drink industry (at that time my biopolymer research largely related to food rather than biology per se). The broad range of people on that committee, and how they came together, fascinated me and I realised committee work was actually rather interesting. Over time I served on many different sorts of committees, internally within the university, with research councils and more and I found it taking up increasing amounts of time but also, on the whole, rewarding.

What really pushed my research over the edge was in 2010 when I took on two roles (neither to do with interdisciplinarity!): I became the University’s first Gender Equality Champion, which gave me the opportunity to work with the senior management to try to implement real policy changes and interventions to level the playing field for all across the university; and I became chair of the Royal Society’s Education Committee, dealing with 5-19 education at the time that Michael Gove as Secretary of State was introducing enormous changes to the curriculum. Neither role had any formal associated time commitment, but  they inevitably grew to fill (and more) the time available.  Both rewarding, both taught me a lot about different issues and ways of interacting with people from very different backgrounds. I continued in both those roles until 2014 when I became Master of Churchill College.

What did you find most difficult when you first had contact with other disciplines?

As I indicated, I had essentially no formal biology training and the world of genetics – and the language – had anyhow changed radically since my education. So the initial problem I faced was in understanding the language. When I was first involved in a collaboration with a plant scientist in the area of starch I suspect we both spent about a year just understanding what the other was saying and what our disciplines could and could not offer each other. To my mind, what is absolutely crucial in this formative stage, is finding the other person congenial enough you want to spend the time working together through this potential barrier.

And what did you find most helpful to familiarize yourself with new concepts and jargon?

Time! There is no short cut to getting to grips with a subject unfamiliar to you. I think it is also important to realise that working at the interface with another discipline does not mean you need to know everything about the other discipline. Recognizing what you absolutely do need to know but also there is plenty that, at least at that point, is not necessary so you can home in on the essentials, is crucial. Otherwise it can just seem an insurmountable problem. Of course over time what is vital to know may expand, but by that point it may seem less formidable a challenge. I think having someone you feel comfortable asking naïve questions of is also important; this comes back to having a good relationship with your collaborators. If you don’t feel relaxed about asking something basic the collaboration is probably not going to flourish. Of course sometimes collaborations will be with multiple individuals, possibly multiple disciplines, and then the tactics may need some modification.

Tell us about your experience the first time you went to a conference outside the field you trained in.

A general sense of confusion is what I remember most clearly. The diagrams – of protein structures – seemed mysterious as their presentation was so different from how a physicist would have approached the problem – and that left me with a profound sense of being out of my depth. If the basics seem incomprehensible it is hard to extract much useful information, however willing one may be. Coming into a new field also means that you probably don’t know anyone else in the room and that sense of isolation can be quite intimidating. Once you have some results (even if only a poster) it provides an entrée, so that other people will come up and introduce themselves. But that first step into the unknown can be daunting.

What would be your advice to a PI leading an interdisciplinary group?

Remember everyone comes with different experiences, skills and jargon. Somehow your job is to keep that constantly in mind like an orchestra conductor, to make sure people respect each other’s skills and make the best use of these they can. It is important not to let someone who is an expert in one area make another student whose skills sit elsewhere feel stupid or group dynamics can go sadly awry.

Is there any anecdote you would like to share?

Moving away from the heart of a discipline can make colleagues very uncomfortable. Working with starch, not the typical sort of material a physicist in the 1990s would have thought ‘respectable’, meant I came in for a lot of flak from my seniors. Being told ‘things have come to a sad pass when people at the Cavendish study starch’ by one of these was depressing. Added to this is the fact that, as a woman, people’s biases probably gave them a lower opinion of me anyhow at the time. Hence I was accused at a conference of doing ‘just domestic science’ – and that after I’d given an invited paper. It was sometimes hard to feel positive in an atmosphere like that. Again, having people around you who you trust and can rely on is vital to provide the balance to any such hostile colleagues.

Interactions: Bart Hoogenboom

Bart Hoogenboom is a professor of biophysics at University College London.

What did you train in? What are you working on now?

My undergraduate degree was in physics, I did a final-year research project on the electronic properties of buckyballs (C60), and a PhD project on high-Tc superconductors, that is, all solid-state physics. During my PhD, I learnt how to build and use scanning tunnelling microscopes, which came handy when as a postdoc, I developed atomic force microscopy methods to image solid–liquid interfaces at atomic/molecular resolution. At present, my lab still makes extensive use of atomic force microscopy, complemented by other methods, largely to study — often by real-time, nanoscale visualisation — how biological molecules interact with each other and self-organize to collectively carry out tasks that are important for health and disease. Examples of such tasks are the repair of DNA damage (important in various cancer therapies, for instance), the perforation of cellular membranes (such as in bacterial attack and immune defence) and the regulation of transport into and out of the cell nucleus (exploited by viruses and in gene therapies, for example).

How do you introduce yourself (e.g. I am a physicist/biologist/…) ? 

By my training and way of thinking, I am very much a physicist. That said, I try to do interesting science, and in doing so am not too concerned about the question whether that science happens to be more physical or biological.

What motivated you to change your field of research?

For my PhD, I was working on intellectually challenging questions regarding local electronic excitations in superconductors, which was great fun. However, to keep me motivated and interested on the longer term, I felt that I would benefit from broadening my research horizons and learning about other fields of science. Biology has the advantage of such broadness, with a nigh-infinite collection of questions and problems and ample scope for physicists to make meaningful contributions.

What did you find most difficult when you first had contact with other disciplines? 

I find biologists on average more conservative than physicists. In my experience, physicists tend to be more open to new concepts and methods, even if their immediate use or validity in a practical context is unclear. By contrast, most biologists know that many concepts may apply in nature and many methods may a priori be helpful; however, the hard work is often not in defining a new concept or new method, but in determining which ones (out of many) are useful for the particular biological problem that they are working on.

And what did you find most helpful to familiarize yourself with new concepts and jargon?

To start with, I worked my way through a cell biology textbook. That took quite some patience, but in the end I could read relevant scientific literature and talk to biologists without feeling excessively ignorant. Next, in such discussions across disciplinary boundaries, it helps to be honest about gaps in one’s knowledge. I must have asked many, many naïve questions (and still do), and I count myself fortunate with many fantastic collaborators willing to answer such questions and even do research projects with me.

Tell us about your experience the first time you went to a conference outside the field you trained in.

I felt rather lost and was wondering what on earth I was doing there.

What would be your advice to a PI leading an interdisciplinary group?

A good interdisciplinary research team is a treasure chest that contains much more knowledge and skills than a PI can have on his/her own, and this can be further enhanced by collaborations with labs that have complementary expertise. For a PI leading such a group, my main advice is to appreciate and make best use of such knowledge and skills, encouraging the team to help each other and show a similar open, communicative and collaborative approach when interacting with other labs.

Is there any anecdote you would like to share?

Interdisciplinary communication can sometimes get a bit lost by lack of proper translation. Some years ago, I had done preliminary experiments to visualise the assembly of immune proteins that punch holes in target cell membranes. My postdoc at that time struggled to replicate my results in a room where the heating – not for the first time on our building – was failing. When he next reported to our biological collaborators how he had solved the problem, ‘I put the sample on a hot-plate’, our collaborators went through the roof. To alleviate their major concerns over what we had done to the delicate proteins, it sufficed to give them the appropriate biological translation of my postdoc’s remark, ‘He incubated the sample at 37oC.’

Interactions: Georgia Francis

Georgia Francis is a Senior Editorial Assistant for the Nature Reviews journals, who works hard to keep Nature Reviews Physics running smoothly.

What is your role? What do you do?

I’m a Senior Editorial Assistant — I act as a first port of call for authors and editors for the online submission system we use to handle all drafts of manuscripts. I am responsible for ad hoc duties, questions and queries, as well as managing  and tracking author and referees via the online database system. I am also responsible for checking and obtaining legal documentation, and ensuring that the flow of manuscripts is timely in relation to peer-review through to acceptance.

What do you enjoy about working on Nature Reviews Physics?

I thoroughly enjoy working with the authors and the editors of Nature Reviews Physics;  they make my job rewarding and fun!

What do you find challenging in interacting with physicists (authors, reviewers, editors)?

Part of my role is to ensure that manuscripts are on track for peer-review. Quite often the reviewers require extra time to complete their duties because they’re exceptionally busy! They’re always very polite in response to my emails however which makes the job a little easier.

Which historical figure would you most like to have dinner with — and why?

The historical figure I would most like to have dinner with is definitely Charles Darwin – I’d just be eager to see what he was like in person and express amazement at his influential work on evolution and humanity in general!


Interactions: Myfanwy Evans

Myfanwy Evans is an Emmy Noether Research Group Leader at the Institute for Mathematics, Technische Universität Berlin. Her research is in the field of geometry and topology in soft matter physics.

What did you train in? What are you working on now?

My undergraduate degree was in science, majoring in mathematics. My PhD was already in an interdisciplinary setting, officially part of “Physical Sciences”. It involved mathematics, physics, with some chemistry and biology on the side. Ever since my research has been swinging between mathematics and physics, depending on my collaborators and students at the time. My current research is focused on a theoretical framework to understand tangling in soft matter systems. It uses geometry and topology to investigate how filaments can tangle in a variety of settings, in the view of making a connection with protein and polymer physics.

Do you think of yourself as a mathematician or physicist?

Both and neither! Much of the content of my research is geometry, but the style in which I do it is more physics. However, I like to define my research via the problem that I am trying to solve rather than a specific discipline and I don’t like to be restricted by the methodology or traditions of a specific discipline.

What motivated you to move to this field of research?

I had already started in this general area as a PhD student, and it really grabbed me as an interesting topic. I finished my PhD with far more questions than answers, and this has snowballed into an array of research topics that I am still working on today. My motivation to continue in this direction is driven by my own curiosity, and a kind of religious belief that the results I am getting are so beautiful that they must be important.

What are the main challenges and the main advantages of working in an interdisciplinary team?

The main advantages are that everyone can bring something unique to the table, and the breadth of expertise opens really interesting research directions. I find that the students feel less constrained by their prior knowledge and disciplinary expertise, and are able to work on broad problems from many perspectives, learning a huge amount along the way. The main challenge is keeping the research also relevant to specific fields, in particular for PhD students who wish to stick to a more traditional discipline. Finding the right place to publish, that means reaching the right readership, is always a key problem too.

Do you find it particularly difficult to obtain funding? Or to get your research published?

I think that interdisciplinary research has become a big focus of many funding agencies, and in general I don’t find any major obstacles in obtaining funding from the standard sources. I find the same with scientific publications, where new interdisciplinary findings are often published. Of course, there are exceptions and I have a handful of examples of journals claiming that the research is “not physics” or “not mathematics”, without refereeing the scientific content. But these are few and far between.


The rise of open source in quantum physics research

Post by Nathan Shammah and Shahnawaz Ahmed.

Open-source scientific computing is empowering research and reproducibility. It forms one of the principles of the ‘open science’ movement, which aims to promote the spread of scientific knowledge without barriers. Open-source software refers to code which can be read, modified and distributed by anyone and for any purpose under the various open-source compliant licenses. This ‘open source way’ could extend beyond just software and is impacting quantum physics research in radically different ways.

Quantum-tech open source

Quantum computing represents a different computational paradigm from conventional computing: it exploits quantum mechanics at the algorithmic level. As quantum algorithms need to be run on quantum devices, advances in hardware development, currently underway, are crucial. At the same time also software for quantum computing needs to be developed for various purposes – compilation, control, noise modeling, simulation and verification. Open source is driving the development of the quantum computing software ecosystem [Fingerhuth18].

To some extent, the very structure of research in quantum technology is being reshaped by open-source projects to a new degree, for example allowing theorists to run quantum physics experiments from the cloud, without ever entering the lab (to the relief of experimentalists) [Zeng17]. In most cases, the tools are open source in a bid to involve the community of researchers and software developers to come together to build the next generation of software for quantum computing.

Beyond quantum computing there is also a broader area of quantum physics research that is being driven by open source. Some projects aim to provide a broad set of tools which can be used for quantum physics research, such as QuTiP, a Python toolbox for open quantum system simulations, which was started as early as 2011 [Johannson12]. Recently tools such as QuantumOptics.jl (a Julia package for quantum optics simulations) or Google-backed Open Fermion (simulating fermionic interactions and other chemistry problems) have been released for tackling different types of research problems. Other projects are purpose-specific, such as Pennylane (focussing on machine learning and quantum physics), ProjectQ (translating quantum programs to “any back-end”), and NetKet (Neural Network Quantum states for solving quantum many body problems). A community-maintained list of software can be found here.

 Factors contributing to the rise of scientific research with open-source software

Scientific progress is fueled by collaborations and development of ideas from others. In the same spirit, open-source is built upon the contributions of the community and there are several factors that are leading to its adoption beyond quantum physics research.

Firstly, open-source libraries allow fast reproducibility of results. By preventing the reinventing of the wheel and the need to start projects from scratch, they allow for a rapid development, testing and prototyping of ideas and extending previous work. This accelerates the rate of discovery, as new results can be investigated by other researchers tinkering with existing code.

Secondly, there are a variety of tools that increase productivity and collaboration. There is a general trend in scientific research in working in larger teams [Fortunato18] and open-source tools are helping in that. Github or Gitlab are websites that coordinate delocalized teams to work on the same coding project (similarly to Dropbox for file syncing and Overleaf for typewriting). One can also work interactively on code with solutions such as the Jupyter Lab computational environment, Google Colaboratory or CoCalc.

Then, there are well established tools for open-source software development from start to finish:  Travis CI, Anaconda, and the community-managed ‘conda-forge’ channel, can all be set-up easily to take care of testing, continuous integration and software packaging and distribution.

Finally, there are tools specifically crafted to better adapt to the modern characteristics of research publication, in which papers in journals have a background of data or software. Zenodo for example allows the publication of open-source software together with published papers and instantly attributes to it a DOI reference, without waiting for the (sometime lengthy) peer-review process. The crystallization of software is also a guarantee for reviewers and other researchers who might want to use the same code.

Python and machine learning as success stories for open source

 The benefits of the open-source approach can be clearly seen in machine learning, especially deep neural networks. Suddenly, it has become very easy to tinker and use even the most advanced methods in machine learning thanks to the availability of code and tools to modify and run them. With Google’s TensorFlow or Facebook-backed PyTorch, the power of deep neural networks reached the masses, leading to very creative applications.

As a result, we are also witnessing the impact of machine learning to all areas of natural sciences and tasks, from designing quantum experiments [Melnikov18] to detecting gravitational waves [Gabbard18].

An important factor for the wide adoption and use of machine learning tools is Python. It is an interpreted programming language that has seen a steady growth in adoption, based on a wide environment of modular independent software packages (libraries) that can be used together for numerics (SciPy), generating visualizations (Matplotlib), sharing code (Jupyter notebooks) and much more.

For some applications, Python’s limited computational performance (generally lower than C, C++ or FORTRAN) can be overcome by writing parts of the code in other languages and calling them from Python or using targeted solutions such as Numba or Cython to compile parts of the code into fast machine code.

But what really sets it apart its intrinsic code-writing efficiency and speed of developing prototypes, as one can more easily debug software on the go. As pointed out by Guido Van Rossum, the creator of Python, in a recent video interview for the MIT AI lecture series, scientific research through numerical means is usually a trial-and error creative approach, where the very investigative process benefits from an interactive feedback loop. The faster the loop, the faster the distillation of code.

Can quantum physics and quantum computing follow in this path by going the open-source way, accelerating the discovery of physical phenomena? Below we provide an example drawn from our recent experience.

PIQS: an example of open source package for physics research

 A major drawback in the development of quantum technology is the emergence of stronger noise as the system size grows, a process generally referred to as decoherence. The quantum system is never completely isolated, like Schrödinger’s cat inside the box, but is ‘open’ to interactions with the environments. The theoretical description of such coherence-averse processes in many-body quantum physics dynamics is itself problematic. This is because the very computational space grows exponentially with the number of qubits N, faster than 2^N (actually a daunting 4^N even if major assumptions simplifying the possible correlations of the open system are made).

We have recently released an open-source library, the permutational invariant quantum solver (PIQS) [Shammah18], to simulate a broad range of effects with an exponential advantage over the straightforward simulation of the open quantum dynamics. With PIQS, it is possible to include local effects in the noisy dynamics and energy dissipation, as well as the incoherent influx of energy from an external source, such as that mediated by a pumped cavity field by intermediate Raman processes in clouds of atoms illuminated by laser light [Baumann10,Bohnet12].

PIQS is quite versatile and addresses a series of open questions in the thermodynamics of quantum systems. This library can describe a broad range non-equilibrium effects in large systems of qubits, or ensembles of two-level systems, such as Dicke superradiance, which is the cooperative emission of light from an ensemble of identical two-level systems, in presence of sub-optimal experimental conditions, such as in solid-state devices, in which inhomogeneous broadening and local dephasing spoil the simple textbook picture of coherent light-matter interaction [Shammah17].

Due to the universality of the mathematical language in which quantum mechanics speaks, this tool can also describe spins in solid state materials and more generally, qubits engineered on a broad variety of platforms, from lattices of atoms to defects in diamond [Bradac17,Angerer18,Rainò18]. The use of permutational invariance has been crucial for the exponential reduction of the system space. The PIQS library joins other numerical investigations and libraries leveraging on symmetries in Lie algebras in tensor spaces [Kirton17,Gegg17].

By integrating the PIQS library into QuTiP, the quantum optics software in Python first released in 2011, this purpose-specific tool is now accessible to a wide community of users already familiar with this other well-established open-source software. This agility is another example of the modularity not only of the Python ecosystem, but of modular libraries themselves.

QuTiP itself is the example of a flexible library, which is used by theorists to test ideas or explore new physics, but also by experimentalists, who might want to analyze data or obtain predictions for how to tune the knobs of their experiments, including those involving the first error-prone quantum computers.

The future of quantum open source

 Open-source libraries like PIQS and QuTiP and the community of developers-researchers seem a key drive to the development of quantum technologies, as they offer the opportunity for creative interactions and novel solutions, as well as the capability to tinker with open problems.

Training more theoretical physicists and experimentalists on how to code collaboratively and develop open-source tools is another important aspect to train the next generation of future quantum programmers. At the same time, making this process easy and efficient, so that it can complement fundamental research, is paramount.

Involving the wider open-source community to use the knowledge and skills of expert software developers can also help to develop better simulation techniques or tools, for example for running simulations on GPUs or clusters. The two communities can learn from each other: one can help to adopt the best software development techniques and the other can demystify quantum quirkiness to facilitate the search for new and creative applications.

Finally, we look forward toward the development of institutional avenues to open-source quantum computing. Currently, only private ventures offer researchers cloud access to quantum machines [Zeng17], due to the costs of hardware development and software engineering infrastructure. As the community and tools of open-source software develop, we can envision in the future of quantum computing — and broader quantum technology research — also a network of scientific and institutional laboratories providing cloud access to experiments. This would contribute to reshape and possibly accelerate the rate of discovery in basic quantum physics research.


[Fingerhuth18] Mark Fingerhuth, Tomáš Babej, and Peter Wittek, Open source software in quantum computing, PLoS ONE 13 (12): e0208561 (2018).

[Zeng17] Will Zeng, et al. “First quantum computers need smart software.” Nature News 549.7671 (2017): 149.

[Johansson12] J. R. Johansson, P. D. Nation, and F. Nori: “QuTiP 2: A Python framework for the dynamics of open quantum systems.”, Comp. Phys. Comm. 184, 1234 (2013); J. R. Johansson, P. D. Nation, and F. Nori: “QuTiP: An open-source Python framework for the dynamics of open quantum systems.”, Comp. Phys. Comm. 183, 1760–1772 (2012)

[Fortunato18] Fortunato, S., Bergstrom, C. T., Börner, K., Evans, J. A., Helbing, D., Milojević, S., … and Vespignani, A. Science of science. Science, 359, 6379, eaao0185 (2018).

[Melnikov18] Alexey A. Melnikov, Hendrik Poulsen Nautrup, Mario Krenn, Vedran Dunjko, Markus Tiersch, Anton Zeilinger, and Hans J. Briegel, Active learning machine learns to create new quantum experiments, PNAS 115 (6) 1221 (2018)

[Gabbard18] Hunter Gabbard, Michael Williams, Fergus Hayes, and Chris Messenger, Matching Matched Filtering with Deep Networks for Gravitational-Wave Astronomy. Phys. Rev. Lett. 120, 141103 (2018)

[Shammah18] Shammah, N., Ahmed, S., Lambert, N., De Liberato, S., and Nori, F, Open quantum systems with local and collective incoherent processes: Efficient numerical simulation using permutational invariance. Phys. Rev. A 98, 063815 (2018)

[Baumann10] Kristian Baumann, Christine Guerlin, Ferdinand Brennecke and Tilman Esslinger, The Dicke Quantum Phase Transition with a Superfluid Gas in an Optical Cavity. Nature 464, 1301 (2010)

[Bohnet12] Justin G. Bohnet, Zilong Chen, Joshua M. Weiner, Dominic Meiser, Murray J. Holland and James K. Thompson, A steady-state superradiant laser with less than one intracavity photonNature 484, 78 (2012)

[Shammah17] Nathan Shammah, Neill Lambert, Franco Nori and Simone De Liberato, Superradiance with local phase-breaking effects. Phys. Rev. A 96, 023863 (2017)

[Bradac17] Carlo Bradac et al, Room-temperature spontaneous superradiance from single diamond nanocrystals. Nat. Commun. 8 1205 (2017).

[Angerer18] Andreas Angerer et al. Superradiant emission from colour centres in diamond. Nature Physics 14, 1168–1172 (2018)

[Rainò18] Gabriele Rainò, Michael A. Becker, Maryna I. Bodnarchuk, Rainer F. Mahrt, Maksym V. Kovalenko and Thilo Stöferle, Superfluorescence from lead halide perovskite quantum dot superlattices. Nature 563, 671 (2018)

 [Kirton17] Peter Kirton, and Jonathan Keeling, Suppressing and restoring the Dicke superradiance transition by dephasing and decay. Physical review letters 118, 123602 (2017).

[Gegg17] Michael, Gegg, and Marten Richter, PsiQuaSP–A library for efficient computation of symmetric open quantum systems. Scientific Reports 7, 16304 (2017).


Interactions: Conversation with Martijn van Calmthout

Post by Christine Horejs, Nature Reviews Materials.

The theoretical physicist Sam Goudsmit had a remarkable life. Not only did he discover the electron spin with his colleague George Uhlenbeck (for which they did not receive the Nobel prize – to the surprise of many colleagues), he was also the scientific leader of the Alsos mission, the United States mission searching for the ‘German nuclear bomb’. After the war, in 1958, he launched the pioneering weekly Physical Review Letters, which became one of the top publications in science.

Martijn van Calmthout, photo by Hilde Harshargen, De Volksrant

Martijn van Calmthout, former science editor of the Amsterdam-based newspaper De Volkskrant and now head of communication at the National Institute for Nuclear and High-Energy Physics (Nikhef), tells the thrilling story of Sam Goudsmit’s life in his book Sam Goudsmit and the hunt for Hitler’s atom bomb (first published in Dutch in 2016, now translated into English by Michiel Horn). From his days as a Physics student of Paul Ehrenfest in Leiden to the crazy times of the Alsos mission during the final days of World War II, Martijn van Calmthout describes a rather humorous theoretical physicist with a very tragic family history – he lost his parents in Auschwitz, despite trying to help them to immigrate to the US. Goudsmit worked with Zeeman, Bohr and Einstein, and was a good friend of Heisenberg, whom he eventually hunted down in Germany during his mission to catch the German nuclear physicists. However, Goudsmit always undermined his own achievements in quantum physics as well as his participation in one of the most exciting times in theoretical Physics: “My God, it is as if you dated Marlene Dietrich or something,” said Goudsmit when asked about his famous Physics friends in the 1920s. “Back then it was all so unimportant.”

We talked to Martijn van Calmthout about his new book and the stories behind it.

How did the idea for the book Sam Goudsmit and the hunt for Hitler’s atom bomb take shape?

In the upshot to the Einstein year 2005, I was doing research for a small book on Einstein, called Einstein’s Light. As Einstein was often in Leiden, I noticed the name of the Leiden student Sam Goudsmit, whom I did not know, but who turned out to be one of the discoverers of electron spin. I was intrigued and as I delved into his story, I also found the war time memoir Alsos, which he wrote. An important Dutch physicist with a real war adventure concerning nuclear developments in Hitler’s Germany. I was surprised that all this was hardly known in the Netherlands. I decided to write a biography. At that time, the archives at the American Physical Society (APS) were getting published online, so research became a lot easier. Read more

Behind the paper: A bridge between theory and experiment

On behalf of Marcus Huber

Christian Murzek 2018

Supposedly, there are two very different species of physicists: theorists and experimentalists. This alleged division is the subject of numerous nerdy jokes, but is more seriously reflected in university curricula, academic positions, grants, papers and non-surprisingly, reviews. Our review is an attempt to bridge the apparent gap that often complicates communication, focussing on a specific area of quantum physics that has seen a close connection between theory and experiment.

The story behind this review starts well before it was conceived. After finishing my PhD in theoretical physics, I remember being approached by experimentalist colleagues, asking seemingly simple questions about quantifying high-dimensional entanglement. At first, I couldn’t comprehend their dissatisfaction with my writing down a self-adjoint operator—after all, this is what constitutes a ‘measurement’ according to the postulates of quantum mechanics. After being presented with a bunch of tangible tools that were screwed to an optical table and asked to explain how to realise that specific measurement, I realised how little I actually understood quantum experiments and how pointless all of my theorems seemed for answering the simplest of questions.

This initially painstaking interaction with the mysterious species of experimentalists eventually bore fruit and led to a series of collaborations with experimental groups. There was a recurrent theme in our interactions experienced also by many theorist colleagues—we were presented with final experimental data and asked to tell if it is possible to certify or even quantify entanglement. The answers would have always been easy had they done the experiment in a slightly different manner, but alas, what was done, was done. I then spent sleepless nights trying to understand what each particular setup meant and how one could construct theoretical tests of entanglement for each specific situation—a process that could have been much simpler had there been a comprehensive review bridging this divide.

At some point, one of my frequent experimental collaborators approached me with an interesting proposition: we could run experiments together. And indeed a short time later, Mehul Malik joined my group as a senior postdoc and we started exploring the intricacies of multipartite and high-dimensional entanglement of ‘twisted’ photons. The first ‘experimental’ papers with a majority of theory authors were born and slowly the entire group developed a common language. Two more senior postdocs of the group had reported very similar experiences in different experimental collaborations, with Giuseppe Vitagliano working on spin squeezing in cold atoms and Nicolai Friis analysing ion traps with 20 qubits. We had often talked and decided the field really needs a review that covers all aspects in a unifying language, but never found the time to actually materialise it.

When I was invited to write a review for Nature Reviews Physics, we knew this was the chance to finally realise that dictionary that should become a handbook for both theorists and experimentalists to talk to each other, while comprehensively showcasing the state-of-the-art of quantum technologies. Of course, our initial dream was a bit too ambitious, given that there are dozens of experimental platforms, each with their own techniques and whole books could be written just about the theory of entanglement. So while trying to remain as objective and comprehensive as possible, we naturally decided to focus on aspects that we found most exciting at the moment.

The time we were planning to write the review also coincided with the move of Mehul Malik to his new professorship in Edinburgh and overlapped with the parental leaves of both Nicolai Friis and Giuseppe Vitagliano. While all joyous occasions, it was hard to gather the crowd even in the same Skype conversation. Collectively editing, planning and writing a comprehensive review with strict length constraints seemed an insurmountable task under these circumstances. So we turned to collaborative online LaTeX editors and at different hours of day and night wrote and commented the present review. When Nature Reviews Physics approached us about whether we would be willing to try Overleaf for collaborating with the editorial team, we were already well acquainted with the workflow, and went through several rounds of excellent editorial feedback, without ever having to worry about version control or sending a single document via email.

Interactions: Anastasiia Novikova

Anastasiia Novikova will join Nature Reviews Physics in January after a PhD at Synchrotron SOLEIL and a postdoc at CEA Saclay in France.

What made you want to be a physicist? 

I was always curious to understand natural phenomena, and physics seemed to explain how almost everything worked in the Universe. Besides, I enjoyed the scientific approach used in physics: experiment and demonstration.

If you weren’t a physicist, what would you like to be (and why)?

If not a physicist, I would definitely be an artist. As a child, I was passionate about drawing and painting (and I still am). Shapes and colours of nature were always hypnotizing me.

Which historical figure would you most like to have dinner with — and why?

I have a whole list of historical figures but the one I would really like to meet is Richard Feynman. To me, he is a person remarkable for his manner of popularizing physics and capturing the audience. The first thing I would ask him: “What is your secret? “

Which is the development that you would really like to see in the next 10 years?

I would like to see the development of Artificial Intelligence in the domain of Genetics to help us understand such issues as genetic disorders.

What’s your favourite particle?

While studying the Physical Chemistry module at Pierre and Marie Curie University, I was fascinated with how the electronic structure of a compound could influence its colour. In this regard, my favourite particle is, definitely, the electron.

What would your dream conference be like?

The conference I dream of would be dedicated to the greatest discoveries of all time. And being imaginary, it would be organized by the pioneers, with, for example, Isaac Newton giving a Welcome speech.