Bygone era: when 3D visualization really was 3D. (Courtesy: CERN)
“The past is a foreign country: they do things differently there,” is probably the only famous sentence written by the English novelist L P Hartley. It also sums up nicely a collection of photographs of CERN in the 1960s and early 1970s showing among other things a jolly worker wearing a beret, scientists wearing white lab coats and ties, and a strange religious-like procession. There are also lots of photos of vintage kit, including one of those huge vacuum-valve-powered oscilloscopes (probably from Tektronix) that would be familiar to physicists of a certain age. My favourite photo is shown above. It was taken in 1965, when 3D data visualization was actually done in 3D! I believe that the collection was put together by CERN’s Alex Brown and you can enjoy looking at all 55 images in the collection here.
The United Arab Emirates (UAE) has announced plans to send a spacecraft to Mars by 2021, which would make it the first Arab country to reach another planet. The unmanned probe’s prospective nine-month journey is timed to coincide with the 50th anniversary of the UAE’s independence from the UK. The UAE is also creating a new national-level space agency intended to “maximize the contribution of space industries to the national economy”, according to Sheikh Mohammed bin Rashid Al Maktoum, ruler of Dubai and the UAE’s vice-president.
The Mars mission and the new space agency are intended to help diversify the country’s economy away from reliance on oil and gas and into hi-tech industries. “The government of Dubai started the Emirates Institution for Advanced Science and Technology (EIAST) in 2006, with the goal of building up local capability in research and innovation,” says Danielle Wood from Johns Hopkins University in Baltimore, Maryland, in the US. Wood has studied the technical and programmatic challenges of government space programmes around the world and visited the EIAST team, finding the researchers “hard working, ambitious and curious about the engineering knowledge they are gaining from the satellite activities”.
Leading role
Together with the South Korean company Satrec Initiative, EIAST has already designed and built two Earth-imaging satellites. EIAST is now taking a leading technical role in the partnership’s third satellite – Khalifa Sat – due to be launched in 2017. Elsewhere in the UAE, the companies YahSat and Thuraya operate satellites bought to provide services including satellite-phone networks, high-definition TV and commercial broadband internet. In total, such projects mean that Emirati investments in space technology have already exceeded AED20bn (£3.4bn). However, the country has relied on other nations for the launch capability that will be critical in the Mars mission.
Wood underlines that the UAE does not currently have the capability to reach Mars, but says it is a feasible goal in principle, given enough funding and effective partnerships with experienced space nations. “The question is how the UAE space agency will choose to partner and how much funding they prioritize,” says Wood. “Ultimately, this project could be an opportunity for engineers within the UAE to learn new capabilities, but their leaders must consider what outcomes they desire – will they emphasize local contributions or will they leverage the knowledge of the global space community to help them?”
A new microscopy technique allowing biologists to see more detail in living specimens without damaging them with intense light has been developed by researchers in the US, Europe and Japan. The method uses interacting beams of light to create an ultrathin “light sheet” that passes through the sample, illuminating only the part of the specimen that is being imaged. This minimizes tissue damage caused by unnecessary illumination, and has allowed the team to make “movies” showing the time evolution of live specimens.
The team is led by Eric Betzig of the Howard Hughes Medical Institute in Virginia, who earlier this month shared the 2014 Nobel Prize for Chemistry for the invention of super-resolution microscopy, which allows researchers to build up nanometre-scale images of static biological samples. However, Betzig has now moved away from the technique. “There’s only so much you’re going to ever learn – even with the highest resolution picture – from static images,” he explains. “The only way you’re going to understand what connects inanimate objects to animate life is by seeing movies.”
Studying tiny living cells in real time is a major challenge because the strong illumination needed to obtain multiple, rapid, high-resolution images can alter biological and chemical processes or even kill the cells. Traditional imaging techniques such as confocal microscopy send a cone of light through the sample to a tiny focus in the image plane. The focus is then swept across the image plane and light propagates back out of the sample to be collected. The problem is that the light cone illuminates – and therefore potentially damages – much of the sample to image a tiny spot.
Thin sheet of light
Light-sheet microscopy gets round this problem by illuminating the sample with a thin sheet of light perpendicular to the imaging direction. The sheet is swept through the sample to produce a 3D image. The technique was popularized by Ernst Stelzer and colleagues at the European Molecular Biology Laboratory in Heidelberg, Germany, who first used it on fly embryos. Unfortunately, it is difficult to produce sheets of light thinner than about 5 μm, whereas the depth of focus of a high-resolution microscope is about 1 μm. This means that most of the light passing through the sample blurs the image instead of enhancing it.
Betzig and colleagues addressed this problem by illuminating the sample with plane waves from multiple directions. Interference between these waves produces a thin optical lattice of standing waves similar to lattices used to trap ultracold atoms. To achieve images at the highest possible resolution, the researchers took multiple images in each plane, gradually shifting the lattice across the plane, before combining the images electronically. They also developed a technique to acquire images much more quickly and with less light going into the sample. This involves shifting the lattice back and forth rapidly, resulting in the effective uniform illumination of the plane with a light sheet only 1 μm thick. Using this latter technique, the researchers we able to record at up to 1000 image frames per second.
Moving pictures
The researchers used their optical-lattice microscope to gain new insights into a variety of biological processes, such as the behaviour of mitochondrial fragments and chromosomes during cell division and the development of fly and worm embryos. By adjusting the frame rate of their microscope, the researchers were able to monitor both slow embryonic processes such as the localization of a particular protein as the embryo divides and grows, and faster processes that occur just before it hatches.
Stelzer, now director of the Buchmann Institute for Molecular Life Sciences in Frankfurt, is impressed, saying that the technique “allows us to work with smaller objects such as cells and get a really good resolution, while, at the same time, maintaining the viability of the specimen”.
Developmental biologist Pavel Tomancak of the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden agrees. “It’s a kind of incremental improvement of the light-sheet paradigm,” he says, “but the paper sells itself by showing these spectacular applications. Looking at the movies, I would say it’s breathtaking!”
When Sir Isaac Newton died early in the morning on Monday 20 March 1727 at his London home, the world lost one of the greatest physicists and mathematicians of all time. There was no immediate family to mourn his loss – Newton never married and had no siblings – but his more distant relatives were well aware of the esteem in which he was held. The snag was that Newton had left no will. So with an eye to making a quick buck from the great man’s possessions, an inventory of everything that Newton owned was quickly prepared, which included such delights as a “cheese toaster”, “one brown teapot”, six chocolate cups and a “crimson mohair bed”.
There were, of course, some things of more lasting value, including a collection of almost 2000 books (sold to the warden of Fleet Prison for £300) and Newton’s many financial investments (he had, after all, served as Master of the Mint), which were worth nearly £30,000. An enormous amount at the time, this sum was divided among Newton’s half-brother, the children of his two half-sisters and eight of his half-nieces and half-nephews. As for Newton’s family estate at Woolsthorpe in Lincolnshire, it was inherited by the “hapless” John Newton, a distant cousin who gambled and drank the estate away over the next six years.
The big question, though, was what to do with the mountains of papers, manuscripts and notebooks that Newton had left behind. We now know that they contained almost eight million words in Newton’s own hand – not just on mathematics and science, but also on theology, alchemy and church history – and represented a lifetime of deep thought and study. Unfortunately, Newton had brought no order to these “reams of loose and foul papers”, as the inventory characterized them, consisting as they did of countless rough drafts – often undated – annotated by numerous revisions. Might these papers, the family wondered, contain anything of value that could be sold for publication?
What happened next is the theme of The Newton Papers: the Strange and True Odyssey of Isaac Newton’s Manuscripts by the UK-based author Sarah Dry. In the immediate aftermath of Newton’s death, John Conduitt – the husband of one of Newton’s half-nieces, and also his successor at the Royal Mint – got in Thomas Pellet, a member of the Royal Society, to examine the papers. Over the course of three days in May 1727, Pellet gave the mass of material a quick skim and saw one document that could be – and was – sold for immediate printing. Two others followed over the next two years, including the last book of Principia Mathematica, which came out in 1728.
But what was in the rest of the stuff? Conduitt, who inherited the reams of material, immediately sought to write a biography of the great man, whom he knew well. Biographies were a relatively new phenomenon in the early 18th century, but Conduitt felt that Newton, as “father of the Enlightenment”, deserved to be fully honoured in this way. But Conduitt quickly realized that Newton held what Dry calls some “highly idiosyncratic” religious views, believing that Christ was subservient (rather than equal) to God. These heretical, “anti-Trinitarian” thoughts – coupled with the sheer complexity of the material – “added up to a mess that was easier kept out of sight” and Conduitt’s biography never materialized.
Newton’s papers were then passed on to Conduitt’s descendants, a family called Portsmouth who lived at Hurstbourne Park in Hampshire. The Portsmouths were reluctant to grant access to the archive – Dry speculates that they feared people might make unauthorized copies of the manuscripts, thereby robbing them of potential income. She also suspects the family kept snoopers out because of the papers’ controversial contents, although a few extracts did get published in the late 18th century after the Royal Society sent the scientist Samuel Horsley to examine the Portsmouth archives. On the whole, though, the picture of Newton that emerged in the 19th century was “like a petrified mummy, all wrapped up and immune from the putrefying forces of history…his earthly frailties lost to memory”.
Seeing further A historical reproduction of a sketch by Isaac Newton of a reflecting telescope and its components. (Courtesy: Library of Congress/Science Photo Library)
At this point, Dry begins a long, complex tale about attempts by various scholars in the early 19th century to reappraise Newton, and in particular to assess whether he – far from being the saintly figure of early portrayals – had actually gone mad, was a bit of a meanie, or both. The remainder of the book is as much about these scholars and the development of the history of science as it is about Newton himself. Indeed, in places Newton barely gets a look-in. What’s more, the “odyssey” of the book’s subtitle is rather an exaggeration as the fate of Newton’s papers is hardly thrilling: after almost 150 years in Hurstbourne Park, the scientific portions of the manuscripts were donated to the University of Cambridge in 1872 by the then Lord Portsmouth.
This portion of the book does, however, include an entertaining account of how Newton’s scientific writings were analysed by two giants of Cambridge physics, George Stokes and John Adams. They were, it appears, not ideal candidates for the job: Stokes was a procrastinator whose office was a “maelstrom of papers” piled up to a foot high, while Adams was a perfectionist who refused to put pen to paper until he was absolutely certain of what he wanted to say. Still, the pair did discover a fair bit, including new material on atmospheric refraction, lunar theory and how a solid moves through a liquid with least resistance. But basically the view that emerged was “the safe and reliable Newton of old”, with nothing dodgy about his work on religion or alchemy.
As for the non-scientific portion of Newton’s papers back in Hampshire, nothing happened to them either until 1936 when Gerard Wallop – heir to the Portsmouth estate – decided to auction them to pay for steep death duties and the costs of his own divorce. With no representatives from any universities or the likes of the British Museum, most buyers were private individuals who bought selected lots merely as “autograph material” – i.e. writing from the hand of Newton. The sale garnered a miserly total of £9000. “And so the bulk of Newton’s remaining manuscripts, kept intact and relatively safe for more than 200 years…were scattered to dozens of buyers all over the world, some never to be seen again.” Gulp.
Except – wait! Annoyed that Newton’s works had been so unceremoniously dispersed, the economist John Maynard Keynes and the Jewish scholar Abraham Yahuda immediately began tracking down and buying back many of the papers. After their deaths, their reassembled collections ended up at the University of Cambridge and the Hebrew University of Jerusalem, respectively. Dry uses this fact as an excuse to examine the development of the history of science as an academic discipline and the growth of “the Newton industry” – his papers offering a factory-line for PhD theses.
I suspect historians of science are the main audience for Dry’s book, as physicists are likely to be less interested in her many digressions on topics such as the development of cataloguing historical papers, the fate of libraries sold by English country houses, and the rise and fall of the book trade. As for what the manuscripts really tell us about Newton, unfortunately there is so much material that I Bernard Cohen – the doyen of Newton experts – once expressed a fear that it would take a dozen scholars a dozen years to carry out a truly comprehensive analysis. This, he noted, “would be an unwise expenditure of…manpower and funds”, and even if such a book came out, it would be of use to none “but the most dedicated specialist”.
Cohen was not the first to be daunted by the sheer magnitude of Newton’s papers, although the job of tackling them may become a bit easier now that many of them are freely available online thanks to initiatives such as the Newton Project. As the British scholar R A Sampson said in the 1920s of the effort in creating a full scholarly analysis of Newton’s archive: “It is an historical task, and, in a sense, one of national importance, but for the advancement of science it matters only in moderate degree.” Well written and carefully researched though it is, one could also say the same about Dry’s book.
A design for a new broad-bandwidth amplifier for detecting single microwave photons has been unveiled by physicists at the University of California, Berkeley and the Lawrence Berkeley National Laboratory in the US. The “Josephson travelling-wave parametric amplifier” uses a technique called “resonant phase matching”, which is expected to boost the gain in the amplifier by more than 10 dB compared with existing Josephson parametric amplifiers (JPAs). The new device is also predicted to have a bandwidth of 3 GHz, and together these properties should allow it be used in quantum circuits that operate at multiple frequencies, as well as finding use in extremely sensitive astronomical detectors.
The readout and control of superconducting quantum bits (qubits) involves the detection of extremely weak microwave signals containing as few as one photon. This can be done using a JPA, which incorporates one or more Josephson junctions, each consisting of a tiny slice of insulator sandwiched between two superconductor contacts. A parametric amplifier works by modulating a circuit parameter such as capacitance or inductance. In a JPA, the Josephson junction behaves like a nonlinear inductor and plays the role of a modulated parameter when it is “pumped” by a microwave signal.
“Our new result is important because JPAs are the most advanced amplifiers available today for making low-noise measurements on systems such as superconducting qubits,” explains team member Kevin O’Brien of the Nanoscale Science and Engineering Center at the University of California, Berkeley.
Cavity-free operation
Although JPAs can reach the so-called quantum limit for minimum added noise, they do suffer from having a relatively narrow bandwidth. This is because the gain of the JPA is boosted by coupling the Josephson junction to a resonant cavity, which puts severe limits on the frequencies at which the JPA can operate. Travelling-wave parametric amplifiers (TWPAs) avoid this problem by dispensing with the cavity altogether. Instead, the amplification occurs in a much longer microwave transmission line. However, this creates another problem: high gain can only be achieved when the nonlinear processes taking place in the system are phase matched.
“We show that by adding many resonant elements into the transmission line, we can achieve both phase matching and exponential gain over a broad bandwidth,” O’Brien explains.
The researchers, led by Berkeley’s Xiang Zhang, integrated these elements by making the transmission line from 2000 unit cells, with each cell comprising a Josephson junction and a resonator. The resonators modify the phase velocity of the pump signal, which allows the pump to efficiently transfer energy throughout the entire device.
Swings and JPAs
To put things more simply, an example of parametric amplification in real life is a playground swing, says O’Brien. “While the JPA is a circuit in which the Josephson junction is the nonlinear element and the pump a microwave field, a swing is a nonlinear oscillator driven by moving your centre of mass. Both the swing’s amplitude and the amplitude of a weak microwave signal will increase over time, as energy transfers from your movements or the microwave pump,” he explains.
“This is all very well if the phase of the pump is correct, but it is another matter if the pump does not have the right phase relationship with the oscillations. In this case, energy transfer from the pump can be less efficient, and in some cases the pump can actually reduce the oscillation’s amplitude. Children learn how to optimize this pump phase through trial and error, and we can now optimize Josephson junction TWPA gain thanks to resonant phase matching,” he continues.
The team is now busy fabricating devices based on its design and is also using these to perform measurements on superconducting qubits.
As a theoretical physicist, S James Gates Jr is used to being patient. In his field, it can take years, and sometimes even decades, to gather enough experimental evidence to prove that a theory is on the right track. The Higgs boson is a good example: as Gates points out, this now-famous particle started out in the 1960s as “a piece of mathematics”, and it took nearly 50 years for its existence to be confirmed.
For Gates, the discovery of the Higgs had personal significance: the long-predicted boson was the first item on his “bucket list” of the physics discoveries he would like to see happen in his lifetime. Furthermore, its detection at CERN’s Large Hadron Collider in 2013 also gave him renewed hope for some of the remaining items on the list. Chief amongst these is the theory of supersymmetry, which predicts that for every fundamental particle we know about, there exists a so-far-undiscovered “superpartner” particle with subtly different properties.
As you’ll hear in this podcast, Gates became interested in supersymmetry in the 1970s, when he stumbled across the then brand-new theory while searching for a PhD thesis topic. He has been fascinated by it ever since, and its principles continue to guide his research at the University of Maryland, where he has been a professor since 1988. But even so, Gates’ conviction that superpartner particles will, eventually, be discovered is tempered with pragmatism about the slow pace of scientific progress, and the knowledge that “if you can’t find evidence for a theory, nobody should believe it”.
Listen to the podcast to learn more about the theory of supersymmetry, Gates’ long involvement with it, and his attitude towards the two other items on his bucket list.
This year has been a special one for the CERN particle-physics lab near Geneva as it turns 60 years old. It was back in 1954 when the CERN convention was ratified by its first 12 member states and the European Organization for Nuclear Research was officially established.
The past few months have seen CERN celebrate in style with a whole host of symposia, meetings, plays, films, concerts and other events being held at the lab and at member states across Europe.
Indeed, researchers at CERN have had a lot to celebrate recently, following the discovery of the Higgs boson at the lab in 2012, and they will be hoping for yet more success when the Large Hadron Collider (LHC) switches on next year following a two-year upgrade and maintenance programme.
In the latest Physics World focus issue on “big science” we look at what has been going on at CERN during the shutdown as the lab gears up to hunt new particles beyond the Higgs boson. Once back online, the LHC will be generating even more data than in its previous run and this focus issue also investigates how researchers are going to deal with the huge volumes of information that will be generated at many upcoming facilities, as well the need to train the next generation of researchers to use them.
A new report that seeks to map out US priorities in fusion research over the next 10 years has received scathing reviews from American fusion researchers. The report was commissioned by the US Department of Energy (DOE), which asked its Fusion Energy Sciences Advisory Committee (FESAC) to come up with a 10-year plan under several very constrained budget scenarios. According to critics, the report – written by a FESAC subcommittee – lacks vision, does not adequately peer review the proposals that it made, and fails to address the real problems faced by fusion research.
Planning problems
“It seems that the committee was put together to ratify the plan that the DOE had already decided upon,” claims Martin Greenwald of the Plasma Science and Fusion Center at the Massachusetts Institute of Technology (MIT). The report comes in the wake of several years of belt-tightening for the US fusion community, which has suffered from the country’s rising financial contributions to the international ITER fusion project being built in France. Indeed, MIT’s own Alcator C-Mod tokamak device had been earmarked for closure in the 2013 budget and was only saved by Congress following aggressive lobbying by Massachusetts politicians.
The FESAC subcommittee was told to devise a plan that assumes the US remains a member of ITER, with funding ranging from a flat budget to modest growth of about 2% above inflation. Its recommendations involve shifting the emphasis away from plasma science and towards the practical needs of power reactors. It calls for two existing facilities – DIII-D in San Diego and NSTX-U at the Princeton Plasma Physics Laboratory (PPPL) – to be upgraded and for C-Mod to be axed. However, it also envisages two new facilities: a simulator to help understand the interaction of plasma with solid surfaces; and a new reactor called the Fusion Nuclear Science Facility.
Written critiques
The report was scheduled to be approved by the full FESAC at a meeting on 22–23 September but was only circulated the day before the meeting. As a result, another Web conference was scheduled for 10 October. Meanwhile, a number of written critiques were sent to the FESAC, including one signed by 50 senior fusion scientists, and several individual submissions. Critics pointed out that the report did not take into account the views of the community and that its facility proposals were not subjected to peer review. “The committee had too little time for such a weighty charge,” says Stewart Prager, director of the PPPL.
The make up of the committee itself has also come under fire as the DOE stipulated that it should not contain any members from the major fusion labs. Greenwald points out, however, that the committee had an unbalanced representation from the Oak Ridge National Laboratory, which is where the report’s proposed new facilities would be built. At the 10 October FESAC meeting, the DOE also asked its 23 members to abstain from voting if they had a connection with a lab that either has – or may get – a major facility. The remaining members voted to pass the report on to DOE by six votes to three.
“I’d been to Cambodia. I’d got a very, very unique insight into the horrible thing of mines that take limbs from children. And I’d thought for a long time that – if I possible could – could I maybe change everybody’s attitude?”
These are the words of Sir Bobby Charlton, the former England and Manchester United footballer, speaking in this film about the science of landmine detection. After visiting several conflict areas in Southeast Asia and meeting with landmine victims, Charlton decided to use his influence to found Find A Better Way – a charity that supports the development of improved techniques for detecting landmines. The hope is that this work will speed up the process of clearing landmines, which can be an intensely risky and laborious process.
“There are literally millions of anti-personnel mines in the ground in places where people need to grow food, or need to walk to the nearest well, or simply go about their daily business – shelter under a tree from the Sun,” explains Bill Lionheart, a mathematician at the University of Manchester in the UK whose work is supported by Find A Better Way. Lionheart and his team are developing ways to reduce the number of false-positives when searching for mines. “So in a way, our challenge is not so much to find mines, but to detect that something’s not a mine,” he says.
For example, it is common for landmine clearance teams to use metal detectors to locate the firing pin and metal percussion caps present in many landmines. Currently, all those bits of metal have to be dug out of the ground before an area can be declared safe and, according to Lionheart, this approach would mean of the order of hundreds of years before people could get their land back. To improve the situation, Lionheart and his colleagues have developed the technology and the underlying maths of metal detectors to develop devices that can not only detect, but also characterize metal objects in the ground. This makes it possible to disregard the signals that relate to harmless bits of scrap metal.
Similarly, Lionheart’s team is developing a form of ground-penetrating radar with multiple sensors. This enables a far more detailed picture of the subsurface to be pieced together than is possible with conventional radar techniques. The charity is confident of the value of its work but also humble in the face of such a vast global problem. “We know that we’re not going to solve the problem in one easy move,” says the charity’s chairman, John Edees. “We’re not seeking the blue horizon – we are seeking to improve the technology and the way things work today, and to improve it in the years ahead.”
Construction of a giant neutrino experiment operated by the Fermi National Accelerator Laboratory (Fermilab) in the US was completed on schedule last month and under budget. The NOvA experiment is made up of two colossal detectors – one at Fermilab near Chicago and the other 800 km away deep in the North Woods, Minnesota. NOvA is the most powerful accelerator-based neutrino experiment to be built in the US and the one with the furthest diatance between detectors in the world.
“Neutrino research is one of the cornerstones of Fermilab’s future and an important part of the worldwide particle-physics programme,” says Fermilab director Nigel Lockyer. “We’re proud of the NOvA team for completing the construction of this world-class experiment, and we’re looking forward to seeing the first results in 2015.” Although the first plans for NOvA were approved by the US Department of Energy in 2007, budget cutbacks meant that its construction only began in 2009.
Ghostly particles
Interacting with matter only via the weak force and being so fiendishly difficult to detect, neutrinos come in three different types or “flavours” – electron, muon and tau – and change or “oscillate” from one type to another as they travel over long distances. NOvAs two detectors sit in the path of an extremely powerful beam of neutrinos that will be sent from Fermilab. The 300-tonne “near detector” is installed underground at Fermilab and aims to observe the neutrinos as they set off. The 14,000-tonne “far detector” – constructed in Ash River near the Canadian border – will spot them after their 800 km trip, which the neutrinos will make in less than three milliseconds.
Beaming out
The far detector in Minnesota is thought to be the largest free-standing plastic structure in the world, at nearly 61 m long, 15 m high and 15 m wide. Both detectors are constructed from PVC and filled with a scintillating liquid that produces a flash of light when a neutrino interacts with it. Fibre-optic cables then transmit the light to a data-acquisition system, which creates 3D pictures of the interactions.
Over the next six years, tens of thousands of neutrinos will be sent from Fermilab towards both detectors each day, but only a scant number of the elusive particles that actually interact with the material in the far detector at Ash River will be spotted. NOvA will analyse the rate at which neutrinos oscillate from one flavour to the other and is specifically designed to study muon neutrinos oscillating into electron neutrinos. The team also hopes to determine the as-yet-unknown masses of all three types of neutrinos.
Take a look at the time-lapse video below, which shows how NOvA’s far detector was built.
The past few months have seen CERN