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Home » Page 1036

Uncertainty for science under Trump

Rick Perry, the former governor of Texas, who has been nominated as the Trump administration’s energy secretary, once expressed his desire to eliminate the Department of Energy (DOE). Scott Pruitt, the nominated head of the Environmental Protection Agency (EPA), sued the agency 14 times during his time as attorney general of Oklahoma. Donald Trump’s choice as secretary of the interior, Republican congressman Ryan Zinke from Montana, recently asserted that human-caused climate change, although “not a hoax”, was “not proven science, either”. And just nine days before his inauguration, Donald Trump appointed a proponent of the discredited link between children’s vaccines and autism to head a government commission on the safety and scientific integrity of vaccines.

“The appointments make one scratch one’s head,” says Rush Holt, the physicist and former Congressional Representative who is chief executive of the American Association for the Advancement of Science (AAAS). “Even though some are not outsiders, they are idiosyncrats or iconoclasts.” These nominees had provided few hints about the administration’s likely policies related to science and technology. Yet at a Senate hearing this month, Perry did express regret that he had called for the DOE to be abolished. He also noted that he would base decisions at the DOE on “sound science” and “protect the men and women of the scientific community from anyone who would attack them, no matter what their reason may be”.

Nevertheless, the overall lack of clarity has caused significant angst within the US scientific community as Trump takes up office. “Since the election, the level of uncertainty and even anxiety has increased,” says Holt. “The president continues to leave everybody guessing as to what he will do.” Holt adds that many of Trump’s statements are cryptic, “all over the place” and sometimes seem contradictory, leaving it hard to know what he actually means. “Combine that with his appointments, at least for science, and it’s almost bewildering, the uncertainty that is there,” he adds.

Poorly prepared

Adding to the uncertainty are the actions – or lack of them – by members of the Trump transition team. “The word from all the science-related agencies is that the transition team has not been very engaged,” Holt says. “It seems to me that the transition process will provide the least preparation for the incoming officers of any administration in many, many years.”

A major issue that worries the scientific community is the Trump-transition-team’s failure to provide any indication of its intentions on appointing a science adviser and making use of the Office of Science and Technology Policy that the adviser heads, despite receiving a letter advocating a fast appointment from the leaders of 29 scientific societies. Indeed, members of the community have sent several letters to the transition team and individuals, expressing their concerns about the future of science-related issues.

Climate-change nixed

The community’s strongest concern focuses on climate change – especially given that all references to climate change were removed from the official White House website within minutes of Trump’s inauguration. Indeed, Trump is noted for once accusing climate change of being a “hoax” set up by China to gain business from the US. Although he has slightly modified his attitude since, his transition team surprised the community by asking the DOE for the names of individuals involved in the Paris agreement and related issues. Department managers refused the request, fearing that the new administration might target those individuals in some way. “Spokespeople said there was no intention to harass them,” Holt says. “But the fact that the information was sought has left climate scientists in government very nervous.”

That feeling is hardly reduced by the line-up of nominees to head the cabinet departments mainly involved with climate matters. It is heavily slanted to individuals with strong connections to the fossil-fuel industry and those opposed to environmental controls. For example, over the past seven years, Pruitt has been suing the EPA to block regulations intended to improve the cleanliness of the environment. His reasoning is that such issues should not be handled by the federal government.

“Some claim Pruitt opposes clean air and water. This could not be further from the truth,” wrote a group of conservative organizations supporting his candidacy. “He understands that many of the nation’s challenges regarding clean air and water are best met at the state and local level.” However, environmental groups do not accept Pruitt or his reasoning. Indeed, the Environmental Defense Fund, a relatively moderate organization, has announced its opposition to Pruitt – the first such action in the fund’s 50 year history.

Increased drilling

Zinke – the nominee for secretary of the interior – is a geologist who spent much of his career in the US Navy. He has had little exposure to the protection of public lands and waters that the department oversees and, like Pruitt, has expressed support for US states to gain control of land currently under the jurisdiction of the federal government. Environmentalists fear that he might agree to increased drilling for oil and gas on those lands. Sally Jewell, the last head of the interior department under president Obama, in contrast, blocked such activity and advocated the development of renewable energy sources.

Even though some are not outsiders, they are idiosyncrats or iconoclasts
Rush Holt, AAAS

Meanwhile, former-Texas-governor Perry’s best known connection to the DOE is his failure to remember it as one of the cabinet departments he wanted to eliminate during a debate in 2012, when he ran unsuccessfully for the Republican presidential nomination. Intriguingly, Perry is not the first DOE nominee to have wanted to discard the department. Spencer Abraham, president George W Bush’s first energy secretary, had voted to do so when representing Michigan in the Senate; the department survived. Given his roots in Texas and his denial of the role of humans in climate change, Perry is expected to give strong support to the oil and gas industries. On the other hand, proponents of renewables point out that Texas emerged as a powerful source of wind power during Perry’s governorship.

Nuclear responsibilities

Dealing with energy sources and climate change represents just one facet of the DOE’s remit. About 60% of its budget goes to the National Nuclear Security Administration, which oversees the US stockpile of nuclear weapons. The expertise informed by that work played a major role in the agreement reached by the Obama administration and its allies to reduce Iran’s stockpile of enriched uranium. Throughout the election campaign, Trump asserted that the agreement was “the worst deal ever negotiated” and said dismantling it was his “number one priority”.

However, a group of senior scientists – organized by physicist and policy-maker Richard Garwin – disagree. They penned a letter to the then-president-elect asserting that the deal “has increased to many months, from just a few weeks, the amount of time that Iran will take to develop a single nuclear weapon”. The 37 signatories include Nobel laureates and senior figures in nuclear policy such as Siegfried Hecker and Sidney Drell (who signed the letter shortly before he died in late December).

The DOE also oversees the country’s 16 national laboratories. In one of his last appearances as outgoing energy secretary, Ernest Moniz introduced the first annual report to Congress on the state of the labs. While identifying areas for improvement, the report notes that collectively “they have pursued actions to substantially improve the laboratory system”. Together, the report continues, “they will continue to work to maintain and develop the most comprehensive network of its kind – a system of national laboratories that can effectively tackle long-term, critical R&D challenges for the nation.”

Obama’s legacy

As for efforts begun by the Obama administration to encourage clean power, they – for the time being – will continue. The $1bn Petra Nova carbon-capture plant – a joint venture between a Houston power company and an oil and gas operation with some government support – started operation last month. Completed on time and under budget, the plant will pump the carbon dioxide (CO2) created when it burns coal to an oilfield 130 km away. The CO2 will be injected into wells to increase the recovery of oil, with the plant being economically viable when the price of oil reaches $50 per barrel.

But as with other energy issues, environmentalists fear that the incoming Trump administration, with its negative attitude to global warming, may end support for carbon capture. Equally at risk is a new approach to coal leases on federal lands suggested by former interior secretary Jewell in early January. The recommendations could make it more expensive for companies to take on the leases.

There is, though, one agency that seems likely to prosper under the new administration: NASA. Some of president Trump’s advisers have spoken enthusiastically about lunar colonies and manned missions to orbit Mars. However, the team has also made clear its disapproval of the agency’s efforts to study global warming and other aspects of Earth science.

Holt now calls on scientists to use the switch to a new administration to their own advantage. “The current transition is an excellent opportunity for young scientists and engineers to engage now with the public and many different audiences, to explain the work you do and why it’s important for expanding human knowledge and improving people’s lives,” he says.

Supporting hi-tech businesses

Big-budget science facilities such as the CERN particle-physics lab near Geneva and the ITER fusion reactor being built in Cadarache, France, are pushing the boundaries of knowledge. Such centres are unique, bringing together thousands of scientists from across the world. They also rely on bespoke specialist equipment that is critical to their operation. Yet the hi-tech businesses supporting these facilities are being threatened by the current economic climate and the need to safeguard public funds when such facilities issue a tender for equipment. The way contracts are defined, awarded and funded is a major issue for small businesses that is now threatening their existence.

Once a company successfully wins a contract bid, it is sometimes paid as little as 10% of the contract value as a down payment to cover the costs of producing all the designs, doing development, sourcing parts, building the kit and covering salaries for the years until delivery. It is often only when the parts are delivered that the firm receive the next payment – typically 60–70% or more of the contract value. About 10–20% is then normally withheld as a warranty performance bond for more than a year. Typically, a profit can only be made between three and five years following a contract. The rest of the time, small businesses are in a “negative cash-flow situation”, where they must pay staff and suppliers up front to realise a profit in the future.

This issue used to be facilitated by bank loans, with the anticipated costs rolled up into the quotation. However, banks are now less willing to make loans to cover negative cash flow. Most big-science projects are not considered credit-worthy by banks as they require unique products that cannot be resold to anybody else should the contract fail. Small businesses are therefore struggling under the twin burden of having to finance their projects with prepayments from other projects and then relying upon the goodwill of their suppliers to accept the same payment terms they were given.

If the status quo continues, the number of suppliers will decline as companies become unprofitable

Some would say this is good for big science as competition ensures good value for the funding body. Well, yes, in the short term, but the situation changes over longer timescales. If the status quo continues, the number of suppliers will decline as companies become unprofitable. This will result in a loss of talented experts and threaten the supply of spare parts for existing systems, representing a blow to institutions that have invested in equipment that should be operable for decades.

Levelling the playing field

So how can we cultivate a healthy business community that supports big science? Firstly, we need to ensure that scientists are closely involved with purchasing teams when deciding who to award a contract to. It is extremely difficult to present a proposal that highlights the nuanced technical advantages of extremely specialist equipment when the tenders are typically awarded by non-technical accountants to the cheapest bidder that ticks most of the boxes. Unfortunately, in tender assessments the price often speaks louder than the details, resulting in a race to the bottom.

My company – Ampegon – has been approached many times by scientists disappointed by other suppliers’ sub-standard equipment that only just meets specification, is unreliable, difficult to use and requires expensive consumables, only to have new contracts for replacements awarded to the same supplier because of a tiny price difference. If tenders focus solely on meeting 80% of the criteria and then looking for the cheapest price, equipment will be made to the absolute minimum possible requirements while businesses are run into the ground trying to compete with each other for the cheapest possible solution.

The requirement that a tender process needs to have multiple bidders should also be left behind. Having to respond to five tenders for each contract simply puts prices up for everyone. It incurs irrecoverable costs that divert the business’s efforts away from contracted projects. Even if two or three companies can supply equivalent products that meet the specifications, the chances are that they will each have strengths and weaknesses that cannot be easily distinguished in a tick-box tender-compliance checklist. If possible, scientific staff should visit manufacturers, make their choice of supplier(s), and then – after per-haps commissioning a design from each – negotiate the price for production with the company offering the best, most functional design. This would preserve the scientific value of proposals while also offering the best value for money.

Finally, and most importantly, we need to level the playing field around the world. There are numerous barriers hindering international co-operation between businesses and science that are often reinforced by government policy. An especially harmful example is the impasse that occurs when a contract is agreed in one currency, and then, two years later when payment is due, the exchange rate has changed. This results in either the supplier making a loss, or conversely, the buyer having insufficient funding to pay in full. There then follows a circus of shadows whereby one party delays either delivery or acceptance, hoping that the exchange rate changes: this can be mitigated somewhat by agreeing smaller, more frequent payments throughout the project. It would also help if facilities could standardize requirements in even some areas. Economies of scale mean that prices would fall and the industrialization of developed technologies would also be easier.

Unless the situation changes, companies supplying the highest specification systems will be driven out of business by cheaper, barely sufficient equipment. This will result in a loss of knowledge and experience, and it will become harder to find suppliers as manufacturers leave for more favourable business sectors. Few small businesses ever became rich from supporting scientific research and we are simply asking that the business environment surrounding big science be modified so survival in it is easier.

Flash Physics: Fishy armour, giant telescope picks leader, E-XFEL welcomes proposals, Bruker buys Hysitron

A fish in shining armour

Fish have inspired a new design for flexible armour. Roberto Martini and Francois Barthelat from McGill University in Montreal, Canada, have looked to nature to design a protective, scaled material. Over millions of years, evolution has ensured animals can protect themselves from physical threats. In particular, the scales of animals such as snakes and fish allow flexibility yet still protect the soft tissue beneath from punctures. While humans have a long history of making scale-like armour, engineers are still exploring how nature achieves this protection so easily. Martini and Barthelat looked at hundreds of fish scales to understand their individual and group properties, finally finding that an alligator gar gave the best answers. “The people at the fish market must have wondered what we were up to,” says Bathelat. They developed a new technique to cover large, soft surfaces with ceramic tiles. Using computer simulations alongside experimental testing, they were able to find the ideal size, shape and arrangement of scales and study how they deform, slide and fracture. The resulting armour is more flexible and resistant to damage than a continuous layer of ceramic, and 10 times more resistant than soft elastomers. The work is presented in Bioinspiration and Biomimetics.

Condensed-matter physicist to lead Giant Magellan Telescope Organization

Photograph of Robert Shelton
President elect: Robert Shelton will lead the Giant Magellan Telescope Organization

The condensed-matter physicist and university administrator Robert Shelton has been appointed president of the Giant Magellan Telescope Organization (GMTO) – which is building what will be the world’s largest optical observatory. Located at the Las Campanas Observatory in Chile and run by an international consortium of universities and astronomy institutes, the Giant Magellan Telescope will have a mirror 24.5 m in diameter and a resolving power 10 times greater than the Hubble Space Telescope. Shelton is currently president of the US-based Research Corporation for Science Advancement, which is a private foundation that provides funding for research in the physical sciences. He will leave his current post and join the GMTO in February. Shelton has also been president of the University of Arizona and has a research career investigating the collective behaviour of electrons in novel materials.

European free-electron laser opens for proposals

Photograph of the Femtosecond X-Ray Experiments instrument
The Femtosecond X-Ray Experiments instrument is readied for action. (Courtesy: E-XFEL)

The European X-ray Free Electron Laser (E-XFEL) in the Hamburg region of Germany has issued its first call for proposals for beam time on the 3.4 km-long facility. The E-XFEL, which is currently being commissioned, will use a superconducting linear accelerator to accelerate electrons before passing them through an “undulator” so they produce coherent X-ray beams 30,000 times per second. Each pulse will last less than 100 fs (10–13 s), allowing researchers to create “movies” of chemical processes such as bonding and the way vibrational energy flows across a material. The user programme at the facility is expected to start later this year for a two-month period with two instruments – the Femtosecond X-Ray Experiments and the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography instrument. The deadline for applications is 20 March, with the next proposal round scheduled for mid-2017 for experiments in early 2018, when it is expected that a further four instruments will come online.

Bruker buys nanoanalysis firm Hysitron

Hysitron, which supplies equipment for making mechanical measurements at the nanometre scale, has been bought by the Bruker Corporation. Hysitron was founded in 1992 in Minneapolis, US. It has annual revenues of about $20m and supplies nanoindentation systems, which are used to measure the hardness of nanomaterials. The firm also makes equipment for tribology and electron microscopy. Bruker was founded in Germany in the 1960s and supplies a wide range of scientific instrumentation. The company is now based near Boston, US, and has more than 6000 employees worldwide. According to Mark Munch, president of Bruker’s NANO Group, Hysitron’s products will complement Bruker’s atomic-force-microscopy systems as well as its mechanical and tribology test instruments.

  • You can find all our daily Flash Physics posts in the website’s news section, as well as on Twitter and Facebook using #FlashPhysics. Tune in to physicsworld.com later today to read today’s extensive news story on the latest on Donald Trump’s science policy.

Acoustic frequency comb measures up

An “acoustic frequency comb”, which produces sound at a precise set of frequencies, has been made by physicists at the University of Cambridge in the UK. The device, which is an acoustic analogue of an optical frequency comb, works at ultrasonic frequencies. With further improvements, the device could be used for imaging, metrology and materials testing.

Conventional optical frequency combs emit a spectrum of light made of thousands of discrete peaks at evenly spaced frequencies, like the teeth of a comb. Developed in the 1990s, such combs have been used in a range of applications such as comparing different atomic clocks.

One way of creating an optical frequency comb is to combine laser light of several different frequencies in a nonlinear optical medium. But in the new work, Adarsh Ganesan, Cuong Do and Ashwin Seshia have discovered that a similar effect occurs when ultrasound waves interact in a silicon wafer covered by a thin layer of aluminium nitride, which vibrates when driven by an electrical signal.

Surprising discovery

The three researchers were initially investigating if such a wafer could be used for sensing applications when they were surprised to see it vibrate at a number of different frequencies when a megahertz signal is applied to it. The gaps between the frequencies all had the same value (about 2 kHz) and the spectrum looked much like a frequency comb. The teeth of the comb extended over a frequency range of about 100 kHz, says Ganesan.

Puzzled by their discovery, the trio soon realized that their system is like a theoretical proposal for an acoustic frequency comb made in 2014 by Peter Schmelcher of the University of Hamburg and colleagues. Schmelcher’s group modelled the atoms in a solid material as a collection of masses connected by springs that have a restoring force with a nonlinear component.

In such a material, sound waves can interact with each other to create waves at several different frequencies. Ganesan told Physics World that while the Schmelcher model does describe some aspects of their acoustic comb, it does not capture the full complexity of the device.

The team is now making more frequency combs and is also thinking about possible applications, which include boosting the accuracy of sensors that operate using mechanical vibrations. Other possible uses include phonon lasers that create phase-coherent sound signals and ultrasonic imaging.

Follow-up studies

Ultrasound expert Bruce Drinkwater at the University of Bristol says the research is “fascinating” but warns that while there could be applications, “until follow-up studies are performed it’s hard to be sure”. If further research succeeds, the phenomenon could be used, says Drinkwater, to create sensitive new sensors that could be used for, say, gas and chemical monitoring. “There is also the intriguing possibility of using it to monitor the degradation of metallic structures, which are known to become increasingly nonlinear as they age,” he adds.

The frequency comb is described in Physical Review Letters.

Flash Physics: Ancient solar system was unstable, light pushes and pulls, detecting hidden machinery

Ancient meteorites reveal solar-system’s unstable past

Ancient micro-meteorites have revealed that the solar-system’s history may not be as stable as we thought. The discovery was made by researchers from Lund University, Sweden, in collaboration with the University of Chicago and University of Wisconsin-Madison in the US. The team studied 43 meteorites found on the ancient sea floor of the Lynna River near St Petersburg in Russia. These objects fell to Earth 470 million years ago and were less than 2 mm across. Unusually, the composition of these tiny meteorites did not match the make-up of modern ones. The findings instead echoed research from 2016 investigating an ancient meteorite named Österplana 065 found in a Swedish quarry. The studies mean that meteorite flow nearly 500 million years ago was completely different to todays. “We have always assumed that the solar system is stable, and have therefore expected that the same type of meteorites have fallen on Earth throughout the history of the solar system, but we have now realized that this is not the case,” says Birger Schmitz, who took part in both studies. The latest finding, reported in Nature Astronomy, means that our current understanding of our solar-system’s stable history needs to be revised.

Light pushes and pulls on a gold plate

Illustration of how and object can be pushed and pulled by light
Back and forth: gold plate moved by light from a tapered fibre. (Courtesy: J Lu et al./ Phys. Rev. Lett.)

When a beam of light strikes an object, momentum is transferred to the object, pushing it away from the source of the light. Light striking one side of an object will also heat up that end of the object, which in turn will heat the surrounding air. The hotter and faster-moving air molecules on the illuminated side will exert a greater force on the object than the cooler molecules on the opposite side – again causing the object to move away from the source of the light. Now, Min Qiu of Zhejiang University in China and colleagues have created a scenario in which these two phenomena work in opposite directions. They placed a hexagonal plate of gold (measuring 10 μm across and 30 nm thick) on an optical fibre that is tapered to a sharp tip, and van der Waals forces cause the plate to stick to the fibre. Light that leaks from the fibre causes the plate to move towards the tip. However, as the plate nears the tip, the intense light that is emitted there causes the near side of the plate to heat up. This causes the plate to reverse its direction of travel along the fibre. While the plate moved back and forth once, the researchers were unable to set it oscillating along the fibre – something that they are currently working. Describing its work in Physical Review Letters, the group says that the system could be used to transport materials in miniature lab-on-a-chip systems or even for generating mechanical energy from light.

Atomic magnetometer detects hidden machinery

A radio-frequency atomic magnetometer (RF AM) has been used by physicists in the UK to detect hidden rotating machinery. Built by Luca Marmugi and colleagues, the RF AM is based on a glass cell that is filled with rubidium atoms at room temperature. The atoms are subject to static and RF magnetic fields – which cause the Larmor precession of the atomic spins. A magnetic field from rotating machinery will disrupt this precession – and this disruption is detected by using a laser-measurement technique. The detector measures about 0.4 × 0.6 m and the team says that it is suitable for outdoor use. Using its device, the team was able to detect magnetic fields produced by spinning steel discs at frequencies of about 10 Hz as well as DC and AC electric motors. The device’s performance is on a par with a commercial magnetic flux detector and the team says that its instrument is particularly good at detecting rotational frequencies lower than about 15 Hz. Detection can be made at distances up to about 1 m, even through concrete walls. Writing in Applied Optics and in a preprint on arXiv, the team says the detector could be further improved and miniaturized and could someday be used in security and surveillance remote sensing.

 

  • You can find all our daily Flash Physics posts in the website’s news section, as well as on Twitter and Facebook using #FlashPhysics. Tune in to physicsworld.com later today to read today’s extensive news story on an acoustic frequency comb.

Mapping the heavens: Xiaohui Fan and David Law reflect on the Sloan Digital Sky Survey

Physics World: How did you get involved in the Sloan Digital Sky Survey (SDSS)?

Xiaohui Fan: In 1994 I was studying for my Master’s degree in China, working on a smaller imaging survey project and developing my method of looking for distant quasars. I came across the SDSS in the literature when the survey was still in the development stage, and I immediately knew what I wanted to do for my PhD. So I applied to Princeton University, basically saying that I wanted to work on the SDSS because it would revolutionize survey astronomy and I thought I had both the interests and the skills needed. I got in and was welcomed to the project with open arms. I spent the next five years working in the SDSS group at Princeton, and in the end, I carried out the observations and analysis that resulted in the discovery of the first sample of distant quasars – including one that broke the record at the time for the most distant quasar. I never thought that I should or could be the lead author of the first paper based on SDSS survey data, because I was a graduate student at the time, and because the survey is so much more this initial discovery – it involved years of work by many people. So I was surprised and humbled by the fact that I was told to lead the paper (Fan et al. 1999 ApJ 117 2528). It was a tremendous responsibility, which I think always brings the best out of your ability.

David Law: A few years ago, when I was a Hubble Fellow, a colleague of mine from graduate school, Kevin Bundy, had an idea for a new integral-field unit (IFU) spectroscopic survey of nearby galaxies. He knew that I had some experience using such systems in the past, and although he was not part of the SDSS, he had been discussing his ideas with Jim Gunn, one of the survey’s founders. Initially, Kevin asked if I could adapt my simulation code to estimate the typical data quality that we could expect in our proposal, but what started as some quick simulations to explore the capabilities of such a new instrument gradually evolved over the next few years into leadership of the software and analysis team of what became the MaNGA (Mapping Nearby Galaxies at APO) project.

PW: What is MaNGA about?

DL: The overall goal of the project is to take the statistical power of the SDSS and use it to explore the internal properties of galaxies – a largely uncharted regime. In previous generations of the SDSS, all of the millions of galaxies that had been observed with spectroscopy used just a single fibre per galaxy – treating the galaxy as a point object. Galaxies aren’t points, though. They have rich and varied structures, with internal motions, chemical evolution and feedback from one generation of star formation influencing the next. In order to study this kind of structure we need spectroscopy. Spectra are what tell us the physics of astronomical objects, what they’re made of, how they’re moving, where they came from and so on. While a few tens to a few hundreds of the brightest, most accessible galaxies had been studied in such a way, the purpose of MaNGA is to observe a representative sample of 10 000 galaxies across a wide range of masses, star formation rates, morphologies and environments. The goal is to understand the “life history” of current-day galaxies.

PW: What have you learned from working as part of the SDSS?

XF: One thing I learned is the paramount importance of the free exchange of ideas and open use of data. SDSS data are available for all collaboration members to explore. There is no restriction on working on any projects one wishes to, provided one follows SDSS rules of announcing the projects so that others can collaborate with you. The SDSS has made many unexpected discoveries, partly because it is so powerful as a survey tool, but also because it encourages open minds and open eyes to look for things beyond our own immediate narrow interests. For example, after the quasar discovery, I was a key member of the team that discovered new classes of brown dwarfs (basically failed stars or free-floating planets) using SDSS data. This is an area that I knew nothing about: we found them simply because they were “contaminants” in our quasar selection process. But there were no pre-defined areas of research, and we were encouraged to work closely with experts on stars.

Another lesson from the SDSS is the importance of encouraging, promoting and really challenging young scientists to take leadership roles, while at the same time providing guidance and protections for them on the policy side. The freedom and the responsibility I had on my first paper experience were really key to my growth. I think many of my peers, who “grew up” in the SDSS as students and postdocs, felt the same way. The SDSS benefited greatly from innovative contributions by a generation of young astronomers who were familiar with the digital age, with big data and with collaborative research, and to make the best use of all that expertise and creativity, it was equally important for the SDSS leadership to promote and protect the interests of junior scientists. We were all extremely grateful for the unselfish service (and, in many cases, sacrifice) of our mentors and leaders, which I think allowed the best science to come out of the project.

DL: At first, what I learned mostly broadened my technical expertise. For example, working with SDSS engineers gave me an appreciation for the interface between software design and the realities of physical hardware, while learning from more senior members of the SDSS collaboration dramatically improved my knowledge of practical large-scale collaborative software development. Later on, as the project reached maturity, it was my scientific expertise that began to expand by bringing my technical knowledge to bear on the variety of science topics being pursued by the rest of the large MaNGA science team.

PW: How did this experience help your career?

XF: After more than 20 years, and now as a senior faculty member, I am still working on SDSS data. It has been the one constant of my career, even as I have expanded my research. My role evolved from hands-on analysis of data, to organizing a team to explore new ways of using the data, and more recently to representing my institution on the SDSS advisory board – setting policies, evaluating progress and planning new directions. The two most important things I learned from SDSS – to prepare for the unexpected discoveries, and to encourage the next generation astronomers – are also the principles of how I conduct my research and lead my own research group and projects. One of my most satisfying experiences as a faculty member happened when one of my students analysed SDSS data in a different way, and this new analysis resulted in the discovery of a remarkable new quasar that was missed by the original SDSS selection method that I developed as a student. This object turned out to be the most luminous quasar in the early universe, powered by a 12 billion solar mass black hole at its centre (Wu et al. 2015 Nature 518 512) – a surprise discovery that is challenging the theory of black hole formation in the early universe.

DL: After a graduate school experience working with a very small and close research group, the opportunity to work with so many SDSS scientists from around the world has been an incredible way of broadening my contacts within the astronomical community. Many of us who started the MaNGA project did so as postdocs, and we have continually been impressed with the leadership roles and responsibilities that were open to us within the project. As the MaNGA data group lead and part of the executive committee, even as a postdoctoral fellow myself I had the opportunity to hire and supervise the team of postdocs tasked with various aspects of the project software development.

All of this experience leading a team to design, build, and operate an IFU software and analysis pipeline while interacting regularly with scientists, engineers and technical staff was invaluable when it came time to apply for permanent positions. Now, as a tenure-track assistant astronomer at the Space Telescope Science Institute, I can look back and see that my experience with the SDSS was nearly ideal preparation.

Quasi-phase transition spotted in water-filled carbon nanotubes

The optical properties of single-walled carbon nanotubes (SWCNTs) change when the tiny structures are filled with water. That is the conclusion of scientists in Belgium and the US, who attribute the change to a “quasi-phase transition” that occurs in the water – although the exact nature of the transition is unknown. The research points to a new technique for studying confined water molecules – which is crucial to various branches of science, but it is surprisingly difficult to do. The study could lead to better ways of delivering drugs in the body and even boost our understanding of quantum mechanics.

SWCNTs are hollow hair-like structures with walls that are one atom thick. Normally they are closed at both ends, but sometimes the ends can be open and Sofie Cambré of the University of Antwerp in Belgium and colleagues have previously shown that open SWCNTs rapidly fill with other molecules and hold on to them. Why this occurs is not well understood, but Cambré says “it seems the energy of a molecule inside a SWCNTs is much lower than when you have them separated.”

SWCNTs are naturally fluorescent, and the colour of the fluorescent light shifts if the nanotube is filled. “You need dedicated equipment to really see these very small shifts”, Cambré says. However, by measuring the shifts, researchers can potentially gain useful insights into the behaviour of confined molecules.

Single file

Cambré and her Antwerp team – together with Xuedan Ma and colleagues at the Center for Integrated Nanotechnologies, part of Los Alamos National Laboratory in New Mexico – looked at SWCNTs around 0.75 nm in diameter. This is large enough to accommodate water molecules in single file. They prepared an aqueous suspension of SWCNTs, causing the open SWCNTs to become filled with water. Then they used ultracentrifugation to separate empty and full SWCNTs. Both were dried to create films, and the filled SWCNTs retained their water during the drying process. The researchers then measured the change in each sample’s fluorescence spectrum as a function of temperature.

The team measured a gradual increase in the emission frequencies of both samples with temperature. This has been seen before and is believed to arise from strain resulting from thermal expansion. They also noticed a fairly sharp increase in the emission frequency of the filled SWCNTs at around 150 K, which was not present in the spectrum of the empty SWCNTs. The researchers attribute the increase to a “quasi-phase transition” in the chain of water molecules. Quasi because a true phase transition is not, strictly speaking, possible in 1D, explains Cambré. “If you just have a single row of water molecules, you cannot describe what is going on as freezing or boiling or anything like that.”

The exact nature of the transition is more puzzling. The researchers believe it is most likely a shift from a state in which the molecules form an orderly arrangement to one in which their orientation is random. However, it could also be a shift between two different ordered arrangements.

Water desalination

The observation of a type of phase transition in a 1D system has fundamental physics interest, Cambré says, but the research could also have applications in numerous other areas of science. The team is now studying the behaviour of water in other nanotubes with different diameters as well as the behaviour of other encapsulated fluids. Understanding confined fluids is a step towards controlling them, which could be useful in filtration applications. “If you could create a membrane that consisted only of nanotubes with one specific diameter, you would have a very selective means of transport,” says Cambré: “If, for example, only water can pass through and ions cannot, then you have desalination of water.”

The ability to transport molecules inside nanotubes and control their release could be used to deliverer drugs to where they are needed in the body while avoiding side effects elsewhere. The confinement of magnetic particles could even be useful for investigating magnetism on the quantum scale. “There are many interesting things we can do and we’re definitely excited about this,” says Ma, now at Argonne National Laboratory in Illinois.

Beautiful experiments

Jeffrey Fagan of the National Institute for Standards and Technology in Boulder, Colorado is impressed. “The important part of this work is that it demonstrates, with a very well defined experimental system, that the behaviour of the filler (in this case water) inside the nanotubes will likely be more complex than simply representing the bulk properties of that material,” he says. “The beauty of their experimental design is such that the effects of this complexity can be observed clearly. Contributions from other extrinsic effects on the nanotube spectra such as the external dielectric environment or strain can be eliminated through comparison of the water-filled nanotube population to the otherwise identical empty nanotube population.”

The research is published in Physical Review Letters.

Flash Physics: Invisibility cloak for foggy days, new topological metals, world’s highest telescope

Invisibility cloak is for foggy days

Invisibility cloaks are still mostly limited to the realms of fantasy and science fiction. While there have been breakthroughs in the field of transformation optics, the resulting cloaks have usually been restricted to microwave wavelengths – and cloaking can be disrupted by pulsed light-detection devices. However, work continues on cloaking, and in this latest research, scientists have designed a material that could hide an object in diffusive light. The team from the Universidad Pública de Navarra and the Universitat Politècnica de València, both in Spain, have focused on environments such as fog, smoke or cloudy water in which light does not propagate in straight lines but instead bounces around. The proposed material would use unimodular transformations that reroute light travelling in a specific direction around the region to be cloaked. Writing in Physical Review A, Carlos García Meca and colleagues show how the cloak could be made by layering two isotropic materials and discuss how pulsed detection devices would not interfere with its invisibility. If the material can be made, potential applications include thermal cloaking and preventing interference within high-speed communication devices. Much more about invisibility devices can be found in this June 2016 feature article “The quest for invisibility”.

New class of topological metals proposed by physicists

Illustration showing symmorphic (top) and nonsymmorphic symmetries
The top two rows of triangles form a lattice with symmorphic symmetry, whereas the bottom two rows form a lattice with nonsymmorphic symmetry. (Courtesy: Lukas Muechler)

A new class of metals that could have a range of useful topological properties has been proposed by physicists in the US and Switzerland. Their work was inspired by the surprising discovery in 2014 that the electrical resistance of tungsten telluride increases as the material is subjected to stronger and stronger magnetic fields. This is unlike other materials in which the magnetoresistance saturates at a maximum value. Now, Lukas Muechler and colleagues at Princeton University, Yale University and the University of Zurich have focussed on the layered atomic structure of the material to try to explain this effect. Each layer has nonsymmorphic symmetry whereby the atomic structure is unchanged when the layer is rotated and then translated by a fraction of the lattice period. They then calculated all of the possible electronic states that are compatible with this symmetry and focused on those states that can be smoothly deformed into each other. These topologically equivalent states suggest that tungsten telluride belongs to a new group of materials called nonsymmorphic topological metals with very high electron mobility that is not affected by impurities – making the metals ideal for making electronic devices. Writing in Physical Review X, the team says that the topological nature of tungsten telluride goes some way to explaining some of its interesting electronic properties, including the magnetoresistance.

World’s highest telescope will hunt primordial “B modes”

Photograph of the Shiquanhe Observatory in Tibet
The Ngari-1 telescope is to be built at 5250 m above sea level near the Shiquanhe Observatory in Tibet. (Courtesy: Chinese Academy of Sciences)

Construction has begun on what will be the world’s highest-altitude telescope to study the cosmic microwave background (CMB). The Ngari-1 telescope is to be built at 5250 m above sea level near the Shiquanhe Observatory in Tibet and is expected to be complete by 2021. It will aim to detect primordial “B-mode” polarization of the CMB – the “curl” of polarized CMB light that is considered to be the smoking gun for cosmic inflation – a period about 10–38 s after the beginning of the universe. The telescope is a collaboration between the Institute of High Energy Physics (IHEP) in Beijing and Stanford University in the US, which is one of the leading institutions behind the BICEP telescope in Antarctica. Ngari-1 will observe the northern CMB sky that telescopes from the South Pole or in the Atacama Desert in Chile cannot see and will operate at 90 and 150 GHz. The telescope will contain thousands of microwave detectors, with the exact number depending on funding and the final design. As China does not currently have the capability to fabricate ultrahigh-frequency, high-sensitivity microwave detectors, Stanford is expected to design and build them.

 

  • You can find all our daily Flash Physics posts in the website’s news section, as well as on Twitter and Facebook using #FlashPhysics. Tune in to physicsworld.com later today to read today’s extensive news story on how water behaves inside a carbon nanotube.

Marie Curie battles downloading robots, happy 50th birthday ILL, a dodgy portrayal of astronomers

Robot proof: Marie Curie makes an appearance (Courtesy: APS)
Robots beware: Marie Curie makes an appearance. (Courtesy: APS)

By Sarah Tesh

Avid readers of the Physical Review series of journals will be used to clicking on a photograph of Albert Einstein before downloading papers. This is a security feature designed to stop robots from the mass downloading of papers. Now, the American Physical Society – which publishes the journals – has added a photograph of Marie Curie to the anti-robot system. The addition of a famous female physicist was the idea of Anna Watts, who is an astrophysicist at the University of Amsterdam. She has since Tweeted “This makes me incredibly happy.”

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Former Lawrence Livermore physicist begins jail term

A former Lawrence Livermore National Laboratory physicist has been sentenced by a court in California to 18 months in prison for submitting false data and reports with the “purpose of defrauding a government agency”. Sean Darin Kinion, 44, who earned his physics PhD from the University of California, Davis, pleaded guilty in June to mail fraud and acknowledged that he was involved in “a scheme to defraud the government out of money intended to fund research”. In addition to his prison term, which will begin on 26 January, Kinion will have to pay $3,317,893 in compensation to the US government. He will also undergo supervision for three years following his release from prison.

According to Lawrence Livermore spokesperson Lynda Seaver, the lab began to see “red flags” in Kinion’s work in late summer 2012 and, after initially putting him on leave, lab administrators sacked the physicist in February 2013. That action was relatively simple because Kinion was not a civil servant – he was a contract employee who could be “dismissed for cause”. The lab then referred the case to the Department of Energy (DOE), which oversees national laboratories in the US. The DOE’s inspector general forwarded the case onto the Department of Justice, which began the process that led to Kinion’s prosecution.

Non-existent experiments

Kinion’s trial focused on funding that he received between 2008 and 2012 from the Intelligence Advanced Research Projects Activity (IARPA), which belongs to the Directorate of National Intelligence. According to the local US attorney’s office, the funding was to let him “design, build, and test experimental components in the field of quantum computing”. Prosecutors put particular focus on an experimental design that involved the deposition of ion-trap electrodes on polished sapphire wafers, which were covered by a layer of niobium that was wet-etched with hydrofluoric acid. The prosecutors noted that Kinion had received a grant of $539,000 for the necessary equipment. “[He] claimed he had used the equipment successfully to build and test [the] experimental components, and submitted reports and information in support of these claims,” the prosecution stated. “Kinion, however, never set up nor operated the equipment.”

The prosecutors also note that Kinion mailed “bogus” non-functioning components to the IARPA’s validation team and also “altered and backdated Federal Express mailing labels and falsely claimed that he mailed items on dates prior to the date he actually mailed them”. According to the prosecutors, he also conducted a three-day “charade” experiment for a scientist visiting Lawrence Livermore to establish the legitimacy of the research he claimed to have carried out.

False and fraudulent data

In court documents, prosecutors noted that Kinion set out to win prestige and advance his career rather than enriching himself. Yet he “presented to the government false and fraudulent data and information in a scheme to defraud IARPA into thinking he had performed the work…[and] took deliberate additional steps to conceal and prevent IARPA from discovering his fraudulent scheme”.

According to Kinion’s lawyer James Phillip Vaughns, “Kinion does not, and did not, admit to any embellishment of his theoretical work.” While no papers were published based on his research, prosecutors charged that the fraud wasted the time and effort of scientists who tried to test and duplicate Kinion’s results, as well as taking IARPA funds that other researchers could have received. Prison time for scientific fraud is extremely rare in the US. But noting that the prosecution had requested 51 months in prison, Vaughns told Retraction Watch that the 18 months Kinion received “could be viewed as a favourable outcome”.

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