Tag Archives: Germany

Unbreakable encrypted message with key that’s shorter than the message

A Sept. 5, 2016 University of Rochester (NY state, US) news release (also on EurekAlert), makes an intriguing announcement,

Researchers at the University of Rochester have moved beyond the theoretical in demonstrating that an unbreakable encrypted message can be sent with a key that’s far shorter than the message—the first time that has ever been done.

Until now, unbreakable encrypted messages were transmitted via a system envisioned by American mathematician Claude Shannon, considered the “father of information theory.” Shannon combined his knowledge of algebra and electrical circuitry to come up with a binary system of transmitting messages that are secure, under three conditions: the key is random, used only once, and is at least as long as the message itself.

The findings by Daniel Lum, a graduate student in physics, and John Howell, a professor of physics, have been published in the journal Physical Review A.

“Daniel’s research amounts to an important step forward, not just for encryption, but for the field of quantum data locking,” said Howell.

Quantum data locking is a method of encryption advanced by Seth Lloyd, a professor of quantum information at Massachusetts Institute of Technology, that uses photons—the smallest particles associated with light—to carry a message. Quantum data locking was thought to have limitations for securely encrypting messages, but Lloyd figured out how to make additional assumptions—namely those involving the boundary between light and matter—to make it a more secure method of sending data.  While a binary system allows for only an on or off position with each bit of information, photon waves can be altered in many more ways: the angle of tilt can be changed, the wavelength can be made longer or shorter, and the size of the amplitude can be modified. Since a photon has more variables—and there are fundamental uncertainties when it comes to quantum measurements—the quantum key for encrypting and deciphering a message can be shorter that the message itself.

Lloyd’s system remained theoretical until this year, when Lum and his team developed a device—a quantum enigma machine—that would put the theory into practice. The device takes its name from the encryption machine used by Germany during World War II, which employed a coding method that the British and Polish intelligence agencies were secretly able to crack.

Let’s assume that Alice wants to send an encrypted message to Bob. She uses the machine to generate photons that travel through free space and into a spatial light modulator (SLM) that alters the properties of the individual photons (e.g. amplitude, tilt) to properly encode the message into flat but tilted wavefronts that can be focused to unique points dictated by the tilt. But the SLM does one more thing: it distorts the shapes of the photons into random patterns, such that the wavefront is no longer flat which means it no longer has a well-defined focus. Alice and Bob both know the keys which identify the implemented scrambling operations, so Bob is able to use his own SLM to flatten the wavefront, re-focus the photons, and translate the altered properties into the distinct elements of the message.

Along with modifying the shape of the photons, Lum and the team made use of the uncertainty principle, which states that the more we know about one property of a particle, the less we know about another of its properties. Because of that, the researchers were able to securely lock in six bits of classical information using only one bit of an encryption key—an operation called data locking.

“While our device is not 100 percent secure, due to photon loss,” said Lum, “it does show that data locking in message encryption is far more than a theory.”

The ultimate goal of the quantum enigma machine is to prevent a third party—for example, someone named Eve—from intercepting and deciphering the message. A crucial principle of quantum theory is that the mere act of measuring a quantum system changes the system. As a result, Eve has only one shot at obtaining and translating the encrypted message—something that is virtually impossible, given the nearly limitless number of patterns that exist for each photon.

The paper by Lum and Howell was one of two papers published simultaneously on the same topic. The other paper, “Quantum data locking,” was from a team led by Chinese physicist Jian-Wei Pan.

“It’s highly unlikely that our free-space implementation will be useful through atmospheric conditions,” said Lum. “Instead, we have identified the use of optic fiber as a more practical route for data locking, a path Pan’s group actually started with. Regardless, the field is still in its infancy with a great deal more research needed.”

Here’s a link to and a citation for the paper,

Quantum enigma machine: Experimentally demonstrating quantum data locking by Daniel J. Lum, John C. Howell, M. S. Allman, Thomas Gerrits, Varun B. Verma, Sae Woo Nam, Cosmo Lupo, and Seth Lloyd. Phys. Rev. A, Vol. 94, Iss. 2 — August 2016 DOI: http://dx.doi.org/10.1103/PhysRevA.94.022315

©2016 American Physical Society

This paper is behind a paywall.

There is an earlier open access version of the paper by the Chinese researchers on arXiv.org,

Experimental quantum data locking by Yang Liu, Zhu Cao, Cheng Wu, Daiji Fukuda, Lixing You, Jiaqiang Zhong, Takayuki Numata, Sijing Chen, Weijun Zhang, Sheng-Cai Shi, Chao-Yang Lu, Zhen Wang, Xiongfeng Ma, Jingyun Fan, Qiang Zhang, Jian-Wei Pan. arXiv.org > quant-ph > arXiv:1605.04030

The Chinese team’s later version of the paper is available here,

Experimental quantum data locking by Yang Liu, Zhu Cao, Cheng Wu, Daiji Fukuda, Lixing You, Jiaqiang Zhong, Takayuki Numata, Sijing Chen, Weijun Zhang, Sheng-Cai Shi, Chao-Yang Lu, Zhen Wang, Xiongfeng Ma, Jingyun Fan, Qiang Zhang, and Jian-Wei Pan. Phys. Rev. A, Vol. 94, Iss. 2 — August 2016 DOI: http://dx.doi.org/10.1103/PhysRevA.94.020301

©2016 American Physical Society

This version is behind a paywall.

Getting back to the folks at the University of Rochester, they have provided this image to illustrate their work,

The quantum enigma machine developed by researchers at the University of Rochester, MIT, and the National Institute of Standards and Technology. (Image by Daniel Lum/University of Rochester)

The quantum enigma machine developed by researchers at the University of Rochester, MIT, and the National Institute of Standards and Technology. (Image by Daniel Lum/University of Rochester)

Innovation and two Canadian universities

I have two news bits and both concern the Canadian universities, the University of British Columbia (UBC) and the University of Toronto (UofT).

Creative Destruction Lab – West

First, the Creative Destruction Lab, a technology commercialization effort based at UofT’s Rotman School of Management, is opening an office in the west according to a Sept. 28, 2016 UBC media release (received via email; Note: Links have been removed; this is a long media release which interestingly does not mention Joseph Schumpeter the man who developed the economic theory which he called: creative destruction),

The UBC Sauder School of Business is launching the Western Canadian version of the Creative Destruction Lab, a successful seed-stage program based at UofT’s Rotman School of Management, to help high-technology ventures driven by university research maximize their commercial impact and benefit to society.

“Creative Destruction Lab – West will provide a much-needed support system to ensure innovations formulated on British Columbia campuses can access the funding they need to scale up and grow in-province,” said Robert Helsley, Dean of the UBC Sauder School of Business. “The success our partners at Rotman have had in helping commercialize the scientific breakthroughs of Canadian talent is remarkable and is exactly what we plan to replicate at UBC Sauder.”

Between 2012 and 2016, companies from CDL’s first four years generated over $800 million in equity value. It has supported a long line of emerging startups, including computer-human interface company Thalmic Labs, which announced nearly USD $120 million in funding on September 19, one of the largest Series B financings in Canadian history.

Focusing on massively scalable high-tech startups, CDL-West will provide coaching from world-leading entrepreneurs, support from dedicated business and science faculty, and access to venture capital. While some of the ventures will originate at UBC, CDL-West will also serve the entire province and extended western region by welcoming ventures from other universities. The program will closely align with existing entrepreneurship programs across UBC, including, e@UBC and HATCH, and actively work with the BC Tech Association [also known as the BC Technology Industry Association] and other partners to offer a critical next step in the venture creation process.

“We created a model for tech venture creation that keeps startups focused on their essential business challenges and dedicated to solving them with world-class support,” said CDL Founder Ajay Agrawal, a professor at the Rotman School of Management and UBC PhD alumnus.

“By partnering with UBC Sauder, we will magnify the impact of CDL by drawing in ventures from one of the country’s other leading research universities and B.C.’s burgeoning startup scene to further build the country’s tech sector and the opportunities for job creation it provides,” said CDL Director, Rachel Harris.

CDL uses a goal-setting model to push ventures along a path toward success. Over nine months, a collective of leading entrepreneurs with experience building and scaling technology companies – called the G7 – sets targets for ventures to hit every eight weeks, with the goal of maximizing their equity-value. Along the way ventures turn to business and technology experts for strategic guidance on how to reach goals, and draw on dedicated UBC Sauder students who apply state-of the-art business skills to help companies decide which market to enter first and how.

Ventures that fail to achieve milestones – approximately 50 per cent in past cohorts – are cut from the process. Those that reach their objectives and graduate from the program attract investment from the G7, as well as other leading venture-capital firms.

Currently being assembled, the CDL-West G7 will be comprised of entrepreneurial luminaries, including Jeff Mallett, the founding President, COO and Director of Yahoo! Inc. from 1995-2002 – a company he led to $4 billion in revenues and grew from a startup to a publicly traded company whose value reached $135 billion. He is now Managing Director of Iconica Partners and Managing Partner of Mallett Sports & Entertainment, with ventures including the San Francisco Giants, AT&T Park and Mission Rock Development, Comcast Bay Area Sports Network, the San Jose Giants, Major League Soccer, Vancouver Whitecaps FC, and a variety of other sports and online ventures.

Already bearing fruit, the Creative Destruction Lab partnership will see several UBC ventures accepted into a Machine Learning Specialist Track run by Rotman’s CDL this fall. This track is designed to create a support network for enterprises focused on artificial intelligence, a research strength at UofT and Canada more generally, which has traditionally migrated to the United States for funding and commercialization. In its second year, CDL-West will launch its own specialist track in an area of strength at UBC that will draw eastern ventures west.

“This new partnership creates the kind of high impact innovation network the Government of Canada wants to encourage,” said Brandon Lee, Canada’s Consul General in San Francisco, who works to connect Canadian innovation to customers and growth capital opportunities in Silicon Valley. “By collaborating across our universities to enhance our capacity to turn the scientific discoveries into businesses in Canada, we can further advance our nation’s global competitiveness in the knowledge-based industries.”

The Creative Destruction Lab is guided by an Advisory Board, co-chaired by Vancouver-based Haig Farris, a pioneer of the Canadian venture capitalist industry, and Bill Graham, Chancellor of Trinity College at UofT and former Canadian cabinet minister.

“By partnering with Rotman, UBC Sauder will be able to scale up its support for high-tech ventures extremely quickly and with tremendous impact,” said Paul Cubbon, Leader of CDL-West and a faculty member at UBC Sauder. “CDL-West will act as a turbo booster for ventures with great ideas, but which lack the strategic roadmap and funding to make them a reality.”

CDL-West launched its competitive application process for the first round of ventures that will begin in January 2017. Interested ventures are encouraged to submit applications via the CDL website at: www.creativedestructionlab.com


UBC Technology ventures represented at media availability

Awake Labs is a wearable technology startup whose products measure and track anxiety in people with Autism Spectrum Disorder to better understand behaviour. Their first device, Reveal, monitors a wearer’s heart-rate, body temperature and sweat levels using high-tech sensors to provide insight into care and promote long term independence.

Acuva Technologies is a Vancouver-based clean technology venture focused on commercializing breakthrough UltraViolet Light Emitting Diode technology for water purification systems. Initially focused on point of use systems for boats, RVs and off grid homes in North American market, where they already have early sales, the company’s goal is to enable water purification in households in developing countries by 2018 and deploy large scale systems by 2021.

Other members of the CDL-West G7 include:

Boris Wertz: One of the top tech early-stage investors in North America and the founding partner of Version One, Wertz is also a board partner with Andreessen Horowitz. Before becoming an investor, Wertz was the Chief Operating Officer of AbeBooks.com, which sold to Amazon in 2008. He was responsible for marketing, business development, product, customer service and international operations. His deep operational experience helps him guide other entrepreneurs to start, build and scale companies.

Lisa Shields: Founder of Hyperwallet Systems Inc., Shields guided Hyperwallet from a technology startup to the leading international payments processor for business to consumer mass payouts. Prior to founding Hyperwallet, Lisa managed payments acceptance and risk management technology teams for high-volume online merchants. She was the founding director of the Wireless Innovation Society of British Columbia and is driven by the social and economic imperatives that shape global payment technologies.

Jeff Booth: Co-founder, President and CEO of Build Direct, a rapidly growing online supplier of home improvement products. Through custom and proprietary web analytics and forecasting tools, BuildDirect is reinventing and redefining how consumers can receive the best prices. BuildDirect has 12 warehouse locations across North America and is headquartered in Vancouver, BC. In 2015, Booth was awarded the BC Technology ‘Person of the Year’ Award by the BC Technology Industry Association.


CDL-west will provide a transformational experience for MBA and senior undergraduate students at UBC Sauder who will act as venture advisors. Replacing traditional classes, students learn by doing during the process of rapid equity-value creation.

Supporting venture development at UBC:

CDL-west will work closely with venture creation programs across UBC to complete the continuum of support aimed at maximizing venture value and investment. It will draw in ventures that are being or have been supported and developed in programs that span campus, including:

University Industry Liaison Office which works to enable research and innovation partnerships with industry, entrepreneurs, government and non-profit organizations.

e@UBC which provides a combination of mentorship, education, venture creation, and seed funding to support UBC students, alumni, faculty and staff.

HATCH, a UBC technology incubator which leverages the expertise of the UBC Sauder School of Business and entrepreneurship@UBC and a seasoned team of domain-specific experts to provide real-world, hands-on guidance in moving from innovative concept to successful venture.

Coast Capital Savings Innovation Hub, a program base at the UBC Sauder Centre for Social Innovation & Impact Investing focused on developing ventures with the goal of creating positive social and environmental impact.

About the Creative Destruction Lab in Toronto:

The Creative Destruction Lab leverages the Rotman School’s leading faculty and industry network as well as its location in the heart of Canada’s business capital to accelerate massively scalable, technology-based ventures that have the potential to transform our social, industrial, and economic landscape. The Lab has had a material impact on many nascent startups, including Deep Genomics, Greenlid, Atomwise, Bridgit, Kepler Communications, Nymi, NVBots, OTI Lumionics, PUSH, Thalmic Labs, Vertical.ai, Revlo, Validere, Growsumo, and VoteCompass, among others. For more information, visit www.creativedestructionlab.com

About the UBC Sauder School of Business

The UBC Sauder School of Business is committed to developing transformational and responsible business leaders for British Columbia and the world. Located in Vancouver, Canada’s gateway to the Pacific Rim, the school is distinguished for its long history of partnership and engagement in Asia, the excellence of its graduates, and the impact of its research which ranks in the top 20 globally. For more information, visit www.sauder.ubc.ca

About the Rotman School of Management

The Rotman School of Management is located in the heart of Canada’s commercial and cultural capital and is part of the University of Toronto, one of the world’s top 20 research universities. The Rotman School fosters a new way to think that enables graduates to tackle today’s global business and societal challenges. For more information, visit www.rotman.utoronto.ca.

It’s good to see a couple of successful (according to the news release) local entrepreneurs on the board although I’m somewhat puzzled by Mallett’s presence since, if memory serves, Yahoo! was not doing that well when he left in 2002. The company was an early success but utterly dwarfed by Google at some point in the early 2000s and these days, its stock (both financial and social) has continued to drift downwards. As for Mallett’s current successes, there is no mention of them.

Reuters Top 100 of the world’s most innovative universities

After reading or skimming through the CDL-West news you might think that the University of Toronto ranked higher than UBC on the Reuters list of the world’s most innovative universities. Before breaking the news about the Canadian rankings, here’s more about the list from a Sept, 28, 2016 Reuters news release (receive via email),

Stanford University, the Massachusetts Institute of Technology and Harvard University top the second annual Reuters Top 100 ranking of the world’s most innovative universities. The Reuters Top 100 ranking aims to identify the institutions doing the most to advance science, invent new technologies and help drive the global economy. Unlike other rankings that often rely entirely or in part on subjective surveys, the ranking uses proprietary data and analysis tools from the Intellectual Property & Science division of Thomson Reuters to examine a series of patent and research-related metrics, and get to the essence of what it means to be truly innovative.

In the fast-changing world of science and technology, if you’re not innovating, you’re falling behind. That’s one of the key findings of this year’s Reuters 100. The 2016 results show that big breakthroughs – even just one highly influential paper or patent – can drive a university way up the list, but when that discovery fades into the past, so does its ranking. Consistency is key, with truly innovative institutions putting out groundbreaking work year after year.

Stanford held fast to its first place ranking by consistently producing new patents and papers that influence researchers elsewhere in academia and in private industry. Researchers at the Massachusetts Institute of Technology (ranked #2) were behind some of the most important innovations of the past century, including the development of digital computers and the completion of the Human Genome Project. Harvard University (ranked #3), is the oldest institution of higher education in the United States, and has produced 47 Nobel laureates over the course of its 380-year history.

Some universities saw significant movement up the list, including, most notably, the University of Chicago, which jumped from #71 last year to #47 in 2016. Other list-climbers include the Netherlands’ Delft University of Technology (#73 to #44) and South Korea’s Sungkyunkwan University (#66 to #46).

The United States continues to dominate the list, with 46 universities in the top 100; Japan is once again the second best performing country, with nine universities. France and South Korea are tied in third, each with eight. Germany has seven ranked universities; the United Kingdom has five; Switzerland, Belgium and Israel have three; Denmark, China and Canada have two; and the Netherlands and Singapore each have one.

You can find the rankings here (scroll down about 75% of the way) and for the impatient, the University of British Columbia ranked 50th and the University of Toronto 57th.

The biggest surprise for me was that China, like Canada, had two universities on the list. I imagine that will change as China continues its quest for science and innovation dominance. Given how they tout their innovation prowess, I had one other surprise, the University of Waterloo’s absence.

Reliable findings on the presence of synthetic (engineered) nanoparticles in bodies of water

An Aug. 29, 2016 news item on Nanowerk announces research into determining the presence of engineered (synthetic) nanoparticles in bodies of water,

For a number of years now, an increasing number of synthetic nanoparticles have been manufactured and incorporated into various products, such as cosmetics. For the first time, a research project at the Technical University of Munich and the Bavarian Ministry of the Environment provides reliable findings on their presence in water bodies.

An Aug. 29, 2016 Technical University of Munich (TUM) press release, which originated the news item, provides more information,

Nanoparticles can improve the properties of materials and products. That is the reason why an increasing number of nanoparticles have been manufactured over the past several years. The worldwide consumption of silver nanoparticles is currently estimated at over 300 metric tons. These nanoparticles have the positive effect of killing bacteria and viruses. Products that are coated with these particles include refrigerators and surgical instruments. Silver nanoparticles can even be found in sportswear. This is because the silver particles can prevent the smell of sweat by killing the bacteria that cause it.

Previously, it was unknown whether and in what concentration these nanoparticles enter the environment and e.g. enter bodies of water. If they do, this poses a problem. That is because the silver nanoparticles are toxic to numerous aquatic organisms, and can upset sensitive ecological balances.

Analytical challenge

In the past, however, nanoparticles have not been easy to detect. That is because they measure only 1 to 100 nanometers across [nanoparticles may be larger than 100nm or smaller than 1nm but the official definitions usually specify up to 100nm although some definitions go up to 1000nm] – a nanometer is a millionth of a millimeter. “In order to know if a toxicological hazard exists, we need to know how many of these particles enter the environment, and in particular bodies of water”, explains Michael Schuster, Professor for Analytical Chemistry at the TU Munich.

This was an analytical challenge for the researchers charged with solving the problem on behalf of the Bavarian Ministry of the Environment. In order to overcome this issue, they used a well-known principle that utilizes the effect of surfactants to separate and concentrate the particles. “Surfactants are also found in washing and cleaning detergents”, explains Schuster. “Basically, what they do is envelop grease and dirt particles in what are called micelles, making it possible for them to float in water.” One side of the surfactant is water-soluble, the other fat-soluble. The fat-soluble ends collect around non-polar, non-water soluble compounds such as grease or around particles, and “trap” them in a micelle. The water-soluble, polar ends of the surfactants, on the other hand, point towards the water molecules, allowing the microscopically small micelle to float in water.

A box of sugar cubes in the Walchensee lake

The researchers applied this principle to the nanoparticles. “When the micelles surrounding the particles are warmed slightly, they start to clump”, explains Schuster. This turns the water cloudy. Using a centrifuge, the surfactants and the nanoparticles trapped in them can then be separated from the water. This procedure is called cloud point extraction. The researchers then use the surfactants that have been separated out in this manner – which contain the particles in an unmodified, but highly concentrated form – to measure how many silver nanoparticles are present. To do this, they use a highly sensitive atomic spectrometer configured to only detect silver. In this manner, concentrations in a range of less than one nanogram per liter can be detected. To put this in perspective, this would be like detecting a box of sugar cubes that had dissolved in the Walchensee lake.

With the help of this analysis procedure, it is possible to gain new insight into the concentration of nanoparticles in drinking and waste water, sewage sludge, rivers, and lakes. In Bavaria, the measurements yielded good news: The concentrations measured in the water bodies were extremely low. In was only in four of the 13 Upper Bavarian lakes examined that the concentration even exceeded the minimum detection limit of 0.2 nanograms per liter. No measured value exceeded 1.3 nanograms per liter. So far, no permissible values have been established for silver nanoparticles.

Representative for watercourses, the Isar river was examined from its source to its mouth at around 30 locations. The concentration of silver nanoparticles was also measured in the inflow and outflow of sewage treatment plants. The findings showed that at least 94 percent of silver nanoparticles are filtered out by the sewage treatment plants.

Unfortunately, the researchers have not published their results.

Nanoavalanches in glass

An Aug. 24, 2016 news item on Nanowerk takes a rather roundabout way to describe some new findings about glass (Note: A link has been removed),

The main purpose of McLaren’s exchange study in Marburg was to learn more about a complex process involving transformations in glass that occur under intense electrical and thermal conditions. New understanding of these mechanisms could lead the way to more energy-efficient glass manufacturing, and even glass supercapacitors that leapfrog the performance of batteries now used for electric cars and solar energy.

“This technology is relevant to companies seeking the next wave of portable, reliable energy,” said Himanshu Jain, McLaren’s advisor and the T. L. Diamond Distinguished Chair in Materials Science and Engineering at Lehigh and director of its International Materials Institute for New Functionality in Glass. “A breakthrough in the use of glass for power storage could unleash a torrent of innovation in the transportation and energy sectors, and even support efforts to curb global warming.”

As part of his doctoral research, McLaren discovered that applying a direct current field across glass reduced its melting temperature. In their experiments, they placed a block of glass between a cathode and anode, and then exerted steady pressure on the glass while gradually heating it. McLaren and Jain, together with colleagues at the University of Colorado, published their discovery in Applied Physics Letters (“Electric field-induced softening of alkali silicate glasses”).

The implications for the finding were intriguing. In addition to making glass formulation viable at lower temperatures and reducing energy needs, designers using electrical current in glass manufacturing would have a tool to make precise manipulations not possible with heat alone.

“You could make a mask for the glass, for example, and apply an electrical field on a micron scale,” said Jain. “This would allow you to deform the glass with high precision, and soften it in a far more selective way than you could with heat, which gets distributed throughout the glass.”

Though McLaren and Jain had isolated the phenomenon and determined how to dial up the variables for optimal results, they did not yet fully understand the mechanisms behind it. McLaren and Jain had been following the work of Dr. Bernard Roling at the University of Marburg, who had discovered some remarkable characteristics of glass using electro-thermal poling, a technique that employs both temperature manipulation and electrical current to create a charge in normally inert glass. The process imparts useful optical and even bioactive qualities to glass.

Roling invited McLaren to spend a semester at Marburg to analyze the behavior of glass under electro-thermal poling, to see if it would reveal more about the fundamental science underlying what McLaren and Jain had observed in their Lehigh lab.

An Aug. 22, 2016 Lehigh University news release by Chris Quirk, which originated the news item, describes the latest work,

McLaren’s work in Marburg revealed a two-step process in which a thin sliver of the glass nearest the anode, called a depletion layer, becomes much more resistant to electrical current than the rest of the glass as alkali ions in the glass migrate away. This is followed by a catastrophic change in the layer, known as dielectric breakdown, which dramatically increases its conductivity. McLaren likens the process of dielectric breakdown to a high-speed avalanche, and uses spectroscopic analysis with electro-thermal poling as a way to see what is happening in slow motion.

“The results in Germany gave us a very good model for what is going on in the electric field-induced softening that we did here. It told us about the start conditions for where dielectric breakdown can begin,” said McLaren.

“Charlie’s work in Marburg has helped us see the kinetics of the process,” Jain said. “We could see it happening abruptly in our experiments here at Lehigh, but we now have a way to separate out what occurs specifically with the depletion layer.”

“The Marburg trip was incredibly useful professionally and enlightening personally,” said McLaren. “Scientifically, it’s always good to see your work from another vantage point, and see how other research groups interpret data or perform experiments. The group in Marburg was extremely hard-working, which I loved, and they were very supportive of each other. If someone submitted a paper, the whole group would have a barbecue to celebrate, and they always gave each other feedback on their work. Sometimes it was brutally honest––they didn’t hold back––but they were things you needed to hear.”

“Working in Marburg also showed me how to interact with a completely different group of people. “You see differences in your own culture best when you have the chance to see other cultures close up. It’s always a fresh perspective.”

Here are links and citations for both the papers mentioned. The first link is for the most recent paper and second link is for the earlier work,

Depletion Layer Formation in Alkali Silicate Glasses by
Electro-Thermal Poling by C. McLaren, M. Balabajew, M. Gellert, B. Roling, and H. Jain. Journal of The Electrochemical Society, 163 (9) H809-H817 (2016) H809 DOI: 10.1149/2.0881609jes Published July 19, 2016

Electric field-induced softening of alkali silicate glasses by C. McLaren, W. Heffner, R. Tessarollo, R. Raj, and H. Jain. Appl. Phys. Lett. 107, 184101 (2015); http://dx.doi.org/10.1063/1.4934945 Published online 03 November 2015

The most recent paper (first link) appears to be open access; the earlier paper (second link) is behind a paywall.

Creating quantum dots (artificial atoms) in graphene

An Aug. 22, 2016 news item on phys.org describes some recent work on artificial atoms and graphene from the Technical University of Vienna (Austria) and partners in Germany and the UK,

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom – for this reason, such electron prisons are often called “artificial atoms”. Artificial atoms may also feature properties beyond those of conventional ones, with the potential for many applications for example in quantum computing. Such additional properties have now been shown for artificial atoms in the carbon material graphene. The results have been published in the journal Nano Letters, the project was a collaboration of scientists from TU Wien (Vienna, Austria), RWTH Aachen (Germany) and the University of Manchester (GB).

“Artificial atoms open up new, exciting possibilities, because we can directly tune their properties”, says Professor Joachim Burgdörfer (TU Wien, Vienna). In semiconductor materials such as gallium arsenide, trapping electrons in tiny confinements has already been shown to be possible. These structures are often referred to as “quantum dots”. Just like in an atom, where the electrons can only circle the nucleus on certain orbits, electrons in these quantum dots are forced into discrete quantum states.

Even more interesting possibilities are opened up by using graphene, a material consisting of a single layer of carbon atoms, which has attracted a lot of attention in the last few years. “In most materials, electrons may occupy two different quantum states at a given energy. The high symmetry of the graphene lattice allows for four different quantum states. This opens up new pathways for quantum information processing and storage” explains Florian Libisch from TU Wien. However, creating well-controlled artificial atoms in graphene turned out to be extremely challenging.

Florian Libisch, explaining the structure of graphene. Courtesy Technical University of Vienna

Florian Libisch, explaining the structure of graphene. Courtesy Technical University of Vienna

An Aug. 22, 2016 Technical University of Vienna press release (also on EurekAlert), which originated the news item, provides more detail,

There are different ways of creating artificial atoms: The simplest one is putting electrons into tiny flakes, cut out of a thin layer of the material. While this works for graphene, the symmetry of the material is broken by the edges of the flake which can never be perfectly smooth. Consequently, the special four-fold multiplicity of states in graphene is reduced to the conventional two-fold one.

Therefore, different ways had to be found: It is not necessary to use small graphene flakes to capture electrons. Using clever combinations of electrical and magnetic fields is a much better option. With the tip of a scanning tunnelling microscope, an electric field can be applied locally. That way, a tiny region is created within the graphene surface, in which low energy electrons can be trapped. At the same time, the electrons are forced into tiny circular orbits by applying a magnetic field. “If we would only use an electric field, quantum effects allow the electrons to quickly leave the trap” explains Libisch.

The artificial atoms were measured at the RWTH Aachen by Nils Freitag and Peter Nemes-Incze in the group of Professor Markus Morgenstern. Simulations and theoretical models were developed at TU Wien (Vienna) by Larisa Chizhova, Florian Libisch and Joachim Burgdörfer. The exceptionally clean graphene sample came from the team around Andre Geim and Kostya Novoselov from Manchester (GB) – these two researchers were awarded the Nobel Prize in 2010 for creating graphene sheets for the first time.

The new artificial atoms now open up new possibilities for many quantum technological experiments: “Four localized electron states with the same energy allow for switching between different quantum states to store information”, says Joachim Burgdörfer. The electrons can preserve arbitrary superpositions for a long time, ideal properties for quantum computers. In addition, the new method has the big advantage of scalability: it should be possible to fit many such artificial atoms on a small chip in order to use them for quantum information applications.

Here’s a link to and a citation for the paper,

Electrostatically Confined Monolayer Graphene Quantum Dots with Orbital and Valley Splittings by Nils M. Freitag, Larisa A. Chizhova, Peter Nemes-Incze, Colin R. Woods, Roman V. Gorbachev, Yang Cao, Andre K. Geim, Kostya S. Novoselov, Joachim Burgdörfer, Florian Libisch, and Markus Morgenstern. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.6b02548 Publication Date (Web): July 28, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Dexter Johnson in an Aug. 23, 2016 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some additional insight into the world of quantum dots,

Quantum dots made from semiconductor materials, like silicon, are beginning to transform the display market. While it is their optoelectronic properties that are being leveraged in displays, the peculiar property of quantum dots that allows their electrons to be forced into discrete quantum states has long held out the promise of enabling quantum computing.

If you have time to read it, Dexter’s post features an email interview with Florian Libisch where they further discuss quantum dots and quantum computing.

Oil-absorbing hairy fern leaves lead to ‘nanofur’ for oil spill cleanups

German researchers have developed a biomimetic material branded as ‘nanofur’ for oil spill cleanups, according to an Aug. 23, 2016 news item on Nanowerk (Note: A link has been removed),

Some water ferns can absorb large volumes of oil within a short time, because their leaves are strongly water-repellent and, at the same time, highly oil-absorbing. Researchers of Karlsruhe Institute of Technology, together with colleagues of Bonn University, have found that the oil-binding capacity of the water plant results from the hairy microstructure of its leaves (Bioinspiration & Biomimetics, “Microstructures of superhydrophobic plant leaves – inspiration for efficient oil spill cleanup materials”). It is now used as a model to further develop the new Nanofur material for the environmentally friendly cleanup of oil spills.

An Aug.(?) 23 (?), 2016 Karlsruhe Institute of Technology (KIT) press release on EurekAlert, which originated the news item, explains the interest in improving technology for oil spill cleanups and provides insight into this  innovation,

Damaged pipelines, oil tanker disasters, and accidents on oil drilling and production platforms may result in pollutions [sic] of water with crude or mineral oil. Conventional methods to clean up the oil spill are associated with specific drawbacks. Oil combustion or the use of chemical substances to accelerate oil decomposition cause secondary environmental pollution. Many natural materials to take up the oil, such as sawdust or plant fibers, are hardly effective, because they also absorb large amounts of water. On their search for an environmentally friendly alternative to clean up oil spills, the researchers compared various species of aquatic ferns. “We already knew that the leaves of these plants repel water, but for the first time now, we have studied their capacity to absorb oil,” Claudia Zeiger says. She conducted the project at KIT’s Institute of Microstructure Technology.

Damaged pipelines, oil tanker disasters, and accidents on oil drilling and production platforms may result in pollutions of water with crude or mineral oil. Conventional methods to clean up the oil spill are associated with specific drawbacks. Oil combustion or the use of chemical substances to accelerate oil decomposition cause secondary environmental pollution. Many natural materials to take up the oil, such as sawdust or plant fibers, are hardly effective, because they also absorb large amounts of water. On their search for an environmentally friendly alternative to clean up oil spills, the researchers compared various species of aquatic ferns. “We already knew that the leaves of these plants repel water, but for the first time now, we have studied their capacity to absorb oil,” Claudia Zeiger says. She conducted the project at KIT’s Institute of Microstructure Technology.

Aquatic ferns originally growing in tropical and subtropical regions can now also be found in parts of Europe. As they reproduce strongly, they are often considered weed. However, they have a considerable potential as low-cost, rapid, and environmentally friendly oil absorbers, which is obvious from a short video (see below). ”The plants might be used in lakes to absorb accidental oil spills,” Zeiger says. After less than 30 seconds, the leaves reach maximum absorption and can be skimmed off together with the absorbed oil. The water plant named salvinia has trichomes on the leaf surface – hairy extensions of 0.3 to 2.5 mm in length. Comparison of different salvinia species revealed that leaves with the longest hairs did not absorb the largest amounts of oil. “Oil-absorbing capacity is determined by the shape of the hair ends,” Zeiger emphasizes. The largest quantity of oil was absorbed by leaves of the water fern salvinia molesta, whose hair ends are shaped like an eggbeater.

Based on this new knowledge on the relationship between surface structure of leaves and their oil-absorbing capacity, the researchers improved the ‘Nanofur’ material developed at their institute. This plastic nanofur mimics the water-repellent and oil-absorbing effect of salvinia to separate oil and water. “We study nanostructures and microstructures in nature for potential technical developments,” says Hendrik Hölscher, Head of the Biomimetic Surfaces Group of the Institute of Microstructure Technology of KIT. He points out that different properties of plants made of the same material frequently result from differences of their finest structures.

Here’s a link to and a citation for the paper,

Microstructures of superhydrophobic plant leaves – inspiration for efficient oil spill cleanup materials by Claudia Zeiger, Isabelle C Rodrigues da Silva, Matthias Mail, Maryna N Kavalenka, Wilhelm Barthlott, and Hendrik Hölscher. Bioinspiration & Biomimetics, Volume 11, Number 5 DOI: http://dx.doi.org/10.1088/1748-3190/11/5/056003

Published 16 August 2016, © 2016 IOP Publishing Ltd

This article appears to be open access.

There is also a video demonstration of the material,


Attosecond science impacts femtochemistry

An Aug. 17, 2016 news item on Nanowerk reveals the latest about attoscience and femtochemistry (Note: A link has been removed),

Attosecond Science is a new exciting frontier in contemporary physics, aimed at time-resolving the motion of electrons in atoms, molecules and solids on their natural timescale. Electronic dynamics derives from the creation and evolution of coherence between different electronic states and proceeds on sub-femtosecond timescales. In contrast, chemical dynamics involves position changes of atomic centers and functional groups and typically proceeds on a slower, femtosecond timescale inherent to nuclear motion.

Nonetheless, there are exciting ways in which chemistry can hugely benefit from the technological developments pushed forward in the vibrant field of Attosecond Science. This was exploited in the work recently published by Lorenz Drescher and coworkers (“XUV transient absorption spectroscopy of iodomethane and iodobenzene photodissociation”).

An Aug. 17, 2016 (?) Forschungsverbund Berlin press release, which originated the news item, provides more detail about the work,

Attosecond pulses are generated in the process of High Harmonic Generation (HHG), in which infrared photons are upconverted to the extreme ultraviolet (XUV) frequency domain in a highly non-linear interaction of intense coherent light and matter. The short duration of attosecond pulses implies a frequency spectrum with photon energies spanning from a few electron volts (eV) to hundreds of eV. Such broad and continuous frequency spectra are ideally suited for core shell absorption measurements in molecules.

Core shell to valence shell transitions are a unique probe of molecular structure and dynamics. Core-to-valence transitions are element specific, due to the highly localized nature of core orbitals on specific atoms. On the other hand the intramolecular local environment of specific atomic sites is encoded, since an electron is lifted from a core orbital to a hole in the valence shell, affected by chemical bonding (…). Importantly, these transitions typically correspond to very short lifetimes of only a few femtoseconds. The use of ultrashort XUV pulses hence gives a new twist to the ultrafast studies of chemistry: It allows to probe chemical dynamics, initiated by a UV pump laser pulse, from the perspective of different reporter atoms within a molecule in an XUV transient absorption experiment. This is now beginning to be explored by a number of groups around the world.

In the experiment carried out by Drescher and coworkers at the MBI, photodissociation of iodomethane (CH3I) and iodobenzene (C6H5I) was studied with time-resolved XUV transient absorption spectroscopy at the iodine pre-N4,5 edge, using femtosecond UV pump pulses and XUV probe pulses from HHG (…). For both molecules the molecular core-to-valence absorption lines were found to fade immediately, within the pump-probe time-resolution. Absorption lines converging to the atomic iodine product however emerge promptly in CH3I but are time-delayed in C6H5I. In CH3I, we interpret this observation as the creation of an instantaneous new target state for XUV absorption by the UV pump pulse, which is then subject to relaxation of the excited valence shell as the molecule dissociates. This relaxation shows in a continuous shift in energy of the emerging atomic absorption lines in CH3I, which we measured in the experiment. In contrast, the delayed appearance of the absorption lines in C6H5I is indicative of a UV created vacancy, which within the molecule is initially spatially distant from the iodine reporter atom and has to first travel intramolecular before being observed. This behaviour is attributed to the dominant π → σ* UV excitation in iodobenzene, which involves the π orbital of the phenyl moiety.

While in the current work only a simplistic independent particle model was used to rationalize the observed experimental findings, MBI with its newly created theory department provides unique opportunities for joint experimental and theory studies on XUV transient absorption of photochemical processes. This will involve a new theoretical approach developed recently by researchers from MBI together with colleagues in Canada, the UK and Switzerland, which was recently submitted as a publication.

Here’s a link to and a citation for the paper,

Communication: XUV transient absorption spectroscopy of iodomethane and iodobenzene photodissociation by L. Drescher, M. C. E. Galbraith, G. Reitsma, J. Dura, N. Zhavoronkov, S. Patchkovskii, M. J. J. Vrakking, and J. Mikosch. J. Chem. Phys. 145, 011101 (2016); http://dx.doi.org/10.1063/1.4955212

This paper appears to be open access.

Sonifying a swimmer’s performance to improve technique by listening)

I imagine since the 2016 Olympic Games are over that athletes and their coaches will soon start training for the 2020 Games. Researchers at Bielefeld University (Germany) have developed a new technique for helping swimmers improve their technique (Note: The following video is German language with English language subtitles),

An Aug. 4, 2016 Bielefeld University press release (also on EurekAlert), tells more,

Since 1896, swimming has been an event in the Olympic games. Back then it was the swimmer’s physical condition that was decisive in securing a win, but today it is mostly technique that determines who takes home the title of world champion. Researchers at Bielefeld University have developed a system that professional swimmers can use to optimize their swimming technique. The system expands the athlete’s perception and feel for the water by enabling them to hear, in real time, how the pressure of the water flows created by the swimmer changes with their movements. This gives the swimmer an advantage over his competitors because he can refine the execution of his technique. This “Swimming Sonification” system was developed at the Cluster of Excellence Cognitive Interaction Technology (CITEC) of Bielefeld University. In a video, Bielefeld University’s own “research_tv” reports on the new system.

“Swimmers see the movements of their hands. They also feel how the water glides over their hands, and they sense how quickly they are moving forwards. However, the majority of swimmers are not very aware of one significant factor: how the pressure exerted by the flow of the water on their bodies changes,” says Dr. Thomas Hermann of the Cluster of Excellence Cognitive Interaction Technology (CITEC). The sound researcher is working on converting data into sounds that can be used to benefit the listener. This is called sonification, a process in which measured data values are systematically turned into audible sounds and noises. “In this project, we are using the pressure from water flows as the data source,” says Hermann, who heads CITEC research group Ambient Intelligence. “We convert into sound how the pressure of water flows changes while swimming – in real time. We play the sounds to the swimmer over headphones so that they can then adjust their movements based on what they hear,” explains Hermann.

For this research project on swimming sonification, Dr. Hermann is working together with Dr. Bodo Ungerechts of the Faculty of Psychology and Sports Science. As a biomechanist, Dr. Ungerechts deals with how human beings control their movements, particularly with swimming. “If a swimmer registers how the flow pressure changes by hearing, he can better judge, for instance, how he can produce more thrust at similar energy costs. This give the swimmer a more encompassing perception for his movements in the water,” says Dr. Ungerechts. The researcher even tested the system out for himself. “I was surprised at just how well the sonification and the effects of the water flow, which I felt myself, corresponded with one another,” he says. The system is intuitive and easy to use. “You immediately starts playing with the sounds to hear, for example, what tonal effect spreading your fingers apart or changing the position of your hand has,” says Ungerechts. The new system should open up new training possibilities for athletes. “By using this system, swimmers develop a harmony – a kind of melody. If a swimmer very quickly masters a lap, they can use the recording of the melody to mentally re-imagine and retrace the successful execution of this lap. This mental training can also help athletes perform successfully in competitions.” To this, Thomas Hermann adds “the ear is great at perceiving rhythm and changes in rhythm. In this way, swimmers can find their own rhythm and use this to orient themselves in the water.”

This system includes two gloves with thin tube ends that serve as pressure sensors and are fixed between the fingers. The swimmer wears these gloves during practice. The tubes are linked to a measuring instrument, which is currently connected to the swimmer via a line while he or she is swimming. The measuring device transmits data about water flow pressure to a laptop. A custom-made software then sonifies the data, meaning that it turns the information into sound. “During repeated hand actions, for instance, the system can make rising and sinking flow pressure audible as increasing or decreasing tonal pitches,” says Thomas Hermann. Other settings that sonify features such as symmetry or steadiness can also be activated as needed.

The sounds are transmitted to the swimmer in real time over headphones. When the swimmer modifies a movement, he hears live how this also changes the sound. With the sonification of aquatic flow pressure, the swimmer can now practice the front crawl in way that, for instance, both hands displace the water masses with the same water flow form – to do this, the swimmer just has make sure that he generates the same sound pattern with each hand. Because the coach also hears the sounds over speakers, he can base the instructions he gives to the swimmer not only on the movements he observes, but also on the sounds generated by the swimmer and their rhythm (e.g. “Move your hands so that the tonal pitch increases faster”).

For this sonification project, Thomas Hermann and Bodo Ungerechts are working with Daniel Cesarini, Ph.D., a researcher from the Department of Information Engineering at the University of Pisa in Italy. Dr. Cesarini developed the measuring device that analyzes the aquatic flow pressure data.

In a practical workshop held in September 2015, professional swimmers tested the system out and confirmed that it indeed helped them to optimize their swimming technique. Of the 10 swimmers who participated, three of them qualify for international competitions, and one of the female swimmers is competing this year at the Paralympics in Rio de Janeiro, Brazil. The workshop was funded by the Cluster of Excellence Cognitive Interaction Technology (CITEC). In addition to this, swim teams at the PSV Eindhoven (Philips Sports Union Eindhoven) in the Netherlands tested the new system out for two months, using it as part of their technique training sessions. The PSV swim club competes in the top swimming league in the Netherlands.

“It is advantageous for swimmers to receive immediate feedback on their swimming form,” says Thomas Hermann. “People learn more quickly when they get direct feedback because they can immediately test how the feedback – in this case, the sound – changes when they try out something new.”

The researchers want to continue developing their current prototype. “We are planning to develop a wearable system that can be used independently by the user, without the help of others,” says Thomas Hermann. In addition to this, the new sonification method is planned to be incorporated into long-term training programs in cooperation with swim clubs.

My first post about sonification was this February 7, 2014 post titled, Data sonification: listening to your data instead of visualizing it.

As for this swimmer’s version of data sonification, you can find out more about the project here and/or here.

Two nano workshops precede OpenTox Euro conference

The main conference OpenTox Euro is focused on novel materials and it’s being preceded by two nano workshops. All of of these events will be taking place in Germany in Oct. 2016. From an Aug. 11, 2016 posting by Lynn L. Bergeson on Nanotechnology Now,

The OpenTox Euro Conference, “Integrating Scientific Evidence Supporting Risk Assessment and Safer Design of Novel Substances,” will be held October 26-28, 2016. … The current topics for the Conference include: (1) computational modeling of mechanisms at the nanoscale; (2) translational bioinformatics applied to safety assessment; (3) advances in cheminformatics; (4) interoperability in action; (5) development and application of adverse outcome pathways; (6) open science applications showcase; (7) toxicokinetics and extrapolation; and (8) risk assessment.

On Oct. 24, 2016, two days before OpenTox Euro, the EU-US Nano EHS [Environmental Health and Safety] 2016 workshop will be held in Germany. The theme is: ‘Enabling a Sustainable Harmonised Knowledge Infrastructure supporting Nano Environmental and Health Safety Assessment’ and the objectives are,

The objective of the workshop is to facilitate networking, knowledge sharing and idea development on the requirements and implementation of a sustainable knowledge infrastructure for Nano Environmental and Health Safety Assessment and Communications. The infrastructure should support the needs required by different stakeholders including scientific researchers, industry, regulators, workers and consumers.

The workshop will also identify funding opportunities and financial models within and beyond current international and national programs. Specifically, the workshop will facilitate active discussions but also identify potential partners for future EU-US cooperation on the development of knowledge infrastructure in the NanoEHS field. Advances in the Nano Safety harmonisation process, including developing an ongoing working consensus on data management and ontology, will be discussed:

– Information needs of stakeholders and applications
– Data collection and management in the area of NanoEHS
– Developments in ontologies supporting NanoEHS goals
– Harmonisation efforts between EU and US programs
– Identify practice and infrastructure gaps and possible solutions
– Identify needs and solutions for different stakeholders
– Propose an overarching sustainable solution for the market and society

The presentations will be focused on the current efforts and concrete achievements within EU and US initiatives and their potential elaboration and extension.

The second workshop is being held by the eNanoMapper (ENM) project on Oct. 25, 2016 and concerns Nano Modelling. The objectives and workshop sessions are:

1. Give the opportunity to research groups working on computational nanotoxicology to disseminate their modelling tools based on hands-on examples and exercises
2. Present a collection of modelling tools that can span the entire lifecycle of nanotox research, starting from the design of experiments until use of models for risk assessment in biological and environmental systems.
3. Engage the workshop participants in using different modelling tools and motivate them to contribute and share their knowledge.

Indicative workshop sessions

• Preparation of datasets to be used for modelling and risk assessment
• Ontologies and databases
• Computation of theoretical descriptors
• NanoQSAR Modelling
• Ab-initio modelling
• Mechanistic modelling
• Modelling based on Omics data
• Filling data gaps-Read Across
• Risk assessment
• Experimental design

We would encourage research teams that have developed tools in the areas of computational nanotoxicology and risk assessment to demonstrate their tools in this workshop.

That’s going to be a very full week in Germany.

You can register for OpenTox Euro and more here.

Generating clean fuel with individual gold atoms

A July 22, 2016 news item on Nanowerk highlights an international collaboration focused on producing clean fuel,

A combined experimental and theoretical study comprising researchers from the Chemistry Department and LCN [London Centre for Nanotechnology], along with groups in Argentina, China, Spain and Germany, has shed new light on the behaviour of individual gold atoms supported on defective thin cerium dioxide films – an important system for catalysis and the generation of clean hydrogen for fuel.

A July ??, 2016 LCN press release, which originated the news item, expands on the theme of catalysts, the research into individual gold atoms, and how all this could result in clean fuel,

Catalysis plays a vital role in our world; an estimated 80% of all chemical and materials are made via processes which involve catalysts, which are commonly a mixture of metals and oxides. The standard motif for these heterogeneous catalysts (where the catalysts are solid and the reactants are in the gas phase) is of a high surface area oxide support that is decorated with metal nanoparticles a few nanometres in diameter. Cerium dioxide (ceria, CeO2) is a widely used support material for many important industrial processes; metal nanoparticles supported on ceria have displayed high activities for applications including car catalytic converters, alcohol synthesis, and for hydrogen production. There are two key attributes of ceria which make it an excellent active support material: its oxygen storage and release ability, and its ability to stabilise small metal particles under reaction conditions. A recent system that has been the focus of much interest has been that of gold nanoparticles and single atoms with ceria, which has demonstrated high activity towards the water-gas-shift reaction, (CO + H2O —> CO2 + H2) a key stage in the generation of clean hydrogen for use in fuel cells.

The nature of the active sites of these catalysts and the role that defects play are still relatively poorly understood; in order to study them in a systematic fashion, the researchers prepared model systems which can be characterised on the atomic scale with a scanning tunnelling microscope.

Figure: STM images of CeO2-x(111) ultrathin films before and after the deposition of Au single atoms at 300 K. The bright lattice is from the oxygen atoms at the surface – vacancies appear as dark spots

These model systems comprised well-ordered, epitaxial ceria films less than 2 nm thick, prepared on a metal single crystal, upon which single atoms and small clusters of gold were evaporated onto under ultra-high-vacuum (essential to prevent contamination of the surfaces). Oxygen vacancy defects – missing oxygen atoms in the top layer of the ceria – are relatively common at the surface and appear as dark spots in the STM images. By mapping the surface before and after the deposition of gold, it is possible to analyse the binding of the metal atoms, in particular there does not appear to be any preference for binding in the vacancy sites at 300 K.

Publishing their results in Physical Review Letters, the researchers combined these experimental results with theoretical studies of the binding energies and diffusion rates across the surface. They showed that kinetic effects governed the behaviour of the gold atoms, prohibiting the expected occupation of the thermodynamically more stable oxygen vacancy sites. They also identified electron transfer between the gold atoms and the ceria, leading to a better understanding of the diffusion phenomena that occur at this scale, and demonstrated that the effect of individual surface defects may be more minor than is normally imagined.

Here’s a link to and a citation for the paper,

Diffusion Barriers Block Defect Occupation on Reduced CeO2(111) by P.G. Lustemberg, Y. Pan, B.-J. Shaw, D. Grinter, Chi Pang, G. Thornton, Rubén Pérez, M. V. Ganduglia-Pirovano, and N. Nilius. Phys. Rev. Lett. Vol. 116, Iss. 23 — 10 June 2016 2016DOI:http://dx.doi.org/10.1103/PhysRevLett.116.236101 Published 9 June 2016

This paper is behind a paywall.