Tyler O'Neal, Staff Editor GOVERNMENT

Russian scientists discover new high-temperature superconductor

A group of scientists led by Artem Oganov of Skoltech and the Moscow Institute of Physics and Technology and Ivan Troyan of the Institute of Crystallography of RAS has succeeded in synthesizing thorium decahydride (ThH10), a new superconducting material with the very high critical temperature of 161 kelvins. The results of their study, supported by a Russian Science Foundation grant, were published in the journal Materials Today.

A truly remarkable property of quantum materials, superconductivity is the complete loss of electrical resistance under quite specific, and sometimes very harsh, conditions. Despite the tremendous potential for quantum supercomputers and high-sensitivity detectors, the application of superconductors is hindered by the fact that their valuable properties typically manifest themselves at very low temperatures or extremely high pressures.

Until recently, the list of superconductors was topped by a mercury-containing cuprate, which becomes superconducting at 135 kelvins, or −138 degrees Celsius. This year, lanthanum decahydride, LaH10, set a new record of −13 C, which is very close to room temperature. Unfortunately, that superconductor requires pressures approaching 2 million atmospheres, which can hardly be maintained in real-life applications. Scientists, therefore, continue their quest for a superconductor that retains its properties at standard conditions. Figure 1. Crystal structure of thorium decahydride, ThH10. {module INSIDE STORY}

In 2018, Alexander Kvashnin, a researcher at Oganov's lab, predicted a new material -- thorium polyhydride, or ThH10 (fig. 1) -- with a critical temperature of −32 C, stable under 1 million atmospheres. In a recent study, researchers from Skoltech, MIPT, the Institute of Crystallography and Lebedev Institute of Physics of the Russian Academy of Sciences (RAS) have successfully obtained ThH10 and studied its transport properties and superconductivity.

The team's findings corroborated the theoretical predictions, proving that ThH10 exists at pressures above 0.85 million atmospheres and exhibits amazing high-temperature superconductivity. The scientists could only determine the critical temperature at 0.7 million atmospheres and found it to be −112 C, which is consistent with the theoretical prediction for that pressure value. This makes ThH10 one of the record-breaking high-temperature superconductors.

"Modern theory, and in particular, the USPEX method developed by myself and my students, yet again displayed their amazing predictive power," said Skoltech and MIPT Professor Artem Oganov, who co-directed the study. "ThH10 pushes the boundaries of classical chemistry and possesses unique properties that were predicted theoretically and recently confirmed by experiment. Most notably, the experimental results obtained by Ivan Troyan's lab are of very high quality."

"We discovered that superconductivity predicted in theory does exist at −112 C and 0.7 million atmospheres," study co-director Ivan Troyan added. "Given the strong consistency between theory and experiment, it would be interesting to check whether ThH10 will show superconductivity at up to −30 C...−40 C and lower pressures as predicted."

"Thorium hydride is just one of the elements in a large and rapidly growing class of hydride superconductors," said the first author of the study, Skoltech PhD student Dmitry Semenok. "I believe that in the coming years, hydride superconductivity will expand beyond the cryogenic range to find application in the design of electronic devices."

WPI wins grant to help New York City youths at risk for human trafficking

Tyler O'Neal, Staff Editor GOVERNMENT

The team will use data analytics and optimization tools to identify and recommend resources

A research team led by professors at Worcester Polytechnic Institute (WPI) will use data analytics and optimization to determine the most efficient use of shelters and services for homeless youths in New York City. Their goal is to disrupt the "supply-side" of human trafficking networks by reducing the vulnerability of those most at risk of exploitation.

Renata Konrad, associate professor at the Foisie Business School at WPI, has received a $535,565 grant from the National Science Foundation's (NSF) Special Initiatives program for the three-year project. Andrew Trapp, also associate professor, is a co-principal investigator on the project. The study will build on previous research led by Konrad using analytics to develop tools to understand and address human trafficking networks.

"To disrupt human trafficking, we need to look at the beginning of the supply chain--at-risk homeless youths," Konrad said. "The question is, can we stop the trafficking process before it happens with shelters and services for homeless youths?" Renata Konrad, associate professor, Foisie Business School at WPI{module INSIDE STORY}

Konrad noted the challenge associated with estimating the number of homeless youths in New York City, and said that not all of those who are homeless will be trafficked or exploited.

The office of New York City Mayor Bill de Blasio, the mayor's Youth Homelessness Task Force, and the Coalition for the Homeless have committed to support the project.

Under the grant, the researchers will first design surveys and gather information about the numbers and needs of homeless youths ages 16 to 24 in New York City. Then the researchers will use that data to inform mathematical models regarding the prevalence of youth homelessness and use optimization to project how the capacity of shelters and services could be deployed to cost-effectively meet those needs. Finally, the researchers will recommend how best to roll out public resources.

"The models we develop can be used to optimize the benefit-cost ratio," Trapp said. "The costs related to providing food and shelter, including building shelters, as well as medical and psychological care, and employment training. And the benefits are rehabilitated lives, less time incarcerated, more productive jobs, and tax revenues going back to society because people are having more stable jobs."

Assaf Naor receives Ostrowski Prize in Higher Mathematics

Tyler O'Neal, Staff Editor GOVERNMENT

The Czech-Israeli mathematician Assaf Naor has been awarded the international Ostrowski Prize in Higher Mathematics 2019. The Ostrowski Prize is worth 100,000 Swiss Francs and named after Alexander M. Ostrowski, a professor of mathematics who taught at the University of Basel.

Assaf Naor, a professor of mathematics at Princeton University (USA), receives the Ostrowski Prize 2019 in recognition of his pioneering achievements at the interface of the geometry of Banach spaces, the structure of metric spaces and algorithms.

Since the mid-1990s, geometric methods have played an influential role in designing algorithms for computational problems that a priori have little connection to geometry. Assaf Naor is the world's leading researcher in this field, building a long-term cohesive research program. He has discovered and applied deep results from the theory of Banach spaces and quantitative metric geometry to solve long-standing algorithmic questions. Prof. Dr. Assaf Naor{module INSIDE STORY}

One particular focus of Assaf Naor's research is the optimal partition of graphs. A graph is a set of nodes together with a set of edges, which are paired connections between the nodes. In graph theory, a cut is a partition of the set of nodes of a graph. The determination of optimal cuts is an NP-complete problem. Therefore, a number of proposed heuristics exist to find an approximation of optimal cuts in a short time. Assaf Naor investigates polynomial-temporal approximation methods, which find the cut that divides a graph into two equally sized parts and thereby divides as few edges as possible (Sparsest Cut Problem).

Assaf Naor, born 1975, is a Czech-Israeli mathematician. He received his doctorate from the Hebrew University in Jerusalem in 2002, under the supervision of the Israeli mathematician Joram Lindenstrauss. After positions at Microsoft Research, the University of Washington and the Courant Institute of Mathematical Sciences, he was appointed a professor of mathematics at Princeton University in 2014.

Prize with Basel history

The Foundation A. M. Ostrowski for an international prize in higher mathematics was established by Alexander Markovich Ostrowski (1893-1986), a former professor of mathematics at the University of Basel. Since 1989, the foundation awards every other year a prize for outstanding achievements in the field of pure mathematics and in the foundations of numerical mathematics.

The jury consists of one representative of each of the following institutions: the University of Basel, the University of Jerusalem, the University of Waterloo (Canada), the Royal Netherlands Academy of Arts and Sciences, the Royal Danish Academy of Sciences and Letters. The prize is awarded irrespective of politics, nationality, religion, or age.

The Ostrowski Prize is awarded for the 16th time this year. In 2017, it was conferred to the US mathematician Akshay Venkatesh. The award ceremony will take place at the University of Basel in the coming months.