An international team of scientists has reported the first experimental observation of the quantum critical point (QCP) in the extensively studied “unconventional superconductor” TiSe2, finding that it does not reside as predicted within the superconducting dome of the phase diagram, but rather at a full GPa higher in pressure.
The surprising result suggests that the emergence of superconductivity in TiSe2 isn’t associated with the melting of a charge density wave (CDW), as prevailing theory holds; in fact the CDW’s amplitude decreases under increasing pressure, but does not disappear at zero resistance. The researchers find that the emergence of superconductivity in this material is connected rather with the formation of domain walls between commensurate and incommensurate phase transitions. The discovery of this new phase boundary has implications for our understanding of superconducting behavior.
Assistant Professor Taylor Hughes has been awarded a 2014 CAREER Award from the National Science Foundation. The Faculty Early Career Development (CAREER) is among NSF’s most prestigious awards, conferred annually in support of junior faculty who exemplify the role of teacher-scholars by integrating outstanding research with excellent education, and by showing great promise for a lifetime of leadership within their respective fields.
Hughes will use the 5-year grant to explore the relationship between topology and geometry in electron systems, with the goal of predicting new, robust phenomena in real materials. By adapting ideas from high-energy physics and gravitation to condensed matter physics, Hughes’s theoretical work in this area has the potential to uncover as-yet undiscovered topological transport phenomena that are universal and quantized.
This would transform our understanding of materials with strong spin-orbit coupling, including topological insulators, topological Weyl semi-metals, and spin-orbit coupled semiconductor heterostructures/quantum wires, with implications for incorporating quantum phenomena into unique devices. Along with the study of realistic materials, there are deep conceptual issues that would be resolved regarding the relationship between topological transport, the geometry of elastic deformations, and quantum field theory.
Faulkner is a theoretical physicist who works at the intersection of high-energy physics and condensed matter physics. Faulkner applies the quantitative mechanical tools of string theory to persistent problems in theoretical condensed matter physics to yield fresh insights into quantum many body systems.
“High energy and condensed matter each have slightly different languages, but quite often share unifying principals, and I find that very interesting,” comments Faulkner.
The merging of quantum many body systems and string theory has its origin in the so-called holographic duality where stringy and gravitational physics is encoded in a quantum hologram in one less dimension. This duality allows unanswered questions about strongly correlated phenomena to be rewritten within field theory in terms of simple problems in classical gravity.
The University of Illinois at Urbana-Champaign is among six universities selected to receive generous funding from the Gordon and Betty Moore Foundation: the Institute for Condensed Matter Theory (ICMT) at Illinois will receive a five-year grant through the foundation’s new Emergent Phenomena in Quantum Systems (EPiQS) initiative, to establish a Gordon and Betty Moore Postdoctoral Scholars program. The program will fund several postdoctoral scientists who show exceptional promise to pursue discovery-driven research topics of their own choosing in collaboration with ICMT members and experimentalists in condensed matter physics.
Through this grant, the Gordon and Betty Moore Foundation aims to increase scientific productivity and to enrich the overall intellectual environment at ICMT, while enabling some of the top young talent in theory to acquire a breadth of expertise through flexible postdoctoral appointments in which they can pursue their interests and work with multiple faculty members.
The graduate program in Condensed Matter Physics at the University of Illinois is now ranked #1 in the nation, according to the 2014 U.S. News & World Report's annual Best Grad School Rankings, released today. Stanford is listed at #2 and MIT at #3. Physics Illinois ranks #9 overall among the nation's physics graduate programs.
In Asia and Africa, nearly 1.5 billion people live in "off the grid" villages with an acute electricity shortage. Often their only source of light is kerosene lamps, which expose families to toxic fumes and risk of home fires.
Patrick Walsh launched Greenlight Planet to change that.
The Chicago-based company produces solar-powered lamps geared toward these rural communities. Since launching in 2009, the startup has sold 1.8 million lamps, which cost between $11 and $40, the equivalent of about two weeks wages in those communities.
Associate Professor Timothy Stelzer has been elected to the chair line of the American Physical Society (APS) Forum on Education (FEd). He will serve three term years, beginning in April 2014 as vice chair, then serving as chair-elect starting in April 2015, then chair in April 2016.
Stelzer received his PhD in theoretical particle physics and is a founding member of the physics education research group whose primary research area is physics education. He points out that many of the most innovative and proven-effective teaching pedagogies for the modern classroom—including peer instruction, just-in-time-teaching, and flipped classrooms—have emerged from undergraduate physics education, which puts the FEd in a good position to take a leadership role in the national dialogue on the future of higher education.
“It’s an important time in higher education right now. Student’s unprecedented access to content online is dramatically changing higher education, allowing us to devote our in-class time to helping students develop their higher order learning and problem solving skills.”
Assistant Professor Taylor Hughes is a recipient of the 2014 Dean’s Award for Excellence in Research from the College of Engineering at the University of Illinois at Urbana-Champaign. Hughes is a condensed matter theorist whose research program addresses leading-edge questions on observable phenomena in condensed matter and quantum physics. He is focused on three primary areas of inquiry: topological phases of matter; characterization of quantum condensed matter systems through quantum-information entanglement techniques; and properties of materials with strong spin-orbit coupling.
Hughes also has a strong interest in related topics, including unconventional superconductivity and superfluidity, topological order, the quantum Hall effect, disordered electronic systems, and the connections between high-energy physics and condensed matter physics.
His fundamental research has long-term implications for quantum computing and understanding exotic phases of quantum matter.
Bacterial cells would pop like overfilled water balloons if they had no means of regulating fluid pressure buildup. Unlike water balloons, however, the cell membranes of bacteria have “safety valves”, channels that open in response to increased mechanical stress caused by excessive fluid buildup. The mechanosensitive channel of large conductance, or MscL, is a non-selective pore that is permeable to ions, water, and small proteins when open.
Now a team of two University of Illinois physics professors, working with two post-docs in the Center for the Physics of Living Cells, showed that in MscL, two helices tilt towards the membrane and open the channel. Professor Paul Selvin and post-doc Yong Wang, used a technique called single-molecule Fluorescence Resonance Energy Transfer, or smFRET, to measure distances that moved a nanometer –or less—as the channel opened in response to pressure changes.
Assistant Professor Shinsei Ryu has been selected for a Sloan Research Fellowship by the Alfred P. Sloan Foundation. The two-year fellowships are awarded annually to 126 early-career scientists and scholars engaged in fundamental research, in recognition of distinguished performance and a unique potential to make substantial contributions to their field.
Ryu is a condensed matter theorist who has made ground-breaking discoveries in the roles of coherence, entanglement, and topology in quantum many-body systems. He is perhaps most noted for his development of a “periodic table” classification system for topological insulators and superconductors in three spatial dimensions, devised with collaborators Andreas Schnyder of the Max-Planck-Institut, Akira Furusaki of the University of Tokyo, and Andreas Ludwig of the University of California at Santa Barbara.
Ryu’s broad research interests are reflected in a long list of publications in peer-reviewed journals, with subjects ranging from strongly correlated phenomena in microscopic systems, including quantum magnetism and the fractional quantum Hall effect, to the behaviors of mesoscopic systems, especially carbon nanotubes, graphene, and topological insulators. A unifying focus of Ryu’s work has been elucidating the roles of the phase degree of freedom of wave functions and entanglement in quantum mechanical systems.