Das Sarma Research Group

Two JQI Fellows are included on the Clarivate Web of Science Group’s 2021 list of Highly Cited Researchers, which recognizes influential scientists for their highly cited papers over the preceding decade. The two researchers are Sankar Das Sarma, who is also the Director of the Condensed Matter Theory Center and the Richard E. Prange Chair and Distinguished University Professor of Physics at the University of Marlyand (UMD), and Christopher Monroe, who is also a College Park Professor.

Two JQI Fellows are included on the Clarivate Web of Science Group’s 2020 list of Highly Cited Researchers, which recognizes influential scientists for their highly cited papers over the preceding decade. The two researchers are Sankar Das Sarma, the Director of the Condensed Matter Theory Center and the Richard E. Prange Chair and Distinguished University Professor of Physics at the University of Marlyand (UMD), and Christopher Monroe, Distinguished University Professor and the Bice Zorn Professor of Physics at UMD and a Fellow of the Joint Center for Quantum Information and Computer Science.

To mark the 50th anniversary of Physical Review B, editors selected “milestone” papers that have made lasting contributions to condensed matter physics, including one co-written by JQI Fellow Sankar Das Sarma. Das Sarma wrote the selected paper, Dielectric function, screening, and plasmons in two-dimensional graphene, with Euyheon Hwang.

In the latest experiment of its kind, researchers have captured the most compelling evidence to date that unusual particles lurk inside a special kind of superconductor. The result, which confirms theoretical predictions first made nearly a decade ago at the Joint Quantum Institute (JQI) and the University of Maryland (UMD), will be published in the April 5 issue of Nature. The stowaways, dubbed Majorana quasiparticles, are different from ordinary matter like electrons or quarks—the stuff that makes up the elements of the periodic table. Unlike those particles, which as far as physicists know can’t be broken down into more basic pieces, Majorana quasiparticles arise from coordinated patterns of many atoms and electrons and only appear under special conditions. They are endowed with unique features that may allow them to form the backbone of one type of quantum computer, and researchers have been chasing after them for years. The latest result is the most tantalizing yet for Majorana hunters, confirming many theoretical predictions and laying the groundwork for more refined experiments in the future. In the new work, researchers measured the electrical current passing through an ultra-thin semiconductor connected to a strip of superconducting aluminum—a recipe that transforms the whole combination into a special kind of superconductor.Experiments of this type expose the nanowire to a strong magnet, which unlocks an extra way for electrons in the wire to organize themselves at low temperatures. With this additional arrangement the wire is predicted to host a Majorana quasiparticle, and experimenters can look for its presence by carefully measuring the wire’s electrical response. The new experiment was conducted by researchers from QuTech at the Technical University of Delft in the Netherlands and Microsoft Research, with samples of the hybrid material prepared at the University of California, Santa Barbara and Eindhoven University of Technology in the Netherlands. Experimenters compared their results to theoretical calculations by JQI Fellow Sankar Das Sarma and JQI graduate student Chun-Xiao Liu.