It is possible to engineer the properties of photons in an optical medium to have an effective mass and repulsive interactions, so that they act like a gas of atoms. These "renormalized photons" are called polaritons. In the past decade, several experiments have demonstrated many of the canonical effects of Bose-Einstein condensation and superfluidity of polaritons. In this talk I will review some of this past work and present recent results with polaritons that have very long lifetime, including movies of equilibration and damped oscillations of a condensate.
Among six Mellon College of Science (MCS) faculty members, Ben Hunt has been honored with a career development professorship that supports scientists at the beginning of their careers. He and the other faculty were recognized at a reception Sept. 12 in the Mellon Institute. “An endowed professorship is one of the highest honors that our institution bestows upon faculty, and this honor symbolizes the high esteem to which they are held,” said Carnegie Mellon University Provost Jim Garrett.
“Each of these faculty members are being recognized for their important work in fields that will be some of the most important of the 21st century,” said Rebecca W. Doerge, Glen de Vries Dean of the Mellon College of Science. “While their discoveries will make a significant impact in the world, that impact is equaled by their contributions to the students who they teach in class and mentor in the lab.”
The Stephen R. Tritch Nuclear Engineering program at the University of Pittsburgh’s Swanson School of Engineering has received three substantial grants from the U.S. Department of Energy’s (DOE) Nuclear Energy University Program (NEUP) totaling $2.3 million. PQI faculty members Dr. Heng Ban, Dr. Jung-Kun Lee, and Dr. Kevin Chen are among the recipients.
The awards are three of the 40 grants in 23 states issued by the DOE, which awarded more than $28.5 million to research programs through the NEUP this year to maintain the U.S.’s leadership in nuclear research.
“Nuclear energy research is a vital and growing source of clean energy in the U.S., and we are at the forefront of this exciting field,” says Heng Ban, PhD, R.K. Mellon Professor in Energy and director of the Stephen R. Tritch Nuclear Engineering Program at the Swanson School of Engineering. “These grants will enable us to collaborate with leading international experts, conducting research that will help shape future of nuclear energy.”
New research from the Giannis (Yanni) Mpourmpakis and his team introduces the first universal adsorption model that accounts for detailed nanoparticle structural characteristics, metal composition and different adsorbates, making it possible to not only predict adsorption behavior on any metal nanoparticles but screen their stability, as well. The research combines computational chemistry modeling with machine learning to fit a large number of data and accurately predict adsorption trends on nanoparticles that have not previously been seen. By connecting adsorption with the stability of nanoparticles, nanoparticles can now be optimized in terms of their synthetic accessibility and application property behavior. This improvement will significantly accelerate nanomaterials design and avoid trial and error experimentation in the lab. Their work was published in Science Advances on Sept. 13, 2019.
In the 5th century BCE, Zeno of Elea devised dozens of arguments against the possibilities of motion, change, and plurality. The loveliest of these, the Arrow Paradox, is briefly stated: "The flying arrow is motionless." In 1970, Wes Salmon published an anthology devoted to Zeno's Paradoxes and amply demonstrating their capacity to reward scrutiny from the perspectives afforded by mathematics and physics as they themselves move forward. Wes's introduction to that anthology was my first assignment in my first philosophy course. In 2019, I'll try to demonstrate that Zeno's paradoxes continue...
Classical chaotic systems exhibit exponentially diverging trajectories due to small differences in their initial state. The analogous diagnostic in quantum many-body systems is an exponential growth of out-of-time-ordered correlation functions (OTOCs). These quantities can be computed for various models, but their experimental study requires the ability to evolve quantum states backward in time, similar to the canonical Loschmidt echo measurement. In some simple systems, backward time evolution can be achieved by reversing the sign of the Hamiltonian; however in most interacting many-...
Semiconductor quantum dots (QDs) are nanoscopic crystals that are often called artificial atoms. Charge carriers trapped within them have discrete energy levels in the fashion of single atoms, and they absorb and emit light at discrete wavelengths corresponding to those energy levels. Because of this, in many ways QDs behave like the canonical two-level quantum system, which makes them suitable for experiments involving the quantum nature of light, which is called quantum optics. For this reason and for their potential uses in quantum information applications, QDs attract great scientific...
Over the past decade, first-principles computation has emerged as a powerful complement to experiment in the discovery of new catalysts and materials. In many cases, computation has excelled most in distilling rules for catalyst structure-property relationships in well defined spaces such as bulk metals into descriptors or linear free energy relationships. More development is needed of computational tools for them to show the same promise in emerging catalytic materials such as single-site metal-organic framework catalysts or single atom catalysts that have increased promise of atom...
Prof. Lillian Chong has been awarded an NIH RO1 renewal for $1.1 million over 4 years to pursue efforts involving "High-Performance Weighted Ensemble Software for Simulation of Complex Bio-Events." The efforts will be carried out in collaboration with co-PI Prof. Daniel Zuckerman (Oregon Health & Science University), co-I Prof. James Faeder (University of Pittsburgh Medical School), and co-I David Aristoff (Colorado State University).
Congratulations Dr. Chong!
Qing Li, assistant professor of electrical and computer engineering at Carnegie Mellon University, is the recipient of a prestigious 2019 Young Faculty Award from the US Defense Advance Research Projects Agency (DARPA). He received the award based on his research proposal titled "Visible and mid-infrared frequency comb generation in wide-bandgap photonic materials."