The Spring 2018 colloquia will be held in the lobby of the Physical Sciences Complex unless otherwise noted

Each week during the semester, the Department of Physics invites faculty, students and the local community to hear prominent scientists discuss intriguing physics research. The Spring 2018 colloquia will be held Tuesdays in the Physical Sciences Complex lobby at 4:00 p.m. (preceded by light refreshments at 3:30 p.m.)

Parking is available in the Regents Drive Parking Garage (PG2). An attendant will direct visitors within the garage. Additionally, a free ShuttleUM bus runs between the College Park Metro Station and Regents Drive at about eight-minute intervals.

For further information, please contact the Physics Department at 301-405-5946 or email This email address is being protected from spambots. You need JavaScript enabled to view it..

January 30
Seung-Hun Lee, University of Virginia
Hosted by Eun-Suk Seo

New Materials for Next Generation Printable Solar Cells

The realization of economical renewable energy technologies is critical for securing long-term prosperity of mankind and mitigating the threat of climate change. Power from the Sun is the most abundant source of renewable energy. In just one hour, more solar energy hits the Earth’s surface than humanity uses in an entire year. Therefore, development of solar cells that can produce electrical power at a cheaper rate than fossil fuel-based electricity is highly desirable.  However, only about one percent of the world’s energy production currently comes from solar cells. This is because conventional technologies, mostly based on silicon solar cells, are too expensive to be competitive with energy generated by burning fossil fuels. What is needed is research on new solar cell materials that can be fabricated into solar cells with high-efficiency and low-cost simultaneously.
Hybrid Organic-Inorganic perovskites (HOIPs) have recently been discovered as one of the most promising next generation solar cell materials. Solar cells based on HOIPs have achieved high efficiency that rivals that of the conventional silicon solar cells. At the same time, HOIPs can be deposited on surfaces from ink solutions which enable low-cost and high-throughput manufacturing of solar cells as if printing out newspapers. In this talk, I will present our recent research that revealed microscopic mechanism of the photovoltaic properties of HOIPs.
February 6
Rob Schoelkopf, Yale University 
CNAM Carr Lecture, hosted by Chris Lobb and Fred Wellstood

The Prospects for Scalable Quantum Computing with Superconducting Circuits

Dramatic progress has been made in the last decade and a half towards realizing solid-state systems for quantum information processing with superconducting quantum circuits. Artificial atoms (or qubits) based on Josephson junctions have improved their coherence times more than a million-fold, have been entangled, and used to perform simple quantum algorithms. The next challenge for the field is demonstrating quantum error correction that actually improves the lifetimes, a necessary step for building more complex systems. At Yale we have been pursuing a hardware-efficient approach for error correction, that relies on encoding information in a bosonic oscillator, the so-called “cat codes.” With this approach, we have applied real-time measurements and feedback to achieve the first extension of the lifetime of a quantum bit through error correction. For scaling, an attractive approach is the modular architecture, in which small quantum processors are networked together into a larger whole. I will present a realization of a gate between logical qubits. This is the first implementation of a teleported C-NOT gate, which is a key building block for the modular approach.


February 13
Matt Green, NC State
Hosted by Carter Hall

Coherent Neutrino Scattering at the SNS

Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) is a neutral-current process in which a neutrino interacts coherently with an entire nucleus. While the coherence of the process leads to a large cross section enhancement with increasing neutron number, the low momentum transfer results in difficult-to-detect low energy nuclear recoils. The COHERENT Collaboration has combined state-of-the-art low-threshold detector technology with the intense flux of neutrinos generated at Oak Ridge National Laboratory’s Spallation Neutron Source (SNS) to detect CEvNS for the first time, and is developing it as a tool for searches for physics beyond the Standard Model, including Non-Standard Neutrino Interactions (NSIs), oscillations into sterile neutrinos, nuclear form factors, and neutrino magnetic moments. This talk will detail the first-ever observation of CEvNS, as reported in our recent publication in Science, and the COHERENT Collaboration's follow-up efforts to fully characterize the interaction with Liquid Argon, High-Purity Germanium, and Sodium-Iodide -based detectors.




February 20
John Paul Chou, Rutgers
Hosted by Sarah Eno

Dark Matter in Collision at the LHC

The Large Hadron Collider at CERN has ushered in a new era in fundamental physics, in which images of proton-proton collisions of unprecedented quality and quantity are recorded at the highest energies ever obtained in a lab. In 2012, the CMS and ATLAS experiments discovered the Higgs boson, completing the picture of the Standard Model of particle physics. Where else will this new era take us? Dark matter, seen astronomically through its gravitational effects, has a natural particle interpretation and should be observable at the LHC. But this simple story may have unexpected twists and turns. I will discuss the different ways that dark matter and related particles could manifest at the LHC and what unexpected secrets may lie in store for the future.

February 27

Martin Savage, UW Seattle
Hosted by Zohreh Davoudi

Quantum Chromodynamics in the Exascale Era with the Emergence of Quantum Computing

A century of coherent experimental and theoretical investigations
uncovered the laws of nature that underly nuclear physics — Quantum Chromodynamics (QCD) and the electroweak interactions.
While analytic techniques of quantum field theory have played a key
role in understanding the dynamics of matter in high energy processes, theybecome inapplicable to low-energy nuclear structure and reactions, and dense systems.  Expected increases in computational resources into the exascale era will enable Lattice QCD calculations to determine a range of important strong interaction processes directly from QCD.  However, important finite density systems, non-equilibrium systems, and inelastic processes are expected to remain a challenge for conventional computation. In this presentation, I will discuss the state-of-the-art Lattice QCD calculations, progress that is expected in the near future, and the potential of quantum computing to address Grand Challenge problems in nuclear physics.
March 6

Fernando Miralles-Wilhelm, UMD Atmospheric & Oceanic Science - cancelled
Hosted by Victor Yakovenko

What would Thomas Malthus tell us in the 21st Century?: Experiences in the Water-Energy-Food Nexus from an International Development Perspective


Ongoing research focused on analyzing the synergies and tradeoffs posed by the water-energy-food nexus is presented. This covers the need for quantitative tools (e.g., data, models) to support the analysis of integrated water, energy and food systems, from a perspective relevant to the work of international development organizations: dialog with countries and increasing awareness of “nexus” thinking and planning, building regional and in-country capacity toward integrated planning and identification/evaluation of trade-offs and synergies in developing such systems, and fostering interdisciplinary expertise in principles, algorithms, and model formulations for understanding and evaluating the potential of implementing nexus approaches within a systems perspective. This research stresses the necessity of integrating areas of disciplinary expertise, the ability to identify and address shared needs of water, energy and food stakeholders, and facilitating tailored analyses over different spatial and temporal scales. Outputs and products of recent nexus work will highlight further research and development needs focused on upstream sector planning in order to identify primary opportunities and constraints to water, energy, and food system development, and also result in an improved understanding of economic and social trade-offs among competing nexus priorities, and particularly prioritization of sector investments. Four recent experiences in South Africa, China, the Middle East and Latin America are presented as examples of nexus tradeoffs offering a rationale for investment rationalization and priorities.

Dr. Fernando Miralles-Wilhelm is a hydrologist and water resources engineer with research expertise in modeling of surface and groundwater hydrology, solute transport with physical, chemical and biological processes in aquatic ecosystems, climate-hydrology-vegetation interactions, stormwater management in urban watersheds, water-energy-food nexus and system dynamics modeling. He currently serves as Executive Director of the Cooperative Institute for Climate and Satellites (CICS) and Interim Director of ESSIC (Earth System Science Interdisciplinary Center), both at the University of Maryland (UMD), where he also holds an appointment as Professor with the Department of Atmospheric and Ocean Sciences. Before joining UMD, Dr. Miralles was a Lead Specialist at the Inter-American Development Bank (IDB), where he managed the bank's investment portfolio in water resources and climate adaptation projects for the IDB’s 26 countries served in the Latin American and the Caribbean region. He is a Fellow of the American Society of Civil Engineers (2009) and a Diplomate of the American Academy of Environmental Engineers (2002) and the American Academy of Water Resources Engineers (2008). He holds a mechanical engineering diploma from Universidad Simón Bolívar in Venezuela, a Masters degree in Engineering from the University of California-Irvine, and a Ph.D. in Civil and Environmental Engineering from the Massachusetts Institute of Technology (MIT).


March 13

Robert Boyd, University of Ottawa, Ottawa, ON Canada & Institute of Optics and Department of Physics and Astronomy University of Rochester, Rochester NY USA 
Hosted by Howard Milchberg

What’s New in Nonlinear Optics

This talk begins with a brief overview of the history of nonlinear optics and a description of some standard nonlinear optical effects. I will then turn to a more detailed discussion of two topics of current interest. The first topic is the role played by nonlinearity in the creation of rogue waves, including oceanic rogue waves. We have performed careful studies of optical wave propagation through nonlinear materials to elucidate the role of nonlinearity in the development of extreme (rogue) events. The second topic is an overview of wave propagation effects through materials characterized by a very small value of the dielectric permittivity, that is, through epsilon-near-zero (ENZ) materials. We describe some of the unusual properties of wave propagation through such materials including the huge nonlinearities that necessarily accompany ENZ conditions.

Hosted by Howard Milchberg

March 27
Liang Fu, MIT
Hosted by Brian Swingle

New quantum transport phenomena under large electric and magnetic fields

The discovery of topological insulators and semimetals has brought into focus Berry phase effects on transport properties of quantum solids. This talk will begin with an overview of anomalous Hall effect driven by Berry phase mechanism. I will then turn to two new transport phenomena. The first is the second-order Hall effect, by which a transverse current occurs in second-order response to an external electric field. I will show that the nonlinear Hall conductivitiy in the DC or low-frequency limit can be nonzero in time-reversal-invariant and inversion-breaking materials, and is governed by the dipole moment of Berry curvature in momentum space.

The second part of this talk is on thermoelectric effect under a large magnetic field. I will show that the thermopower of semimetals and narrow-gap semiconductors can be dramatically boosted in the quantum limit. In particular, the thermopower of Dirac/Weyl semimetals increases with the field without saturation and can reach extremely high values. These theoretical results suggest an immediate pathway for achieving record-high thermopower and thermoelectric figure of merit, and compare well with a recent experiment on Pb1−xSnxSe.



April 3

Chan Joshi, UCLA
Hosted by Howard Milchberg




April 10
David Schwartz
Hosted by Nick Hadley




April 17
Zohreh Davoudi, University of Maryland
Hosted by Brian Swingle



April 24
Smitha Vishveshwara, UIUC
Hosted by Jay Deep Sau




May 1
Mark Van Raamsdonk, UBC
Hosted by Brian Swingle



May 8
Rudolf Tromp, IBM
Hosted by Ichiro Takeuchi




Upcoming Events


Tue, Mar 20, 2018 4:00 pm - 5:00 pm


Wed, Mar 21, 2018 11:00 am - 11:30 am


Wed, Mar 21, 2018 3:00 pm - 4:00 pm


Thu, Mar 22, 2018 12:30 pm - 1:30 pm


Thu, Mar 22, 2018 2:00 pm - 3:00 pm


Fri, Mar 23, 2018 4:00 pm - 5:00 pm


Fri, Mar 23, 2018 7:00 pm - 8:30 pm


Sat, Mar 24, 2018 7:00 pm - 8:30 pm