Colloquium Schedule Spring 2026
Monday, April 27, 2026
Speaker: Eduardo Baldini (University of Texas, Austin)
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Host: Darius Torchinsky
Monday, April 20, 2026
Speaker: Tim Lian (University of Pennsylvania)
Title: Electrochemical Control of Static and Ultrafast Electrode-Induction Effects: from electrochemical Stark effect to plasmon-driven mode-selective adsorbate excitation
Abstract: Attaching molecular catalysts on (photo-) electrodes offers a promising approach for modular and rational design of hybrid catalysts for (photo-) electrochemical transformations. The design and improvement of such hybrid catalysts require fundamental understanding of the structure and microenvironment of catalysts, interfacial field, and adsorbate-electrode interaction as well as their effects on adsorbate/catalysts excited state dynamics. To probe these electrode-adsorbate interactions at the molecular level, we have been developing and applying time-resolved vibrational sum frequency generation (VSFG) spectroscopy and surface enhanced Raman spectroscopy (SERS) as in situ interface specific/sensitive vibrational spectroscopic tools. In this talk, I will discuss two recent studies in this area. 1) We have observed surprisingly large electrochemical-Stark effect of adsorbed molecules and molecular CO2 reduction catalysts. We demonstrated that the Stark-effect is dominated by through bond interaction of the electrode on the adsorbates (i.e. the electrode induction effect), and this result suggests a potential new approach for design and control of catalysts. 2) Using time-resolved SERS, we directly observe plasmon-driven mode-selective adsorbate vibrational excitation caused by strong adsorbate-metal interaction (i.e. the dynamic electrode induction effect). This finding suggests possible electrochemical control of photocatalysis on plasmonic metal surface and/or light-enhanced electrocatalysis.
Host: Xifan Wu
Monday, April 13, 2026
Speaker: Danielle Norcini, Assistant Professor, Department of Physics and Astronomy, Johns Hopkins University
Title: Imaging dark matter at the eV scale
Abstract: The identity of dark matter remains one of the central open questions in physics. While traditional direct detection experiments have focused on dark matter heavier than the proton, new detector technologies now enable sensitive searches for lighter candidates that deposit only a few electrons of measurable energy. The DAMIC-M (DArk Matter In CCDs at Modane) experiment will deploy kilogram-scale skipper CCD imaging detectors underground at the Laboratoire Souterrain de Modane (LSM), providing world-leading sensitivity to dark matter in the MeV to GeV mass range. At the same time, ongoing research aims to develop new imaging detector architectures capable of extending sensitivity to even smaller energy deposits, opening new opportunities to probe light dark matter and other rare interactions at the eV scale.
Host: Jim Napolitano
Monday, April 6, 2026
Speaker: Ramona Vogt (Lawrence Livermore National Laboratory)
Title: Modeling fission in the lab and the universe
Abstract: Nuclear fission, while well known for the energy it can produce, is not yet well understood, even after 80 years. The fission process, involving three of the four known forces of nature, is very complex and parts of the process take place over very different time scales, each of which has its own signatures. Given its complex nature, it is only recently that theory and modeling efforts to explain fission are beginning to be more tractable. Phenomenological models bridge the gap between many-body theory and experiment, including the essential physics for studying all aspects of the fission process and comparing to all types of available data, whether for science or applications. The event-by-event model of fission, FREYA, generates complete events and follows the process from excitation of the compound nucleus to breakup into two fragments and their de-excitation step-by-step, making it possible to model the fission fragment characteristics, the neutrons and photons they emit, and the correlations between them. FREYA, inspired by event generators for high energy particle collisions, depends on a few physics-based parameters, which, when optimized, can provide some predictive capabilities. The model can then be used to gain insights into an array of processes from reactor neutrino spectra, through multi-messenger astrophysics, and more down-to-earth applied studies. This talk describes the physics of FREYA and outlines some of the applications of FREYA.
Host: Bernd Surrow
Monday, March 30, 2026
Speaker: Paul Julienne (Joint Quantum Institute (JQI) of NIST and University of Maryland)
Title: The unity of physics: The beauty and power of spectroscopy
Abstract: Spectroscopy was a key component in developing the “old” or original quantum physics of the last century, but is also essential for successful implementation of the exotic “new” quantum physics of our current “second quantum revolution.” Knowing the spectrum of a complex quantum system is the best way to characterize and control it quantitatively. This talk will look at some basic principles of ultracold atomic and molecular physics, and the importance of good spectroscopy as an underlying, enabling method of building highly quantitative Hamiltonians and predictive models of tunable cold atom scattering and bound states. A comparative examination of the large differences in the characteristics of near-dissociation bound states of the three Li2 isotopologues demonstrate the need for good spectroscopically derived molecular potentials as a basis for comprehensive quantitative understanding of the dynamics of ultracold atomic systems and their various applications in physics and chemistry.
Host: Marjatta Lyyra
Monday, March 23, 2026
Speaker: Xiao-Gang Wen (MIT)
Title: Symmetry as a Shadow of Topological Order from a Higher Dimension
Abstract: We usually think of symmetry as a simple idea: something stays the same when you rotate it, flip it, or shift it. Physicists formalized this intuition using mathematical objects called groups, and for a long time, that seemed like the whole story. But it turns out this picture is only the surface. In this talk, I’ll explain why symmetry is better understood not as a fixed rule, but as something that emerges from the kinds of local actions a physical system allows. When we look at symmetry this way, entirely new possibilities appear — exotic symmetries that can act on extended objects, behave strangely at the quantum level, or cannot even be reversed. Surprisingly, these unusual symmetries are not random. They organize themselves according to rules of “fusion” and “braiding,” much like the way particles can combine and weave around one another in quantum systems. This structure points to a remarkable idea: what we call symmetry in our world may actually be a shadow cast by a topological order that lives in one higher dimension. I’ll show how this deep connection between symmetry and topological order reshapes our understanding of phases of matter and how they change. Rather than being classified by symmetry alone, phases of matter may be best understood as different ways higher-dimensional patterns project themselves into the physics we observe.
Host: Rongjia Tao
Monday, March 16, 2026 OPEN
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Monday, March 9, 2026
Speaker: Ron Gilman (Department of Physics and Astronomy, Rutgers University)
Title: The Proton Radius Puzzle
Abstract: Two themes in subatomic physics have been understanding how baryons and mesons can be explained through quantum chromodynamics and investigating whether there is physics in the subatomic world that suggests novel physics beyond the standard model. When it was found that the proton radius obtained with muonic hydrogen spectroscopy differed by several sigma from that obtained in atomic hydrogen spectroscopy and electron scattering, possible explanations arose from both of these areas. I will describe the background to the radius puzzle and the work that has followed in subsequent years.
Host: Nikos Sparveris
Monday, March 2, 2026 - SPRING BREAK
Monday, February 23, 2026 - CANCELED / SNOW DAY
Monday, February 16, 2026
Speaker: Dr. Swati Chaudhary (The University of Tokyo)
Title: Design principles for on-demand functionalities in quantum materials
Abstract: Quantum materials lie at the forefront of emerging quantum technologies and are poised to transform fields ranging from energy harvesting to quantum computation and sensing. Realizing this potential requires a deeper understanding of how these materials couple and respond to external stimuli, and of the organizing principles that govern those responses. The response of quantum materials is shaped by a complex interplay of different degrees of freedom such as charge, spin, orbitals, and lattice. In this talk, I will discuss how this interplay can be harnessed to engineer unconventional phenomena that not only lead to new functionalities but also reveal design principles rooted in symmetry and quantum structure. I will highlight how features encoded in the electronic wavefunction, such as quantum geometric structure, give rise to nonlinear optical effects beyond conventional limits, and how these insights guide the design of optoelectronic responses in moiré and multilayer systems. Furthermore, I would discuss when these ideas are extended to collective excitations such as phonons, they can result in new phononic processes and novel probes of hidden order. Together, these examples point toward a broader framework in which connecting microscopic understanding with material design can guide the discovery of new functionalities and advance the development of quantum technologies.
Host: Martha Constantinou
Monday, February 9, 2026
Speaker: Thomas Iadecola (Department of Physics, The Pennsylvania State University)
Title: How much information can be stored in a quantum many-body system?
Abstract: Quantum computing is based on the idea that quantum systems can store and process information in a manner fundamentally different from classical ones. In this colloquium, I will try to make the case that viewing quantum systems as means of storing and processing information provides an interesting new perspective on quantum many-body physics. To do this, I will describe two examples where simply imposing symmetries (a compulsion of theoretical physicists) guarantees that a quantum many-body system preserves some amount of quantum information. The first example reframes the surface code, widely considered a viable route towards quantum error correction, as a family of many-body systems storing one qubit. The second example demonstrates how the addition of dynamical constraints, which commonly arise in strongly interacting systems, can allow for a single many-body system to protect exponentially many qubits’ worth of information.
Host: Jim Napolitano
Monday, February 2, 2026
Speaker: Jonathan Curtis (Physics Department, ETH Zurich)
Title: Nonlinear Noise Spectroscopy for Quantum Materials
Abstract: Quantum materials such as superconductors, magnets, and topological insulators have great potential for realizing advanced electronic and computing devices, but characterizing and understanding these materials has remained a challenge. While tools such as ultrafast optics have generally been successful at characterizing nonlinear spectra, these tools are often limited in their spatial resolution. Especially given the rise of two-dimensional moiré materials, it has become more important than ever to find probes which can resolve the rich spatial and dynamical correlations present in these materials. One promising such technique is noise magnetometry, which utilizes nanoscale spin qubits to map out the landscape of magnetic fluctuations in a material with spatial resolution on the order of 10’s of nm. In this talk I will provide an example of how nanoscale noise spectroscopy can theoretically be used to uncover superconducting fluctuations in a two-dimensional material, before highlighting the need for nonlinear probes. I will then unveil a new set of protocols which can be used to study nonlinear correlations in the magnetic noise, blending the crisp spatial resolution of noise spectroscopy with the insights of nonlinear spectroscopy. As an example, I will show how this technique can be used to study critical magnetic fluctuations in a two-dimensional material, such as a Van der Waals magnet, and how cooperative noise onsets near a phase transition. I will then conclude by providing an outlook on the next generation of probes which can use multiple qubits to detect spatially non-local correlations, and what we can look for using these tools
Host: Alex Gray
Monday, January 26, 2026 - Snowday
Monday, January 19, 2026 - Dr. Martin Luther King Day
Monday, January 12, 2026
Speaker: Karen Masters (Haverford College)
Title: Observing Spiral Arms in Galaxies
Abstract: The iconic spiral arms that decorate the disks of massive galaxies (like our own Milky Way) have been studied observationally and theoretically since they were first recorded 180 years ago, nevertheless the exact details of their physical nature remains elusive. I will review the basic physics of spiral galaxy dynamics, with an emphasis on what is known observationally about spiral arms, including results from the citizen science project Galaxy Zoo (www.galaxyzoo.org) and the large galaxy survey “MaNGA” (Mapping Nearby Galaxies at Apache Point Observatory - part of the Sloan Digital Sky Surveys). I will discuss how these and other observational data are currently being used to constrain the variety of different physical models which have been proposed to explain spiral arms in galaxies.
Host: Martha Constantinou