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Colloquium

The colloquium is currently held at 3:45 PM on Tuesdays in Harriman 137. Cookies, tea and coffee are served from 3:30 PM outside the lecture hall.

Colloquium committee: Rouven Essig (Chair), Jennifer Cano (Vice Chair), Abhay Deshpande, Will Farr, Harold Metcalf, Jesus Perez Rios, Giacinto Piacquadio

Archive of colloquia from 1999 to the present


Spring 2025 Colloquia
Date Speaker Title & Abstract
DateJan 28 Speaker

Andre De Gouvea

Northwestern University

Title & Abstract

The Brave Nu World


The discovery of nonzero neutrino masses shook the particle physics world at the turn of the 21st century and remains the only concrete evidence that there is something missing from the standard model of particle physics. I provide an overview of the current status of neutrino physics, including some of the open questions and the many avenues we are pursuing to answer them.

DateFeb 4 Speaker

Raymond Blackwell

Stony Brook University

Title & Abstract

Visualizing Correlated Phenomena via Scanning Tunneling Microscopy


Strong interactions between electrons in a material give rise to a diverse set of phenomena including superconductivity, density waves, and magnetism. One of the most powerful techniques to study these correlated phenomena is Spectroscopic Imaging Scanning Tunneling Microscopy (SI-STM), a real space probe capable of visualizing local electronic information at sub-nanometer length scale. In this talk, I will discuss the insights that SI-STM provides about the normal state in the recently discovered high Tc superconductor La3Ni2O7. Additionally I will show evidence that ytterbium dopants drastically alter the properties of graphene leading to spatial heterogeneity in the electronic structure and the appearance of a charge density wave.

DateFeb 11 Speaker

Jainendra Jain

Penn State University

Title & Abstract

Absolutely mindboggling! Weirder than we ever thought.


The history of physics is replete with examples, referred to as paradigm shifts, where a complex and apparently disconnected set of phenomena is unified by a more fundamental principle. In this talk, I will show how the enormously rich and mysterious phenomenology of 2D electrons in a magnetic field becomes obvious when viewed from the perspective of a new kind of emergent particles called the composite fermions. In particular, the composite fermions are seen to be the fundamental building blocks of the fractional quantum Hall states, which are among the most stunning, the most consequential, and the best understood strongly correlated states discovered in nature. I will mention the latest developments, intriguing ideas for fault tolerant quantum computation, new surprises, and open issues. The talk will be accessible to first year graduate students.

DateFeb 18 Speaker

Tom Hartman

Cornell University

Title & Abstract

Black Holes in Quantum Gravity: Old Puzzles and New Connections


Black holes in quantum gravity are complex objects, and the theory that governs them provides a bridge between quantum field theory, statistical mechanics, and quantum information theory. In this talk, I will describe some of these connections and give a status report on the quantum theory of black holes. The emphasis is on the recent discovery that spacetimes with higher topology --- multiple black holes, connected through their interiors --- play an important role in the path integral of quantum gravity. The talk will be an overview geared toward a general physics audience.

DateFeb 25 Speaker

Dominik Schneble

Stony Brook University

Title & Abstract

Simulating Waveguide QED with Atomic Matter Waves


Understanding and harnessing light-matter interactions in novel contexts is central to the development of modern quantum technologies. One example is the emerging field of waveguide quantum electrodynamics (wQED) which investigates the coherent coupling between one or more quantum emitters and an engineered low-dimensional photonic bath. While recent experiments have observed modified spontaneous emission, bound-state mediated interactions, and superradiance, a clean access to the underlying mechanisms often remains challenging. We approach wQED with an unconventional platform in which artificial quantum emitters, realized with ultracold atoms in an optical lattice, undergo spontaneous radiative decay by emitting single atoms, rather than single photons. I will introduce the unique aspects of our matter-wave platform and present some recent work on simulating radiative many-body effects at the boundary between atomic physics, quantum optics and condensed-matter physics.

DateMar 4 Speaker

Alan Robock

Rutgers University

Title & Abstract

Global Famine after Nuclear War


    The world as we know it could end any day as a result of an accidental nuclear war between the United States and Russia.  The fires produced by attacks on cities and industrial areas would generate smoke that would blow around the world, persist for years, and block out sunlight, producing a nuclear winter.  Because temperatures would plunge below freezing, crops would die and massive starvation could kill most of humanity.  Even a nuclear war between new nuclear states, such as India and Pakistan, could produce climate change unprecedented in recorded human history and massive disruptions to the world’s food supply. 

    This talk will show climate and crop model simulations, as well as analogs, which support this theory.  It will also discuss policy changes that can immediately lessen the chance of such scenarios happening and that can lead to the abolition of nuclear weapons.  The myth of nuclear deterrence has allowed nuclear weapons to persist for too long.  However, as a result of international negotiations pushed by civil society led by the International Campaign to Abolish Nuclear Weapons (ICAN), and referencing this work, the United Nations passed the Treaty on the Prohibition of Nuclear Weapons (TPNW) on July 7, 2017.  On December 10, 2017, ICAN accepted the Nobel Peace Prize and the TPNW came into force on January 22, 2021, but the nine nuclear nations continue to ignore the TPNW and the will of the rest of the world.  An option for physicists interested in getting involved is to join the Physicists Coalition for Nuclear Threat Reduction, http://physicistscoalition.org/, a project to engage and activate the global physics community, which is headquartered at the Princeton University Program on Science and Global Security. 

DateMar 11 Speaker

Hui Cao

Yale University

Title & Abstract

Four-Decade Search for Anderson localization of light


Anderson localization marks a halt of diffusive propagation in disordered systems, and it exists for various types of waves. Despite extensive studies over the past 40 years, Anderson localization of light in three dimensions remained elusive, leading to the question of its very existence. Recent computational advances enabled large-scale numerical calculations, allowing us to conduct brute-force simulations of light transport in fully disordered three-dimensional systems with unprecedented dimension and refractive index difference. We show numerically three-dimensional localization of vector electromagnetic waves in in random packings of metallic spheres, in sharp contrast to its absence in the dielectric systems. We also identify a mobility edge that separates diffusive transport and Anderson localization, and reveal a sharp transition from diffusion to localization for light. Our work opens a wide range of avenues in both fundamental research related to Anderson localization and potential applications using three-dimensional localized light.

DateMar 18 Speaker-- Title & AbstractNo Colloquium. Spring Break.
DateMar 25 Speaker

Thomas Allison

Stony Brook University

Title & Abstract

Momentum-Space Imaging of Electron and Exciton Dynamics in 2D Materials


Our conceptual pictures and theoretical formulations regarding the dynamics of quasi-particles in crystalline materials, such as electrons, holes, and excitons, are formulated in momentum space. For example, when we think about how a semiconductor absorbs or emits light, we draw the band structure and arrows connecting the valence band and conduction band, along with scattering mechanisms characterized by energy and crystal momentum. However, our observables of these phenomena involve integrals over many states in momentum space, and are also blind to so-called “dark” states that do not interact with light. Significant interpretation is then required to connect optical spectra to the underlying momentum-space dynamics, and it is easy to get these interpretations wrong. 

Recently, breakthroughs in technology for time- and angle-resolved photoemission (tr-ARPES), developed at Stony Brook and a few other labs, make direct momentum-space snapshots of electron dynamics across the full Brillouin zone no longer just a theoretical construct but a recorded reality. In this talk, I will discuss both the optical science behind these recent breakthroughs in tr-ARPES and recent results from my lab. Specifically, I will discuss pseudo-spin dynamics in graphene, valley polarization dynamics in monolayer WS2, and the mixture of metastable exciton states produced in MoSe2/WSheterostructures after above-bandgap excitation. Direct visualization of momentum-space wave functions enables new discoveries unseen in previous measurements in each case, but this only represents a small glimpse of the science now accessible with these new techniques. Finally, I will present an outlook for some upcoming experiments and where the field is going with further advances in the techniques.

DateApr 1 Speaker

Christoph Paus

Massachusetts Institute of Technology

Title & Abstract

TBA.

DateApr 8 Speaker

Katerina Chatziioannou

California Institute of Technology

Title & Abstract

TBA.

DateApr 15 Speaker

Undergraduate Colloquium

Title & Abstract

TBA.

DateApr 22 Speaker

Thomas Roser

Brookhaven National Laboratory

Title & Abstract

Sustainability of accelerator and collider facilities


In our world of increasing Global Warming and extreme weather events this talk explores the steps that can be taken to build and operate accelerators and colliders in a more sustainable and responsible way. After a general discussion of sustainability I will describe the work of the ICFA Panel on Sustainable Accelerators and Colliders and the on-going planning efforts towards more sustainable future large accelerators.

DateApr 29 Speaker

David Goldhaber-Gordon

Stanford University

Title & Abstract

TBA.

DateMay 6 Speaker

Graduate Colloquium

Title & Abstract

TBA.


Archived Colloquium Schedules