When the dimensionality of an electron system is reduced from three dimensions to two dimensions, new behavior emerges. This has been demonstrated in gallium arsenide quantum Hall systems since the 1980’s, and more recently in van der Waals (vdW) materials, such as graphene. The discovery of vdW materials with intrinsic magnetic order in 2017 has given rise to new avenues for the study of emergent phenomena in reduced dimensions. These materials are at the forefront of condensed matter physics research. How many vdW magnetic materials exist in nature? What are their properties? How do these... Read more about Monday Colloquium: Trevor David Rhone (RPI) "Data-driven studies of magnetic van der Waals materials"
This talk explores next steps in the search for new physics in the neutrino sector. The discovery of neutrino oscillations has changed the way we think about our model of particle physics. We must now incorporate tiny neutrino masses into our theory, as well as consider the possibility of other unexpected properties. You might ask what a tiny mass particle has to do with elephants? To learn this, you need to come to the colloquium.
In this talk, I will describe my efforts to understand the nature of the mysterious dark matter. I provide an overview of the general problem and then describe my current approach to it, which is to characterize the behavior of a proposed dark matter particle, the axion. I will give some insight into how I am using a range of tools -- model building, computation, and high energy astrophysics -- to get at the basic question of “what is the statistical mechanics of axion dark matter?” I will discuss work that shows that the self-interaction should not be ignored and that the sign of the...
Broken-symmetry states in condensed matter offer the unprecedented opportunity to observe collective electronic modes behaving as particle-like excitations. Superconductors offers a plethora of collective excitations connected to amplitude (Higgs) and phase (Goldstone) excitations of the superconducting order parameter, and their combinations in multiband superconductors (as the Leggett mode). However, their effect remains elusive in standard equilibrium spectroscopy, due to the weak coupling to light in ordinary conditions . On the other hand, strong THz pulses trigger non-linear optical... Read more about Monday Colloquium: Lara Benfatto (Sapienza University of Rome) "Manipulating matter with light: the case of superconductors"
Somitogenesis, the segmentation of the antero-posterior axis in vertebrates, is thought to result from the interactions between a genetic oscillator and a posterior-moving determination wavefront. The segment (somite) size is set by the product of the oscillator period and the velocity of the determination wavefront. Surprisingly, while the segmentation period can vary by a factor three between 20°C and 31°C, the somite size is constant. How this temperature independence is achieved is a mystery that I will address in my talk. Using RT-qPCR we showed that the endogenous fgf8 mRNA... Read more about Monday Colloquium: David Bensimon (CNRS & UCLA) "Temperature Independence of Somitogenesis and Critical Slowing Down"
Connecting theoretical models for exotic quantum states to real materials is a key goal in quantum material synthesis. Among such theoretical models, a “toy model” is one made deliberately simplistic in order to demonstrate new physical concepts and their underlying mechanisms. We describe here our recent progress in experimentally realizing “toy model” quantum materials which, in analogy to their theoretical counterparts, are designed to capture simple model systems by lattice and superlattice design. Examples include the realization of massless and infinitely massive electrons in...
Modern machine learning has had an outsized impact on many scientific fields, and particle physics is no exception. What is special about particle physics, though, is the vast amount of theoretical and experimental knowledge that we already have about many problems in the field. In this colloquium, I present two cases studies involving quantum chromodynamics (QCD) at the Large Hadron Collider (LHC), highlighting the fascinating interplay between theoretical principles and machine learning strategies. First, by cataloging the space of all possible QCD measurements, we (re)discovered...
Optical and near-IR Microwave Kinetic Inductance Detectors, or MKIDs, are superconducting detectors that can tell you the energy and arrival time of each individual photon without false counts. In this talk I will discuss the recent progress my group has made improving MKID and fielding them at some of the largest telescopes in the world. I will also discuss our efforts to broaden the scientific relevance of these detectors to other fields, including biological microscopy and dark matter detection.
Martin White (UC, Berkley) "Modeling large-scale structure for the golden era of cosmological surveys"
Abstract: The Universe we observe exhibits order on a wide range of scales, and the study of this large-scale structure provides one of our premier laboratories for fundamental physics, cosmology and astrophysics. I will present recent advances in analytic models of this large scale structure applicable to the numerous observational programs getting underway or under construction in this golden era of cosmological surveys.