College of Arts and Sciences

Rescheduled, new date to be determined

Continue reading… Andrea Alù (City University of New York)

Gundzik lecture: How do we communicate with the Universe?

Throughout our history, we have gathered information from the Universe that surrounds us through the light it emits. We have seen the Universe through our own eyes and instruments. The direct detection of gravitational waves in 2015 has marked the beginning of a new era for science where we are now able to “hear” the Universe through a new channel, with an opportunity to probe gravity at its most fundamental level. But how much do we actually know about gravity and how gravitational waves propagate?

Continue reading… Claudia de Rham (Imperial College)

Michelson Postdoctoral Prize Colloquium

Modelling and engineering burnt-bridge ratchet molecular motors

Abstract: Molecular motors are protein-based machines essential for directional transport of cellular components. Nature has evolved many mechanisms for achieving directed motion on the subcellular level. The burnt-bridge ratchet (BBR) is one mechanism used to achieve superdiffusive molecular motion over long distances through the successive cleavage of surface-bound energy-rich substrate sites. The BBR mechanism is utilized throughout Nature: it can be found in bacteria, plants, insects, humans, as well as non-life forms such as influenza. Inspired by biology,

Continue reading… Chapin Korosec (York University)

Photonic Metamaterial Time Crystals and Timetronics

Light-driven nonreciprocal forces in an array of nano-opto-mechanical oscillators can underpin the functionality of Time Crystal, a many-body interacting system that exhibits a spontaneous mobilization transition to the robust state of oscillation under an infinitely small change of the external driving force. Such time crystals are a form of Active Matter with life-mimicking dynamics accompanied by the breaking of time translation symmetry, ergodicity, and local entropy decrease. This is of interest to optical “timetronics” – a data processing and communications technology relying on the unique functionalities of time crystals.

Short Bio: Professor Nikolay Zheludev is a Fellow of the Royal Society (UK) and Member of the National Academy of Engineering (USA).

Continue reading… Nikolay Zheludev (University of Southampton)

What’s beyond Neptune? Search and Discovery in the Kuiper Belt and Beyond 
 
The region beyond Neptune is home to thousands of small, icy worlds that are “cosmic leftovers” from the material from which the Earth and the other planets formed. Because these objects are so distant and faint, they’re extremely difficult to detect: over 60 years passed between the discovery of Pluto in 1930 and the discovery of the next trans-Neptunian object. I’ll describe how we use telescopes on the ground and in space, together with the tools of modern data science, to discover hundreds of new objects and understand this vast “third zone”

Continue reading… David Gerdes (CWRU Physics)

Physics and Astrophysics with Nanohertz Gravitational Waves
 
Pulsar timing array experiments around the world have recently published the first evidence of nanohertz gravitational waves in the form of a stochastic gravitational wave background. This discovery opens another window on the gravitational wave universe that we can use to study a variety of astrophysical and cosmological sources, as well as perform tests of gravity. Pulsar timing arrays search for gravitational waves by looking for interpulsar correlations in the timing residuals of a collection of millisecond pulsars. In this talk, I will discuss how pulsar timing arrays work,

Continue reading… Sarah Vigeland (University of Wisconsin, Milwaukee)

Seeing is believing: Zooming in on bacteriophages with cryo-electron microscopy

The most abundant biological entities on Earth are bacteriophages, viruses that infect bacteria. Around the world, these natural predators are being deployed alongside antibiotics to fight dangerous drug-resistant superbugs. Phages can be viewed as biological nanoparticles with four conserved structural elements: a genome (1) that is packaged into a protein shell called a capsid (2), which connects to tail machinery (3) via a molecular motor known as the portal (4). These structural elements determine important factors like phage stability, bacterial host-range, particle immunogenicity, and more. Since bacteriophages are increasingly used as antimicrobial therapies,

Continue reading… Krista Freeman (University of Pittsburgh)

Catland: A Journey Through the Quantum Multiverse

100 years after the origins of quantum theory, there remains no consensus on how best to understand what this theory is telling us about our universe. Quantum theory rests on two legs. The first is the idea that matter can be described as a wave, whose evolution in the non-relativistic case is given by the Schrodinger equation. The second is the idea that we cannot directly observe these waves, but instead postulate a set of probabilistic rules that govern what we do observe when we make a “measurement.” The first leg results in phenomena such as interference and tunneling that would be surprising if one imagined matter to consist of billiard-ball-like particles.

Continue reading… Jesse Berezovsky (Physics, CWRU)

New materials from uncharted places

Over the past decades, quantum materials – materials in which quantum phenomena govern physical properties – have become essential for everyday applications. In most cases, technological advances are driven by the discovery of new solid-state materials and a deeper understanding of the existing ones.

In this talk, I will show different families of solid-state materials discovered in our group. We develop empirical tools for targeting new materials with desired properties.1,2 We can access materials that so far remained out of reach3–5 due to their toxicity, radioactivity, or air sensitivity.

Continue reading… Eteri Svanidze (Max Planck Institute for Chemical Physics of Solids)

Science in a Divided World: Communication Across Cosmic and Political Boundaries

In the mid-20th century, efforts by radio astronomers to search for extraterrestrial intelligence unfolded against the backdrop of the Cold War, a period marked by intense political division and competing ideologies. Despite these divides, scientists from both sides of the Iron Curtain engaged in surprising acts of collaboration and dialogue, driven by the shared ambition of understanding humanity’s place in the universe. This talk explores the challenges and opportunities of communication—not only with potential extraterrestrial civilizations but also across the deeply fractured political landscapes of Earth.

Continue reading… Rebecca Charbonneau (National Radio Astronomy Observatory and American Institute of Physics)

The first decade of Gravitational Wave Astronomy and a look to the future

It is now almost a decade since the LIGO observatory first detected gravitational waves from the collision of two black holes. Since then, the LIGO and Virgo instruments have detected hundreds of additional signals, include the spectacular binary neutron star merger GW170817, and several mixed black hole – neutron star binaries. These discoveries have lead to new insights into stellar evolution, constraints on the nuclear equation of state, and precision tests of general relativity in the strong field regime. Last year, multiple pulsar timing teams from around the world presented evidence for a very low frequency gravitational wave stochastic background.

Continue reading… Neil Cornish (Montana State University)

Low-Temperature Reaction Kinetics Tools for Quantum-State-Resolved Chemistry

Many laboratory methodologies have grown out of developments in the field of atomic, molecular, and optical physics that are ripe for breakthrough studies in the hands of physical chemists. Exquisite control over quantum-state populations now enables chemical reactions to be studied to a level of detail not previously attainable. In this talk, I will describe how we have adopted buffer-gas-cooling (sympathetic/collisional cooling) techniques along with radiofrequency ion traps to investigate chemical reactions that depend sensitively on the initial quantum state of the reactants.

I will describe our work to measure reaction rate constants for radiative-association reactions,

Continue reading… Leah Dodson (University of Maryland, Chemistry and Biochemistry)

Tracing orbits and measuring dark matter with stellar and dynamical invariants

Dynamical times in the Milky Way are measured in units of tens of millions of years; how will we ever see an orbit? The surface abundances (element abundances) of a star are (nearly) invariant quantities, as are the dynamical actions in any integrable potential. We combine these ideas with Orbital Torus Imaging, a new way to precisely measure stellar orbits from kinematic and abundance data. We are using data from the SDSS APOGEE and ESA Gaia instruments to measure the acceleration field and dark matter distribution in the Milky Way.

Continue reading… David Hogg (New York University)

Seeing with the Rainbow: Hyperspectral Remote Sensing with SPHEREx and CubeSounder

Advances in sensor technologies continue to improve the capabilities of passive remote sensing systems to image and characterize the world around us, and in smaller size/weight/power/cost (SWaP-C) envelopes that bring these capabilities to new platforms. In this talk, I will discuss SPHEREx and CubeSounder, two new sensor systems in development at ASU. SPHEREx is a NASA infrared satellite with a wide range of key science goals, including precision mapping of the three-dimensional distribution of galaxies to probe the physics of cosmic inflation. At ASU I am leading a team developing an optimal scheduling system that enables SPHEREx to survey the entire sky while efficiently operating within the challenging operational constraints of LEO.

Continue reading… Sean Bryan (Arizona State University)

Thinking about sinking: the settling of shaped solids

The gravitational settling of particles in a viscous fluid is a common process in nature and in industrial contexts.  This familiar process is a confounding problem in many-body physics due to the long-range, directional interactions between sinking particles.  After discussing some known facts and known puzzles in the field, I will present results that show qualitatively new behaviour when the particles have non-trivial shape and orientational degrees of freedom, as do snowflakes, plankton, crystals, and other natural sediment. As examples of the richness that emerges from shape, I will discuss unusual phenomena in the sedimentation of individual polar and polygonal objects,

Continue reading… Narayanan Menon (University of Massachusetts, Amherst)