College of Arts and Sciences

Continue reading… Mark Griswold (CWRU Radiology)

The Dark Side of Cosmic Dawn.

Dark matter constitutes more than 5/6 of the matter in the universe, but its nature and interactions remain one of the great puzzles of fundamental physics. Dark matter collisions or decays, occurring throughout the universe’s past, have the potential to produce high-energy particles; such particles may already have reshaped the history of our cosmos, leaving traces of their existence in ionization and heating of the intergalactic medium. I will discuss possible signatures of new dark matter physics in cosmological observations, from the cosmic dark ages to the epoch of reionization,

Continue reading… Tracy Slatyer (MIT)

Plasmons at the Interface Between Physics and Cancer Nanotechnology: The Next Big Thing will be at the Nanoscale

In recent years significant efforts have been made to design and fabricate functional nanomaterials for biomedical applications. These research activities unlocked a complete new research field known as nano-biophotonics. Extreme optics of artificial materials characterized by hyperbolic dispersion allowed to access new physical effects and mechanisms. The unbound isofrequency surface of hyperbolic metamaterials opened the way for virtually infinite photonic density of states and ultrahigh confinement of electromagnetic fields in multilayered nanostructures. This has lead to speed up significantly the spontaneous emission of quantum emitters1,

Continue reading… Pino Strangi (CWRU Physics)

Flat Optics: from Metalenses to New Polarization Optics and New Routes to Vector Beam Generation 

Arrays of optically thin, sub-wavelength spaced optical elements (meta surfaces) have major potential for wavefront shaping through local control of the phase, amplitude and polarization of light [1]. Flat optics has emerged from this approach [2] with the goals of replacing refractive lenses in most applications requiring aberrations’ correction [3,4] as well as conventional phase plates used in polarization optics [5] and last but not least of providing a new path to the creation of structured light [6]. 

Continue reading… Federico Capasso (Harvard Univ)

Conserving Helium: A story of MgB2 superconducting wire and MRI magnets

The fabrication of MgB2 superconducting wire has enabled the development of novel magnet designs for MRI systems. Compared to MRI magnets in use today, which are submerged in a bath of liquid helium, the higher critical temperature (39K) of the MgB2 facilitates conduction cooling which reduces the use of liquid helium by a factor of 100 or more. In collaboration with Hyper Tech Research, a world leader in the manufacture of MgB2 wire, and the Center for Superconducting and Magnetic Materials at the Ohio State University,

Continue reading… Mike Martens (CWRU Physics)

The art of neutrino detection: What does it take, and why?

Neutrinos are fundamental blocks of matter. As we’ve learned more and more about them and their properties over the past few decades, we’ve also been led to some important questions about the role of neutrinos in the evolution of our universe; we have also gathered perplexing evidence that makes us question our assumptions about neutrinos in the first place. This talk will review what we know about neutrinos, questions about them that we have yet to answer, and some challenging engineering quests we have embarked on in order to try and settle those questions.

Continue reading… Georgia Karagiorgi (Columbia University)

Fundamental Physics with the Simons Observatory

The Simons Observatory is a new cosmic microwave background experiment being built on Cerro Toco in Chile, due to begin observations in the early 2020s. I will describe the scientific goals of the experiment, motivate its design, and forecast its performance. The Simons Observatory will measure the temperature and polarization anisotropy of the cosmic microwave background with arcminute resolution over approximately 40% of the sky in six frequency bands: 27, 39, 93, 145, 225 and 280 GHz. In its initial phase, three small-aperture (0.5-meter diameter) telescopes and one large-aperture (6-meter diameter) telescope will be fielded.

Continue reading… Brian Keating (UC San Diego)

2018 Michelson Postdoctoral Prize Lecture 3: Colloquium 

Indirect Searches for Weakly-Interacting Massive Particles

Recent observations at gamma-ray and radio energies, as well as local observations of charged cosmic-rays, have placed increasingly stringent constraints on the annihilation cross-section of Weakly Interacting Massive Particle (WIMP) dark matter. Excitingly, these studies have begun to rule out the infamous “thermal annihilation cross-section”, where WIMP models are expected to naturally obtain the observed relic abundance. As expected when multiple cutting-edge observations coincide, there is currently tension between different studies. For example, strong limits from gamma-ray searches in dwarf-spheroidal galaxies lie in significant tension with dark matter explanations for the observed “Galactic Center excess” observed near the center of the Milky Way.

Continue reading… Tim Linden (Ohio State University)

The WIMP is Dead. Long Live the WIMP!
 
Abstract: Although weakly interacting massive particles (WIMPs) have long been the leading class of candidates for the dark matter of our universe, the lack of a confirmed detection of these particles has left the community increasingly skeptical of their existence. In this talk, I will ask the following questions: How surprised should we be that WIMPs have not yet been detected? What assumptions might we change in order to explain the lack of any clear signals of dark matter? In light of the current experimental situation, what are the prospects for future direct,

Continue reading… Dan Hooper (Fermilab)

Manipulation of Topological Defects in Liquid Crystals

 A topological defect (TD) occurs at a wall, line, or point where the relevant order parameter — in our case the liquid crystal’s orientational order parameter — becomes ill-defined, and where this singularity cannot be removed by varying the order parameter continuously. Studies of TDs can be used to obtain values of elastic constants and surface tension, and can serve as an important signature when determining the symmetry of phases. Defect dynamics provide another important field of study, as defect motion is extremely sensitive to boundary effects and provides information about surfaces and impurities.

Continue reading… Charles Rosenblatt (CWRU Physics)

Missile Defense and Space Weapons

Missile defenses and space weapons have been pursued at modest levels for many decades, but both are poised to see an enormous increase in funding and scope in the United States. Developments in North Korean nuclear and missile programs are providing justification to build more of existing missile defense systems as well as new types of systems.  And recent policy directs the Pentagon to create a Space Force and to begin building both offensive and defensive space systems.

Missile defense and space weapons are also closely related technologically. Defense systems designed to target ballistic missiles have inherent capabilities as anti-satellite weapons.

Continue reading… Laura Grego (Union of Concerned Scientists)

The Brave nu World

I review the current theoretical and phenomenological status of neutrino physics. I will discuss our current understanding of neutrino properties, open questions, some new physics ideas behind nonzero neutrino masses, and the challenges of piecing together the neutrino mass puzzle. I will also comment on the new physics reach of the current and the next generation of neutrino oscillation experiments.

Continue reading… Andre De Gouvea (Northwestern University)