Fall 2024
September 20, 2024 (Friday) 4:00-5:00p.m.
Location: Small Hall 111
Speaker: Dr. Saikat Chakraborty Thakur
Hosts: S. Mordijck & I. Novikova
Title: Explorations in plasma turbulence, self organization and structure formation in magnetized plasmas
Abstract: Plasmas are ubiquitous in Nature and depending on the specific circumstances, plasmas can sustain various kinds of instabilities leading to turbulence. In addition, presence of an external magnetic field can reduce the effective dimensionality of plasma transport, thus closely resembling classical 2-D turbulence, which can in turn lead to self-organization and pattern formation. In this talk, we will learn about two such examples related to plasma turbulence and self-organization. In the Controlled Shear De-correlation eXperiment (CSDX), a high-density helicon plasma device, we show the existence of simultaneously present, radially separated, multiple plasma instabilities. At a certain magnetic field threshold, we observe a global, self-organized transition to a more coherent plasma state, which has important implications to the physics of the helicon blue core formation and axial plasma detachment. In the Magnetized Dusty Plasma eXperiment (MDPX), a low density, low temperature, capacitively coupled plasma device, immersed in a high magnetic field (up to 4 Tesla), we observe the formation of field aligned plasma filaments of various shapes as the ions also get magnetized. Recent studies shed light on the properties of these filaments and show that they emerge as self-organized structures from the background plasma turbulence in MDPX.
October 4, 2024 (Friday) 4:00-5:00p.m.
Location: Small Hall 111
Speaker: Dr. Joseph Reiner
Host: S. Aubin
Title: Nanoparticle-enhanced nanopore detection of ovarian cancer-marking peptides
Abstract: Nanopore sensing provides numerous advantages for single molecule detection. Early efforts focused on the development of DNA sequencing, but more recent work has focused on protein and peptide detection. My lab is exploring the use of cluster-modified nanopore detection to isolate and analyze water soluble peptides up to 2 kDa. Our goal is to develop a single molecule sensor capable of detecting cancer-marking peptides for early onset diagnosis. This talk will provide a background on cluster-modified nanopore detection, its application towards peptide sensing, detection of ovarian cancer marker peptides in urine and preliminary results related to the detection of phosphorylated peptides. Work supported by NSF-CBET 2011173.
October 25, 2024 (Friday) 4:00-5:00p.m.
Location: Small Hall 111
Speaker: Dr. Georg Raithel
Host: S. Aubin
Title: Rydberg atoms in fundamental physics and quantum-technology applications
Abstract: Rydberg atoms, which are atoms with a tenuously bound valence electron, are highly sensitive to external electromagnetic fields and to other atoms. Fundamental work on cold Rydberg atoms and ions includes the study of molecular bonding based on low-energy electron scattering and long-range multipolar interactions, characterization and utilization of trapping forces and A-square transitions afforded by the ponderomotive interaction, high-precision measurement of physical constants, such as the Rydberg constant, and potential QED-style searches for axionic dark matter. I will describe several activities of my group in these areas. Further, recent applications of Rydberg atoms include quantum simulators and quantum information methods, as well as sensors for dc and rf electric fields in vapor cells and in high vacuum. I will present results on Rydberg dc electric field sensing in vapor cells and in high-vacuum cold-ion sources, and on Rydberg level shifts and broadening due to inert buffer gases. Prospects in spectroscopic diagnostics of low-pressure plasma will be discussed.
November 1, 2024 (Friday) 4:00-5:00p.m.
Location: Small Hall 111
Speaker: Dr. Wei Pan
Host: E. Rossi
Title: Quantum enhanced Josephson junction field effect transistor for microelectronics applications
Abstract: Exploration of novel materials and device architectures is warranted, in order to meet the enormous power-consumption demand for computation, information, and communication. Superconducting electronics is promising for low-energy, power-efficient circuit applications. It has been estimated that the powerconsumption of superconducting computing could be at least 10 times lower than the most efficient exascale conventional silicon computing for the same performance.
In this talk, I will discuss our recent work on quantum enhanced Josephson junction field-effect transistors (JJFETs). JJFETs are particularly useful for low power microelectronics applications as, in the superconducting regime, they are operated with zero-voltage drop across their source and drain electrodes. The feasibility of using JJFETs for Boolean logic operations has also been studied. However, in JJFETs with conventional semiconductor channel, the gain factor (~ 0.001 reported) is too small for logic applications. We show that by replacing the conventional semiconductor channel materials with a novel semiconductor material stack such as InAs/GaSb heterostructures that can undergo quantum phase transition the gain factor can be greatly enhanced. We will also discuss several optimization approaches that may ultimately enable a gain factor larger than 1, needed for logic applications.
November 15, 2024 (Friday) 4:00-5:00p.m.
Location: Small Hall 111
Speaker: Dr. Lucian Harland-Lang
Hosts: J. Erlich & J. Qiu
Title: Pinning down proton structure at the LHC and beyond
Abstract: While our current best understanding of particles and their interactions - the Standard Model - has been remarkably successful, it is known to be incomplete, and there is much about it that we still do not understand. By colliding particles at high energy, we can push our understanding of it into new regimes, and even discover new physics that lies beyond it. The LHC is the biggest and most ambitious scientific experiment ever devised and has the potential to test the limits of the Standard Model at an unprecedented level. It is also a proton colliding machine, and hence in order to do this we must first understand the structure of the proton with matching precision and accuracy.
November 22, 2024 (Friday) 4:00-5:00p.m.
Location: Small Hall 111
Speaker: Dr. Joshua Erlich
Title: Randomness in quantum mechanics, gravity, and quantum gravity
Abstract: A mathematical description of nature that includes both quantum theory and general relativity has eluded physicists for over a century. I will summarize some modern attempts towards quantum gravity, with a focus on a framework in which both quantum mechanics and gravity arise as emergent descriptions of a more-fundamental theory. I will conclude with suggestions for how some of these ideas might be tested experimentally.
