We might be past the worst of the cold, but it will still be cold enough to stay in tomorrow.  Why don’t you come say HI during Physics Table?  12:25, Tuesday the 16th!

Amelia Broman                                                                                                                                                      Wednesday, February 17 2021                                                                                                                       4:20 pm on Zoom

Radiation Detection for Nuclear Security 

Nuclear power presents a potentially attractive alternative to fossil fuels, but its implementation raises an international security question — how can we prevent nuclear materials from being secretly diverted for the purpose of building a nuclear weapon? Nuclear safeguards, implemented by the International Atomic Energy Agency (IAEA), aim to mitigate this risk through a broad set of legal and technical methods. A key component of this strategy is the detection of radiation.   My talk explores the use of radiation detectors to assay plutonium and uranium materials for safeguards purposes. I will examine the physics behind how IAEA inspectors verify the contents of two common items in the nuclear fuel cycle — a plutonium dioxide canister and a uranium hexafluoride cylinder. To do this, I will investigate the inner workings of two types of detectors, the gas-filled proportional counter for neutron detection and the semiconductor detector for gamma ray detection. My talk will piece together a fascinating physics puzzle: how can we determine the radioactive contents of a container without ever looking inside?

Charlie Bushman                                                                                                                                                   Friday, February 19 2021                                                                                                                           4:20 pm on Zoom

Quantum Reservoir Computing

Reservoir computing is a subclass of machine learning wherein a high dimensional, nonlinear neural network, the reservoir, transforms input data to a space in which it can be linearly classified by a single output layer. Over the last decade, physical systems which meet certain criteria — having complex nonlinearity, high dimensionality and the echo state property — have been implemented as reservoirs, harnessing the natural complexity of their dynamics to reduce computational complexity on computers. Two example reservoirs which we investigate are an ensemble of coupled mechanical Duffing oscillators and a recurrent quantum circuit that couples transmon qubits on one of IBM’s cloud-based quantum computers. While this is still a relatively new field, the potential for chaotic systems prediction, smart physical sensors and more is potentially revolutionary across a wide range of sciences and industries.

Gregor Dairaghi                                                                                                                                                     Monday, February 22 2021                                                                                                                        8:30 am on Zoom

Graphene: Properties and Smartphone Applications

Graphene, the atom-thin equivalent of the graphite found in pencil lead, is often touted as a futuristic wonder material set to revolutionize modern technology. With a wide range of superlative mechanical, electronic, optical, thermal, and chemical properties, it is no wonder people are excited about its uses.Since its Nobel prize-winning discovery in 2004, people have been proposing potential applications of graphene in fields as wide-ranging as electronics, aerospace engineering, water purification, pharmaceuticals, biotechnology, and more. The media hype surrounding graphene has led some to wonder how and when graphene will be successfully commercialized, if ever. In this talk I will introduce some of graphene’s most notable properties through a careful consideration of its unique crystal structure. Following will be a discussion of how to take advantage of these properties, focusing on smartphone technologies including graphene-based transistors, touchscreens, Li-ion rechargeable batteries and heat management films. While there are challenges facing each of these technologies, graphene may soon be a common component in all of our mobile devices.

Do you have questions about physics courses next term? Do you want to know more about the department and the major? Do you just feel like hanging out with two cool physics majors? Gregor and Freja are hosting SDA office hours on 7th Tuesday 2/16 8:30-9:30pm and 7th Sunday 2/21 1-2pm in gathertown’s virtual ground state. See you there!