Physics Commons^™

Understanding Electronic Structure And Transport Properties In Nanoscale Junctions, Kamal B. Dhungana

Dissertations, Master's Theses and Master's Reports - Open

Understanding the electronic structure and the transport properties of nanoscale materials are pivotal for designing future nano-scale electronic devices. Nanoscale materials could be individual or groups of molecules, nanotubes, semiconducting quantum dots, and biomolecules. Among these several alternatives, organic molecules are very promising and the field of molecular electronics has progressed significantly over the past few decades. Despite these progresses, it has not yet been possible to achieve atomic level control at the metal-molecule interface during a conductance measurement, which hinders the progress in this field. The lack of atomic level information of the interface also makes it much harder …

Study Of Non-Reciprocal Dichroism In Photonic Structures, Anindya Majumdar

Dissertations, Master's Theses and Master's Reports - Open

Non-reciprocal phenomena are widely used in photonic devices. Important applications such as isolators and circulator waveguide structures depend on non-reciprocal effects. The basis of these phenomena is a difference in phase or refractive index for an electromagnetic wave of a given polarization as it travels through a medium in opposite directions. Generally this applies to the real part of the refractive index. The present report addresses a less studied phenomenon in non-reciprocal propagation, namely differences in optical absorption loss for a given polarization state in opposite propagation directions, a phenomenon we have termed non-reciprocal dichroism. Nonreciprocal dichroism can be defined …

A Method For Determining The Mass Composition Of Ultra-High Energy Cosmic Rays By Predicting The Depth Of First Interaction Of Individual Extensive Air Showers, Tolga Yapici

Dissertations, Master's Theses and Master's Reports - Open

Particle accelerators have been used to characterize the properties of particle and subatomic particles. The most advanced particle accelerators built, LHC, can run at 1017 eV. It is not possible with current technology to accelerate particle to the energies that can be detected by cosmic ray observatories.

In the past, by the direct measurements of cosmic rays, scientists discovered sub-atomic particles. Being accelerated to energies higher than 1018 eV, cosmic rays carry important information for particle physics. We have developed a method, which is a combination of Artificial Neural Networks and simple algebraic method that uses parameters from the extensive …

Search For Tev Gamma-Ray Sources In The Galactic Plane With The Hawc Observatory, Hao Zhou

Dissertations, Master's Theses and Master's Reports

Cosmic rays, with an energy density of $\sim1\,\text{eV}\,\text{cm}^{-3}$, play an important role in the evolution of our Galaxy. Very high energy (TeV) gamma rays provide unique information about the acceleration sites of Galactic cosmic rays. The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is an all-sky surveying instrument sensitive to gamma rays from 100\:GeV to 100\:TeV with a 2\,steradian instantaneous field of view and a duty cycle of $>95\%$. The array is located in Sierra Negra, Mexico at an elevation of 4,100\,m and was inaugurated in March 2015. Thanks to its modular design, science operation began in Summer 2013 …