Spring 2021

Spring 2021

  • An Introduction to Modern Cosmology

  • Applications of Quantum Optics in Experimental Quantum Information

  • Biophysical Studies of SARS-CoV-2

  • Cavity Optomechanics and Nanomechanical Resonators

  • Classical Mechanics and Symplectic Geometry

  • Deep Learning (as approached by physicists)

  • Electrodynamics of atomic ensembles

  • Introduction to Superconductivity

  • May I take your disorder?

  • Modern Microscopy Techniques in Biophysics

  • Optical Second Harmonic Generation

  • Particle Detectors and Signal Processing

  • Precision Measurement with Atom Interferometry

  • Signal Processing Methods for MEG/EEG Systems

  • The Role of Mathematics in Physics Education Research

  • Quantum Scattering Theory


An Introduction to Modern Cosmology with John Franklin Crenshaw


The "concordance model" of cosmology (Lambda-CDM) has had great success describing the origin, contents, and evolution of the universe. Despite this success, the nature of dark matter and dark energy is still unknown, and divergent measurements of the expansion of the universe (aka the Hubble tension) may be evidence of some deeper problem with the theory. In the first half of this project, the student will learn about the major components of the concordance model, including the Big Bang, the Cosmic Microwave Background, dark matter, the formation of large scale structure, and dark energy. The second half of the project will focus on how modern astronomical surveys measure dark matter and dark energy, as well as the major questions and problems that face the field today.


Requirements: Phys 224, Phys 225, Phys 329

Some basic background in astronomy would be helpful, but not required. The content and difficulty of the project can be adjusted to the student's background and interest, whether they are a new-comer to cosmology, or already have extensive knowledge.

Reading: Modern Cosmology by Scott Dodelson (research guide can provide a copy); various papers on the arxiv



Applications of Quantum Optics in Experimental Quantum Information with Vasilis Niaouris


In recent years, we have seen vast growth in the field of quantum information. Various disparate qubit systems (e.g. trapped atoms/ions, superconducting qubits, solid state qubits etc.) have been developed and optimized to push the limits of quantum technologies, such as quantum computing, quantum sensing and quantum communication. One of the best candidates for transfer of information over long distances are photons. Photon-based quantum technologies can be used as quantum memories and quantum repeaters, quantum processors etc. The goal of this course is to acquaint the student with the fundamental physics behind quantum optics and introduce them to real life experimental applications. Depending on student interest and progress, we will focus on either photon-mediated entanglement or optical quantum memories via electromagnetically induced transparency.


Reading: "Quantum Optics", Scully and Zubairy

Papers: [1] Lijun Ma et al. J. Opt. 19, 043001 (2017)

[2] P. Maunz, D. Moehring, S. Olmschenk et al. Nature Phys 3, 538–541 (2007).


Prerequisites: PHYS 322 (EM 2), PHYS 325 (QM 2)


Biophysical Studies of SARS-CoV-2 with Chris Thomas


With the emergence of the COVID-19 pandemic, many physics labs interested in biological

systems have pivoted their research towards the SARS-CoV-2 virus in hopes of better

understanding the pathogen. Biophysical techniques have proved invaluable in this regard, able

to probe the inner workings of the virus with perspectives outside of biology and biochemistry.

In this project, we will dissect several cutting-edge articles and preprints published in 2020 to

understand the viral mechanisms of SARS-CoV-2 through biophysical techniques such as optical

tweezers, atomic force microscopy, and cryo electron microscopy. Note that because this

content resides at the intersection of many different fields, we will be dealing with a wide

breadth of scientific knowledge including biology and biochemistry.


Reading:

  • Mickolajczyk, K. et al. Force-dependent stimulation of RNA unwinding by SARS-CoV-2 nsp13 helicase. Biophysical Journal. (2020). https://www.biorxiv.org/content/10.1101/2020.07.31.231274v1.full

  • Kokic, G. et al. Mechanism of SARS-CoV-2 polymerase stalling by remdesivir. Nat Commun 12, 279 (2021). https://www.nature.com/articles/s41467-020-20542-0?s=09

  • Yang, J. et al. Molecular interaction and inhibition of SARS-CoV-2 binding to the ACE2 receptor. Nat Commun 11, 4541 (2020). https://www.nature.com/articles/s41467-020-18319-6


Strongly Recommended: PHYS 224 (Thermal), PHYS 429 (Biophysics), any general introductory biology course, any general introductory chemistry course covering biochemistry.



Cavity Optomechanics and Nanomechanical Resonators with Arnab Manna


Cavity optomechanics is the study of interaction between nano(micro-)mechanical systems and light on extremely low-energy scales. It is a highly interdisciplinary field involving quantum optics, solid-state physics and materials science. Possible applications range from novel high-bandwidth mechanical sensing devices through the generation of squeezed optical or mechanical states, to tests of fundamental quantum mechanics. In this project we will first learn the basics of optical microcavities, nano-mechanical resonators and principles of optomechanical coupling, and then explore some fascinating phenomena in strong coupling regime like radiation-pressure cooling and optomechanically induced transparency.


Reading: “Cavity optomechanics” Markus Aspelmeyer, Tobias J. Kippenberg, and Florian Marquardt, Rev. Mod. Phys.(2014); various other papers


Prerequisites: PHYS 324 (Quantum 1), PHYS 321 (E&M)


Recommended: PHYS 325 (Quantum 2)



Classical Mechanics and Symplectic Geometry with John Goldak


Classical mechanics (at the level of Lagrangian and Hamiltonian mechanics) is a surprisingly rich mathematical theory that forms the physical motivation for an area of mathematics called symplectic geometry. Beyond classical mechanics, many mathematically oriented questions in physics, such as how the procedure of quantizing a classical theory into a quantum theory works, can be studied using symplectic geometry. Symplectic geometry offers an excellent starting point for physicists who want to study highly mathematical theories, allowing them the opportunity to start learning much of the geometric machinery used by theoretical physicists. In this project, we will begin by discussing some of the prerequisite pieces of mathematical machinery needed to study symplectic geometry, namely manifolds and differential forms. Next we will apply this machinery to define and study Hamiltonian mechanics and specific topics such as the Hamilton-Jacobi equations and perturbation theory.


Reading: Mathematical Methods of Classical Mechanics, V.I. Arnold (for the math); Lectures on Classical Dynamics, David Tong (for the physics).


Requirements: PHYS 329 (Mathematical Methods and Classical Mechanics), PHYS 227-228 (Math Methods 1-2), some formal mathematical maturity is strongly recommended (proof writing, parsing mathematical statements).


Deep Learning (as approached by physicists) with Olivia Thomas

Whether we like it or not, deep learning is becoming more ubiquitous across all areas of research, including in academic, industrial, and technological fields. In contrast to many of the more traditional machine learning techniques, deep learning lacks a robust theory to explain why it is so successful at learning patterns in complex datasets. In this DRiP course, we will explore how deep learning is being used and studied by physicists. In particular, we will explore how physicists are addressing the "black-box" problem of deep learning. No prior knowledge of machine learning or deep learning is required, as we will start by studying basic machine learning and deep learning algorithms. Depending on the student's coding experience, this course can be hands-on and incorporate some practice in building machine learning algorithms or it can be more theoretically-focused.

Prerequisites: PHYS 228 (Math Methods 2)

Recommended: PHYS 329 (Stat Mech), some experience with Python and/or MATLAB

Readings: Gradient-Based Learning Applied to Document Recognition by LeCun, et. al, Machine learning and the physical sciences by Carleo et. al


Electrodynamics of atomic ensembles with David Rosser

Everything we perceive in the world manifests by an interaction between matter and electromagnetic fields. Motivated by the applications of room-temperature quantum coherent media we will investigate how light interacts with atomic ensembles. Depending on the inclinations of the reader we can also perform simple experiments on a rubidium vapor cell.


Prerequisites: Quantum Mechanics, Electromagnetism, Statistical Physics


Reading: Lectures on Light – Nonlinear and Quantum Optics Using the Density Matrix by Stephen C. Rand


K. Hammerer, A. S. Sorensen, and E. S. Polzik. Quantum interface between light and atomic ensembles. DOI: 10.1103/RevModPhys.82.1041


Introduction to Superconductivity with Eric Anderson


Superconductors are well known for the striking property of perfect DC conductivity, as well as their expulsion of magnetic fields (the Meissner effect). While the direct technological implications of this behavior have been profound, the process of developing a theory of superconductivity has also had broad implications for our understanding of fundamental physics.

During the first part of the course, we will cover the basics of BCS theory, Ginzburg-Landau theory, and the Cooper pairing mechanism. We will then move on to experimental signatures of the Josephson effect and explore the relationship between superconductivity and magnetic order in various device architectures.


Reading: Introduction to Superconductivity by Michael Tinkham, various papers TBD


Prerequisites: PHYS 322 (EM 2), PHYS 325 (QM 2), PHYS 328 (Stat Mech)


Recommended: Solid State Physics


May I take your disorder? with Ryan Lanzetta


The discovery of the quantum Hall effect (QHE), in both its integer and fractional incarnations, has inspired decades of advances in condensed matter physics, particularly in the realm of topological phenomena. At least theoretically, the QHE is produced in a very simple situation: electrons restricted to move in two dimensions subject to external magnetic and electric fields. In the case of the integer QHE, it is striking that disorder––irregularities in the underlying material in which the electrons are restricted––plays a key role in making the precise quantization of the Hall conductance more pronounced. This quarter, we will study the QHE. Through this example, we will also get a taste of how topology plays a role in many-body quantum systems.


Reading: “The Quantum Hall Effect: Novel Excitations and Broken Symmetries” - Steven M. Girvin and “Lectures on the Quantum Hall Effect” - David Tong


Prerequisites: PHYS 324, PHYS 321, PHYS 329



Modern Microscopy Techniques in Biophysics with Isaac Shelby

Form an understanding of microscopy from the ground up. From bright-field microscopy to structured illumination super-resolution, learn the techniques that allow biophysicists to probe the mechanics of cells. Due to the wide nature of the field, and the depth with which any one of these topics can be explored, the exact structure and material covered can be shifted for the interests of the individual student's interests. Potential topics include: fluorescence microscopy, optical aberrations, the mechanics of modern scientific cameras, super-resolution techniques, how to design and build a microscope.

Outline texts (to be supplemented with papers): Principles of Optics - Born and Wolf, Optics - Hecht.

Requirements: Trigonometry and physics 123 or some sort of waves/optics equivalent. Beyond that the more the better, but course structure is adaptable. Knowledge of calculus and some statistics may be useful, but again, not required.


Optical Second Harmonic Generation with Jordan Fonseca

The invention of the laser made it possible to generate intense, directed beams of monochromatic light. Because light has wavelike properties, its optical frequency (color) can be changed when it passes through a material, much like the pitch of a violin’s note can be changed by gently resting a finger on the string. The efficiency with which laser light at a “fundamental” frequency can be doubled to its second harmonic depends sensitively on the material’s crystallographic symmetry, as well as on the relative orientation between the light’s polarization and the crystal axes. Because of the intimate relationship between symmetry and SHG response, the technique can serve as a sensitive optical probe of symmetry and symmetry breaking in materials. We will spend the first part of the course understanding the origin of SHG in materials and build toward theoretically modeling a 2D material’s polarization-resolved SHG response based on its symmetry class.

Reading:

Boyd, Nonlinear Optics, 3rd edition, Ch. 1 & 2

Zernike & Midwinter Applied Nonlinear Optics, Ch. 1, 2, & 5

P. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich, “Generation of Optical Harmonics,” Phys. Rev. Lett. 7, 118 (1961).

Assorted recent papers on SHG characterization of 2D materials, to be chosen based on student interest

Requirements: PHYS 321-323 (E&M I-III)


Particle Detectors and Signal Processing with Heather Harrington

All particle and nuclear physics experiments from CENPA to CERN use particle detectors, but how do these work, what signals do they produce, and how do we turn these into something that we can analyze? In this reading course we will investigate general principles of particle interactions, energy resolution, detection efficiency, and deadtime. We will then read about modern detector technologies including ionization detectors, scintillation detectors and solid state detectors. We will end with reading on aspects of signal processing such as the importance of pulse shaping, counting, and timing.

Reading: G. Knoll - Radiation Detection and Measurement

Requirements: PHYS 321-322, PHYS 324

Recommended: PHYS 226



Precision Measurement with Atom Interferometry with Anna Wirth-Singh

When you think of interferometry, a large-scale experiment like LIGO might come to mind. But you can also do interferometry on a quantum scale, and with ultracold matter taking the role of light beams. Clouds of ultracold atoms, with wave-like properties, can be split and combined yet behave as a single object. This project will delve into how a matter-wave interferometer is produced and the applications of such an interferometer; in particular, for fundamental tests of gravity and quantum electrodynamics. The reading list will include sections of Ph.D. theses and published journal articles.

Reading:

Plotkin-Swing, B.T., 2018. “Large Momentum Separation Matter Wave Interferometry.” University of Washington Ph.D. Thesis. Chapter 1.

Fixler, J.B., Foster, G.T., McGuirk, J.M., and Kasevich, M.A., 2007. “Atom Interferometer Measurement of the Newtonian Constant of Gravity.” Science.

Chung, K.Y., Chiow, S., Herrmann, S., Chu, S., and Müller, H., 2009. “Atom Interferometry Tests of Local Lorentz Invariance in Gravity and Electrodynamics.” Phys. Rev. D.

Suggested but not required: PHYS 324-325 (QM 1-2)


Signal Processing Methods for MEG/EEG Systems with Wan Jin Yeo

Magnetoencephalography (MEG) and electroencephalography (EEG) are non-invasive neuroimaging methods that allow us to measure magnetic fields and electric potentials produced by brain activity. However, the signals measured typically require much processing to be useful due to noise interferences. The inverse problem of finding the current source configuration that produces these signals, which is extremely ill-posed due to the lack of a unique solution, further complicates things. In this reading course, we will first get up to speed with some common/basic forward/inverse modelling of MEG/EEG, then proceed to focus on signal decomposition and representation methods (mostly via multipolar expansions and the like) and/or other relevant topics the student is interested in.

Reading: - Background reading: "Magnetoencephalography -- theory, instrumentation, and applications to noninvasive studies of the working human brain" by M. Hamalainen et. al. Chapters 3-4, maybe 6.

- Other relevant papers thereafter

Recommended: Familiarity with EM and interest in maths.


The Role of Mathematics in Physics Education Research with Charlotte Zimmerman

Quantitative reasoning, or how we make sense of the world through the application of mathematics, is essential to “thinking like a physicist” and therefore at the heart of much of our undergraduate physics curriculum. Recent work in physics education research suggests that physics and mathematics are so cognitively intertwined that they cannot be separated, yet “math in math class” is distinctly different from “math in physics class.” Together, we will explore how mathematics manifests in undergraduate physics curriculum and the education research that is being conducted to better understand how students are using quantitative reasoning and how we can improve our courses. As this topic is being explored at all levels of physics education, from high school through undergraduate quantum mechanics, our direct focus will be determined by the participant’s interest.

Reading:

[1] Sherin, B. L. (2001). How Students Understand Physics Equations. Cognition and Instruction, 19(4), 479–541.

[2] Redish, E. F., & Kuo, E. (2015). Language of Physics, Language of Math: Disciplinary Culture and Dynamic Epistemology. Science and Education, 24(5–6), 561–590.

Requirements: Experience in the subject you would like to explore (i.e. if you are interested in the introductory sequence, all you need is completion of 12X. If you are interested in the linear algebra of quantum mechanics, you’ll need to have completed Phys 324 and 325.)



Quantum Scattering Theory with Roland Farrell

Smashing particles together and observing the outcome offers one of the most direct ways to probe the microscopic world. Important scattering experiments range from the Rutherford gold-foil experiment, which established the structure of atoms, to the discovery of the Higgs at the LHC. This project will focus on building up the mathematical tools and intuition used in analyzing scattering processes. We will start with the Born expansion and partial wave analysis and then use these ideas to learn about bound states and resonances.

Reading: Murayama’s lecture notes on Scattering Theory 1-3. Modern Quantum Mechanics by Sakurai, chapters 3 & 6.

Requirements: PHYS 325 (QM 2), PHYS 228 (Math Methods 2)

Recommended: PHYS 329 (Classical Mechanics)