# 2020 REU Program

### Nonequilibrium and Disorder Properties in Relaxor and Regular Ferroelectrics

**Faculty Advisor**: Eugene V Colla

Relaxors are dielectric materials with short-range ferroelectric order, but which do not develop long range ferroelectric order spontaneously at low electric field. Since the short-range order can re-orient in response to applied fields, they keep those high dielectric and piezoelectric constants over a broad temperature range, allowing them to be used for practical electromechanical transducers in many applications. Some regular ferroelectric like BaTiO3, KH2P04 and KD2PO4 show also some nonequilibrium properties similar to those observed in ferroelectric relaxors. These materials unlike the relaxors undergo the phase transition to long-range ferroelectric state and form the macroscopic domain pattern typical to all other ferroelectric. In the same time below critical temperature they show large low field dielectric susceptibility which cannot be explained by macroscopic domain dynamics. This high dielectric susceptibility state is not equilibrium and is the subject for aging -koll decreasing of the susceptibility in time. This project includes working on sample preparation, and measuring and analyzing dielectric and pyroelectric properties, investigation of ferroelectric domains using polarizing microscope. No prior experience necessary. This is a great hands-on experimental physics opportunity! [Experimental]

### Far-from-equilibrium behavior of ultrarelativistic gases

**Faculty Advisor**: Jorge Jose Leite Noronha, Jr

Boltzmann equation plays a prominent role in understanding the complex non-equilibrium dynamics displayed by dilute relativistic gases. It has applications in many areas of physics including, e.g., the theoretical description of the quark-gluon plasma, neutrino transport in supernovae, and structure formation in cosmology. In this project the student will learn about the physics behind the relativistic Boltzmann equation and its applications in the early universe and in heavy-ion collisions. Numerical solutions will be found (using MATHEMATICA or C++ as programing languages) to understand how the assumptions regarding the microscopic interactions in the gas affect its macroscopic evolution and determine its path towards thermal equilibrium. [High energy nuclear theory]

### An Investigation in Quantum Nonlocality

**Faculty Advisor**: Eric Chitambar

Quantum nonlocality is a highly non-classical feature of multi-part quantum systems. Recently much work has been devoted to understanding nonlocality as a resource in quantum information processing. A basic and challenging question arises as to which quantum states can generate nonlocal correlations by local measurements, and which always yield measurement statistics that can be simulated by a local hidden variable model. In this research project, the student will first learn the basic definitions and mathematical properties of Bell inequalities and quantum nonlocality. One research goal will then be to find quantum violations of Bell Inequalities in different scenarios. This research will involve performing both analytical calculations using pen and paper along with numerical optimizations. [65% Theory/ 35% Computational]

### Topological networks of coupled mechanical oscillators

**Faculty Advisor**: Bryce Gadway

This project involves the use of arrays of coupled mechanical oscillators for the engineering of new types of artificial "materials" with designer properties related to nontrivial topology, kinetic frustration, and disorder. The student will learn ideas from the areas of quantum simulation and condensed matter physics, will gain experience in experiments involved mechanical networks, lasers and optics, electronics, using Labview for experimental control, and modeling based on theory/computation. [Hybrid of experimental/computational]

### Rare-earth atoms in solids for quantum light-matter interfaces

**Faculty Advisor**: Elizabeth Goldschmidt

Quantum light-matter interfaces are a vital component in optical quantum information systems. Reversibly mapping quantum information between light and atoms or coherent atom-like emitters is a major challenge in the field. We work with rare-earth atoms in solids due to their excellent coherence properties and potential for integration with photonic systems. We use optics, lasers, cryogenic systems, rf and microwave electronics and a variety of other experimental tools, but no prior experience is necessary. Some familiarity with python is helpful for the experimental control, but not required. [Primarily Experimental]

### Cosmology from Above the Clouds

**Faculty Advisor**: Jeffrey P Filippini

Our group develops and uses novel instruments to tease out new details of fundamental physics and cosmic history from astrophysical observations. We are currently preparing hardware and software for the second flight of SPIDER, an ambitious instrument using cryogenic detectors to observe the cosmic microwave background - the afterglow of the Big Bang - from a balloon high above the Antarctic ice. We are also involved in development efforts for future ground, balloon, and space-based instruments. There are several possible student projects, including hardware construction and characterization and design simulations for future instrumentation. No specific skills are required, but some computer experience (especially in python) is useful. [Experimental]

### Determining the Rules of Life for a Minimal Cell

**Faculty Advisor**: Zaida Ann Luthey-Schulten

The minimal cell, JCVI-syn3A, represents a new paradigm for the role of stochasticity in cellular functions. It was synthesized at the J. Craig Venter Institute (JCVI), contains the smallest bacterial genome to-date (493 genes), yet is capable of carrying out all essential cellular functions including cell division within 100 minutes. We aim to use this “model” organism to determine the rules of life for a minimal bacterial cell. The goals of this research and the associated REU projects are to identify the basic principles of life. To accomplish these goals requires the analysis of several factors and events occurring in a population of minimal cells over the average 100 minute cell cycle. A partial list includes: What are the noise-contributions to the cellular functions of metabolism, genetic information processing and cell division? What percentage of cells have a high fraction of near zero-mRNAs for genes with low expression? Is there a scaling law between transcription of genes and volume? What is are the correlations between the function and timing of the various cellular networks? Can low resolution models of the physical cell be combined with the chemical networks using grand canonical simulations? Many of these questions can be probed with our computational model of the minimal cell and validated with further experiments being performed at CPLC while others require the development of new statistical mechanical treatments to bridge the multiple scales and processes. The 2019 REU student working in the Luthey-Schulten laboratory was one of the co-authors of the Frontiers 2019 article in which he modeled the stochastic processes that initiated DNA replication in the minimal cell. He learned to carry out stochastic simulations using the direct Gillespie method implemented into our Lattice Microbe software. REU students should have a knowledge of statistical mechanics, kinetics, and a computational methodology such as python. They will learn to present their results using Jupyter Python notebooks which allow them to be easily shared with experimentalist. [Primarily computational and theoretical with integration of experimental data]

### Visualizing many-body elecronic wave functions

**Faculty Advisor**: Lucas K. Wagner

The way almost everything in everyday life behaves is determined by the quantum behavior of electrons interacting with each other. Using high performance computing, it is possible to simulate the behavior of the electrons to very high accuracy, but it is challenging to understand what exactly the electrons are doing, since there are hundreds or thousands of them operating collectively. You will use Python and visualization tools to understand how electrons behave in reality. You'll learn about quantum mechanics, and learn how to present information taken from very high dimensional data. [Primarily Computational]

### Design and fabrication of low-energy pyroelectric THz detectors and 3D printed THz filters

**Faculty Advisor**: Fahad Mahmood

This experimental project consists of designing and fabricating pyroelectric detectors for sensitive detection of low energy (0.2 to 3 THz) radiation. This will involve electronic circuit design, learning about electro-optic systems and establishing calibration procedures for the new detector. The student will also look into ways to implement the detector with a ultra-high vacuum (UHV) system. In addition, the student will use electromagnetic simulation software such as comsol to model various metamaterial structures to act as THz band-pass filters. The student will then use 3D printing techniques such as micro-lithography to realize these filters and will work with graduate students to test them. [Primarily Experimental]

### Development of a Zero Degree Calorimeter for the ATLAS Experiment at the LHC

**Faculty Advisor**: Matthias Grosse Perdekamp

The ATLAS experiment at the Large Hadron Collider at CERN uses collisions of protons and Pb-ions to discover fundamental building blocs of matter and to study their interactions. The ATLAS Zero Degree Calorimeter (ZDC) observes the non-interacting nuclear fragments from Pb-Pb ion collisions. Through this observation the impact parameter of the nuclear collisions can be determined. The current ZDC operates at radiation doses beyond the levels tolerable by existing detector technology and requires regular repair. Our group is developing a novel calorimeter based on advanced fused silica materials that can be operated continuously under very high radiation exposure. The REU project will focus on R&D for the photomultiplier tubes used to readout the ZDC in the LHC tunnel. [Primarily Experimental]

### sPHENIX Calorimeter Block Evaluation

**Faculty Advisor**: Anne M Sickles, Caroline Kathrin Riedl

Less than a second after the Big Bang, only a hot, dense state of matter, called the Quark Gluon Plasma (QGP), was present in the early universe. In order to study the QGP, the sPHENIX detector is currently being constructed and UIUC is producing its electromagnetic calorimeter (EMCal) blocks. The EMCal blocks consist of scintillating fibers embedded in a mix of tungsten powder and epoxy. Over 6000 blocks will be produced and tested in the next 2-3 years. The block quality control includes tests of density, light transmission, scintillation and dimensions. Additionally, a pre-prototype of the EMCal was tested at the Fermilab Test Beam Facility in 2018. In this project, the student will work on evaluating the blocks, as well as obtaining correlations of their physical properties with existing testbeam data. This project with use provide both hardware experience in the lab and coding (C++) experience. [Primarily Experimental (hardware/software)]

### Finding the smallest droplet of the most perfect fluid

**Faculty Advisor**: Jaki Noronha-Hostler

Using large particle accelerators that collide specs of lead at 99.9999% the speed of light, nuclear physicists can create the tiniest droplets of fluid known to humanity (~10^-22 meters). This tiny fluid is known as the Quark-Gluon Plasma and it has the smallest viscosity of any fluid in nature (essentially the completely opposite of tar or honey). In order to test the limits of the size of this tiny fluid, theorists run relativistic hydrodynamic simulations and compare them directly to experimental observables. In this project, the student will learn about relativistic hydrodynamics and run simulations of this very tiny fluid on high-performance computers. We will make direct comparisons to experimental data at the Large Hadron collider. No previous computational knowledge is required. Throughout the project the student will learn to code in C++ and will learn about relativistic fluids, Big Data statistical analysis techniques, and modern nuclear physics. [Theoretical/Computational physics in high-energy nuclear theory]

### Developing coherence between qualitative and quantitative reasoning in learning physics

**Faculty Advisor**: Eric Kuo

Coherence between qualitative and quantitative reasoning is a powerful tool for physicists. It allows experts to adapt what they know to solve new problems and to recognize errors. However, use of this coherence is not always easy for students, and the complexity of this reasoning could be a source of student difficulties in learning physics. We are developing cognitive models of how students learn to take up the coherence between qualitative/quantitative reasoning as they develop their physics expertise, with the goal of informing new instructional methods for physics education. Researchers on this project can expect to gain a familiarity with current issues in Physics Education Research and experience with modern education research methodologies, such as clinical interviewing, discourse analysis, educational experimental design, and statistical testing. No prior experience is necessary, but an interest in the mechanisms governing how people think and learn is desirable.[Physics Education Research - theoretical & experimental]

### Super-resolution microscopy to capture molecular dynamics in real time in living cells

**Faculty Advisor**: Sangjin Kim

Proteins are essential for life. Often a protein’s function relies on its dynamics, but it is technically challenging to measure protein dynamics, especially in living cells. This project involves using super-resolution microscopy to measure protein dynamics in real-time inside cells. The REU student will use a new super-resolution fluorescence microscopy system and learn about image analysis. This experimental work will be combined with Brownian dynamics simulations to interpret experimental observations. [Experimental]

### Entanglement in Topological States of Matter Protected by Point Group Symmetries

**Faculty Advisor**: Taylor L Hughes

This theoretical project will explore properties of quantum entanglement in topological insulators and superconductors protected by spatial symmetries. We will consider the entanglement entropy and entanglement spectra and use these quantum informational measures to characterize these novel states of matter. We will learn some of the basic theory of topological insulators and entanglement and perform analytic and numerical calculations to study these systems. This project requires one semester of quantum mechanics and will involve numerical calculations so an ability to program in either Mathematica, MATLAB, C/C++, or FORTRAN is necessary to participate.

### Nano-electronic devices

**Faculty Advisor**: Nadya Mason

The project involves fabricating and measuring nanostructures such as semiconductor nanowires and layered two-dimensional platelets. These materials are useful for the next generation of nano-electronic devices. The student will use a new nano-manipulator system to control the placement and configuration of nanowires and nano-plates. The student will study the devices using advanced tools such as atomic force microscopy and scanning electron microscopy. In addition, the student will work with a graduate student to perform electrical transport measurements on these devices. [Experimental]