# Events Archive

FPO - Yaqiong Li - "Probing the Cosmic Microwave Background Radiation Using Large Superconducting Detector Arrays"
Thu, Sep 24, 2020, 9:00 am9:00 am
The discovery and measurements of the Cosmic Microwave Background (CMB) radiation have laid the foundation of the current cosmological model, in which the universe is primarily composed of dark energy and dark matter. Higher-precision measurements of the CMB temperature and polarization anisotropies, enabled by installation of larger numbers of…
FPO - Laura Chang - Dark Matter in the Milky Way
Fri, Sep 4, 2020, 11:00 am11:00 am

We have entered a data-driven era of astrophysics and cosmology, providing a wealth of datasets within which to search for the answers to some of the most fundamental open questions in the physics of our Universe. One of these questions is the nature of dark matter (DM)—while there is phenomenal agreement between the theories of DM and the data…

FPO - Kelvin Mei - "A Search for Scalar Top Quarks in Final States with High Jet Multiplicity and a Lepton with the CMS detector at the Large Hadron Collider"
Mon, Aug 31, 2020, 3:30 pm3:30 pm

A search is conducted for scalar top quarks decaying in the Full Run II dataset for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) of 137.2\fbinv collected at a center of mass energy of √s = 14 TeV. The particular models being investigated involve pair production of scalar top quarks decaying either through an R…

FPO - Tong Gao - Thermal Transport Properties of Quantum Spin Liquid Materials
Fri, Aug 28, 2020, 10:00 am10:00 am

Abstract Quantum spin liquids(QSL) have fascinated physicists for nearly half a century since Anderson first introduced this concept with his resonating-valence-bond(RVB) idea in 1973. Although many progresses had been made, more challenges emerge from both theoretical and experimental perspectives. On the theory side, dealing with quantum…

FPO - JaeUk Kim - Hyperuniformity of Point Patterns and Two-Phase Composite Media
Fri, Aug 28, 2020, 10:00 am10:00 am

This dissertation focuses on the generation of certain special disordered systems, as well as general tools that have been developed to characterize their microstructures. Particular attention is devoted to disordered hyperuniform systems, which are ex- otic amorphous states of matter that lie between crystals and liquids. In the first part of…

FPO - Zheng Ma - "Generation and Structural Characterization of Non-Hyperuniform and Hyperuniform Disordered Systems"
Thu, Aug 27, 2020, 11:30 am11:30 am

This dissertation focuses on the generation of certain special disordered systems, as well as general tools that have been developed to characterize their microstructures. Particular attention is devoted to disordered hyperuniform systems, which are ex- otic amorphous states of matter that lie between crystals and liquids. In the first part of…

FPO - Jiaqi Jiang "Selected problems in quantum field theory in different dimensions"
Mon, Jul 27, 2020, 10:00 am10:00 am
This thesis examines quantum field theories in different dimensions. We investigate three models defined in different dimensions and spacetime backgrounds: the generalized large q Sachdev-Ye-Kitaev (SYK) model in one dimension, the holographic dual theory to the giant Wilson loops in anti-de Sitter space (AdS) of two dimensions, and the field…
FPO - Alexey Milekhin - "Quantum mechanical systems with holographic duals"
Fri, Jul 24, 2020, 11:00 am11:00 am

This thesis is devoted to studying quantum mechanical systems with gravity duals. It is interesting to study holographic correspondence for quantum mechanical systems since we have much more theoretical control over them compared to quantum field theories. At the same time, gravity duals to quantum mechanical systems are quite rich as they can…

FPO - Justin Ripley - "General relativity and its classical modification in gravitational collapse"
Wed, Jul 1, 2020, 11:00 am11:00 am

In this thesis, we describe numerical spherical collapse solutions to a modified gravity'' theory, Einstein dilaton Gauss-Bonnet (EdGB) gravity. Of the class of all known modified gravity theories, EdGB gravity has attracted recent attention due to speculations that the theory may have a classically well-posed initial value formulation and…

FPO - Jingjing Lin "Transport Properties of Topological Chalcogenides under Pressure"
Tue, Jun 30, 2020, 2:00 pm2:00 pm

Magnetic breakdown refers to the tunneling of electrons between distinct orbitals beyond a critical magnetic field. In the past, studies on magnetic breakdown have largely focused on the semiclassical regime, by detecting the interference difference frequencies (usually designated as β − α) in the Shubnikov-de Haas or de Haas-van Alphen…

FPO - Luca Iliesiu - "On Two-Dimensional Quantum Gravity"
Fri, Jun 26, 2020, 1:00 pm1:00 pm

his thesis explores topics in two-dimensional quantum gravity, focusing on the specific model of Jackiw-Teitelboim (JT) gravity and its relation to higher-dimensional black holes (BHs). Such a study is motivated by (i) the fact that JT gravity is a full-fledged theory of quantum gravity and (ii) because problematic features in…

FPO - Sanjay Moudgalya - "New Forms of Ergodicity Breaking in Quantum Many-Body Systems"
Thu, Jun 25, 2020, 11:00 am11:00 am

Generic isolated interacting quantum systems are believed to be ergodic, i.e. any simple initial state evolves to a thermal state at late-times, forming a barrier to the protection of quantum information. A sufficient condition for the thermalization of initial states in an isolated quantum system is the Eigenstate Thermalization Hypothesis …

FPO - Yonglong Xie - "Visualizing emergent phenomena in quantum materials: from Majorana zero mode to many-body correlations"
Tue, Sep 17, 2019, 10:30 am10:30 am

Topology and correlation, fundamental ingredients that often dictate the ground states of quantum matter, leave distinct local electronic fingerprints that can be detected with scanning tunneling microscopy (STM). In this dissertation, we first introduce a unique spin signature of Majorana zero mode (MZM) in atomic chains and present how we…

FPO - Peter Brown - "Probing dynamical quantities in the 2D Fermi-Hubbard model with quantum gas microscopy"
Thu, Aug 1, 2019, 2:00 pm2:00 pm

The recent development of fermionic quantum gas microscopes has enabled studies of cold atom Fermi-Hubbard systems with single-site resolution, revealing a variety of interesting phenomena in regimes which are difficult to access with existing theory techniques. The Fermi-Hubbard model is of great intrinsic interest as a toy model for strongly…

FPO - Ilya Belopolski - "Discovery of Magnetic Topological Crystals"
Thu, Apr 25, 2019, 11:00 am11:00 am

Abstract

Topological phases of matter have established a new paradigm in physics, bringing quantum phenomena to the macroscopic scale and hosting exotic emergent quasiparticles. In this thesis, I demonstrate with my collaborators the first Weyl semimetal, TaAs, using angle-resolved photoemission spectroscopy (ARPES),…

FPO - Jiming Sun - "High Pressure Superionic Ice Phase Diagram"
Thu, Feb 7, 2019, 1:00 pm1:00 pm

Water is one of the most common substances in the universe and is found in many different phases. At extremely high temperature and pressure, water ice forms a superionic phase (SI) in which the water molecules dissociate into ions, with the oxygen ions forming a crystal lattice structure and the hydrogen ions flowing through the lattice like a…

FPO - Vladimir Kirilin - "Higher spin operators in conformal field theories"
Fri, Sep 28, 2018, 11:15 am11:15 am

Abstract

In this thesis we study higher spin operators in conformal field theories with weakly broken higher spin symmetry. Exact higher spin symmetry is known to be very constraining, containing the usual conformal group as a subgroup, and…

FPO - Bin Xu "Protein Phase Separation In and Out of Cells"
Fri, May 4, 2018, 2:00 pm2:00 pm