Dissertation Defense: Jeffrey Cohn
Candidate Name: Jeffrey Cohn
Advisor: James Freericks, Ph.D.
Title: Exploring Nature with Quantum Simulators and Digital Quantum Computers
Exact simulation of quantum systems is intractable on current classical computers due to the time required to calculate the exponential number of amplitudes which represent a quantum state. This thesis explores how highly tuned quantum devises, such as quantum simulators and digital quantum computers, can be utilized to gain a deeper understanding of nature. In chapter 1 we begin by reviewing some of the basics of quantum information. Chapter 2 highlights the advantages of using entangled states in metrology and how quantum simulators can be realized on a system of trapped ions. Chapter 3 develops the gate model of quantum computing and reviews many of the foundational algorithms needed to simulate many-body systems. Chapter 4 originates from the paper "Verifcation of a many-ion simulator of the Dicke model through slow quenches across a phase transition." This chapter examines how a system of trapped ions can be engineered to emulate a famous model known as the Dicke model, which involves coupling many spins to a single bosonic mode. After confirming that the Dicke model indeed has been realized, we show in Chapter 5 how simple protocols can be used to prepare highly entangled states. This chapter originates from the paper, "Bang-bang shortcut to adiabaticity in the Dicke model as realized in a Penning trap experiment". These states have the potential to provide giant gains in making precision measurements. Finally, with the use of universal quantum computers on the horizon, we develop a framework, in Chapter 6, for extracting thermal properties of many-body systems on these machines. This chapter eminates from the paper "Minimal Elective Gibbs Ansatz (MEGA): A simple protocol for extracting an accurate thermal representation for quantum simulation". Chapter 7 contains the concluding remarks .
Wednesday, April 3, 2019 at 12:15pm to 2:00pm
Regents Hall, 239
3700 O St. NW