Spring 2020

Dissertation Committee Chair: Prof. Christopher Monroe 
Committee: 
Prof. Christopher Jarzynski, Dean’s RepresentativeProf. Gretchen CampbellProf. James WilliamsProf. Norbert Linke
 
Abstract:

Dissertation Committee Chair: Professor Victor Galitski

Committee:
Professor Christopher Jarzynski
Professor Gretchen Campbell
Professor Jay Deep Sau
Professor James Williams

Abstract:

Gauge theories are the back-bone of our understanding of nature at the most fundamental level as captured by the standard model. Despite their elegance and conceptual simplicity, gauge theories have historically represented a major computational challenge in many-body theory - including, for instance, the real-time dynamics describing heavy-ion collisions at colliders, which is inaccessible to classical simulations based on Monte Carlo sampling.

Prethermalization has been extensively studied in systems close tointegrability. We discuss a more general, yet conceptually simpler, setup forthis phenomenon. We consider a--possibly nonintegrable--reference dynamics,weakly perturbed so that the perturbation breaks at least one conservationlaw. We argue then that the evolution of the system proceeds via intermediate(generalized) equilibrium states of the reference dynamics. The motion on themanifold of equilibrium states is governed by an autonomous equation, flowing

Engineering coherent systems is a central goal of quantum science and quantum information processing. Point defects in diamond known as color centers are a promising physical platform. As atom-like systems, they can exhibit excellent spin coherence and can be manipulated with light. As solid-state defects, they can be produced at high densities and incorporated into scalable devices. Diamond is a uniquely excellent host: it has a large band gap, can be synthesized with sub-ppb impurity concentrations, and can be isotopically purified to eliminate magnetic noise from nuclear spins.

This talk will review applications of quantum simulators that make use of machine learning techniques. Snapshots of many-body states obtained from quantum gas microscopes can be used to perform hypothesis testing using convolutional neural networks. The application of this technique to the Fermi Hubbard model has demonstrated that geometrical string model provides a better description of the experimental data than the pi-flux RVB model. I will also discuss the idea of combing quantum simulators with machine learning to perform inference of NMR spectra for small biological molecules.

Time-reversal symmetry is a defining property for wave phenomena in linear stationary media. However, broken time-reversal symmetry is required for producing essential nonreciprocal devices like isolators, circulators, and gyrators. Magneto-optic methods can enable nonreciprocal behavior for electromagnetic waves, but this approach does not readily translate to the microscale or for atomic-PNT technologies, compelling us to search for nonmagnetic solutions.

Pioneered by topological insulators and semimetals, topological states of matter have shaped a significant part of contemporary condensed matter physics, and have largely branched out into adjacent fields such as photonics, mechanics, and other metamaterial setups. Recently, the frontier has shifted to topological systems which embody enrichments such as non-Hermiticity and non-linearity.

"Mana" is a measure of the degree to which a state cannot be approximated the result of Clifford gates; consequently, it can measure both the difficulty of state preparation on a quantum computer, and the degree to which entanglement is non-Bell-pair. I will show numerical calculations of the mana of ground states of the one-dimensional Z3 Potts model, chosen for convenience, in which we find that the mana is extensive and peaked at the phase transition.

The AdS/CFT correspondence is a concrete instance ofholographic duality, where a bulk theory of quantum gravity in d+1dimensions can emerge from a conformal field theory (CFT) in ddimensions. In particular, we expect the semi-classical spacetime ofd+1 dimensions to emerge from the entanglement patterns of certainquantum states in the CFT. Therefore, it is crucial to understand whatkind of states encode such spacetime geometries and how to explicitlyreconstruct these geometries from quantum entanglement. In this talk,