Reducing circuit depth of commuting Pauli Strings diagonalization
Abstract: A variety of quantum algorithms employ Pauli operators as a convenient basis for studying the spectrum or evolution of Hamiltonians or measuring multibody observables. One strategy to reduce circuit depth in such algorithms involves simultaneous diagonalization of Pauli operators generating unitary evolution operators or observables of interest. We propose an algorithm yielding quantum circuits with depths O(nlogr) diagonalizing n-qubit operators generated by r Pauli operators.
Universal dynamics of nonequilibrium quantum matter
Abstract: Today’s programmable quantum simulators offer versatile platforms for exploring many-body phases and dynamics in correlated quantum systems. In this talk, we present some new—and surprising—insights into nonequilibrium quantum dynamics inspired by such recent experimental advances. First, we focus on understanding the evolution of closed quantum systems driven through a phase transition, which is crucial for quantum state preparation and adiabatic algorithms.
Quantum-enhanced electric field sensing using 2D Crystals of over 100 Ions in a Penning Trap
Abstract: Utilizing quantum mechanical effects such as entanglement can allow sensors to have sensitivities below those imposed on purely classical states. As an example, our experiment has utilized entanglement of the spin and collective motion of 2D crystals of over 100 ions in a Penning trap to demonstrate a sensitivity to displacements of 8.8 ± 0.4 decibels below the standard quantum limit [Science 373, 673 (2021)].
One-shot quantum information theory and quantum gravity
Abstract: The unification of quantum mechanics and gravity is a major outstanding goal. One modern approach to understanding this unification goes by the name ``holography’’, in which gravity can be understood as an emergent description of some more fundamental, purely quantum mechanical system. In this talk I will describe some recent results in holography that elucidate how this emergence works. A starring role will be played by one-shot quantum information theory.
Photon-Mediated Interactions in Lattices of Coplanar Waveguide Resonators
Abstract: Circuit quantum electrodynamics (circuit QED) has become one of the main platforms for quantum simulation and computation. One of its notable advantages is its ability to facilitate the study of new regimes of light-matter interactions. This is achieved due to the native strong coupling between superconducting qubits and microwave resonators, and the ability to lithographically define a large variety of resonant microwave structures, for example, photonic crystals.
Ultracold Gases in a Two-Frequency Breathing Lattice
Dissertation Committee Chair: Prof. Steve Rolston
Committee:
Prof. Gretchen Campbell
Prof. Nathan Schine
Prof. Ron Walsworth
Prof. Ki-yong Kim
Microscopic and Emergent Dynamics of Quantum Information Flows
Abstract: The past fifty years of scientific and technological progress have clearly highlighted information as a physical resource - one that can be traded for heat, work, and other energetic resources. With the ongoing new wave of quantum-based technologies, understanding the microscopic and emergent dynamics of quantum information in many-body quantum systems has thus become a priority.
Ferromagnetism in the Hubbard Model: Squares, Rings and More
Abstract: Nagaoka ferromagnetism (NF) is a long-predicted example of itinerant ferromagnetism in the Hubbard model and has been studied theoretically for many years. NF occurs when there is one hole in a half-filled band and a large onsite Coulomb repulsion, which does not arise naturally in materials. Quantum dots systems like dopant arrays in Si, can be fabricated with atomically precise complex geometries to create highly controllable systems. This makes them good candidates to study itinerant ferromagnetism in different array geometries.
High Performance Nanophotonic Cavities and Interconnects for Optical Parametric Oscillators and Quantum Emitters
Dissertation Committee Chair: Mohammad Hafezi and Kartik Srinivasan
Committee:
Yanne Chemo
Efrain Rodriguez
Edo Waks
Xiyuan Lu
Towards a Renormalization Group scheme for field theories on loops
Abstract: Theories whose fluctuating degrees of freedom live on extended loops as opposed to points, are abundant in nature. One example is the action obtained upon eliminating the redundant gauge fields in a gauge theory. Formulating a Renormalization Group (RG) procedure for such a theory is an open problem. In this work, we outline a procedure that in principle computes the outcome of coarse-graining and rescaling of such a theory. We make estimates that lead to qualitative agreement with known results of phase transitions in gauge theories and the XY-model.