A DMRG Study of Excitons in the 2D t-J Model
Abstract: Antiferromagnetic materials with microscopic behavior resembling that of the Fermi-Hubbard model are expected to host excitons, or bound electron-hole pairs. In order to investigate such behavior, we have optimized states of the t-J model in the single-particle-single-hole sector using the density matrix renormalization group (DMRG).
QCVV: Making Quantum Computers Less Broken
Abstract: Quantum computing hardware capabilities have grown tremendously over the past decade, as evidenced by demonstrations of both quantum advantage and error-corrected logical qubits. These breakthroughs have been driven, in part, by advances in quantum characterization, verification, and validation (QCVV). I will discuss how QCVV provides a hardware-agnostic framework for assessing the performance of quantum computers; I will describe in detail how specific QCVV protocols (such as gate set tomography and robust phase estimation) have been used to characterize and sig
Electron-Photon Exchange-Correlation Functional in the Weak and Strong Light–Matter Coupling Regimes
Abstract: The intersection of quantum electrodynamics (QED) and density-functional theory (DFT) has opened up exciting opportunities in controlling quantum matter through light-matter coupling. This frontier, however, is beset with computational challenges, especially in the weak and strong coupling regimes. Building upon previous research, we present the results of nonperturbative QED functional in the long-wavelength limit, centered solely on the matter Hilbert space.
TBA 5/2/2024
Abstract: TBA
How to relate quantum position verification to information-theoretic cryptography, and new steps towards practical implementation
Abstract: The task of quantum position verification (QPV) deploys quantum information with the aim to use a party's position as a cryptographic credential. One well-studied proposed protocol for this task, f-routing, involves a mixture of classical information and a single quantum bit that has to be routed somewhere as a function of the classical information.
Quantum Advantage in Sensing and Simulation
Dissertation Committee Chair: Steven Rolston
Committee:
Alexey Gorshkov (co-chair)
Andrew Childs (Dean’s Representative)
Nathan Schine
Michael Gullans
Dynamic codes and quantum computation
Abstract: I will review the concept of Floquet quantum error-correcting codes, and, more generally, dynamic codes. These codes are defined through sequences of low-weight measurements that change the instantaneous code in time and enable error correction. I will explain a few viewpoints on these codes, including state teleportation and anyon condensation, and will explain how to implement gates purely by adjusting the sequences of low-weight measurement.
On the optimal error exponents for classical and quantum antidistinguishability
Abstract: The concept of antidistinguishability of quantum states has been studied to investigate foundational questions in quantum mechanics. It is also called quantum state elimination, because the goal of such a protocol is to guess which state, among finitely many chosen at random, the system is not prepared in (that is, it can be thought of as the first step in a process of elimination). Antidistinguishability has been used to investigate the reality of quantum states, ruling out psi-epistemic ontological models of quantum mechanics [Pusey et al., Nat. Phys., 8(6):475-478, 2012].
Towards Experimental Realization of Topological Floquet Models in Circuit QED
Abstract: Topological band structures are well known to produce symmetry-protected chiral edge states which transport particles unidirectionally. These same effects can be harnessed in the frequency domain using a spin-1/2 system subject to periodic drives.
Collective light scattering in cold atomic ensembles: super-radiance, driven Dicke model and correlations
Abstract: This talk will present our work on the observation of super-radiance in a cloud of cold atoms driven by a laser. We start from an elongated cloud of laser cooled atoms that we excite either perpendicularly or along its main axis. This situation bears some similarities with cavity quantum electrodynamics: here the cavity mode is replaced by the diffraction mode of the elongated cloud. We observe superradiant pulses of light after population inversion.