Spring 2023

Abstract: Optical quantum memories can be used for storage or generation and subsequent retrieval of quantum light for the purpose of long-distance quantum communication. However, it is beneficial to consider more functions of quantum memories, which may then become parts of more complex hybrid quantum networks. In my works I have demonstrated protocols for spin-wave processing based on interference in multiplexed optical quantum memories [1,2].

Abstract: In this talk, I will summarise recent theoretical work on understanding nonlinear response functions in systems with interacting quasiparticles.

Dissertation Committee Chair: Prof. Jay D Sau

Committee:

Abstract: In an isolated quantum many-body system undergoing unitary evolution, the entropy of a subsystem (smaller than half the system size) thermalizes if at long times, it is to leading order equal to the thermodynamic entropy of the subsystem at the same energy. We prove entropy thermalization for a nearly integrable Sachdev-Ye-Kitaev model initialized in a pure product state. The model is obtained by adding random all-to-all 4-body interactions as a perturbation to a random free-fermion model.

Circuit QED enables the combined use of qubits and oscillator modes. Despite a variety of available gate sets, many hybrid qubit-boson (i.e., oscillator) operations are realizable only through optimal control theory (OCT) which is oftentimes intractable and uninterpretable. We introduce an analytic approach with rigorously proven error bounds for realizing specific classes of operations via two matrix product formulas commonly used in Hamiltonian simulation, the Lie–Trotter and Baker–Campbell–Hausdorff product formulas.

Dissertation Committee Chair: Professor Maissam Barkeshli (advisor)

Committee: 

Abstract: Trapped ions are a leading quantum technology for quantum computation and simulation, with the capability to solve computationally hard problems and deepen our understanding of complex quantum systems.

Abstract: "In this talk, we discuss a new kind of symmetry that underlies a wide class of driven-dissipative quantum systems, a *hidden time-reversal symmetry*. This symmetry represents a generalization of the notion of “detailed balance” that is fully applicable to truly quantum systems. The introduction of this symmetry resolves the problem of how to usefully define “detailed balance” in a quantum setting (a problem that has been studied since the early 70’s by AMO physicists).

Rhombohedral graphenes host van Hove singularities near the band edge which have been found to host magnetism and superconductivity.  These systems have no no moire superlattice, and a ballistic mean free path far exceeding device dimensions, allowing precise measurements of the interplay of different symmetry breaking orders, including a cascade of half- and quarter metals with broken spin and/or valley symmetry as well as both spin-singlet and spin-triplet superconducting states.  I will provide an overview of the physics of these systems, focusing on some r

Abstract: Interaction between individual photons forms the foundation of gate-based optical quantum computing among other quantum-enabled technologies. Quantum emitter-mediated photon interactions are fundamentally constrained by stringent operation conditions and the available photon wavelength and bandwidth, posing difficulty in upscaling and practical applications.