Seminars

(Oct. 14, 2pm) Dr. Yao Wang, Emory University. Location: Howey N110.

Title: Spectral Witness of Entanglement for Quantum Materials

Abstract: The rapidly advancing field of quantum materials demands increasingly precise methods for characterizing and controlling entanglement. While early progress was made in quantum optics, extending these approaches to complex many-body systems in quantum materials remains a major challenge. In this talk, I will introduce the entanglement witness framework for characterizing the bounds of entanglement depth using solid-state spectroscopies. In the first half of the talk, I will begin with the detection of spin entanglement in quantum magnets through the quantum metrology and spin quantum Fisher information (QFI). These metrics can be accessed via inelastic neutron scattering and resonant inelastic x-ray scattering (RIXS). Importantly, RIXS provides a route to extend such probes far out of equilibrium, enabling the control of entanglement with light. In the second half of the talk, I will move beyond entanglement among distinguishable local modes to explore entanglement in systems of indistinguishable fermions. I will present a generalized framework for multi-particle entanglement among electrons, based on the cumulant reduced density matrix and the nonlinear response characteristics of RIXS. In the end, I will briefly discuss the potential connections of these entanglement witnesses to sensing and transport techniques.

(Oct. 24, 11am) Dr. Yuan Liu, North Carolina State University. Location: Howey N201/202.

Title: Quantum Computing with Qubits and Oscillators

Abstract: Quantum computing with discrete-variable (DV, qubit) hardware is rapidly approaching the scales required for computations beyond the reach of classical methods. Separately, platforms with native continuous-variable (CV, oscillator) systems have emerged as promising alternatives. In this talk, I will introduce a new hybrid CV-DV quantum computing paradigm that combines the strengths of both architectures, and highlight novel quantum algorithms and applications enabled by them. I will start with the qubit land, and present novel state preparation and dynamics simulation algorithms with application to quantum chemistry and beyond. This includes the first benchmarking study of a novel quantum embedding algorithm on real quantum hardware. I will then switch to hybrid CV-DV, and begin with a pedagogical overview of CV-DV processors, their instruction set architectures, and universal programmability. I will then present a variety of new hybrid CV-DV algorithms and applications, including the extension of quantum signal processing concepts to CV-DV systems and strategies to simulate systems of interacting spins, fermions, and bosons. These developments together open new frontiers for quantum simulation and computation for challenging problems across science and engineering. I will conclude with open questions and future opportunities.