Xiantao Li's Group, Department of Mathematics, Penn State University
Quantum computing harnesses unique properties of quantum mechanics, such as entanglement and superposition, to offer capabilities exceeding conventional supercomputers. Our overarching objective is to devise rigorous, efficient quantum algorithms tailored for scientific computing, addressing problems that remain intractable for classical methods.
We develop efficient quantum circuits to implement the unitary evolution U = e-iHt. These algorithms serve as the fundamental building blocks for simulating quantum dynamics and solving ground state problems in chemistry and physics.
Real-world quantum devices are inherently noisy. We design algorithms to simulate Lindblad master equations and non-Markovian dynamics, bridging the gap between ideal theoretical models and current NISQ hardware.
We apply quantum algorithms to Density Functional Theory (DFT) and electronic structure problems. Our goal is to enable first-principle calculations that predict material properties with precision surpassing classical approximations.
We create quantum solvers specifically designed for high-dimensional Partial Differential Equations (PDEs). Our work utilizes techniques like Schrödingerisation to map classical fluid and wave dynamics onto quantum processors.
We construct Quantum System Identification methods. Using measurement data, these algorithms infer Hamiltonian interactions and dissipative parameters, enabling better calibration and control of quantum devices.
We leverage quantum walks and amplitude amplification to accelerate Markov Chain Monte Carlo (MCMC) methods. Our algorithms aim to reduce mixing times and improve sampling efficiency for complex optimization landscapes.
To address hardware noise, we develop rigorous mathematical frameworks for error mitigation. This includes Non-Markovian Quantum Error Mitigation (QEM) and the theoretical analysis of Zero-Noise Extrapolation (ZNE) using polynomial extrapolation methods.
Our work focuses on the convergence of hybrid quantum-classical algorithms. We proposed the random coordinate descent method, analyzed hybrid convergence, and developed Hamiltonian diagonalization algorithms for fast-forwarding dynamics.
We have developed unitary dilation frameworks for simulating Linear Stochastic Differential Equations (SDEs). These methods allow for the rigorous propagation of 2nd-order statistics and the simulation of diffusive dynamics directly on quantum circuits.
Professor, Penn State
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