CAREER: Controlled nonequilibrium dynamics of quantum matter and machines

Western Washington University, Bellingham WA

Investigators

Abstract

NONTECHNICAL SUMMARY This CAREER award supports research and education on the controlled dynamics of quantum systems and devices, with applications to quantum information processing. Quantum technology is still in its infancy, but rapid developments are underway. On the theoretical side, fundamental questions need to be addressed regarding how to control the dynamics of quantum systems, as well as the effects of noise and environment. The PI and his group will pursue research to uncover critical characteristics of intricately controlled dynamics of quantum states. An example is determining how best to control the time dependence of an initial quantum state to prepare a desired quantum mechanical state. Theoretical insights gained will be applied to simulating on quantum computers problems that are intractable on traditional modern computers, including simulating complex quantum materials. The PI will focus on quantum computers based on superconducting qubits, which harnesses a state of matter where the electrons in some materials at sufficiently low temperature can collectively behave quantum mechanically. The PI will also explore the development of robust methods and algorithms for computing on another platform that harnesses a different many-electron quantum mechanical state that offers reduced susceptibility to noise based on topological properties of materials. The research project involves condensed-matter physics and quantum information science and will contribute to the development of efficient quantum software for near-term quantum computers. The research will be performed with undergraduate students and postdocs, helping to develop the workforce in the emerging area of quantum science and technology, and providing a broad range of career opportunities. The education and outreach component of the project will reform and expand the quantum course offering at the PI's institution, develop innovative educational material on undergraduate-level quantum information and computation, and involve local high school and community college students in quantum science. TECHNICAL SUMMARY This CAREER award supports research and education on the fundamental characteristics of controlled nonequilibrium quantum dynamics and its application to the simulation of strongly correlated quantum systems. One promising near-term approach, known as the variational quantum algorithm which suffers from a large number of variational parameters, and the absence of suitable ansatzes for the variational protocols. This project will investigate the use of quantum optimal control theory to overcome these challenges to the use of the variational quantum algorithm. The objectives of the research are to: (i) discover the salient qualitative, quantitative, and universal features of the optimally controlled quantum dynamics of many-body systems, such as speed limits, patterns in the optimal dynamical protocols, and the evolution of entanglement and correlations. (ii) further develop the theory of noise-driven quantum systems and use stochastic driving as a resource for creating desired states. (iii) devise practical ways of simulating strongly correlated many-body models of fermions and spins with superconducting qubits. (iv) engineer fast and robust schemes, based on optimal control, for quantum information processing with topological anyons, which beat the adiabatic performance barrier. The PI will utilize Monte Carlo simulations, Pontryagin's theory of optimal control, theoretical methods for strongly correlated systems, and the density-matrix renormalization group to achieve these objectives. The education and outreach activities are aimed to reform and expand the upper-division quantum-mechanics sequence at the PI's institution, create an accessible undergraduate-level course on quantum computing, develop and disseminate hands-on student-centered teaching material, and give outreach presentations on quantum research at local high schools and community colleges. The project involves undergraduate students in authentic quantum research, contributing to workforce development in this field. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.