Identifying and Correcting Quantum Systems with Initial System-Environment Correlations

Southern Illinois University At Carbondale, Carbondale IL

Investigators

Abstract

Quantum information processing holds promise for more secure communication, for solving computing problems that can't be solved in a timely manner on classical machines, and for simulating a variety of quantum many-body systems using quantum systems. However, to realize these advances, one needs to understand how quantum systems interact with various environments. This project will aid in the development of quantum technologies by adding to the theoretical approaches that can be used to plan optimum control of quantum systems. In particular, this project will investigate how to avoid errors in quantum computation that arise because of prior correlations between quantum systems and their environment. This is important because understanding how quantum systems behave in various environments will lead to new knowledge in several fields ranging from biological systems, to materials science, fundamental physics, and molecular scale machines. This work could thus enable better health care, better materials for use in industry as well as everyday life, and a variety of technologies that operate on the molecular scale. This project will train students to use quantum physics techniques and to understand the physical concepts. Outreach activities intended to reach a broader audience will also be undertaken as part of this project. In order to achieve reliable quantum information processing we must develop methods for controlling quantum systems. This includes modeling quantum systems that are noisy due to interactions with their environment. A standard method for describing the evolution of open quantum systems is to assume the environment and the system in question are initially decoupled, evolve under some joint evolution, and then average over the environmental degrees of freedom to obtain an effective noisy evolution. This method of modeling the evolution is inadequate under some conditions such as strong coupling and quantum systems that are initially coupled to their environment. The objective of this work is to aid in the development of quantum technologies by helping understand and describe requirements for practical modeling and error prevention strategies in these circumstances by understanding the limitations of previous work and finding ways to describe systems that do not satisfy the standard assumptions. Both theoretical and numerical work will be employed to achieve the results and describe specific examples that are relevant to experiment. 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.