Rahul Trivedi [MPQ]

Title: A quantum-information-theoretic viewpoint of open quantum systems

Abstract: Many-body systems interacting with an environment describe a wide range of experimentally relevant systems, ranging from quantum-information-processing devices, quantum-optical systems as well as systems in condensed matter and high-energy physics. In particular, due to their implication on quantum computation and simulation, understanding the complexity of such systems has recently become a question of central importance. I will provide an overview of our work on developing an understanding of many-body open quantum systems by answering two questions:

What kind of states can be prepared by using open system dynamics? Here, I will show that universal quantum computation can be performed with open systems in 1D and 2D. Furthermore, I will also show how open systems can be used to prepare tensor network states in 1 and higher dimension in exactly logarithmic time, including certain states where no known unitary protocol matches the same preparation time. What is the quantum/classical resourced required to simulate open quantum systems? Here, I will present our work on developing near-optimal quantum algorithms to simulate open quantum systems under certain smoothness assumptions on the system-environment model. I will also review our work on developing provably efficient classical algorithms for simulating the high-dissipation limit of open system models.