Many-Body Localization in a Quasiperiodic System with a Mobility Edge

Project: Research

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Quantum technology, such as quantum computation, quantum cryptography, and quantum simulation, is likely to become one of the driving force for the development of human society in future. Such technologies have enormous potentials because they can achieve goals far beyond today's classical computer power. Recently, Google has announced that it has reached the first milestone towards such quantum supremacy. As a result, competitions on building infrastructures for future quantum technology has become increasingly important.One of the fundamental requirements for future quantum technology is that quantum information must be stored and coherent manipulated for an extended period of time. However, this is impossible for generic quantum many-body systems, because they will generally relax towards the state of thermalization (which we will call an `ergodic' system) under its own dynamics. As a result, any quantum information stored in the initial states will quickly become lost and can no longer be recovered by local measurements. One of the conventional solutions to this problem is to use the ground states of a quantum many-body system, which can be non-ergodic despite that the majority of the energy spectrum consists of ergodic eigenstates. The downside of this conventional solution is that it is not always easy or even practical to prepare a macroscopic quantum system in its ground states. Often, the most accessible states in the experiments are the highly excited states in the middle of the energy spectrum.Recently, people have realized that disorder may provide an alternative solution for us. In particular, an isolated interacting many-body quantum system can generally break ergodicity if strong quenched disorder is present. This phenomenon, now known as many-body localization (MBL), has attracted enormous interest in the research community because all eigenstates in the energy spectrum break ergodicity. Thus, quantum information stored in a generic initial state may be retained for an arbitrarily long time, which presents a great potential for quantum information storage and manipulation.In this work, we will study many-body localization in a quasiperiodic system, which is one of the most realistic platforms for MBL experiments to date. We will address outstanding challenges faced in current experiments, analyze how the phase transition between thermal and MBL phases occur, and also search for possible other novel quantum phases of matter in such out-of-equilibrium systems. During this project, we will also apply and develop new machine learning methods to analyze this type of novel quantum phases.


Project number9048186
Grant typeECS
Effective start/end date1/01/21 → …