Theoretical Studies of Dynamical Quantum Phase Transitions in Non-Equilibrium Interacting Many-Body Systems

Project: Research

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Phase transitions (e.g., when water boils into steam or ice melts into water as the temperature changes) are common phenomena in nature. Under certain external conditions, including temperature and pressure, one phase may be more energetically favourable than another and transformations between different phases occur when the external condition varies. Such transformations are referred to as phase transitions. In the past century, the study of phase transition phenomena in many-body systems at equilibrium has attracted much interest. Today, the subject is relatively well understood and the theories developed for this purpose have uncovered numerous applications across different disciplines. A case in point is the advancement in comprehending superconductivity. In recent years, research on phase transitions has reached the next level. When a quantum many-body system is brought out of equilibrium by, for instance, a sudden change in the system’s internal parameters such as the interaction strength amongst its constituents, new physics can emerge. Non-equilibrium phases and a new type of phase transition, known as dynamical quantum phase transitions (DQPTs), arise. However, theoretical understandings of these phenomena are still far from complete. The overarching goal of this project is to identify the underlying principles and universal patterns of DQPTs using state-of-the-art analytical and computational techniques. This project will seek to answer the following open questions about DQPTs: 1) What criteria are necessary for DQPT to occur and how do the criteria relate to a system’s equilibrium quantum phase transitions; and 2) How can the dynamical order parameter that characterises the transition be determined systematically? The explorations of the fundamentals of DQPT will enable us to better understand the non-equilibrium phases of matter and the dynamics of quantum many-body systems. The insights derived from such examination will not only expand the boundaries of academic knowledge and interest but also lay the groundwork for future technological developments. These prospects hold true, especially in the realisation of a scalable quantum computer, in which the dynamics of quantum many-body systems will play an important role and the non-equilibrium phases of matter may also find an application.


Project number9048185
Grant typeECS
StatusNot started
Effective start/end date1/01/21 → …