This CAREER award supports theoretical research and education in the dynamics of complex quantum systems away from equilibrium. Recent experimental advances in laser physics have enabled the control of electrons in materials at ultrafast time scales, before they can equilibrate. Likewise, the production of ultracold gases of atoms that are well isolated from their surroundings has enabled the real-time observation of their quantum dynamics. These developments have opened up a new regime of inquiry within quantum mechanics. This research seeks to elucidate complex quantum dynamics in specific settings.
The most unexpected discovery in this context is that even extremely energetic quantum particles can remain spatially localized under a broad range of experimental conditions. This is in striking contrast with usual intuition from classical mechanics: if one rapidly shakes a box full of marbles, they do not stay still. When quantum particles localize, not only do they stay still, but they also become potentially usable for controlled quantum computation. The project aims to clarify the precise conditions under which this localization arises, determine near-term experimental observables, and build towards a complete theory of this poorly understood phenomenon.
On driving the support of a simple pendulum quickly, the effects of gravity can be undone: the pendulum bob can settle in the inverted position above the point of support. Recent experiments in electronic systems suggest that strong laser radiation can similarly stabilize exotic quantum effects, such as superconductivity at short times, in materials which do not normally superconduct. Another aim of the project is to develop a theory of such dynamically stabilized states so as to control and engineer them for computation and other applications.
In addition to mentoring and training graduate and undergraduate students participating in the research program, the PI aims to inspire local middle- and high-school students to explore careers in STEM through "Physics days" involving lab tours, demonstrations, and faculty interactions. Furthermore, this award will support the PI's role in a new public lecture series, which aims to engage the broader Boston community on everyday physics and the frontiers of research. As the future of nonequilibrium physics increasingly relies on physicists with interdisciplinary skills, the PI proposes to develop a new course unifying the approaches to out-of-equilibrium physics in quantum, optical, and biological settings.
This CAREER award supports theoretical research and education in discovering, characterizing, and controlling quantum orders in many-body systems far from equilibrium. Through a multipronged approach that includes studies in model systems, developing general theorems about quantum steady states, perturbation theory and numerical computation, this project proposes to address the following fundamental issues:
1) Strong quenched disorder can indefinitely prevent local equilibration in a well-isolated system, a remarkable phenomenon known as many-body localization. The PI will investigate foundational aspects of many-body localization in higher dimensions, in quasiperiodic settings, and the interplay of localization and topology.
2) Exotic nonequilibrium orders with no equilibrium counterpart can arise in driven quantum systems, offering a unique window into robust quantum coherent many-body phenomena. The PI will discover and classify the complex orders accessible with multitone driving and investigate their stability.
3) Environmental properties are crucial in state preparation and stabilizing fragile topological states. The PI will investigate the properties of unconventional environments, including anyon baths and baths with memory in experimentally relevant systems and extract their universal features.
Remarkable experimental advances in the past decade in the ultrafast spectroscopy of correlated materials and in the construction of well-isolated ultracold atomic and molecular gases have brought real-time dynamics of many-body quantum systems into sharp focus. Concurrently, the quest to build a quantum computer in experimental platforms like superconducting qubits and trapped ions has raised many interesting questions about coherence in driven dissipative systems and has led to a rich exchange of ideas between quantum information theory and condensed matter. Theoretically, the understanding of far-from-equilibrium systems remains challenging because the assumptions underlying statistical mechanics typically fail to apply. The proposed research seeks to broadly advance our understanding of quantum many-body dynamics in closed, driven, and open settings, and to specifically apply it to the observation of novel quantum orders in dynamical settings. The development of new computational methods and the understanding of microscopic time scales in realistic experimental systems will also be a priority.
In addition to mentoring and training graduate and undergraduate students participating in the research program, the PI aims to inspire local middle- and high-school students to explore careers in STEM through "Physics days" involving lab tours, demonstrations, and faculty interactions. Furthermore, this award will support the PI's role in a new public lecture series, which aims to engage the broader Boston community on everyday physics and the frontiers of research. As the future of nonequilibrium physics increasingly relies on physicists with interdisciplinary skills, the PI proposes to develop a new course unifying the approaches to out-of-equilibrium physics in quantum, optical, and biological settings.
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.
