Novel Phases and Dynamics of Optical Lattice gases under continuous quantum measurement

Cornell University, Ithaca NY

Investigators

Abstract

Efforts to harness quantum science for the realization of novel materials or quantum computation generally hinge on the ability to create robust quantum systems that are isolated from sources of dissipation and decoherence. In reality, however, all quantum systems are 'open', i.e. they interact constantly with their environment. In most cases, this interaction leads to the destruction of quantum effects. However, there is growing appreciation of how the interplay between quantum dynamics and dissipation can sometimes result in novel and robust nonequilibrium quantum behavior in open quantum systems. This project will examine such behavior. Interestingly, these open systems can exhibit properties that defy conventional descriptions based on central paradigms of symmetry, scale invariance and universality. As a result, the emergent phases and dynamics of such open systems are currently poorly understood and present a challenge that lies at the interface of atomic physics, condensed matter physics and information science. At present, the theoretical activity in this arena stands in stark contrast to the dearth of rigorous experimental studies on open systems. This project will conduct a series of experiments on the phase transitions and emergent phases of a clean, tunable open quantum system consisting of an ultracold gas of atoms interacting with photons. These studies will shed light on universal aspects of open quantum systems and aid in the development of quantum systems that will have applications in quantum metrology and quantum computation. Students that participate in this project will gain experience with research methods and quantum technologies that will help them participate in high tech industry or academic careers. This experimental program aims to shed light on the nature of open, interacting quantum systems in the specific context of an ultracold lattice gas. Building upon this group's recent work controlling the dynamics of optical lattice gases using two-photon imaging techniques, this project will explore the nonequilibrium dynamics and phases of the Bose-Hubbard model in the presence of tunable dissipation and continuous quantum measurements in the form of light scattering. First, this team will extend their studies on the quantum-to-classical transition in a lattice gas in the presence of weak dissipation by studying the influence of many-body interactions, quantum interference and particle indistinguishability on this transition. Next, they aim to realize and explore driven, dissipative transitions and emergent dynamical phases in the lattice gas due to the interplay between quantum coherence, many-body interactions and dissipation. In particular, they propose to realize a metal-to-insulator transition and a many-body localized transition driven by tunable dissipation. These transitions and the resulting emergent phases have close correspondences to various models of quantum percolation and magnetic frustration with hitherto unknown critical behavior. The experimental studies supported by this project promise to shed light on these models and serve as experimental touchstones for broader, more universal descriptions of the phenomenology of open quantum systems.