CAREER: Quantum mechanics far from equilibrium: Matter-wave turbulence

Yale University, New Haven CT

Investigators

Abstract

Non-technical abstract The understanding of equilibrium phases of quantum matter has enormously progressed in the past decades. The tools of statistical mechanics and linear response theory are well suited to understand the equilibrium and near-equilibrium properties of such phases. This general approach has yielded the most important paradigms and technological breakthroughs in condensed-matter physics of the past century. On the other hand, far-from-equilibrium quantum many-body physics is a frontier in modern physics, and the search for novel paradigms and novel dynamic phases of matter is open and very active. Turbulent states - far-from-equilibrium dynamic states of fields characterized by spatio-temporal chaos - are arguably the least understood of the family of non-equilibrium many-body states. The central scientific goal of this project is to develop the nascent field of matter-wave turbulence as a framework to understand such states and generic far-from-equilibrium quantum dynamics problems. Matter waves of ultracold atoms trapped and controlled in programmable optical potentials offer a near ideal platform for this work. Because quantum technologies are playing an increasingly important role in today’s society, the educational component of this project aims at exposing a broader audience to quantum physics, through lectures series, hands-on workshop and more advanced experiments. Technical abstract Far-from-equilibrium dynamics of both classical and quantum fields almost inevitably leads to turbulent phenomena. However, to date turbulence and quantum dynamics are mostly investigated by separate scientific communities. Given the ubiquity of hydrodynamics as an effective theory to describe the long-distance long-time behavior of quantum many-body systems, these topics are bound to intersect more often in the future. This project aims at providing a bridge between these two important themes by developing the field of matter-wave turbulence. The project consists of a web of scientific issues that include the observation of a novel form of condensation formed from the far-from-equilibrium particle flow of an inverse turbulent cascade, the study of quantum effects as source of dissipation in wave-turbulent cascades, and the investigation of the existence of threshold effects in wave turbulence. The experimental platforms for this project are bosonic and fermionic atomic superfluids; new forms of forcing, dissipation and probing of these fluids will be performed by leveraging recent technical advances in the shaping of arbitrary potentials on atoms using programmable electro-optic devices. This work likely provides blueprints to tackle other quantum dynamics problems because the generic picture of wave turbulence as a cascade of excitations could be relevant to the elementary excitations of various quantum many-body systems. 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.