Collaborative Research: 1D Nanoconfined Helium: A Versatile Platform for Exploring Luttinger Liquid Physics

University Of Vermont & State Agricultural College, Burlington VT

Investigators

Abstract

NONTECHNICAL SUMMARY This award funds a collaborative effort to explore the physics of one-dimensional (1D) systems. Ordinary matter confined in 1D can behave quite differently than in two or three dimensions. Understanding this behavior has become increasingly important as the feature sizes in electronic devices continue to decrease. To explore the effects of confinement in 1D, the research team will use a model system of helium atoms confined in tailored materials with nanometer channels that are only a few atoms wide. This system offers the unique advantage that the interactions of the particles can be varied over a large range: from weak interactions, relevant to trapped atoms used for quantum computing, to strong interactions, as in one-dimensional electronic wires in integrated circuits. Neutron scattering studies which can probe both the structure and motion of the nanoconfined helium will allow the investigators to measure and discover unique physical behavior in one dimension. State-of-the-art computer simulations will be used to perform numerical experiments in tandem with those undertaken in the laboratory, providing an opportunity to test theoretical predictions. This project will also support broad interdisciplinary training of graduate students in sample synthesis and characterization, and in experimental and high-performance computational techniques. In addition, the researchers will develop an online course in Quantum Fluids and Solids, filling an existing curricular gap and engaging with a broad group of students on a topic of fundamental and technological importance. TECHNICAL SUMMARY This award supports joint experimental and theoretical research to explore quantum many-body physics in one spatial dimension using helium as a model system. One-dimensional systems have been of long-standing interest due to a profound difference from their two- and three-dimensional counterparts, whose properties can be described in terms of quasiparticles. This quasiparticle picture breaks down completely in one dimension where the fundamental excitations are collective and described by the universal Tomonaga-Luttinger-liquid (TLL) theory. The research team will develop, optimize, and explore a novel platform for TLL physics. The project consists of tightly coupled experimental and quantum-simulation research to (1) fabricate ordered templated porous materials preplated with rare-gas adsorbates as a confinement platform exhibiting nanometer-scale pores; (2) Perform elastic neutron scattering measurements of the static correlation function; and (3) Carry out inelastic neutron scattering measurements. The main focus of the research team will be on two areas where theory predicts novel new behavior that has not been verified experimentally: (1) static correlations where TLL predicts an algebraic decay in the correlations even though no true long-range order is possible; and (2) the dynamical excitations of the liquid where a particle-hole-like excitation spectrum is predicted independent of the particle statistics. The integration of ab initio simulations with experimental scattering measurements will yield unambiguous confirmation of exotic field theory predictions in the laboratory. This research will develop a deeper fundamental understanding of a model that is not only central to many areas of current interest, but also has technological applications in nanoelectronics, atomtronics, quantum sensing, and quantum-information science. The project will also provide students with broad interdisciplinary training in synthesis and characterization, low-temperature techniques, x-ray and neutron scattering, use of national facilities, as well as field theory and high-performance computation. In addition, the researchers will develop an online course in Quantum Fluids and Solids, filling an existing curricular gap and engaging with a broad group of students on a topic of fundamental and technological importance. 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.