Novel phenomena in Coulomb coupled Luttinger liquids

Non-technical Abstract: Current flowing in a wire can induce electron movement in the adjacent wire. The naive expectation is that the electron motion will mirror the direction of the current. However, recent findings in quantum wires have revealed that these systems can sometimes behave like a diode, allowing electrons in the nearby wire to move in only one direction, regardless of the current's direction. By studying this effect in detail, the research team aims to deepen our fundamental understanding of electron-electron interactions in one-dimensional systems. This knowledge could pave the way for the development of heat-harvesting devices and the discovery of novel quantum phases of matter. Additionally, the project offers valuable opportunities for educating and training undergraduate and graduate students in quantum devices, nanodevice fabrication, and cryogenic operations. It also promotes careers in quantum science and technology at the University of Florida. TECHNICAL SUMMARY: The project aims to investigate interactions between quasi-one-dimensional quantum wires coupled at the nanoscale using Coulomb drag measurements. While electron-electron interactions in individual Tomonaga-Luttinger liquids are well understood, the physics of Coulomb-coupled Tomonaga-Luttinger liquids remains less established. This project seeks to map the phase space of various drag-inducing mechanisms by examining the dependence of one-dimensional Coulomb drag on magnetic field, interwire separation, and disorder. Special emphasis is placed on studying Coulomb drag in the spin-polarized regime and on exploring the recently observed non-reciprocal contribution to 1D Coulomb drag, which is identified through measurements with reversed drive current directions. Furthermore, by quantifying the strength of electron interactions in 1D wires with proximity-induced superconductivity, the project addresses a key question regarding the fate of superconductivity in strongly interacting one-dimensional systems. Both laterally and vertically coupled quantum wire devices will be employed to achieve these objectives. The outcomes will expand our understanding of TLLs in closely coupled systems—particularly their magnetic field dependence—and pave the way for engineering next-generation quantum devices for heat harvesting and topological superconductivity. In addition, the project provides valuable opportunities for educating and training undergraduate and graduate students in quantum devices, nanodevice fabrication, and cryogenic operations. It also supports the promotion of careers in quantum science and technology at the University of Florida. 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.