Quantized Nonlinear Transport with Ultracold Atoms

Abstract

In this letter, we propose how to measure the quantized nonlinear transport using two-dimensional ultracold atomic Fermi gases in a harmonic trap. This scheme requires successively applying two optical pulses in the left and lower half-planes and then measuring the number of extra atoms in the first quadrant. In ideal situations, this nonlinear density response to two successive pulses is quantized, and the quantization value probes the Euler characteristic of the local Fermi sea at the trap center. We investigate the practical effects in experiments, including finite pulse duration, finite edge width of pulses, and finite temperature, which can lead to deviation from quantization. We propose a method to reduce the deviation by averaging measurements performed at the first and third quadrants, inspired by symmetry considerations. With this method, the quantized nonlinear response can be observed reasonably well with experimental conditions readily achieved with ultracold atoms.

7 pages, 3 figures, expanded introduction, added an appendix, added new references, accepted by Quantum

References in corpus (5)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Observation of Quantized Conductance in Neutral Matter
• Two-terminal transport measurements with cold atoms
• Quantized Nonlinear Conductance in Ballistic Metals
• Topological Multipartite Entanglement in a Fermi Liquid

Cited by in corpus (8)

• Probing Fermi sea topology by Andreev state transport
• Topological Andreev Rectification
• Topological Density Correlations in a Fermi Gas
• Quantized Topological Response in Trapped Quantum Gases
• Non-Adiabatic Effect in Topological and Interacting Charge Pumping
• Euler--Chern Correspondence via Topological Superconductivity
• Generic reduction theory for Fermi sea topology in metallic systems
• Quantized nonlinear transport and its breakdown in Fermi gases with Berry curvature