Journal Article

Unitary p-wave interactions between fermions in an optical lattice

Bilitewski, Thomas, Thywissen, Joseph H., Rey, Ana Maria, Fujiwara, Cora J., D’Incao, Jose P., Venu, Vijin, Xu, Peihang, Mamaev, Mikhail, Corapi, Frank

2023

Overview

Exchange-antisymmetric pair wavefunctions in fermionic systems can give rise to unconventional superconductors and superfluids 1 – 3 . The realization of these states in controllable quantum systems, such as ultracold gases, could enable new types of quantum simulations 4 – 8 , topological quantum gates 9 – 11 and exotic few-body states 12 – 15 . However, p -wave and other antisymmetric interactions are weak in naturally occurring systems 16 , 17 , and their enhancement via Feshbach resonances in ultracold systems has been limited by three-body loss 18 – 24 . Here we create isolated pairs of spin-polarized fermionic atoms in a multiorbital three-dimensional optical lattice. We spectroscopically measure elastic p -wave interaction energies of strongly interacting pairs of atoms near a magnetic Feshbach resonance. The interaction strengths are widely tunable by the magnetic field and confinement strength, and yet collapse onto a universal curve when rescaled by the harmonic energy and length scales of a single lattice site. The absence of three-body processes enables the observation of elastic unitary p -wave interactions, as well as coherent oscillations between free-atom and interacting-pair states. All observations are compared both to an exact solution using a p -wave pseudopotential and to numerical solutions using an ab initio interaction potential. The understanding and control of on-site p -wave interactions provides a necessary component for the assembly of multiorbital lattice models 25 , 26 and a starting point for investigations of how to protect such systems from three-body recombination in the presence of tunnelling, for instance using Pauli blocking and lattice engineering 27 , 28 . The authors measure elastic p -wave interaction energies in pairs of fermionic atoms occupying the lowest two orbitals of an optical lattice; isolation of individual pairs of atoms protects against three-body recombination, enabling a theoretical maximum of interaction energy to be achieved.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 639/766/119/999 / 639/766/36/1125 / Energy / Fermions / Humanities and Social Sciences / Magnetic fields / multidisciplinary / Optical lattices / P waves / Recombination / Science / Science (multidisciplinary) / Symmetry / Wave interaction