arXiv subjects

Jun Hui See Toh

Publications and source records attributed to Jun Hui See Toh.

4 recordsLinked to original sources

arXiv2023

Many-Body Anderson Metal-Insulator Transition using Kicked Quantum Gases

Understanding the interplay of interactions and disorder in quantum transport poses long-standing scientific challenges, with many-body quantum transport phenomena in high-dimensional disordered systems remaining largely unexplored experimentally. We utilize a momentum space lattice platform using quasi-periodically kicked ultracold atomic gases to experimentally investigate many-body effects on the three-dimensional Anderson metal-insulator transition. We observe interaction-driven sub-diffusion and a divergence of delocalization onset time on approaching the many-body phase boundary. Mean-field numerical simulations are in qualitative agreement with experimental observations.

cond-mat.quant-gas↗

arXiv2021

Observation of Many-body Dynamical Delocalization in a Kicked Ultracold Gas

Contrary to a driven classical system that exhibits chaos phenomena and diffusive energy growth, a driven quantum system can exhibit dynamical localization that features energy saturation. However, the evolution of the dynamically localized state in the presence of many-body interactions has long remained an open question. Here we experimentally study an interacting 1D ultracold gas periodically kicked by a pulsed optical lattice, and observe the interaction-driven emergence of dynamical delocalization and many-body quantum chaos. The observed dynamics feature a sub-diffusive energy growth manifest over a broad parameter range of interaction and kick strengths, and shed light on an area where theoretical approaches are extremely challenging.

cond-mat.quant-gas↗

arXiv2019

Feshbach resonances in $p$-wave three-body recombination within Fermi-Fermi mixtures of open-shell $^6$Li and closed-shell $^{173}$Yb atoms

We report on observations and modeling of interspecies magnetic Feshbach resonances in dilute ultracold mixtures of open-shell alkali-metal $^6$Li and closed-shell $^{173}$Yb atoms with temperatures just above quantum degeneracy for both fermionic species. Resonances are located by detecting magnetic-field-dependent atom loss due to three-body recombination. We resolve closely-located resonances that originate from a weak separation-dependent hyperfine coupling between the electronic spin of $^6$Li and the nuclear spin of $^{173}$Yb, and confirm their magnetic field spacing by ab initio electronic-structure calculations. Through quantitative comparisons of theoretical atom-loss profiles and experimental data at various temperatures between 1 $μ$K and 20 $μ$K, we show that three-body recombination in fermionic mixtures has a $p$-wave Wigner threshold behavior leading to characteristic asymmetric loss profiles. Such resonances can be applied towards the formation of ultracold doublet ground-state molecules and quantum simulation of superfluid $p$-wave pairing.

physics.atom-ph↗

arXiv2019

Two-photon photoassociation spectroscopy of the $^{2}Σ^+$ YbLi molecular ground state

We report on measurements of the binding energies of several weakly bound vibrational states of the paramagnetic $^{174}$Yb$^{6}$Li molecule in the electronic ground state using two-photon spectroscopy in an ultracold atomic mixture confined in an optical dipole trap. We theoretically analyze the experimental spectrum to obtain an accurate description of the long-range potential of the ground state molecule. Based on the measured binding energies, we arrive at an improved value of the interspecies $s$-wave scattering length $a_{s0}=30$ $a_0$. Employing coherent two-photon spectroscopy we also observe the creation of ''dark'' atom-molecule superposition states in the heteronuclear Yb-Li system. This work is an important step towards the efficient production of ultracold YbLi molecules via association from an ultracold atomic mixture.

physics.atom-ph↗