# Trapping ultracold atoms at 100 nm from a chip surface in a 0.7-micrometer-period magnetic lattice

## TL;DR

This paper demonstrates trapping ultracold rubidium atoms in a 0.7 micron-period magnetic lattice on an atom chip, achieving close proximity to the surface and high trapping frequencies, advancing quantum simulation capabilities.

## Contribution

First successful trapping of ultracold atoms in a sub-micron magnetic lattice with detailed analysis of trap lifetimes and limitations.

## Key findings

- Atoms trapped at ~100 nm from surface
- Trap frequencies up to 800 kHz
- Lifetimes limited mainly by surface-induced thermal evaporation

## Abstract

We report the trapping of ultracold 87Rb atoms in a 0.7 micron-period 2D triangular magnetic lattice on an atom chip. The magnetic lattice is created by a lithographically patterned magnetic Co/Pd multilayer film plus bias fields. Rubidium atoms in the F=1, mF=-1 low-field seeking state are trapped at estimated distances down to about 100 nm from the chip surface and with calculated mean trapping frequencies as high as 800 kHz. The measured lifetimes of the atoms trapped in the magnetic lattice are in the range 0.4 - 1.7 ms, depending on distance from the chip surface. Model calculations suggest the trap lifetimes are currently limited mainly by losses due to surface-induced thermal evaporation following loading of the atoms from the Z-wire trap into the very tight magnetic lattice traps, rather than by fundamental loss processes such as surface interactions, three-body recombination or spin flips due to Johnson magnetic noise. The trapping of atoms in a 0.7 micrometer-period magnetic lattice represents a significant step towards using magnetic lattices for quantum tunneling experiments and to simulate condensed matter and many-body phenomena in nontrivial lattice geometries.