Neutral atoms can be trapped in microscopic potentials resulting from electromagnetic fields. These microtraps might ultimately be used for quantum information applications. This paper considers generalized measurements on atoms in microtraps.
Electromagnetic trapping of neutral atoms is a new branch of applied physics that has potential for use in very many areas, including metrology and high-resolution precision spectroscopy. It has the possibility of leading toward the spectroscopic ideal of an isolated atom at rest, available for interaction with electromagnetic field probes. We present an introduction to trapping in both dc magnetic fields and optical fields (laser beams). The basic ideas and fundamental limitations are discussed and the first successful experiments are reviewed.
We have realized a two-dimensional permanent magnetic lattice of Ioffe-Pritchard microtraps for ultracold atoms. The lattice is formed by a single $300\text{\ensuremath{-}}\mathrm{nm}$ magnetized layer of FePt, patterned using optical lithography. Our magnetic lattice consists of more than 15 000 tightly confining microtraps with a density of 1250traps∕mm2. Simple analytical approximations for the magnetic fields produced by the lattice are used to derive relevant trap parameters. We load ultracold atoms into at least 30 lattice sites at a distance of approximately $10\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ from the film surface. The present result is an important first step toward quantum information processing with neutral atoms in magnetic lattice potentials.
A single microscopic magnetic trap for neutral atoms using planar current-carrying wires was proposed and studied theoretically by Weinstein et al.In this paper,we propose three structures of composite current-carrying wires to provide 1D,2D and 3D arrays of microscopic magnetic traps for cold alkali atoms.The spatial distributions of magnetic fields generated by these structures are calculated and the field gradient and curvature in each single microtrap are analysed.Our study shows that arrays of microscopic magnetic traps can be used to provide 1D,2D or 3D atomic magnetic lattices,and even to realize 1D,2D and 3D arrays of magneto-optical traps,and so on.