Sub-poissonian loading of single atoms in a microscopic dipole trap

Abstract

The ability to manipulate individual atoms, ions or photons allows controlled engineering of the quantum state of small sets of trapped particles; this is necessary to encode and process information at the quantum level. Recent achievements in this direction have used either trapped ions or trapped photons in cavity quantum-electrodynamical systems. A third possibility that has been studied theoretically is to use trapped neutral atoms. Such schemes would benefit greatly from the ability to trap and address individual atoms with high spatial resolution. Here we demonstrate a method for loading and detecting individual atoms in an optical dipole trap of submicrometre size. Because of the extremely small trapping volume, only one atom can be loaded at a time, so that the statistics of the number of atoms in the trap, N, are strongly sub-poissonian (DeltaN2 approximately 0.5N). We present a simple model for describing the observed behaviour, and we discuss the possibilities for trapping and addressing several atoms in separate traps, for applications in quantum information processing.

Single atoms in the ring lattice for quantum information processing and quantum simulation

“…Once the counting rate exceeds the blue line, meaning that two single atoms are trapped in the double well with one each, we trigger the control system to start the following experimental sequence: shutting off the MOT beams for 150 ms and playing the holograms movie to transform the trap shape and transfer atoms, then switching on the MOT beams to induce collisions and detecting atoms in the microscopic FORT for 60 ms. The final result that two atoms could not stay in the same microscopic FORT with the MOT beams on is in accord with "collision blockade" [13] theory. The one body loss rate is about 15.5% derived from Figure 10(c).…”

“…The process of two or more atoms in a very small trap volume being ejected from the trap occurs as a result of light-assisted collision induced by the resonant laser at 780 nm, known as the "collisional blockade" mechanism [13,14]. To assure that the upper fluorescence level corresponds to one atom, we make the Hanbury Brown and Twiss (HBT) effect measurement [20,21].…”

“…Instead of being adiabatically transferred from ultracold atomic ensemble, in our experiment single atom array is built one by one based on "collisional blockade" mechanism [13,14] that locks the atom number either zero or one in ultra small dipole trap in the presence of near-resonant laser light. Here, we demonstrate trapping single neutral rubidium atoms in the ring lattice generated by a computer controlled spatial light modulator (SLM), and present several kinds of manipulations of single atom array.…”

Bell-Type Inequalities for Cold Heteronuclear Molecules

“…For typical values of τ , this means that the observers should be separated by a distance greater than a few hundred µm. A possible experimental setup allowing for such molecular separation and manipulation are optical tweezers, currently used as individual atoms traps [23]. The protocol is thus the following: after collecting orientation measurements for different times t i , observers A and B compare their results and construct the quantity (4).…”

Cavity-enhanced toroidal dipole force traps for dark-field seeking species

“…The cavity-enhanced dipole force has already been applied to studies of cavity quantum electrodynamics [17,18,24] and quantum computing [7,25]. Dissipative interaction with the cavity field has also been proposed as a mechanism for cooling the confined sample [26][27][28].…”