Laser cooling at high density in deep far-detuned optical lattices

Winoto, S. Lukman; DePue, Marshall T.; Bramall, N.; Weiss, David S.

doi:10.1103/physreva.59.r19

Cited by 63 publications

(51 citation statements)

References 26 publications

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“…In that case, atoms are trapped on a distance scale that is smaller than the polarization gradients, so τ osc can exceed τ op (ref. 22).…”

Section: Laser Coolingmentioning

confidence: 99%

“…Cooling depends on polarization gradients in the cooling light, and specifically on the Sisyphus effect 22,30 . The process works in the far-off-resonance lattice because the large a.c. Stark shifts associated with the lattice are the same for all magnetic sublevels.…”

Section: Laser Coolingmentioning

confidence: 99%

“…In the final state, a random half of the lattice sites have a single atom. After 5 ms, we shut off the magneto-optic trap light and magnetic field and turn on a set of six optical molasses laser beams to further polarization-gradient cool the trapped atoms 22 . To observe where the atoms are, we image the spontaneously scattered laser cooling light onto a CCD (charge-coupled device).…”

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confidence: 99%

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Imaging single atoms in a three-dimensional array

2007

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“…In that case, atoms are trapped on a distance scale that is smaller than the polarization gradients, so τ osc can exceed τ op (ref. 22).…”

Section: Laser Coolingmentioning

confidence: 99%

Section: Laser Coolingmentioning

confidence: 99%

mentioning

confidence: 99%

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Imaging single atoms in a three-dimensional array

2007

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“…If necessary, the temperature of the atoms can be reduced in the trap by a variety of methods polarization gradient cooling [19,22,23]. The two-species sample in this trap should have N > ∼ 10 7 atoms with density n > ∼ 10 11 cm −3 and T < ∼ 20 µK.…”

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confidence: 99%

Quantum Computation with Trapped Polar Molecules

2002

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We propose a novel physical realization of a quantum computer. The qubits are electric dipole moments of ultracold diatomic molecules, oriented along or against an external electric field. Individual molecules are held in a 1-D trap array, with an electric field gradient allowing spectroscopic addressing of each site. Bits are coupled via the electric dipole-dipole interaction. Using technologies similar to those already demonstrated, this design can plausibly lead to a quantum computer with > ∼ 10 4 qubits, which can perform ∼ 10 5 CNOT gates in the anticipated decoherence time of ∼ 5 s.PACS numbers: 03.67. Lx, 33.80.Ps, 33.55.Be We describe a new technical approach to the design of a quantum computer (QC). The basic QC architecture is shown in Fig. 1. The qubits consist of the electric dipole moments of diatomic molecules, oriented along or against an external electric field. Bits are coupled by the electric dipole-dipole interaction. Individual molecules are held in a 1-D trap array, with an electric field gradient allowing spectroscopic addressing of each site. Loading with ultracold molecules makes it possible to use a weak trapping potential, which should allow long decoherence times for the system. This design bears various features in common with other recent proposals which employ electric dipole couplings [1,2,3]. However, the technical parameters of our design appear very favorable, and apparently only incremental improvements of demonstrated techniques are required in order to build a QC of unprecedented size.We describe the molecular qubits as permanent electric dipoles oriented along (|0 ) or against (|1 ) an external electric field ( E ext ). (This model reproduces the exact behavior well in a certain regime.) Lattice sites are equally spaced in the x-direction and each contains one molecule, prepared initially in its ground state |0 . The external field is perpendicular to the trap axis and consists of a constant bias field plus a linear gradient:, where H 0 is the internal energy of a bit, d a is the electric dipole moment of bit a, and E a = E ext (x a ) + E int (x a ) is the total electric field at x a . The internal field E int is created by the electric dipole moments of neighboring bits:The scheme for gate operations is as outlined for the electric dipole moments of quantum dots in Ref. [1]. Transitions between qubit states can be driven by electric resonance, either directly in the microwave region or indirectly by an optical stimulated Raman process. Resonant drive pulses are tuned to frequency ν a = ν 0 + d ef f E a /h, where hν 0 is the difference in internal energies between states |0 and |1 in zero field; the effective dipole momentis the dipole moment in state |0 (|1 ); and h is Planck's constant. Pulses of sufficient temporal length to resolve the energy splitting due to E int can be used for CNOT gates; shorter pulses suffice for one-bit rotations. Final-state readout can be accomplished by state-selective, resonant multiphoton ionization [4] and imaging detection of the resulti...

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“…The pinning lattice was chosen to be near the D 1 atomic transition to allow efficient filtration of the intense lattice light from the weaker fluorescence light during the measurement. The pinning lattice frequency detuning is chosen to be much greater than the hyperfine structure of the D 1 line, and the lattice polarizations chosen to be linear, in order minimize the potential energy differences between the ground-state sublevels (see Section II B and [8,26]). …”

Section: A Simulated Scenariosmentioning

confidence: 99%

Large-photon-number extraction from individual atoms trapped in an optical lattice

Shotter

2011

Phys. Rev. A

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The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral atoms confined in a short-period optical lattice to measure the position of individual atoms in the sample. A crucial condition for the measurements is that atomic hopping between lattice sites must be strongly suppressed despite substantial photon recoil heating. This article models three-dimensional polarization gradient cooling of atoms trapped within a far-detuned optical lattice. The atomic dynamics are simulated using a hybrid Monte Carlo and master equation analysis in order to predict the frequency of processes which give rise to degradation or loss of the fluorescent signal during measurements. It is shown, consistent with the experimental results, that there exists a wide parameter range in which the lifetime of strongly-fluorescing isolated lattice-trapped atoms is limited by background gas collisions rather than radiative processes. In these cases the total number of scattered photons can be as large as 10 8 per atom. The performance of the technique is related to relevant experimental parameters.

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Laser cooling at high density in deep far-detuned optical lattices

Cited by 63 publications

References 26 publications

Imaging single atoms in a three-dimensional array

Imaging single atoms in a three-dimensional array

Quantum Computation with Trapped Polar Molecules

Large-photon-number extraction from individual atoms trapped in an optical lattice

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