Enhancement of laser cooling by the use of magnetic gradients

We present a laser cooling scheme for trapped ions and atoms using a combination of laser couplings and a magnetic gradient field. In a Schrieffer-Wolff transformed picture, this setup cancels the carrier and blue sideband terms completely resulting in an improved cooling behaviour compared to standard cooling schemes (e.g. sideband cooling) and allowing cooling to the vibrational ground state. A condition for optimal cooling rates is presented and the cooling behaviour for different Lamb-Dicke parameters and spontaneous decay rates is discussed. Cooling rates of one order of magnitude less than the trapping frequency are achieved using the new cooling method. Furthermore the scheme turns out to be robust under deviations from the optimal parameters and moreover provides good cooling rates also in the multi particle case.Comment: 14 pages, 8 figure

Trapped ion chain as a neural network

We demonstrate the possibility of realizing a neural network in a chain of trapped ions with induced long range interactions. Such models permit to store information distributed over the whole system. The storage capacity of such network, which depends on the phonon spectrum of the system, can be controlled by changing the external trapping potential and/or by applying longitudinal local magnetic fields. The system properties suggest the possibility of implementing robust distributed realizations of quantum logic.Comment: 4 pages, 3 figure

Spin and Orbital Splitting in Ferromagnetic Contacted Single Wall Carbon Nanotube Devices

We observed the coulomb blockade phenomena in ferromagnetic contacting single wall semiconducting carbon nanotube devices. No obvious Coulomb peaks shift was observed with existing only the Zeeman splitting at 4K. Combining with other effects, the ferromagnetic leads prevent the orbital spin states splitting with magnetic field up to 2 Tesla at 4K. With increasing magnetic field further, both positive or negative coulomb peaks shift slopes are observed associating with clockwise and anticlockwise orbital state splitting. The strongly suppressed/enhanced of the conductance has been observed associating with the magnetic field induced orbital states splitting/converging

Systematics of the odd-even effect in the resonance ionization of Os and Ti

Measurements of the odd-even effect in the mass spectrometric analysis of Ti and Os isotopes by resonance ionization mass spectrometry have been performed for ΔJ = + 1, 0 and -1 transitions. Under saturating conditions of the ionization and for ΔJ = + 1 transitions odd-even effects are reduced below the 0.5% level. Depending on the polarization state of the laser large odd isotope enrichments are observed for ΔJ = 0 and -1 transitions which can be reduced below the 0.5% level by depolarization of the laser field

Systematics of isotope ratio measurements with resonant laser photoionization sources

Sources of laser-induced even-even and odd-even isotopic selectivity in the resonance ionization mass spectroscopy of Os and Ti have been investigated experimentally for various types of transitions. A set of conditions with regard to laser bandwidth and frequency tuning, polarization state and intensity was obtained for which isotopic selectivity is either absent or reduced below the 2 % level

Anomalous Hall effect and weak localization corrections in a ferromagnet

In this paper, we report results on the anomalous Hall effect. First, we summarize analytical calculations based on the Kubo formalism : explicit expressions for both skew-scattering and side-jump are derived and weak-localization corrections are discussed. Next, we present numerical calculations of the anomalous Hall resistivity based on the Dirac equation. Qualitative agreement with experiments is obtained.Comment: Proceeding JEMS'0