Results 1 - 10 of 314
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[en] We experimentally investigate an optical clock based on 171Yb (I=1/2) atoms confined in an optical lattice. We have evaluated all known frequency shifts to the clock transition, including a density-dependent collision shift, with a fractional uncertainty of 3.4x10-16, limited principally by uncertainty in the blackbody radiation Stark shift. We measured the absolute clock transition frequency relative to the NIST-F1 Cs fountain clock and find the frequency to be 518 295 836 590 865.2(0.7) Hz.
[en] We discuss how adiabatic potentials can be used to create addressable lattices on a subwavelength scale, which can be used as a tool for local operations and readout within a lattice substructure, while taking advantage of the faster timescales and higher energy and temperature scales determined by the shorter lattice spacing. For alkaline-earth-like atoms with nonzero nuclear spin, these potentials can be made state-dependent, for which we give specific examples with 171Yb atoms. We discuss in detail the limitations in generating the lattice potentials, in particular non-adiabatic losses, and show that the loss rates can always be made exponentially small by increasing the laser power
[en] The ability to individually manipulate the increasing number of qubits is one of the many challenges towards scalable quantum information processing with trapped ions. Using micro-mirrors fabricated with micro-electromechanical systems technology, we focus laser beams on individual ions in a linear chain and steer the focal point in two dimensions. We demonstrate sequential single qubit gates on multiple 171Yb+ qubits and characterize the gate performance using quantum state tomography. Our system features negligible crosstalk to neighboring ions (<3×10−4), and switching speed comparable to typical single qubit gate times (<2 μs)
[en] Accurate time is the basis for communication, navigation, positioning of satellites in their orbits, meteorology, digital archiving, secured electronic transactions, network surveillance, mapping of underground resources, automatic signaling system and many more. Astronomical observations, precision measurements for exploring fundamental sciences, geodesy relies on ultra-precise time. For all these, atomic clocks are the backbone for generation and maintenance of accurate time. Atomic clocks based on forbidden optical transitions are much more accurate than the microwave clocks that defines the SI second at present. We have started developing an ultra-precise frequency standards based on the highly forbidden 4f146s 2S1/2 - 4f136s2 2F7/2 electric octupole (E3) optical transitions of ytterbium-ion (171Yb+). For this, a single ytterbium-ion is confined in a Paul trap and laser cooled to mK temperature, which is then used for probing it's E3-clock transition and precise measurement of the transition frequency. Ytterbium-ion is also a potential candidate for the future redefinition of the SI second. Overall progress at CSIR-NPL on this activity and its applications will be presented in the meeting. (author)
[en] When an off-resonant light field is coupled with atomic spins, its polarization can rotate depending on the direction of the spins via Faraday rotation, which has been used for monitoring and controlling the atomic spins. We observed Faraday rotation by an angle of more than 10 deg for a single nuclear spin of 1/2 of a 171Yb atom in a high-finesse optical cavity. By employing the coupling between the single nuclear spin and a photon, we have also demonstrated that the spin can be projected or weakly measured through the projection of the transmitted single ancillary photon.
[en] In a nucleus 171Yb are investigated the relations intensities gamma-transitions going between levels of rotational bands 7/2- and 5/2-. It is marked a deviation of the relations intensities gamma-beams from rule Alaga. For assumed presence of another statuses 7/23/2- in a level 7/2 7/2- it is determined parameter Z=2.16(17) and also presence of another statuses 9/27/2- in alevel 9/25/2- it is determined parameter Z=0.542(7) specified rules Alaga. The consent of specified rule Alaga with experience is received. (author)
[en] We present a magneto optical trap (MOT) of Yb atoms with high-power violet laser diode (LD). An injection -locked violet LD with a 25 mW frequency-stabilized output was used for the violet MOT. Typical number of 4.0 X 106 (1.4 X 106) for 174Yb (171Yb) atoms with trap density of 1.0 x108/cm3 was obtained. A 10 mW violet extent-cavity LD was used for slowing effusive Yb atomic beam resulting in 35-fold increase of the trapped atom numbers.
[en] To benchmark the validity of using the (d,pγ) reaction as a surrogate for (n,γ), the 171,173Yb(d,pγ) reactions were measured with the goal to reproduce the known neutron capture cross section ratio of these nuclei. Preliminary surrogate results reproduced the measured values within 15%.
[en] We have investigated the frequency shifts caused by inhomogeneous excitation in a 171Yb optical lattice clock. The dependences of the inhomogeneity on the temperature of the cold ytterbium atoms and the misaligning angle between the lattice laser and the clock laser are analyzed by numerical calculations. The dependence of the fractional collisional frequency shift on the ground state fraction under different cold atom temperatures, atom numbers, lattice trap depths and unequal transverse and longitudinal temperatures are also shown. The results show that the uncertainty of the ytterbium clocks, contributed by the inhomogeneous excitation, can be reduced to be 10−19 or even lower with certain conditions. (letter)