Association of ultracold double-species bosonic molecules

We report on the creation of heterospecies bosonic molecules, associated from an ultracold Bose-Bose mixture of 41K and 87Rb, by using a resonantly modulated magnetic field close to two Feshbach resonances. We measure the binding energy of the weakly bound molecular states versus the Feshbach field and compare our results to theoretical predictions. We observe the broadening and asymmetry of the association spectrum due to thermal distribution of the atoms, and a frequency shift occurring when the binding energy depends nonlinearly on the Feshbach field. A simple model is developed to quantitatively describe the association process. Our work marks an important step forward in the experimental route towards Bose-Einstein condensates of dipolar molecules.Comment: 5 pages, 4 figure

Double species condensate with tunable interspecies interactions

We produce Bose-Einstein condensates of two different species, $^{87}$Rb and $^{41}$K, in an optical dipole trap in proximity of interspecies Feshbach resonances. We discover and characterize two Feshbach resonances, located around 35 and 79 G, by observing the three-body losses and the elastic cross-section. The narrower resonance is exploited to create a double species condensate with tunable interactions. Our system opens the way to the exploration of double species Mott insulators and, more in general, of the quantum phase diagram of the two species Bose-Hubbard model.Comment: 4 pages, 4 figure

Intense slow beams of bosonic potassium isotopes

We report on an experimental realization of a two-dimensional magneto-optical trap (2D-MOT) that allows the generation of cold atomic beams of 39K and 41K bosonic potassium isotopes. The high measured fluxes up to 1.0x10^11 atoms/s and low atomic velocities around 33 m/s are well suited for a fast and reliable 3D-MOT loading, a basilar feature for new generation experiments on Bose-Einstein condensation of dilute atomic samples. We also present a simple multilevel theoretical model for the calculation of the light-induced force acting on an atom moving in a MOT. The model gives a good agreement between predicted and measured flux and velocity values for our 2D-MOT.Comment: Updated references, 1 figure added, 10 pages, 9 figure

Collisional properties of sympathetically cooled 39^{39}K

We report the experimental evidence of the sympathetic cooling of $^{39}$K with $^{87}$Rb down to 1 $\mu$K, obtained in a novel tight confining magnetic trap. This allowed us to perform the first direct measurement of the elastic cross section of $^{39}$K below 50 $\mu$K. The result obtained for the triplet scattering length, $a_T = -51(7)$ Bohr radii, agrees with previous results derived from photoassociation spectra and from Feshbach spectroscopy of $^{40}$K.Comment: 7 pages, 4 figures, submitted to Phys. Rev.

Pelatihan Pengembangan Media Pembelajaran Interaktif dengan Power Point untuk Peningkatan Kompetensi Guru SD

Perkembangan Teknologi Informasi di dunia pendidikan khususnya pendidikan dasar atau sekolah dasar ternyata tidak diiringi dengan kemampuan guru dalam memanfaatkan teknologi informasi tersebut, penggunaan media pembelajaran power point masih belum di maksimalkan oleh guru SD di lingkungan UPTD Pendidikan Semarang Selatan, Pengabdian masyarakat yang dilakukakan memang sangat diharapkan oleh UPTD Pendidikan Semarang Selatan guna meningkatkan kompetensi guru seiring dengan mulai diterapkannya SDC (Semarang Digital Class), metode yang digunakan dalam pengabdian masyarakat ini adalah identifikasi, pelatihan dan pendampingan, pelatihan diikuti oleh 22 guru SD dengan materi pembuatan media pembelajaran interaktif menggunakan power point, setelah pelatihan diadakan evaluasi pembuatan media pembelajaran yang interaktif, kemudian diadakan pendampingan ke SD untuk melihat penerapan hasil pelatihan, disamping pendampingan juga diadakan lomba dengan kriteria terbaik dalam pembuatan media pembelajaran, diharapkan guru semakin kreatif sehingga tujuan peningkatan kompetensi guru dapat dicapai

Observation of heteronuclear atomic Efimov resonances

The Efimov effect represents a cornerstone in few-body physics. Building on the recent experimental observation with ultracold atoms, we report the first experimental signature of Efimov physics in a heteronuclear system. A mixture of $^{41}$K and $^{87}$Rb atoms was cooled to few hundred nanoKelvins and stored in an optical dipole trap. Exploiting a broad interspecies Feshbach resonance, the losses due to three-body collisions were studied as a function of the interspecies scattering length. We observe an enhancement of the three-body collisions for three distinct values of the interspecies scattering lengths, both positive and negative. We attribute the two features at negative scattering length to the existence of two kind of Efimov trimers, namely KKRb and KRbRb.Comment: 4 pages, 4 figure

Device for producing and enclosing a hot plasma

1391103 High-frequency discharge tubes EUROPEAN ATOMIC ENERGY COM- MUNITY 24 July 1972 [23 July 1971] 34566/72 Heading H1D A device for producing and enclosing a hot plasma comprises a toroidal vessel 1 having means 2 for generating a magnetic field along the azimuthal axis 3 of the torus to induce annular electric currents along said axis, and means 6, 7 for generating an oscillating electric field in the vessel having a component parallel to the magnetic field and a frequency at or near the bounce frequency (i.e. about ten times the collison frequency of ions.) A second toroidal vessel or liner 4 is disposed in the first vessel 1, and the diameter of the plasma is limited by annular discs 5. The electric field is generated by annular electrodes 6 and 7 disposed above and below the axis 3 and connected through insulated ducts 8 to a generator producing oscillations having a fre- quency between 10 and 100 KHz. The electric field may alternatively be produced by an aerial disposed in an aperture in the vessel wall and fed with a signal having a fundamental frequency corresponding to the plasma frequency which is amplitude modulated at the bounce frequency

Three dimensional imaging of short pulses

We exploit a slightly noncollinear second-harmonic cross-correlation scheme to map the 3D space-time intensity distribution of an unknown complex-shaped ultrashort optical pulse. We show the capability of the technique to reconstruct both the amplitude and the phase of the field through the coherence of the nonlinear interaction down to a resolution of 10 $\mu$m in space and 200 fs in time. This implies that the concept of second-harmonic holography can be employed down to the sub-ps time scale, and used to discuss the features of the technique in terms of the reconstructed fields.Comment: 16 pages, 6 figure

Collisional and molecular spectroscopy in an ultracold Bose-Bose mixture

The route toward a Bose-Einstein condensate of dipolar molecules requires the ability to efficiently associate dimers of different chemical species and transfer them to the stable rovibrational ground state. Here, we report on recent spectroscopic measurements of two weakly bound molecular levels and newly observed narrow d-wave Feshbach resonances. The data are used to improve the collisional model for the Bose-Bose mixture 41K87Rb, among the most promising candidates to create a molecular dipolar BEC.Comment: 13 pages, 3 figure