tag:www.physik.uni-hamburg.de,2005:/en/iqp/sengstock/research/ytterbium-quantum-gases/research-newsStatus of the experiment2023-08-25T12:40:28ZNAGR-fakmin-34980752-production2023-05-11T15:12:00ZCreation and optimization of SLM generated optical tweezers<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/34996753/yb-first-tweezer-a72e5c22435de091ca3074b7739197989af4ce84.jpg" /><p>Using an LCoS spatial light modulator and a high resolution diffraction limited imaging system we have created and optimzed arrays of optical tweezers using the Gerchberg-Saxton algorithm for the first time in the Lab. </p><p>Photo: Jonas Rauchfuss / UHH</p>NAGR-fakmin-34984523-production2023-02-10T16:12:00ZOur new glass has safely arrived<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/34984563/yb-new-glass-cell-209685a04c9cdbd0d3b0bc579891714818d79bf5.jpg" /><p>The new glass cell has finally arrived in Hamburg after travelling around the world for almost a year!</p><p>Photo: Christoph Becker / UHH</p>NAGR-fakmin-34981361-production2022-04-08T15:12:00ZA new sorting algorithm for cold atoms in optical tweezer arrays<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/34996467/yb-sorting-algorithm-397a4800423556d08dc91442cc90f9662c76cb37.jpg" /><p>We have developed a new sorting algorithm based on the well-known compression algorithm that minimizes exception handling and leads to a faster and generally more sucessfull sorting of a sparse ensemble of neutral atoms in optical tweezer arrays. More details can be found in the Bachelor thesis of Henning Mollenhauer</p><p>Photo: Henning Mollenhauer / UHH</p>NAGR-fakmin-34984030-production2022-02-24T16:12:00ZSuccessful test of our high-NA microscope objectives<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/34996447/yb-objektiv-test-ee163ec4b303f39eb0d733fdbcd60a359d7de450.jpg" /><p>Our custom-made high NA microscope objectives neccessary for trapping and manipulation of neutral Yb atoms at various different wavelengths have been extensively tested and perform to specs. More details can be found in the Bchelor thesis of Jan Philip Deppe.</p><p>Photo: Jan Philip Deppe / UHH</p>NAGR-fakmin-34981521-production2021-10-14T15:12:00ZGerchberg-Saxton algorithm for homogenous optical tweezer arrays<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/34996423/yb-gsa-ae344f4d77e858505dce9efaa8ba59a08ff6dc3c.jpg" /><p>We have successfully implemented a modified Gerchberg-Saxton algorithm for fast high-fidelity optimization and homogenization of optical tweezer arrays generated by a phase-only spatial light modulator. More details can be found in the Bachelor thesis of Timo Eikelmann.</p><p>Photo: Timo Eikelmann / UHH</p>NAGR-fakmin-20494877-production2018-11-21T16:12:00ZPrecision spectroscopy of spin mixtures in 171Yb<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/20928829/yb-spin-exchange-spec-1bea3364d4cbe5052c015eb253d20c3fded8739f.jpg" /><p>We load fermionic 171Yb atoms in a deep 3D optical lattice and perform precision spectroscopy on the ultra-narrow 1S0 - 3P0 transition. If two atoms in different spin states occupy the same lattice site they can be excited to two different mixed orbital states where the spin triplet state requires an orbital singlet state to fulfil the fermoinic antisymmetrization and vice versa. The energy difference between these two states defines a spin-exchange interaction relevant for the implementation of the Kondo lattie model with ultracild Yb atoms. We have determined this exchange interaction and find it to be anti-ferromagnetic and moderate in strength, which is an ideal starting point for further investigation of the Kondo lattice model with 171Yb.</p><p>Photo: UHH/Abeln</p>NAGR-fakmin-20494806-production2018-07-05T13:51:00ZCreation of quantum degenerate Fermi-Fermi mixtures in Yb<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/20928781/yb-mixtures-3f7c167517f6df4e75c0c40dcffb61e900fe322c.jpg" /><p>We have created quantum degenerate mixtures of the two fermionic isotopes 171Yb and 173Yb. By adjusting the correspondning MOT loading times we are able to produce 50:50 mixtures of up to 40000 particels per species at temperatures of 0.25 TF.</p><p>Photo: UHH/Sponselee</p>NAGR-fakmin-18135183-production2015-12-09T23:00:00ZDissipative dynamics of meta-stable Fermions in an optical lattice<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/18136554/news5-4175f41411a82e401a8f4f24a0a3dd37149c988b.png" /><p>We have analyzed the dynamical behaviour of ultracold fermions in a metastable state trapped in a 1D optical lattice. Strong dissipative interactions modify the usual Fermi-Hubbard Hamiltonian and lead to the build-up of correlations in the system which counterintuitively suppress further atom loss. Our finding might be useful for disspative quantum state engeneering or thermometry of Fermi Hubbard systems at ultralow temperatures where no other experimental tools are available.<br> <br>Particle loss measurements for a 1-dimensional 2-component Fermi gas loaded into an optical lattice of varying lattice depth. Times is given in units of (hbar*U/J^2). Clearly two different timescales can be identified. The two-body correlation function g(2) decreases over time and indicates the build-up of correlations in the system.</p><p>Photo: AG Sengstock</p>NAGR-fakmin-18135196-production2013-12-04T23:00:00ZHigh precission spectroscopy of ultracold Fermions in a triangular optical lattice<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/18136524/news3-da41645672fab86b7005c0a623148fecda9ccc07.png" /><p>First spectroscopic measurements using the ultra-stable clock laser have been performed on the doubly forbidden 1S0-3P0 transition. A sample of spin polarized fermionic 173Yb atoms has been interrogated in 3D triangular optical lattice. The spectroscopic data reveals Fourier-limited resolution.<br> <br>(left) Heterodyne measurement of two individually stabilized clock lasers at 578nm (right) Fourier-limited spectrum of spin polarized Fermions in a 3D optical lattice interrogated on the clock transition.</p><p>Photo: AG Sengstock</p>NAGR-fakmin-18135209-production2013-07-09T22:00:00ZMott insulator of Yb in a triangular optical lattice<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/18136614/news2-e346e944395da1fd1ac5824099de6b809d3bfd30.png" /><p>Last night we have observed the superfluid-to-Mott-insulator transition in a triangular optical lattice. The pictures show the vanishing visibility of the interference peaks when crossing the quantum phase transition.<br>Time-of-Flight picture of bosonic Yb atoms released from a 3D triangular optical lattice for increasing lattice depth.</p><p>Photo: AG Sengstock</p>NAGR-fakmin-18135222-production2012-12-06T23:00:00ZFirst quantum degenrate Fermi gas of Ytterbium in Hamburg<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/18136484/news1-15eaab6a0d0fd2620401ae7782ccd68669e478d9.png" /><p>We have successfully cooled fermionic 173Yb atoms to quantum degeneracy. Typically the Fermi seas we produce contain up to 5 *105 atoms at temperatures around 0.1 TF. Through internal state preparation it is possible to create either spin-polarized samples or vary the number of involved spin components from two to six.<br> <br>Time-of-Flight absorption images (top row) and column-sums of the corresponding picture (bottom row) of fermionic Ytterbium atoms released from a crossed optical dipole trap.</p><p>Photo: AG Sengstock</p>NAGR-fakmin-18135235-production2012-06-12T22:00:00ZFirst Ytterbium BEC in Hamburg<img width="293" height="165" style="float:left" src="https://assets.rrz.uni-hamburg.de/instance_assets/fakmin/18136654/bluenews-09b6893fe143286ca26cddb17a7b362bd9eeaf4e.png" /><p>Wednesday night, June 13th 2012, we achieved our first BEC of 174Yb containing about 10000 atoms. In this experiment we prepared about 4x107 atoms in a MOT on the narrow 1S0-3P1 intercombination transition at 556 nm, which was loaded from a 2D-MOT operating on the broad 1S0-1P1 transition at 399 nm. We then transferred the atoms into a crossed dipole trap and cooled evaporatively to quantum degeneracy. The figure shows the buildup of a BEC as we cooled across the BEC phase transition.<br> <br>Absorption pictures of 174Yb showing the transition from a thermal cloud to a almost pure Bose-Einstein condensate (left to right).</p><p>Photo: AG Sengstock</p>