IAP logo UniBonn logo
EnglishDeutsch
  • Increase font size
  • Default font size
  • Decrease font size

Quantum technologies

Dieter Meschede's research group
Home Group members Jonathan Zopes
Print
Group members
Jonathan Zopes
Contact
Last position
in our group:
Postgraduate student
Field of research
in our group:
Few-atom quantum systems
 

Publications(up to 2017)

  • C. Robens, J. Zopes, W. Alt, S. Brakhane, D. Meschede and A. Alberti
    Low-entropy states of neutral atoms in polarization-synthesized optical lattices, Phys. Rev. Lett. 118, 065302 (2017)arXivBibTeXPDF
    ABSTRACT »

    We create low-entropy states of neutral atoms by utilizing a conceptually new optical-lattice technique that relies on a high-precision, high-bandwidth synthesis of light polarization. Polarization-synthesized optical lattices provide two fully controllable optical lattice potentials, each of them confining only atoms in either one of the two long-lived hyperfine states. By employing one lattice as the storage register and the other one as the shift register, we provide a proof of concept using four atoms that selected regions of the periodic potential can be filled with one particle per site. We expect that our results can be scaled up to thousands of atoms by employing an atom-sorting algorithm with logarithmic complexity, which is enabled by polarization-synthesized optical lattices. Vibrational entropy is subsequently removed by sideband cooling methods. Our results pave the way for a bottom-up approach to creating ultralow-entropy states of a many-body system.

  • C. Robens, S. Brakhane, W. Alt, D. Meschede, J. Zopes and A. Alberti
    Fast, high-precision optical polarization synthesizer for ultracold-atom experiments, arXiv:1608.02410, (2016)arXivBibTeXPDF
    ABSTRACT »

    We propose a novel approach to precisely synthesize arbitrary polarization states of light with a high modulation bandwidth. Our approach consists in superposing two laser light fields with the same wavelength, but with opposite circular polarizations, where the phase and amplitude of each light field are individually controlled. To assess the precision of the synthesized polarization states, we characterize static spatial variations of the polarization over the wavefront, as well as the noise spectral density of temporal fluctuations. We find that static polarization distortions limit the extinction ratio to 2x10-5, corresponding to a 0.01% reduction of the degree of polarization (DOP). We also obtain that temporal fluctuations give rise to a 0.2º uncertainty in the state of polarization (SOP). We recently demonstrated an application of the polarization synthesizer (Robens et al., arXiv:1608.02410) to create two fully independent, controllable optical lattices, which trap atoms depending on their internal spin state. Probing ultracold atoms in polarization-synthesized optical lattices, we obtain an independent, complementary characterization of the optical performance of the polarization synthesizer.

  • J. Zopes
    Sorting atoms in spin-dependent optical lattices, (2014), Master thesisBibTeXPDF
    ABSTRACT »

    This work reports on the implementation of feedback methods for position control of single Cesium atoms in spin-dependent optical lattices. For this purpose a new control software has been developed. It encapsulates experimental control, fluorescence image acquisition and analysis into a single program. Combining the new software with spin-dependent transport and position-dependent addressing, we have developed a versatile feedback algorithm to deterministically arrange arbitrary patterns of up to 6 atoms. In addition, we have prepared two atoms in a common lattice site. We observed light-assisted collisions between both atoms and thereby characterized the preparation effciency of 83 ± 4 %. The results pave the way for the study of controlled interactions between precisely two atoms in a single well of the optical lattice potential, enabling the realization of a fundamental quantum logic gate.

  • J. Zopes
    Einzelplatz-Detektion im optischen Gitter unterhalb des Beugungslimits, (2012), Bachelor thesisBibTeX