Lasersystem

• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: Funded in 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 222593815

• Final Report Year: 2016

Final Report Abstract

The Lasersystem that hat been funded is a versatile source for laser radiation of the wavelength 1120nm, 560nm and 280nm, the latter provided by home build Second Harmonic Generation cavities. The wavelength at 280nm has been exploited on a daily basis for a variety of purposes, mainly to cool, detect, control and coherently manipulate Mg ions in ion traps. Due to its generic purpose in our group, it has been substantially contributed to the following projects: (1) In the context of experimental, analogue quantum simulations: In 2008, we had demonstrated the possibility to run experimental quantum simulations based on trapped ions and now scaled our approach in size and dimension, realizing artificial Coulomb Crystals (CC) of individually controlled ions. This ansatz is promising to keep the unique level of individual control for a wide range of AQSs, while reaching the mesoscopic scale. On the other hand, we investigated thermalization of a subsystem within a closed quantum system - a single spin non- linearly coupled to the mesoscopic bath of phonons. Additionally, we enable coupling to an external environment, assisting coherence by dissipation (sympathetic cooling - Plenio) or decoherence to enhance spectroscopical sensitivity. (2) In the context of optically trapping of ions, in the absence of any rf-fields We had achieved the trapping of single ions in an optical dipole potential and, with the novel system, demonstrated optical trapping of an ion in a 1D-optical lattice. There is a long-term prospect for combining the advantages of ions with versatile optical potential landscapes. Here, we want to directly benefit from the absence of rf-fields, e.g. the related absence of rf-driven micromotion affecting/heating ensembles via interaction between ions as well as ions and atoms. (3) In the context of topologically protected defects in Coulomb Crystals: After observing topological defects for the first time in the year 2010, we further elaborated on their creation, parameters and dynamics. We demonstrated that they can oscillate as trapped quasi particles in their self-induced confining potential within the CC. We reported about the classical properties of these quasi-particles (kinks, solitons), such as, the different species of defects, their coupling to the mesoscopic environment of the crystal, their mutual interaction. In addition, we developed a proposal to study the potential prospects on accessing the quantum regime, taking advantage of the unique, gapped structure of the related localized motional modes of the kink. Recently, we identified the normal modes related to the kink by spectroscopical means and derived its potential barriers by exciting the axial motion of the kink. To summarize: Within the field of trapped ions, we further propelled theory, methodology and novel approaches for confinement to enhance the control on the quantum level.

Publications

• “Single ions trapped in a one-dimensional optical lattice”. Phys. Rev. Lett. 109, 233004 (2012)
  M. Enderlein, T. Huber, Ch. Schneider, T.Schaetz
  
• „Dissipation-Assisted Quantum Information Procesing with Trapped Ions“. Phys. Rev. Lett. 110, 110502 (2013)
  A.Bermudez, T. Schaetz, M. B. Plenio
  
• „Focus on quantum simulation“. New J. Phys. 15, 085009 (2013)
  T. Schaetz, C. Monroe, T. Esslinger
  
• „Trapping of Topological-Structural Defects in Coulomb Crystals“. Phys. Rev. Lett. 110, 133004 (2013)
  M. Mielenz, J. Brox, S. Kahra, G. Leschhorn, M. Albert, H. Landa, B. Reznik, T. Schaetz
  
• „Decoherence-assisted spectroscopy of a single Mg+ ion”. Phys. Rev. Lett. 112, 113003 (2014)
  G. Clos, M. Enderlein, U. Warring, T.Schaetz, D.Leibfried
  
• „Entanglement Generation Using Discrete Solitons in Coulomb Crystals“. Phys. Rev. Lett. 113, 053001 (2014)
  H. Landa, A. Retzker, T. Schaetz, B. Reznik
  
• “Time-resolved observation of thermalization in an isolated quantum system”. Physical Review Letters
  G. Clos, D. Porras, U. Warring, T. Schaetz
  
• Motional-mode analysis of trapped ions. Phys. Rev. A 94, 023401 (2016)
  H. Kalis, F. Hakelberg, M. Wittemer, M.Mielenz, U. Warring, T. Schaetz
  
• „Arrays of individually controlled ions suitable for two-dimensional quantum simulations“. Nat. Commun. 7, 11839 (2016)
  M. Mielenz, H. Kalis, M. Wittemer, F. Hakelberg, R. Schmied, M. Blain, P. Maunz, D.L. Moehring, D. Leibfried, U. Warring, T. Schaetz
  
• „Quantum Transport of Energy in Controlled Synthetic Quantum Magnets“. New J. Phys. 18, 083006 (2016)
  A. Bermudez, T. Schaetz