Control of Quantum Correlations in Tailored Matter
SFB/TRR 21 - Stuttgart, Ulm, Tübingen
 © Universität Stuttgart | Impressum

Project C9:
Molecular nanostructures and quantum gases


The scientific objective of the project C9 is the interaction of ultracold atoms and carbon nanotubes. We investigate interaction potentials between cold atoms and nanotubes, and the coherent manipulation of atoms by means of carbon nanotube potentials. We plan the realization of nanomechanical resonators based on carbon nanotubes, the cooling of nanomechanical resonators by scattering cold atom beams on nanotubes, and the construction of cold atom – nanomechanical hybrid quantum systems. Goals of the project are tailoring new dynamic cooperative quantum states and controlling cold atomnanodevice interactions. The experiments are supported by a PhD project in theory carried out in the group of Wolfgang Schleich at the University of Ulm.

At first place we plane to scatter ultracold atoms on nanotubes in order to determine the Casimir-Polder interaction between them. For this purpose, ultracold rubidium atoms are transported in an integrated magnetic conveyor belt to a room temperature chip surface containing structures of carbon nanotubes. The Casimir-Polder interaction shall be derived from scattering data.

In a second step we plan to investigate whether mechanical vibrations of a nanotube can be cooled by a cold atom beam. We plan to fabricate nanomechanical resonators based on carbon nanotubes which will be mounted on the surface of Helium flow cryostat and pre-cooled to a temperature of 4 K by 4He or to 300 mK by 3He, respectively. The precooling removes a large number of oscillation quanta from the mechanical resonator before scattering cold atoms on it. An evidence of further cooling by the cold atom beam would have significant consequences for pushing mechanical resonator towards the quantum regime. Quantum dynamics would show up in position-momentum uncertainty of the mechanical object and in the appearance quantized energy states. The cold atom – nanoresonator system is a promising candidate for constructing novel hybrid quantum systems.

The potential of a carbon nanotube (magnetic, electrostatic, or Casimir- Polder) decays over a distance of 10-100 nm, introducing a new length scale for potential shaping in atom optics. We plan to exploit this property for constructing potential structures on the submicron scale and use them for the coherent manipulation of ultracold atoms. Promising subjects are the construction of “Fabry-Perot interferometers” for atomic wave functions, and the transport of atoms through periodic, periodic and disordered potentials of carbon nanotubes. Molecular wires and nanostructures at cryogenically cooled surfaces shall be used to push the atom chip technology in terms of miniaturization towards the limits.

Project leaders

Prof. Dr. József Fortágh, Physikalisches Institut, Universität Tübingen

Refs & Publications

M. Stecker, H. Schefzyk, J. Fortágh and A. Günther
"A high resolution ion microscope for cold atoms"
New J. Phys. 19, 043020 (2017); doi: 10.1088/1367-2630/aa6741

P. Federsel, C. Rogulj, T. Menold, Z. Darázs P. Domokos,  A. Günther and J. Fortágh
"Noise spectroscopy with a quantum gas"
Phys. Rev. A 95, 043603 (2017); doi: 10.1103/PhysRevA.95.043603

T. Menold, P. Federsel, C. Rogulj, H. Hölscher, J. Fortágh and A. Günther
"Dynamic of cold-atoms tips in anharmonic potentials"
Beilstein J. Nanotechnol. 7, 1543-1555 (2016); doi: 10.3762/bjnano.7.148

P. Federsel, C. Rogulj, T. Menold, J. Fortágh, and A. Günther
"Spectral response of magnetically trapped Bose gases to weak microwave fields"
Phys. Rev. A 92, 033601 (2015); doi: 10.1103/PhysRevA.92.033601

J. Märkle, A.J. Allen, P. Federsel, B. Jetter, A. Günther, J. Fortágh, N.P. Proukakis, T.E. Judd
"Evaporative cooling of cold atoms at surfaces"
Phys. Rev. A 90, 023614 (2014); doi: 10.1103/PhysRevA.90.023614

Z. Darázs, Z. Kurucz, O. Kálmán, T. Kiss, J. Fortágh, and P. Domokos
"Parametric Amplification of the Mechanical Vibrations of a Suspended Nanowire by Magnetic Coupling to a Bose-Einstein Condensate"
Phys. Rev. Lett. 112, 133603 (2014); doi: 10.1103/PhysRevLett.112.133603

C. T. Weiß, P. V. Mironova, J. Fortágh, W. P. Schleich, and R. Walser
"Immersing carbon nanotubes in cold atomic gases"
Phys. Rev. A 88, 043623 (2013); doi: 10.1103/PhysRevA.88.043623

A. Günther, H. Hölscher, and J. Fortágh
"Cold Atom Scanning Probe Microscopy: An Overview"
Book chapter in Fundamentals of Picoscience, ed. Klaus D. Sattler, Taylor & Francis; 2013

B. Jetter, J. Märkle, P. Schneeweiss, M. Gierling, S. Scheel, A. Günther, J. Fortágh, and T. E. Judd
"Scattering and absorption of ultracold atoms by nanotubes"
New J. Phys. 15, 073009 (2013); doi: 10.1088/1367-2630/15/7/073009

P. Schneeweiß, M. Gierling, G. Visanescu, D. P. Kern, T. E. Judd, A. Günther, and J. Fortágh
"Dispersion forces between ultracold atoms and a carbon nanotube"
Nature Nanotechnology 7, 515-519 (2012); doi: 10.1038/NNANO.2012.93

O. Kalman, T. Kiss, J. Fortágh, and P. Domokos
"Quantum Galvanometer by Interfacing a Vibrating Nanowire and Cold Atoms"
Nano Lett. 12, 435–439 (2012); doi: 10.1021/nl203762g

R. Löffler, M. Häffner, G. Visanescu, H. Weigand, X. Wang, D. Zhang, M. Fleischer, A.J. Meixner, J. Fortágh, and D.P. Kern
"Optimization of plasma-enhanced chemical vapor deposition parameters for the growth of individual vertical carbon nanotubes as field emitters"
Carbon 49, Issue 13, 4197-4203 (2011); doi: 10.1016/j.carbon.2011.05.055

M. Gierling, P. Schneeweiss, G. Visanescu, P. Federsel, M. Häffner, D. Kern, T. E. Judd, A. Günther, and J. Fortágh
"Cold-atom scanning probe microscopy"
Nature Nanotechnology 6, 446-451 (2011); doi: 10.1038/NNANO.2011.80

A. Stibor, S. Kühnhold, J. Fortágh, C. Zimmermann, and A. Günther
"Single-atom detection on a chip: from realization to application"
New J. Phys. 12, 065034 (2010); doi: 10.1088/1367-2630/12/6/065034

B. Grüner, M. Jag, A. Stibor, G. Visanescu, M. Häffner, D. Kern, A. Günther, and J. Fortágh
"Integrated Atom Detector Based on Field Ionization near Carbon Nanotubes"
Phys. Rev. A 80, 063422 (2009); doi: 10.1103/PhysRevA.80.063422