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SUMMARY:Ultracold Atoms near superconductors and carbon nanotubes - Dr Joz
 sef Fortagh
DTSTART:20091110T160000Z
DTEND:20091110T170000Z
UID:TALK21318@talks.cam.ac.uk
CONTACT:6270
DESCRIPTION:The construction of hybrid quantum systems which combine ultra
 -cold\natoms with solid state devices has attracted considerable interest 
 in the last\nfew years because of a number of promising applications in pr
 ecision\nsensing and quantum information processing. I report on our exper
 imental\napproach towards the realization of such systems and present\nmea
 surements on ultracold atoms in the vicinity of superconducting\nsurfaces 
 and ultracold atoms near carbon nanotubes.\nThe cold atom/superconductor e
 xperiment consists of a rubidium BEC\napparatus and a thermally shielded h
 elium flow cryostat at 4.2 K in the\nsame ultrahigh vacuum system. Atom cl
 ouds are loaded into a standard\nmagnetic microtrap formed near a supercon
 ducting niobium wire. We\nobserve the impact of the Meissner effect on the
  trap parameters and\nmeasure the spin coherence time of atoms near superc
 onductors. The\ncoherence times are the longest yet observed in the vicini
 ty of a highly\nconducting material and confirm the suppression of Johnson
  noise in\nsuperconductors. The results have implications for the developm
 ent of\ncoherently coupled cold atom/solid state quantum devices\, in whic
 h cold\natoms serve as long term quantum memory.\nIn a second experiment\,
  we investigate the interaction between atoms\nand carbon nanotubes. Free 
 standing\, single nanotubes\, periodic structures\,\nand “carpets” of 
 nanotubes are grown on the surface of an atom chip. We\ndescribe first int
 eraction signals between cold atoms and carbon nanotubes\,\nin particular 
 a non-optical measurement of the position and length of\ncarbon nanotubes 
 using atom clouds. In addition\, we describe a novel atom\ndetector based 
 on field ionization of ground state atoms near carbon\nnanotubes and subse
 quent ion counting.
LOCATION:Pippard Lecture Theatre\, Cavendish Laboratory
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