MAGNETIC FIELDS NEAR MICROSTRUCTUREDSURFACES: APPLICATION TO ATOM CHIPSDISSERTATIONZUR ERLANGUNG DES AKADEMISCHEN GRADESDOKTOR DER NATURWISSENSCHAFTEN (DR. RER. NAT.)IN DER WISSENSCHAFTSDISZIPLIN QUANTEN OPTIKEINGEREICHT AN DER¨MATHEMATISCH-NATURWISSENSCHAFTLICHEN FAKULTAT¨DER UNIVERSITAT POTSDAMVONBO ZHANGSUPERVISED BYPROF. MARTIN WILKENSDR. CARSTEN HENKELPOTSDAM5TH, NOVEMBER 2008 Online published at the Institutional Repository of the Potsdam University: http://opus.kobv.de/ubp/volltexte/2009/2898/ urn:nbn:de:kobv:517-opus-28984 [http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-28984] AbstractMicrofabricated solid-state surfaces, also called ‘atom chip’, have become a well-establishedtechnique to trap and manipulate atoms. This has simplified applications in atom interferom-etry, quantum information processing, and studies of many-body systems. Magnetic trappingpotentials with arbitrary geommetries are generated with atom chip by miniaturized current-carrying conductors integrated on a solid substrate. Atoms can be trapped and cooled toKand even nK temperatures in such microchip trap. However, cold atoms can be significantlyperturbed by the chip surface, typically held at room temperature. The magnetic field fluctu-ations generated by thermal currents in the chip elements may induce spin flips of atoms andresult in loss, heating and decoherence.