No abstract

W e dem onstrate num eri cal l y the e ci ent generati on of vorti ces i n B ose-Ei nstei n condensates (B EC ) by usi ng a \phase i m pri nti ng" m ethod. T he m ethod consi st of passi ng a far o resonant l aser pul se through an absorpti on pl ate w i th azi m uthal l y dependent absorpti on coe ci ent,i m agi ng the l aserbeam onto a B EC ,and thuscreati ng the correspondi ng non-di ssi pati ve Stark shi ftpotenti al and condensate phase shi ft. In ourcal cul ati onsw e take i nto accountexperi m entali m perfecti ons. W e al so propose an i nterference m ethod to detectvorti ces by coherentl y pushi ng partofthe condensate usi ng opti cal l y i nduced B ragg scatteri ng. 03. 75. Fi ,32. 80. Pj,42. 50. V k O ne of the rem ai ni ng chal l enges of the physi cs of trapped B ose-Ei nstei n condensates (B EC ) [ 1{4] , concernsthe dem onstrati on ofthei rsuper ui d behavi or.Super ui di ty i s i nevi tabl y rel ated to the exi stence of vorti ces and persi stent currents i n B EC ,w hi ch so far have not been observed experi m ental l y,despi te seri ous e orts [ 5] .T wo aspectsofthe vortex probl em havebeen studi ed i ntensi vel y:i )i n rotati ng trapsvorti cesappeari n a naturalway as therm odynam i c ground states w i th quanti zed angul arm om entum [ 6] .Stabi l i ty and otherproperti esof vorti ces i n rotati ng traps have been throughl y di scussed i n R ef.[ 7{9] ;i i ) i n stati onary traps creati on ofvorti ces (or rel ated dark sol i tons i n 1D ) requi res the use of dynam icalm eans,and an i ndependent stabi l i ty anal ysi s.Several m ethods were proposed to generate vorti ces i n non-rotati ng traps: sti rri ng the condensate usi ng a bl ue detuned l aser [ 10, 11] , or several l aser beam s [ 12] ; adi abati c passage [ 13] or R am an transi ti ons [ 14] i n bicondensate system s. Such vorti ces are typi cal l y not stabl e,and can exhi bi tdynam i calorenergeti ci nstabi l i ty.In the rstcasevorti cesdecay rapi dl y,i n thesecond thevorti ces are stabl e w i thi n the fram ework ofthe m ean el d theory, and thei r correspondi ng decay requi res to take i nto account i nteracti ons of the B EC w i th the therm al cl oud. In the l attercase the vortex dynam i csi sexpected to besu ci entl y sl ow ,and thusexperi m ental l y accessi bl e [ 15] .In thi sC om m uni cati on we propose and i nvesti gate yet anotherprocedure ofvortex generati on usi ng \phase i mpri nti ng". T hi s m ethod consi sts of i ) passi ng a far o resonant l aser pul se through an absorpti on pl ate w hose absorpti on coe ci ent depends on the rotati on angl e ' around the propagati on axi s and i i ) creati ng the correspondi ng Stark shi ft potenti ali nsi de a B EC by i m agi ng the l aser pul se onto the condensate w hi ch l eads to a ' dependent phase shi ft i n the condensate wave functi on. T hi s m ethod i s very e ci ent and robust,and al l ow s for 1

We experimentally demonstrate interferometer-type guiding structures for neutral atoms based on dipole potentials created by micro-fabricated optical systems. As a central element we use an array of atom waveguides being formed by focusing a red-detuned laser beam with an array of cylindrical microlenses. Combining two of these arrays, we realize X-shaped beam splitters and more complex systems like the geometries for Mach-Zehnder and Michelson-type interferometers for atoms.

Three-level atom optics is introduced as a simple, efficient, and robust method to coherently manipulate and transport neutral atoms. The tunneling interaction among three trapped states allows us to realize the spatial analog of the stimulated Raman adiabatic passage, coherent population trapping, and electromagnetically induced transparency techniques and offers a wide range of possible applications. We investigate an implementation in optical microtrap arrays and show that under realistic parameters the coherent manipulation and transfer of neutral atoms among dipole traps could be realized in the millisecond range.

We review experimental work on cold, trapped metastable noble gases. We emphasize the aspects which distinguish work with these atoms from the large body of work on cold, trapped atoms in general. These aspects include detection techniques and collision processes unique to metastable atoms. We describe several experiments exploiting these unique features in fields including atom optics and statistical physics. We also discuss precision measurements on these atoms including fine structure splittings, isotope shifts, and atomic lifetimes.