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SUMMARY:Orbital interactions between strongly confined fermions - Prof Jos
 eph Thywissen\, Toronto
DTSTART:20221013T093000Z
DTEND:20221013T103000Z
UID:TALK184013@talks.cam.ac.uk
CONTACT:Dr Ulrich Schneider
DESCRIPTION:Exchange-antisymmetric pair wavefunctions in fermionic systems
  hold the promise of new types of quantum simulations\, topological quantu
 m gates\, and exotic few-body states. However\, p-wave and other antisymme
 tric interactions are weak in naturally occurring systems\, and their enha
 ncement via Feshbach resonances in ultracold systems has been limited by t
 hree-body loss. Here we revisit p-wave interactions in the presence of str
 ong confinement.\n\nIn a first scenario\, we study the two-body correlatio
 n strength of quasi-one-dimensional (q1D) ensembles of spin-polarized ferm
 ionic potassium. The strength and spatial symmetry of interactions are tun
 ed by a nearby p-wave Feshbach resonance and by confinement anisotropy. Su
 rprisingly\, we find a scattering channel that has even particle-exchange 
 parity along the q1D axis. These emergent s-wave collisions are enabled by
  orbital singlet wave functions in the transverse directions\, which also 
 confer high-momentum components to low-energy q1D collisions.\n\nIn a seco
 nd scenario\, we create isolated pairs of spin-polarised fermionic atoms i
 n a multi-orbital three-dimensional optical lattice. We measure elastic p-
 wave interaction energies of strongly interacting pairs of atoms and find 
 pair lifetimes to be up to fifty times larger than in free space. We demon
 strate that on-site interaction strengths can be widely tuned but collapse
  onto a universal single-parameter curve when rescaled by the harmonic ene
 rgy and length scales of a single lattice site. Since three-body processes
  are absent in this scenario\, we are able to observe elastic unitary p-wa
 ve interactions for the first time. Observations are compared both to an a
 nalytic solution for two harmonically confined atoms interacting via a p-w
 ave pseudopotential and to numerical solutions using an ab-initio interact
 ion potential. \n
LOCATION:Ryle Seminar Room (930) 
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