Density-dependent spin-orbit coupling in degenerate quantum gases

In this letter we propose a method to realize kind of spin-orbit coupling in ultracold Bose and Fermi gases whose format strength depend on density atoms. Our combines two-photon Raman transition periodical modulation spin-dependent interaction, which gives rise the direct process interaction assisted process, latter depends These two processes have opposite effects term spin-momentum locking compete with each other. As increases, system undergoes crossover from dominated regime regime. For crossover, show that for bosons, both condensate momentum chirality wave function change sign, fermions, surface distortion is inverted. We highlight there exists an emergent spatial reflection symmetry regime, can manifest itself universally gases. paves way novel phenomena non-abelian gauge field intrinsic dynamics.