Solitons & Quantum Macroscopic Coherence
Creating a Quantum Coherent State of the Relative Distance between Two Solitons in a Breather
We are exploring a possibility for a creation of a coherent quantum state of the macroscopic degrees of freedom of BEC solitons. In particular, we showed that in a quench from a single soliton to a breather (a bi-soliton), the relative coordinate of the two constituent daughter solitons is emerges cold and coherent, regardless of how hot the center of mass of the mother soliton was[YMHOA17][MMODHY20][ABBMMKetal21][DDO22].
Creation of a breather in realistic conditions is optimized in[GRDMOD18]. The quantum-fluctuation-induced spatial separation of the constituent solitons can be accelerated using repulsive barriers[MMYODH19]. The underlying integrability can be shown to remain intact for a wide range of parameters[DO15].
We participated in an experiment where breathers were experimentally observed and characterized[LJNMMYDOH20].
In the nearest future, we would like to explore connections between quantum dynamics of massive objects and quantum search algorithms[AGHJOA20].
Interferometry with the Center-of-Mass of a Quantum Solitons
We are investigating the ways of protecting the center of mass state of single solitons: in particular, adding a lattice enforces an energy gap between the solitonic ground state and its excitations[NGMMOA18]. We demonstrate numerically that for the same interferometer geometry, the absolute lower bound for a detectable angular velocity decreases N-fold when the individual atoms are lumped into a single soliton[NGDPOAM19]. Recently, we showed numerically, via exact diagonalization for a six-atom soliton, that the center-of-mass coherence appears to be robust against decoherence to "ionization": even when the soliton kinetic energy exceeds the total ionization threshold, quantum-macroscopic interferometric fringes survive intact[NDDAMO22]. This observation renders the center-of-mass interferometry with solitons more flexible than expected [C. Weiss and Y. Castin, Phys. Rev. Lett. 102, 010403 (2009)].