Oliver Thewalt

    Oliver Thewalt

    Theoretical Physics | Quantum Biology | Dark Matter Research Cluster


    This is why the Positive Energy Theorem is wrong

    This is why the Positive Energy Theorem is wrong!


    Negative-Mass Hydrodynamics in a Spin-Orbit–Coupled Bose-Einstein Condensate

    A negative effective mass can be realized in quantum systems by engineering the dispersion relation. A powerful method is provided by spin-orbit coupling, which is currently at the center of intense research efforts. Here we measure an expanding spin-orbit coupled Bose-Einstein condensate whose dispersion features a region of negative effective mass. We observe a range of dynamical phenomena, including the breaking of parity and of Galilean covariance, dynamical instabilities, and self-trapping. The experimental findings are reproduced by a single-band Gross-Pitaevskii simulation, demonstrating that the emerging features—shock waves, soliton trains, self-trapping, etc.—originate from a modified dispersion. Our work also sheds new light on related phenomena in optical lattices, where the underlying periodic structure often complicates their interpretation.

    Schematic representation of the 1D expansion of a SOC BEC


    Anisotropic expansion of a BEC along the direction of spin-orbit coupling


    Note about imaginary negative mass in a beyond Dirac world view – seen from (higgs) string vacua foldings - BH states - BH identity- and electron nuclear shell model





    A new proof of the positive energy theorem