I was under the impression that there were potential positive-energy solutions to this problem that don't require antimatter: https://iopscience.iop.org/article

I was under the impression that there were potential positive-energy solutions to this problem that don't require antimatter: https://iopscience.iop.org/article/10.1088/1361-6382/abe692 https://iopscience.iop.org/article/10.1088/1361-6382/abe692