Symmetries of the similarity renormalization group for nuclear forces

We analyze the role played by long-distance symmetries within the context of the similarity renormalization group (SRG) approach, which is based on phase-shift-preserving continuous unitary transformations that evolve Hamiltonians with a cutoff on energy differences. We find that there is a SRG cutoff for which almost perfect fulfillment of Wigner symmetry is found. We discuss the possible consequences of such a finding.