  Configuration-constrained calculations of potential-energy surfaces in
even-even superheavy nuclei reveal systematically the existence at low
excitation energies of multi-quasiparticle states with deformed axially
symmetric shapes and large angular momenta. These results indicate the
prevalence of long-lived, multi-quasiparticle isomers. In a quantal system, the
ground state is usually more stable than the excited states. In contrast, in
superheavy nuclei the multi-qausiparticle excitations decrease the probability
for both fission and $\alpha$ decay, implying enhanced stability. Hence, the
systematic occurrence of multi-qausiparticle isomers may become crucial for
future production and study of even heavier nuclei. The energies of
multi-quasiparticle states and their $\alpha$ decays are calculated and
compared to available data.
