  Quantum plasmonic systems suffer from significant decoherence due to the
intrinsically large dissipative and radiative dampings. Based on our quantum
simulations via a quantum tensor network algorithm, we numerically demonstrate
the mitigation of this restrictive drawback by hybridizing a plasmonic
nanocavity with an emitter ensemble with inhomogeneously-broadened transition
frequencies. By burning two narrow spectral holes in the spectral density of
the emitter ensemble, the coherent time of Rabi oscillation for the hybrid
system is increased tenfold. With the suppressed decoherence, we move one step
further in bringing plasmonic systems into practical quantum applications.
