  The unique capability of quantum mechanics to evolve alternative
possibilities in parallel is appealing and over the years a number of quantum
algorithms have been developed offering great computational benefits. Systems
coupled to the environment lose quantum coherence quickly and realization of
schemes based on unitarity might be impossible. Recent discovery of room
temperature quantum coherence in light harvesting complexes opens up new
possibilities to borrow concepts from biology to use quantum effects for
computational purposes. While it has been conjectured that light harvesting
complexes such as the Fenna-Matthews-Olson (FMO) complex in the green sulfur
bacteria performs an efficient quantum search similar to the quantum Grover's
algorithm the analogy has yet to be established.
  In this work we show that quantum dissipation plays an essential role in the
quantum search performed in the FMO complex and it is fundamentally different
from known algorithms. In the FMO complex not just the optimal level of phase
breaking is present to avoid both quantum localization and Zeno trapping but it
can harness quantum dissipation as well to speed the process even further up.
With detailed quantum calculations taking into account both phase breaking and
quantum dissipation we show that the design of the FMO complex has been
evolutionarily optimized and works faster than pure quantum or
classical-stochastic algorithms. Inspired by the findings we introduce a new
computational concept based on decoherent quantum evolution. While it is
inspired by light harvesting systems, the new computational devices can also be
realized on different material basis opening new magnitude scales for
miniaturization and speed.
