  We propose a method for protecting fragile quantum superpositions in
many-particle systems from dephasing by external classical noise. We call
superpositions "fragile" if dephasing occurs particularly fast, because the
noise couples very differently to the superposed states. The method consists of
letting a quantum superposition evolve under the internal thermalization
dynamics of the system, followed by a time reversal manipulation known as
Loschmidt echo. The thermalization dynamics makes the superposed states almost
indistinguishable during most of the above procedure. We validate the method by
applying it to a cluster of spins-1/2.
