  We propose to use the spin-blockade regime in double quantum dots to reduce
nuclear spin polarization fluctuations in analogy with optical Doppler cooling.
The Overhauser shift brings electron levels in and out of resonance, creating
feedback to suppress fluctuations. Coupling to the disordered nuclear spin
background is a major source of noise and dephasing in electron spin
measurements in such systems. Estimates indicate that a better than 10-fold
reduction of fluctuations is possible.
