Quantum noise minimization in transistor amplifiers
  General quantum restrictions on the noise performance of linear transistor amplifiers are used to identify the region in parameter space where the quantum-limited performance is achievable and to construct a practical procedure for approaching it experimentally using only the knowledge of directly measurable quantities: the gain, (differential) conductance and the output noise. A specific example of resonant barrier transistors is discussed. 
U. Gavish, B. Yurke, Y. Imry