88 CHAPTER 3 Nanomorphic electronics Substituting (A2.6) into (A2.5) we obtain the result for minimum travel time (3.55): s ¼ L s H a H (A2.7) LIST OF SYMBOLS Symbol a a H a HB BIT C d e E E b Meaning Energy barrier width, tile size Heisenberg distinguishability length Boltzmann-Heisenberg length Maximum binary throughput Capacitance Distance Electron charge, e ¼ 1.6 Â 10 ­19 C Energy Energy barrier height