  Recently, our efforts to clarify the old question, if a memristor is a
passive or active device [1], triggered debates between engineers, who have had
advanced definitions of passivity/activity of devices, and physicists with
significantly different views about this seemingly simple question. This debate
triggered our efforts to test the well-known engineering concepts about
passivity/activity in a deeper way, challenging them by statistical physics. It
is shown that the advanced engineering definition of passivity/activity of
devices is self-contradictory when a thermodynamical system executing
Johnson-Nyquist noise is present. A new, statistical physical, self-consistent
definition based on the Second Law of Thermodynamics is introduced. It is also
shown that, in a system with uniform temperature distribution, any rectifier
circuitry that can rectify thermal noise must contain an active circuit
element, according to both the engineering and statistical physical
definitions.
