A physical system is called coherent when its quantum state phase is well defined. An ensemble of fluctuating atoms/molecules – since they are made up of charged particles – are producing an electromagnetic field that in turn drives the fluctuating particles, and so on.
At a fixed temperature, when the density of the particles exceeds a threshold, there is a self-consistent physical state where particles oscillate in unison between two definite energetic configurations in tune with a non vanishing electromagnetic field.
In this condition, the transition to this new physical state is spontaneous because it is driving the system to a lower energy configuration.
Many experimental data, especially in the last 30 years, are showing with more and more evidence that many macroscopic systems appear to follow this natural “law”.
The conceptual and practical consequences of this “law” are astonishingly wide.
Starting as early as 2011, the International Conference on Materials and Applications for Sensors and Transducers (ICMAST), has a dedicated LECS Session, whose Chairman is Roberto Germano (PROMETE’s CEO).