Systems and processes studied in the Theoretical Division reveal essential quantum coherence. We are interested in three different problems. First, in a response of relatively small molecules to a series of coherent light pulses one can observe dephasing and reconstitution of phases, the so called quantum echo, with the help of which it is possible to learn more about interaction of electrons with vibrations. Coherent processes also appear in large biomolecules, e.g. chlorophyll, where they form the basis of the quantum biology - the second family of problems. Third, macroscopic quantum coherence lies in the heart of all unusual phenomena of superconductivity.