As for Barbara Fredrickson, she defines love as a positive resonance that manifests when three events occur simultaneously: the sharing of one or several positive emotions, a synchrony between the behavior and physiological reactions of two people, and the intention to contribute to the other's well-being, an intention that engenders mutual care. 4 This resonance of positive emotions can last for a certain amount of time, or be amplified like the reverberation of an echo, until, inevitably, as is the fate of all emotions, it vanishes.
According to this definition, love is both vaster and more open, and its duration shorter than we generally think: "Love is not lasting. It's actually far more fleeting than most of us would care to acknowledge. On the upside, though, love is forever renewable." The research of Fredrickson and her colleagues has in fact shown that although love is very sensitive to circumstances and requires certain preliminary conditions, once these conditions have been identified, one can reproduce this feeling of love an incalculable number of times each day."
Ricard, Matthieu (2015-06). Altruism: The Power of Compassion to Change Yourself and the World (p. 66). Little, Brown and Company.