The Coming of the Quantum Cats can - given different social conditions - develop completely different character traits (timid or assertive, benevolent or predatory, etc.) The title refers to the famous thought-experiment known as "Schrödinger's Cat", where the outcome of a real-world event depends on a quantum event. By some interpretations, the real-world object, in this case a cat, must be in two states simultaneously until it is observed. However, the story is more closely related to the many-worlds interpretation of quantum mechanics where all possible outcomes of an event occur, each in its own parallel universe. The same concept was treated, somewhat more pessimistically, in
Introduction to quantum mechanics by a small amount, where only one line was expected. Pauli formulated his "exclusion principle", stating that "There cannot exist an atom in such a quantum state that two electrons within [it] have the same set of quantum numbers." A year later, [[George Eugene Uhlenbeck|Uhlenbeck]] and [[Samuel Goudsmit|Goudsmit]] identified Pauli's new degree of freedom with the property called [[spin (physics)|spin]] whose effects were observed in the Stern–Gerlach experiment. Bohr's model of the atom was essentially a planetary one, with the electrons orbiting around the nuclear "sun." However, the uncertainty principle states that an electron cannot simultaneously have an exact location