The idea that the entire universe is a single quantum object is a radical one, but it is one that is gaining increasing attention among physicists. There are a number of reasons why this might be the case.
First, quantum mechanics tells us that all objects, including the universe itself, are made up of waves of probability. These waves can interfere with each other, just like the waves of light that create an interference pattern in a double-slit experiment. This means that the universe could be in a superposition of states, meaning that it could be in multiple states at the same time.
Second, quantum entanglement is a phenomenon in which two particles are linked together in such a way that they share the same fate, even if they are separated by a great distance. This suggests that the universe may be a single, entangled system.
Third, the laws of quantum mechanics seem to break down at the very large scale. This is known as the quantum-to-classical transition, and it is not fully understood. However, it is possible that the entire universe is a quantum object that has simply become "classical" due to its enormous size.
Of course, there are also some challenges to the idea that the universe is a single quantum object. For example, it is not clear how we would measure such a large and complex system. However, the possibility is intriguing, and it is one that is worth exploring further.
In the meantime, physicists are conducting experiments to test the idea that the universe is a quantum object. These experiments are still in their early stages, but they have the potential to revolutionize our understanding of reality.