The assumption that macroscopic objects can undergo quantum tunneling, albeit with extremely small probabilities, is based on the principles of quantum mechanics and the wave-particle duality of matter. Quantum mechanics describes the behavior of particles at the microscopic level, where they can exhibit wave-like properties.
According to quantum mechanics, particles are described by wave functions that represent the probability distribution of their properties, such as position or energy. Quantum tunneling occurs when a particle with wave-like properties encounters a potential barrier that would classically prevent it from crossing. In quantum mechanics, there is a non-zero probability that the particle can "tunnel" through the barrier and appear on the other side, even though it does not have enough energy to overcome the barrier classically.
Macroscopic objects, such as everyday objects or even larger systems, are made up of an enormous number of particles. When these particles collectively behave quantum mechanically, their wave functions can become entangled and exhibit coherence, allowing for the possibility of macroscopic quantum phenomena.
While quantum tunneling is typically associated with individual particles, it has been theoretically proposed that under certain conditions, macroscopic objects could also exhibit quantum tunneling behavior. This idea is based on the concept of wave function delocalization, where the wave function of a macroscopic object can spread out over different positions, including regions behind a potential barrier.
The probability of macroscopic objects undergoing quantum tunneling becomes exceedingly small as the objects increase in size and complexity. This is due to the rapid decoherence and interaction with the environment that macroscopic systems experience, which disrupts the delicate quantum states and transitions. The scale at which macroscopic quantum effects become negligible and classical behavior dominates is known as the quantum-classical boundary or the "measurement problem."
While experimental evidence of macroscopic quantum tunneling remains elusive, some physicists explore the possibility and study systems where macroscopic objects, such as superconducting circuits or Bose-Einstein condensates, exhibit quantum behavior. These studies aim to better understand the boundaries between quantum and classical realms and explore potential applications in quantum technologies.
It's important to note that the assumption of macroscopic quantum tunneling is still a topic of active research and debate within the scientific community. The exploration of quantum phenomena at larger scales is a complex and challenging field, and further advancements in experimental techniques and theoretical frameworks are necessary to fully understand and characterize the behavior of macroscopic systems in the quantum realm.