The second law of thermodynamics is a fundamental principle in physics that describes the behavior of macroscopic systems and the flow of heat. It states that the entropy of an isolated system tends to increase over time or, at best, remains constant in reversible processes. The law provides a statistical understanding of the direction of natural processes, particularly the irreversibility of certain macroscopic phenomena.
The prohibition on breaking the second law of thermodynamics arises from the empirical observation that, in the vast majority of cases, macroscopic systems naturally tend to evolve towards states of higher entropy. This observation is supported by a large body of experimental evidence and has been successfully applied in various fields, such as engineering, chemistry, and biology.
The principle of macroscopic tunneling, on the other hand, is a concept that arises from quantum mechanics. It involves the quantum phenomenon where a particle can penetrate a classically forbidden energy barrier or cross an energy barrier without the need for classical energy. Macroscopic tunneling refers to the tunneling of larger, more complex objects, such as superconducting circuits or even small biological systems, through barriers.
The reason why physicists do not state that macroscopic tunneling is prohibited is because it is a phenomenon that can occur in specific quantum systems under certain conditions. While macroscopic tunneling is less common and less easily observable in everyday macroscopic objects due to the exponential decrease in probability with increasing size and complexity, it is a well-established phenomenon within the framework of quantum mechanics.
The key distinction is that the second law of thermodynamics is a fundamental principle that describes the behavior of macroscopic systems on average, based on statistical considerations, while macroscopic tunneling is a quantum mechanical phenomenon that can occur in certain quantum systems under specific conditions.
It is important to note that the second law of thermodynamics and macroscopic tunneling are not contradictory. The second law provides a statistical framework for the behavior of macroscopic systems, while macroscopic tunneling is a quantum effect that operates at the microscopic level. Both concepts have their respective domains of applicability and do not violate each other.