Quantum effects are generally not observed on macroscopic scales or large objects because of a process called decoherence. Decoherence refers to the interaction of a quantum system with its surrounding environment, which leads to the suppression or "washing out" of quantum behavior on larger scales. Let's explore this further:
Interaction with the Environment: When a quantum system interacts with its environment, it becomes entangled with the environmental degrees of freedom. This entanglement causes the delicate quantum superpositions to rapidly degrade and lose coherence. The more particles and degrees of freedom involved, the more likely and faster the decoherence process occurs.
Amplification of Small Differences: Quantum systems are highly sensitive to their initial conditions and any external disturbances. Even tiny differences or fluctuations in the environment can have a significant impact on the quantum state of a system. As interactions with the environment increase, these small differences become amplified, causing the system to quickly lose its quantum properties and behave classically.
Many-Body Interactions: Large objects consist of an enormous number of particles and degrees of freedom, all interacting with each other. This leads to complex and chaotic behavior, which can overwhelm and dominate any subtle quantum effects. In such systems, the individual quantum behaviors of particles average out, resulting in classical behavior at the macroscopic level.
Energy Considerations: Quantum effects often become negligible at macroscopic scales due to the large energy involved. The characteristic energies associated with quantum behavior, such as the energy levels of atoms or subatomic particles, are typically much smaller than the thermal energy of macroscopic objects. As a result, thermal fluctuations and random motions of particles in large objects tend to overshadow the quantum effects.
However, it is worth mentioning that there are some exceptions to this general rule. Certain macroscopic phenomena, such as superconductivity and superfluidity, can exhibit collective quantum behavior that persists on larger scales. These phenomena arise due to cooperative effects and specific conditions that protect quantum coherence from decoherence processes.
In summary, quantum effects tend to be suppressed or "washed out" on macroscopic scales due to the interaction with the environment, amplification of small differences, many-body interactions, and the dominance of thermal energy. These factors collectively contribute to the classical behavior observed in everyday objects.