In the framework of quantum mechanics, entanglement is a fundamental and pervasive phenomenon. It arises when two or more particles become correlated in such a way that the state of one particle cannot be described independently of the others. This means that if two particles are entangled, measuring the state of one particle instantaneously affects the state of the other particle, regardless of the physical distance between them.
Given the ubiquity of entanglement in quantum mechanics, it is generally expected that most systems in the quantum world can exhibit entanglement. However, it is important to note that entanglement depends on the specific interactions and conditions of the system under consideration. In certain situations, such as when particles are non-interacting or are in separable states, they may not exhibit entanglement.
For example, if two particles are in independent, uncorrelated states, they are considered separable, and there is no entanglement between them. Additionally, macroscopic objects with a large number of particles can often be effectively described without invoking entanglement because the entanglement tends to diminish as the number of particles increases.
In summary, while entanglement is a fundamental feature of quantum mechanics, there can be situations where particles or systems do not exhibit entanglement. The presence or absence of entanglement depends on the specific conditions, interactions, and states of the particles or systems involved.