No, qubits do not have to be physically close to each other to become initially entangled. Entanglement is a property of the quantum state that can arise regardless of the spatial separation between the qubits.
Entanglement is a phenomenon in which the quantum states of multiple particles become correlated in such a way that the state of one particle cannot be described independently of the state of the other particles. When qubits are entangled, the quantum state of the combined system cannot be expressed as a simple product of individual qubit states.
Entanglement can occur through various processes, such as interactions between qubits or through measurements performed on a larger quantum system. These interactions can occur even if the qubits are physically separated by large distances.
In fact, the ability to generate and manipulate entanglement between qubits that are physically distant from each other is one of the key challenges in quantum information processing and quantum communication. It is an area of active research, and several protocols have been proposed to generate entanglement between remote qubits, including using entanglement swapping and distributed entanglement generation schemes.
While physical proximity can simplify the generation of entanglement between qubits, it is not a strict requirement. The entanglement between qubits can be established and manipulated through various means, irrespective of their spatial separation.