In the context of quantum mechanics, entanglement refers to a phenomenon where two or more particles become correlated in such a way that the state of one particle is dependent on the state of the others, regardless of the distance between them. This correlation persists even when the particles are physically separated, and their states remain intertwined or "entangled" with each other.
To understand how entanglement works, let's consider an example involving two particles, A and B. Quantum mechanics describes the state of each particle using a mathematical construct called a wavefunction. When particles A and B are in an entangled state, their individual wavefunctions become intertwined, forming a combined wavefunction that describes the entire system.
The entangled state of particles A and B is typically created through a process such as interaction or decay, where the resulting state is a superposition of all possible combinations of their properties. For instance, if we have a pair of entangled particles with an uncertain spin orientation (a property of particles), their combined state could be something like:
|A: spin up⟩ ⊗ |B: spin down⟩ - |A: spin down⟩ ⊗ |B: spin up⟩
This means that the spin state of particle A is entangled with the spin state of particle B. The fascinating aspect of entanglement is that measuring the spin of one particle, say particle A, instantaneously affects the spin of particle B, regardless of the spatial separation between them. The measurement outcome of one particle becomes correlated or linked to the other particle's measurement outcome.
However, it's important to note that entanglement is a property observed at the microscopic scale and is typically not applicable to macroscopic objects like rocks or larger systems. Entanglement requires delicate quantum systems and controlled conditions to maintain coherence. While there are ongoing research efforts in exploring quantum phenomena in larger systems, the ability to become entangled with a macroscopic object like a rock is currently beyond our technological capabilities and understanding.