Quantum Entanglement
Definition
Quantum entanglement is a physical phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in such a way that the quantum state of each particle of the group cannot be described independently of the state of the others, even when the particles are separated by a large distance.
Why It Matters
Entanglement creates a deep connection between qubits. If you measure the state of one entangled qubit, you instantly know the state of the other, no matter how far apart they are. This property is essential for many quantum computing algorithms and for quantum communication.
Contextual Example
Imagine two entangled coins. If you flip one and it lands on heads, you instantly know the other coin, even if it's on the other side of the world, must have landed on tails. This is the "spooky action at a distance" that Einstein famously described.
Common Misunderstandings
- Entanglement does not allow for faster-than-light communication, because you still need to use a classical communication channel to know what measurement to perform or what the result was.
- It is a key resource in quantum computing.