🔗 Quantum Entanglement
Explore the mysterious correlation Einstein called "spooky action at a distance"
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👻 What is Entanglement?
Quantum entanglement occurs when two or more qubits become correlated in a way that has no classical equivalent. Once entangled, measuring one qubit instantly determines the state of the other, regardless of the distance separating them—even if they're on opposite sides of the universe.
Einstein was deeply troubled by entanglement because it seemed to violate locality—the principle that objects are only influenced by their immediate surroundings
🎯 How Entanglement Works
Two qubits become entangled when their quantum states cannot be described independently. The entire system must be described as a single quantum state.
Apply CNOT gate or similar to create correlation
Qubits can be separated by any distance
Measuring one instantly affects the other
⚡ Key Properties
Instantaneous Correlation
The correlation happens instantly, faster than light could travel between the qubits. However, no information is transmitted—you can't use entanglement for communication.
Perfect Correlation
While individual measurements are random, the correlation between entangled qubits is 100% predictable. If one measures 0, you know with certainty what the other will measure.
Measurement Destroys Entanglement
Once you measure one qubit, the entanglement is broken. Both qubits collapse to definite states and are no longer correlated quantumly.
🌍 Applications of Entanglement
Quantum Cryptography
Entanglement enables provably secure communication through quantum key distribution (QKD)
Quantum Teleportation
Transfer quantum states across distances using entanglement and classical communication
Quantum Computing
Many quantum algorithms rely on entanglement for exponential speedup
Quantum Sensing
Entangled states enable ultra-precise measurements beyond classical limits
⚠️ Important Clarification
Entanglement does not allow faster-than-light communication. While the correlation is instant, you need classical communication to compare measurements, which is limited by light speed. This preserves causality and relativity.