Playground
超密 Superdense
Send 2 classical bits using only 1 qubit
Protocol Visualization
Alice
State
½ of |Φ⁺⟩
Message
00
Quantum Channel
Bob
State
½ of |Φ⁺⟩
1
Setup: Shared Entanglement
Alice and Bob share a Bell pair: (|00⟩ + |11⟩)/√2
Select Message (2 bits)
Encoding Operation
I (Identity)
Do nothing
00 → I (Identity)
01 → X (Bit flip)
10 → Z (Phase flip)
11 → ZX (Both)
How It Works
- • Pre-shared entanglement enables this
- • Alice encodes 2 bits into 1 qubit
- • Only 1 qubit travels the channel
- • Bob uses both qubits to decode
- • Opposite of quantum teleportation!
Classical vs Quantum
Classical:2 bits → 2 bits sent
Quantum:2 bits → 1 qubit sent