Quantum Teleportation
Quantum Teleportation
One-line summary: Transferring an unknown quantum state to a distant particle using shared entanglement plus a classical channel — the state moves, the particle doesn't, and nothing exceeds light speed.
The insight
Quantum teleportation reconstructs an unknown quantum state at a remote location by consuming a shared entangled pair and a Bell-state measurement, with the result sent over a classical channel. It is a cornerstone protocol for quantum networks (state transfer between nodes). Crucially it does not violate no-signaling: the classical channel is mandatory, so teleportation is light-speed-limited like everything else.
Evidence
- From 2026-05-30-academic-research-quantum-entanglement: metropolitan-scale teleportation over a 64-km fiber channel at 7.1 Hz, single-photon fidelity ≥90.6% (beating the classical 2/3 bound) (Shen et al. 2023, Light: Science & Applications).
- From 2026-05-30-academic-research-quantum-entanglement: high-dimensional (3-level) teleportation in a six-photon system, process fidelity F = 0.596, using two auxiliary entangled photons for a deterministic 3D Bell-state measurement (Hu et al. 2020, PRL).
- From 2026-05-30-academic-research-quantum-entanglement: between two remote semiconductor quantum dots at telecom wavelength (via frequency conversion), post-selected fidelity 0.721 (Strobel et al. 2025, Nature Communications) — this is the peer-reviewed primary source behind the Stuttgart result the web pass cited from a news outlet (see quantum-internet).
Why it matters
Teleportation is how quantum information moves between network nodes without physically transporting the carrier — a building block for the quantum-internet alongside entanglement swapping. The fidelity bar to clear is the classical limit (2/3 for single-qubit); all three results above exceed it.
Open questions
- Pushing rate × distance × fidelity simultaneously (Shen et al. note high-rate metro teleportation is "extremely desired").
- Deterministic (vs post-selected) teleportation between independent solid-state sources.