Experiment #56 · Scientific experiment

Quantum Teleportation

Transferring quantum states using entanglement and classical communication

Bouwmeester, Pan, Mattle, Eibl, Weinfurter, Zeilinger (experiment); Bennett et al. (1993, theory) · 1997 (first experiment); 1993 (theory) · Quantum information

First published: D. Bouwmeester et al., "Experimental Quantum Teleportation", *Nature* 390 (1997): 575–579; theory: C. H. Bennett et al., *Phys. Rev. Lett.* 70 (1993): 1895.

Alice can transfer the quantum state of a particle to Bob — destroying it in the process — using only a shared entangled pair and two classical bits.

Quantum teleportation transfers an unknown quantum state from one particle to another without physically moving the original particle. Alice and Bob share a pair of entangled particles; Alice has a third particle in an unknown state she wishes to transfer. She performs a joint measurement on her two particles (a Bell-state measurement), destroying the original's state in the process. The outcome (2 bits) is sent to Bob by classical channel; Bob applies a corresponding unitary operation to his entangled particle, recovering Alice's original state. The no-cloning theorem guarantees Alice's original cannot be reconstructed; the classical-information requirement guarantees no faster-than-light transmission. The 1997 Innsbruck experiment demonstrated the protocol for photon polarisation states, and later experiments extended it to atoms, ions, and eventually satellite-scale distances (Micius, 2017). The phenomenon is a foundational protocol for quantum information and a clean test of entanglement's computational substance.

Formulation

Alice has unknown qubit |ψ⟩. Alice and Bob share entangled pair |Φ⁺⟩. Alice performs Bell-state measurement on |ψ⟩ and her half of the pair, obtains 2-bit outcome. Sends outcome classically to Bob; Bob applies corresponding Pauli operation to his half of pair → his particle is now in state |ψ⟩. Alice's original state is destroyed by the Bell measurement.

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Dimensions Engaged

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Information

A foundational case for Information · Ontological Status: quantum information is a definite resource that can be transferred, but subject to constraints (no-cloning, classical-channel requirement) absent in classical information.

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Space

Engages Space · Locality in a refined way: entanglement is non-local, but actual information transfer requires a classical channel, preserving relativistic causality.

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Matter

Indirectly: highlights the distinction between matter (the substrate) and the quantum state (the information) — what is transferred is the state, not the matter.

Responses — How Schools Engage

Affirms / takes the bait 5

Quantum Realism

A canonical demonstration of entanglement as a real physical resource. Quantum states are transferable objects, with reality independent of any particular physical substrate.

Dataism / Information Ontology

A foundational moment: information is shown to be distinct from its substrate and transferable in quantum-mechanical units. The information ontology of physics gains crisp empirical content.

Naturalism

A canonical proof-of-concept for quantum information processing. The protocol is implemented and works; the foundations of quantum computing rest on this and related experiments.

Structuralism

A textbook case of structural physics: what is "transferred" is a quantum state, identified by its place in Hilbert space rather than by any intrinsic substantival nature.

Logical Positivism

A model operational success: a protocol predicted in theory and realised in the laboratory, with verifiable outcomes at every step. No metaphysical baggage required.

Reframes the question 1

Multiverse Theory

Everettian: the "teleportation" is a particular correlation between branches, achieved by decoherence and selection. The classical bits identify which branch Bob is in.