Quantum Energy Teleportation

Hotta's 2008 Quantum Energy Teleportation protocol shows that when two observers share the ground state of an interacting Hamiltonian, one can "teleport" locally-accessible energy by measuring their half and sending the outcome as a single classical bit. The receiver applies a conditional rotation and — impossibly, at first glance — extracts a negative amount of local energy while global energy conservation is preserved by the exchange.

Ikeda's 2023 IBM hardware demonstration confirmed the protocol experimentally. This showcase reproduces the full protocol on a 2-qubit ground state, verifies Bob's optimum matches the analytical θ = π/2, and demonstrates that Qubital's ZNE mitigation recovers the fragile negative-energy signature with 632× less error than raw Heron-scale noise.

VQE preparation of the 2-qubit interacting ground state (RY–CX–RY ansatz, 4 parameters, SPSA optimizer). Alice performs a projective Z-measurement on qubit 0 and sends the outcome as a classical bit. Bob applies a conditional rotation R_Y(±θ) on qubit 1 and Qubital reads out ⟨H_B⟩ = h⟨X_1⟩ via an X-basis measurement.

For the mitigation demo, we deliberately amplify device noise, apply global circuit folding at fold factors {1×, 3×, 5×}, and use Richardson linear extrapolation to recover the noiseless value at scale = 0.