Quantum communication employs the counter-intuitive features of quantum physics fortasks that are impossible in the classical world. It is crucial for testing the foundations ofquantum theory and promises to revolutionize information and communication technologies.However, to execute even the simplest quantum transmission, one must establish, andmaintain, a shared reference frame. This introduces a considerable overhead in resources,particularly if the parties are in motion or rotating relative to each other. Here we experimentallyshow how to circumvent this problem with the transmission of quantum information encodedin rotationally invariant states of single photons. By developing a complete toolbox forthe efficient encoding and decoding of quantum information in such photonic qubits, wedemonstrate the feasibility of alignment-free quantum key-distribution, and perform proofof-principle demonstrations of alignment-free entanglement distribution and Bell-inequalityviolation. The scheme should find applications in fundamental tests of quantum mechanics andsatellite-based quantum communication.
展开▼
