Nondestructive detection of photonic qubits
arXiv:2103.14677 · doi:10.1038/s41586-021-03290-z
Abstract
One of the biggest challenges in experimental quantum information is to keep the fragile superposition state of a qubit alive. Long lifetimes can be achieved for material qubit carriers as memories, at least in principle, but not for propagating photons that are rapidly lost by absorption, diffraction or scattering. The loss problem can be mitigated with a nondestructive photonic qubit detector that heralds the photon without destroying the encoded qubit. Such detector is envisioned to facilitate protocols where distributed tasks depend on the successful dissemination of photonic qubits, to improve loss-sensitive qubit measurements, and to enable certain quantum key distribution attacks. Here we demonstrate such a detector based on a single atom in two crossed fibre-based optical resonators, one for qubit-insensitive atom-photon coupling, the other for atomic-state detection. We achieve a nondestructive detection efficiency upon qubit survival of , a photon survival probability of , and preserve the qubit information with a fidelity of . To illustrate the potential of our detector we show that it can provide, already with current parameters, an advantage for long-distance entanglement and quantum-state distribution, resource optimization via qubit amplification, and detection-loophole-free Bell tests.
27 pages, main text and methods, 4 main figures, 3 extended data figures, 1 extended data table, for supplementary information see journal reference
References in corpus (13)
- An Elementary Quantum Network of Single Atoms in Optical Cavities
- Progressive field-state collapse and quantum non-demolition photon counting
- A Single-Atom Quantum Memory
- Fiber Fabry-Perot cavity with high finesse
- Quantum Non-demolition Detection of Single Microwave Photons in a Circuit
- Proposal for Implementing Device-Independent Quantum Key Distribution based on a Heralded Qubit Amplification
- Detection loophole in asymmetric Bell experiments
- Entanglement over global distances via quantum repeaters with satellite links
- A Quantum Network Node with Crossed Optical Fibre Cavities
- Heralded Storage of a Photonic Quantum Bit in a Single Atom
- Decoherence-protected memory for a single-photon qubit
- Frequency splitting of polarization eigenmodes in microscopic Fabry-Perot cavities
- Single-Photon Distillation via a Photonic Parity Measurement Using Cavity QED