Quantum teleportation from a telecom-wavelength photon to a solid-state quantum memory (1401.6958v1)

Abstract: In quantum teleportation, the state of a single quantum system is disembodied into classical information and purely quantum correlations, to be later reconstructed onto a second system that has never directly interacted with the first one. This counterintuitive phenomenon is a cornerstone of quantum information science due to its essential role in several important tasks such as the long-distance transmission of quantum information using quantum repeaters. In this context, a challenge of paramount importance is the distribution of entanglement between remote nodes, and to use this entanglement as a resource for long-distance light-to-matter quantum teleportation. Here we demonstrate quantum teleportation of the polarization state of a telecom-wavelength photon onto the state of a solid-state quantum memory. Entanglement is established between a rare-earth-ion doped crystal storing a single photon that is polarization-entangled with a flying telecom-wavelength photon. The latter is jointly measured with another flying qubit carrying the polarization state to be teleported, which heralds the teleportation. The fidelity of the polarization state of the photon retrieved from the memory is shown to be greater than the maximum fidelity achievable without entanglement, even when the combined distances travelled by the two flying qubits is 25 km of standard optical fibre. This light-to-matter teleportation channel paves the way towards long-distance implementations of quantum networks with solid-state quantum memories.

• The paper presents a pioneering demonstration of teleporting the polarization state from a telecom-wavelength photon to a rare-earth-doped quantum memory with fidelity surpassing classical limits.
• It employs superconducting nanowire single-photon detectors and rare-earth-ion doped crystals for efficient multimode storage and state retrieval.
• The experiment, conducted over 25 km of optical fiber, highlights a scalable approach for integrating quantum networks with existing telecom infrastructures.

Quantum Teleportation from a Telecom-Wavelength Photon to a Solid-State Quantum Memory

The paper in question explores a pioneering demonstration of quantum teleportation, specifically, from a telecom-wavelength photon to a solid-state quantum memory. This research highlights a significant stride in advancing the implementation of quantum networks by effectively leveraging the utility of quantum memories with photon entanglement.

Overview of Quantum Teleportation Techniques and Memory Integration

Quantum teleportation, first proposed by Bennett et al., is an integral component for quantum communication and computation frameworks. The technique relies on entangling two remote systems and using classical communication to transfer the quantum state of a particle from one location to another. In the domain of quantum networking, teleportation must also efficiently integrate quantum memories. These memories, previously demonstrated with atomic ensembles or quantum dot spin qubits, store quantum information, thus enabling scalable, long-distance quantum communication using schemes like quantum repeaters.

This paper addresses the challenge of combining quantum teleportation with solid-state quantum memories, which hold promise due to their multimode storage capabilities and large bandwidths. Specifically, the researchers focus on quantum memories based on rare-earth-ion doped crystals, known for their robustness and efficiency in terms of storage and retrieval of quantum information under multimode operation.

Experimental Implementation and Results

The experimental setup employed here distinctive relies on the generation of entangled photon pairs using spontaneous parametric downconversion, involving one photon being telecom-wavelength and the other being stored in a nearby quantum memory. The essence of the experimental procedure was to set the teleportation of the polarization state of the telecom-wavelength photon onto the rare-earth-ion doped quantum memory.

Two noteworthy aspects of the experiment include the use of superconducting nanowire single-photon detectors, which significantly enhance the success rate of teleportation, and the effective polarization-preserving aspect of the memory that ensures high fidelity of recoveries. Notably, the fidelity of the teleported state was measured to surpass classical limits, demonstrating the adequacy of entanglement in mediating quantum state transfer.

In terms of long-distance capabilities, the paper reports achieving successful teleportation over a 25-km optical fiber, exhibiting the potential scalability of the technique for wider applications.

Implications and Future Directions

The presented paper holds profound implications for the future of quantum network architectures, especially in establishing practical long-distance quantum communication networks. The integration of telecom-wavelength photons with solid-state memories makes it highly feasible to deploy such systems over existing fiber-optic infrastructures. Moreover, achieving high fidelity over significant distances sketches a promising future for real-world quantum repeater networks.

The quest for enhancing the efficiency of quantum memories continues, with ongoing efforts to develop memories with on-demand readout capabilities, exploring spin level storage and optimizing spectral multimode storage to alleviate constraints on performance. Furthermore, coupling these quantum memories with superconducting qubits might pave the way for deterministic quantum logical operations within solid-state quantum networks.

Conclusively, this paper delineates an insightful experimental exploration into the amalgamation of quantum teleportation and memory technologies, setting the stage for robust and scalable quantum information networks.