A Single-Atom Quantum Memory

Abstract

The faithful storage of a quantum bit of light is essential for long-distance quantum communication, quantum networking and distributed quantum computing. The required optical quantum memory must, first, be able to receive and recreate the photonic qubit and, second, store an unknown quantum state of light better than any classical device. These two requirements have so far been met only by ensembles of material particles storing the information in collective excitations. Recent developments, however, have paved the way for a new approach in which the information exchange happens between single quanta of light and matter. This single-particle approach allows one to address the material qubit and thus has fundamental advantages for realistic implementations: First, to combat inevitable losses and finite efficiencies, it enables a heralding mechanism that signals the successful storage of a photon by means of state detection. Second, it allows for individual qubit manipulations, opening up avenues for in situ processing of the stored quantum information. Here we demonstrate the most fundamental implementation of such a quantum memory by mapping arbitrary polarization states of light into and out of a single atom trapped inside an optical cavity. The memory performance is analyzed through full quantum process tomography. The average fidelity is measured to be 93% and low decoherence rates result in storage times exceeding 180μs. This makes our system a versatile quantum node with excellent perspectives for optical quantum gates and quantum repeaters.

7 pages, 5 figures including supplementary information; 2 movies in Flash Video format as ancillary files

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Cited by in corpus (26)

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• An Elementary Quantum Network of Single Atoms in Optical Cavities
• Quantum information transfer using photons
• Efficient Teleportation between Remote Single-Atom Quantum Memories
• Efficient and long-lived quantum memory with cold atoms inside a ring cavity
• A solid state spin-wave quantum memory for time-bin qubits
• Spatially dependent electromagnetically induced transparency
• Coherent spin control at the quantum level in an ensemble-based optical memory
• Storage and retrieval of ultrafast single photons using a room-temperature diamond quantum memory
• Heralded Storage of a Photonic Quantum Bit in a Single Atom
• Interfacing GHz-bandwidth heralded single photons with a room-temperature Raman quantum memory
• Quantum storage of polarization qubits in birefringent and anisotropically absorbing materials
• Decoherence-protected memory for a single-photon qubit
• Experimental realization of 105-qubit random access quantum memory
• Quantum dynamics of a driven two-level molecule with variable dephasing
• Quantum Zeno and Anti-Zeno Effects on the Entanglement Dynamics of Qubits Dissipating into a Common and non-Markovian Environment
• Quantum phase gate Based on Electromagnetically Induced Transparency in Optical Cavities
• Entanglement dynamics for qubits dissipating into a common environment
• Photon emission and absorption of a single ion coupled to an optical fiber-cavity
• Microtoroid cavity QED with fiber overcoupling and strong atom-field coupling: a single-atom quantum switch for coherent light fields
• Dynamical scattering models in optomechanics: Going beyond the 'coupled cavities' model
• Two-color quantum memory in double Λ-media
• Towards continuous-wave regime teleportation for light matter quantum relay stations
• Squeezed Dirac and Topological Magnons in a Bosonic Honeycomb Optical Lattice
• Demonstration of a passive photon-atom swap gate
• High efficiency photonic storage of single photons in cold atoms