Phys.org April 15, 2024 An international team of researchers (Denmark, Croatia) demonstrated a memory for light based on optomechanically induced transparency. They achieved a long storage time by leveraging the ultralow dissipation of a soft-clamped mechanical membrane resonator, which oscillated at MHz frequencies. At room temperature, they demonstrated a lifetime T1≈23 ms and a retrieval efficiency η≈40% for classical coherent pulses. According to the researchers the storage of quantum light is possible at moderate cryogenic conditions (T≈10K) and such systems could find applications in emerging quantum networks, where they could serve as long-lived optical quantum memories by storing optical information in […]
Tag Archives: Quantum memory
Materials research explores design rules and synthesis of quantum memory candidates
Phys.org March 11, 2024 Stoichiometric Eu3+ compounds have recently shown promise for building dense, optically addressable quantum memory as the cations’ long nuclear spin coherence times and shielded 4f electron optical transitions provide reliable memory platforms but finding rare linewidth behavior within a wide range of potential chemical spaces remains difficult. Researchers at the University of Illinois, Urbana─Champaign, have found density functional theory (DFT) procedures that reliably reproduce known phase diagrams and correctly predict two experimentally realized quantum memory candidates. They synthesized the double perovskite halide Cs2NaEuF6 which is an air-stable compound with a calculated band gap of 5.0 eV […]
Researchers achieve record entanglement of quantum memories
Phys.org July 7, 2022 To fully use entanglement over long-distance quantum network links it is mandatory to know it is available at the nodes before the entangled state decays. An international team of researchers (Austria, Germany) demonstrated entanglement between two independently trapped single rubidium atoms generated over fibre links with a length up to 33 km. They generated atom–photon entanglement in two nodes located in buildings 400 m line-of-sight apart and to overcome high-attenuation losses in the fibres converted the photons to telecom wavelength using polarization-preserving quantum frequency conversion. The long fibres guided the photons to a Bell-state measurement setup in which […]
Researchers report breakthrough that enables practical semiconductor spintronics
Phys.org April 8, 2021 By remote spin filtering of InAs quantum-dot electrons via an adjacent tunnelling-coupled GaNAs spin filter an international team of researchers (Sweden, Finland, Japan) demonstrated successful generation of conduction electron spin polarization exceeding 90% at room temperature without a magnetic field in a non-magnetic all-semiconductor nanostructure, which remains high even up to 110 °C. They also showed that the quantum-dot electron spin can be remotely manipulated by spin control in the adjacent spin filter, paving the way for remote spin encoding and writing of quantum memory as well as for remote spin control of spin–photon interfaces. This work […]
Tunable diamond string may hold key to quantum memory
Science Daily May 22, 2018 The uncontrolled interaction of a quantum system with its environment is detrimental for quantum coherence. An international team of researchers (USA – Harvard University, Sandia National Laboratory, UK) used a nano-electro-mechanical system to mitigate the effect of thermal phonons on a spin qubit, the silicon vacancy color center, without changing the system temperature. By controlling the strain environment of the colour centre, they tuned its electronic levels to probe, control, and eventually suppress the interaction of its spin with the thermal bath. Strain control provided both large tunability of the optical transitions and significantly improved […]