## Summary

Losses in physical channels, such as optical fibres, limit existing quantum communication systems to modest distance ranges. Since amplification of quantum signals is fundamentally not possible, we look to extend the range and functionality of these quantum channels by adding quantum memory nodes that can daisy-chain multiple lengths of quantum channels through entanglement and thus extend the communication distance — an approach known as ‘quantum repeater’. Quantum repeaters are by necessity hybrid devices, as they connect flying qubits (photons) to small processors for error correction and privacy amplification. In this project we develop a two-node proof-of-principle hybrid quantum repeater system. We generate entangled photon pairs from quantum dots embedded in semiconductor nanowire and store them in atomic quantum memories following a frequency up-conversion. We expect this will enable quantum key distribution over long distances at rates exceeding those possible through a direct link. The photon-pair sources, the frequency converters, as well as the quantum memories will be implemented in compact on-chip platforms. This novel approach combines the advantages available from a deterministic and tunable solid-state source of bright entangled photon pairs with the potential for high-efficiency long-lived quantum memory that is achievable with laser cooled atoms. The ultimate goal is to achieve a working pair of quantum repeater nodes at practically relevant wavelengths that would lead to useful rates for long-distance quantum key distribution.

## Related Content

## Materials for Majorana-based Topological Qubits

Summary Topological qubits offer a novel pathway to scalable quantum computing by simultaneously allowing for ease of coupling between qubits and strong decoupling of qubits from noise and dissipation. The most promising direction explores the topologically induced protection of theoretically predicted exotic quasiparticles, the so-called Majorana Zero Modes or MZMs. To-date MZMs, which follow […]

January 28, 2019

## Mesoscopic systems as coherent control elements

Summary Mesoscopic systems provide a new tool for quantum systems design. In particular, they are enabling of robust quantum control. Here “mesoscopic system” refers to a connected network where each element, if studied alone, would be a quantum bit. The network is too big to be treated fully quantum mechanically. We do not have individual […]

September 1, 2016

## Silicon Platform for Electron Spin Qubits

Summary Scaling solid-state quantum processors to a useful threshold while maintaining the requisite precision in quantum control remains a challenge. We propose a quantum metal-oxide-semiconductor (QMOS) architecture operating at cryogenic temperatures that is based on a network/node approach as a means to scalability. By working with QMOS, we benefit from the deep investments and […]

December 7, 2018

## Free-space Polarization-selective Microcavity based on Chiral Metasurfaces

Summary Developing a new type of Fabry-Pérot cavity that allows improved control of the atoms’ emission into the cavity mode will result in enhancement of the efficiency and fidelity of quantum state transfer from photons to atoms and back. This in turn can be used to improve the performance of quantum networks and repeaters, as […]

September 19, 2019