V. Dominguez Tubio
Please Note
4 records found
1
Quantum networks with satellites
Hardware, protocol and architectures
To this end, we begin by exploring how current satellite links can be made more efficient, specifically, how to increase the amount of quantum information reaching the ground stations, avoiding the requirement of long coherent time in the quantum memories and without altering the satellite hardware. We propose the use of high-dimensional encoding, showing an improvement in the rate of entanglement compared with conventional qubit encoding.
From there, the discussion expands to a full quantum network architecture using several quantum repeaters place in space, with the aim of achieving secure liks across intercontinental distances. We propose a setup based on individually trapped atoms acting as both single-photon sources and quantum memories. Incorporating hardware imperfections and modeling transmission losses through free space and the atmosphere, we estimate the hardware performance required to achieve high-fidelity entanglement at a chosen transmission rate.
Finally, we go to a more specific example of distributing quantum key (QKD) to different cities of the Iberian Peninsula. Taking into account real-time weather conditions, atmospheric effects, and propagating losses, we analyze the feasibility of deploying current use cases of satellite-based QKD. ...
To this end, we begin by exploring how current satellite links can be made more efficient, specifically, how to increase the amount of quantum information reaching the ground stations, avoiding the requirement of long coherent time in the quantum memories and without altering the satellite hardware. We propose the use of high-dimensional encoding, showing an improvement in the rate of entanglement compared with conventional qubit encoding.
From there, the discussion expands to a full quantum network architecture using several quantum repeaters place in space, with the aim of achieving secure liks across intercontinental distances. We propose a setup based on individually trapped atoms acting as both single-photon sources and quantum memories. Incorporating hardware imperfections and modeling transmission losses through free space and the atmosphere, we estimate the hardware performance required to achieve high-fidelity entanglement at a chosen transmission rate.
Finally, we go to a more specific example of distributing quantum key (QKD) to different cities of the Iberian Peninsula. Taking into account real-time weather conditions, atmospheric effects, and propagating losses, we analyze the feasibility of deploying current use cases of satellite-based QKD.
Satellite-based quantum repeaters are a promising means of reaching global distances in quantum networking due to the polynomial decrease of optical transmission with distance in free space, in contrast to the exponential decrease in optical fibers. We propose a satellite-based quantum repeater architecture with trapped individual atomic qubits, which can serve both as quantum memories and true single-photon sources. This hardware allows for nearly deterministic Bell measurements and exhibits long coherence times, without the need for costly cryogenic technology in space. We develop a detailed analytical model of the repeater, which includes the main imperfections of the quantum hardware and the optical link, assuming high-altitude ground stations, and consequently working in a regime of weak atmospheric turbulence. Our model allows us to estimate that high-rate and high-fidelity entanglement distribution can be achieved over intercontinental distances. In particular, we find that high-fidelity entanglement distribution over thousands of kilometres at a rate of 100 Hz can be achieved with orders of magnitude fewer memory modes than conventional architectures based on optical Bell state measurements.
Satellite-assisted entanglement distribution is a promising approach for realizing long-range quantum networking. However, the limited coherence time of existing quantum memories makes it challenging to obtain multiple event-ready entangled pairs between ground stations since one pair decoheres before the successful distribution of another. We demonstrate how this can be circumvented by pairing existing satellite-compatible spontaneous parametric down conversion (SPDC) sources with qudit-compatible quantum memories on ground. By operating the SPDC source as a source of time-bin encoded photonic qudits, simultaneous distribution of multiple entangled pairs between the ground stations can be achieved at a significantly higher rate than if the SPDC sources was operated as a source of photonic qubits. We find that for achievable coherence times of seconds and demonstrated satellite performances from the Micius satellite, the qudit operation leads to several orders of magnitude faster distribution rates than the qubit-based operation when more than one event-ready high-quality (Bell pair fidelity (Formula presented) (Formula presented) as well as for fidelity (Formula presented) (Formula presented) ) entangled pair is desired. To ensure high-quality entanglement distribution, we consider multiplexed quantum memory operation storage and, in the qubit case, we also consider storage cutoff times.