QTX-4 | October 2020

QTX-4 was held as a virtual workshop on 30 October 2020. Recordings of the full program, including talks as listed below, are available.

Satellite Quantum Communications

3.00pm (GMT+08:00): Chithrabhanu Perumangatt (CQT, NUS)
3.20pm (GMT+08:00): Daniel Oi (ROKS)
3.40pm (GMT+08:00): Mustafa Gündogan (HU/FBH)
4.00pm (GMT+08:00): Questions and Answers

Video recording of this session is available on YouTube: https://youtu.be/7sPkKEVXbd4

Satellite Quantum Technologies

4.30pm (GMT+08:00): Aaron Strangfeld (HU/FBH)
4.50pm (GMT+08:00): Michael Holynski (CASPA)
5.10pm (GMT+08:00): David C. Aveline (JPL)
5.30pm (GMT+08:00): Questions and Answers

Video recording of this session is available on YouTube: https://youtu.be/i2PmtRA347s

Titles and Abstracts

Satellite Quantum Communications

Chithrabhanu Perumangatt (CQT, NUS)
Title: Tabletop demonstration of satellite to ground quantum key distribution
Abstract: Entanglement and quantum key distribution (QKD) between satellite and ground stations are essential steps towards global quantum network. For estimating the performance of the full QKD system, we have developed a key rate model considering the realistic scenarios and losses. To validate this key rate model, we have implemented a representative tabletop experiment with tunable parameters. We experimentally simulate satellite passes, with different initial conditions (brightness of the entangled source, background counts at the ground station and timestamping resolution) to obtain a secret key between sender and receiver stations. Based on the results, one can optimize the QKD hardware and software to obtain a maximum secret key rate for a given quantum link. In this talk, I will discuss the key rate model and the results from tabletop experimental demonstration.

Daniel Oi (ROKS)
Title: ROKS Mission Architecture
Abstract: The UK CubeSat QKD programme Quantum Research CubeSat (QUARC), which traces its heritage to joint work with the Centre for Quantum Technologies, has been developing miniaturised QKD systems for nanosatellites. The output of QUARC has been incorporated into an in-orbit demonstration mission (IOD-6), Responsive Operations for Key Services (ROKS), led by Craft Prospect Ltd, planned for launch in 2022. ROKS will be a trusted-node system employing a WCP decoy state BB84 source in downlink configuration on a 6U platform. In this talk, I shall outline the system architecture, covering payload optics, APT, source, beaconing, and OGS design. The challenges and approaches to the design of a low power, compact, and robust system will be described.

Mustafa Gündogan (HU/FBH)
Title: Space-borne quantum memories for global quantum communication
Abstract: Quantum memories (QM) are necessary devices for storing quantum information, which is especially critical for future satellite based global quantum communication networks. They can be realized with technology based on the controlled interaction of laser light with atomic ensembles. I present performance requirements for satellite-based quantum memories and envisioned space missions on nanosatellites.
For this work, I acknowledge the support by the German Space Agency DLR with funds provided by the Federal Ministry of Economics and Technology (BMWi) under grant numbers 50WM1958 (OPTIMO), 50WM2055 (OPTIMO-2).

Satellite Quantum Technologies

Aaron Strangfeld (HU/FBH)
Title: Mission of Joint Lab Integrated Quantum Sensors
Abstract: Optical frequency references are key components for future GNSS systems and satellite based earth observation missions utilizing optical atomic clocks and atom interferometry, respectively. By using technology for the integration of laser diodes and warm atomic vapor cells, systems can be made considerably smaller. I present progress towards the necessary miniaturization of the stabilized laser systems and envisioned space missions on nanosatellites.
This work has been done in a joint project between Humboldt-Universität zu Berlin and National University of Signgapore, supported by the Berlin University Alliance.

Michael Holynski (CASPA)
Title: Cold atom space payload
Abstract: Quantum sensing based on cold atoms has been proposed for several space applications, including Earth observation and fundamental physics. Over recent years, the CASPA consortium has focused on improving the technology readiness of cold atom systems and enabling their operation on small satellites. In this talk I will present the realisation of a 6U Cubesat demonstrator for magneto-optical trapping. This has been achieved within a 4U payload volume at 4 kg mass and a peak power consumption of 40 W. The payload has passed NASA GEVS random vibration testing across 20 Hz to 20 kHz. I will also present the follow-on activity aiming to realise accelerometry and gravity gradiometry in Cubesat payloads.

David C. Aveline (JPL)
Title: On-orbit production and study of quantum gases aboard the International Space Station
Abstract: We report on the successful commissioning and continued operation of the Cold Atom Lab (CAL), a first-of-its-kind atomic physics research facility studying quantum gases in low-Earth orbit aboard the International Space Station (ISS). This talk discusses the results recently published in Nature on June 11, 2020, reporting the first Bose-Einstein condensates produced and manipulated in orbit. With routine BEC production, on-going operations support long-term investigations of fundamental physics, as well as development of advanced atom cooling techniques, novel atom-laser sources, and quantum sensor technology.