A5089800197- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Quantum Computing Algorithms and Architecture
- Quantum optics and atomic interactions
- Molecular Communication and Nanonetworks
- Mechanical and Optical Resonators
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy and Laser Applications
- Advanced Optical Sensing Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Satellite Communication Systems
- Atmospheric Ozone and Climate
- Physical Unclonable Functions (PUFs) and Hardware Security
- Photonic and Optical Devices
- Neural Networks and Reservoir Computing
- Atmospheric and Environmental Gas Dynamics
- Orbital Angular Momentum in Optics
- Spacecraft Design and Technology
- Random lasers and scattering media
- Radiation Effects in Electronics
- Quantum-Dot Cellular Automata
- Space Science and Extraterrestrial Life
- Space Satellite Systems and Control
- Analytical Chemistry and Sensors
- Hemodynamic Monitoring and Therapy
University of Bristol
2016-2024
Hewlett Packard Enterprise (United States)
2024
Bristol Robotics Laboratory
2019-2023
Uttaranchal University
2023
Austrian Academy of Sciences
2016-2020
Quantum Technology Sciences (United States)
2018-2020
Institute for Quantum Optics and Quantum Information Innsbruck
2016-2019
Vienna Center for Quantum Science and Technology
2018-2019
University of Vienna
2018
University of Michigan
2015
Quantum communication is rapidly gaining popularity due to its high security and technological maturity. However, most implementations are limited just two communicating parties (users). networks aim connect a multitude of users. Here, we present fully connected quantum network on city-wide scale without active switching or trusted nodes. We demonstrate simultaneous secure connections between all 28 pairings eight Our novel topology easily scalable many users, allows traffic management...
Significance Entanglement, the existence of correlations in distant systems stronger than those allowed by classical physics, is one most astonishing features quantum physics. By distributing entangled photon pairs over a 96-km-long submarine fiber, which part existing infrastructure carrying internet traffic, we demonstrate that polarization entanglement-based key distribution (QKD) can be implemented real-world scenarios. QKD facilitates secure communication links between two parties,...
We present a ground-to-space quantum key distribution (QKD) mission concept and the accompanying feasibility study for development of associated low earth orbit nanosatellite payload. The information is carried by single photons with binary codes represented polarization states photons. Distribution entangled between ground satellite can be used to certify nature link: guarantee that no eavesdropping take place. By placing photon source on ground, space segments contains "only" less complex...
Engineering apparatus that harness quantum theory promises to offer practical advantages over current technology. A fundamentally more powerful prospect is such technologies could out-perform any future iteration of their classical counterparts, no matter how well the attributes those strategies can be improved. Here, for optical direct absorption measurement, we experimentally demonstrate an instance absolute advantage per photon probe exposed absorbative sample. We use correlated intensity...
Quantum key distribution (QKD) offers future proof security based on fundamental laws of physics. Long-distance QKD spanning regions such as the United Kingdom (UK) may employ a constellation satellites. Small satellites, CubeSats in particular, low Earth orbit are relatively low-cost alternative to traditional, large platforms. They allow deployment number spacecrafts, ensuring greater coverage and mitigating some risk associated with availability due cloud cover. We present our mission...
We demonstrate a novel MIR methane sensor shifting measurement wavelength to SWIR (1.55 μ m) by using non-linear interferometry. The technique exploits the interference effects seen in three-wave mixing when pump, signal, and idler modes make double pass through nonlinear crystal. method allows sensing at wavelengths where detectors are poor (>3 detection photon counting sensitivity can be achieved. In first experimental demonstration, we measured small concentration inside gas cell with...
Single-photon detectors, like Avalanche Photo Diodes (APDs), have a great importance in many fields quantum key distribution, laser ranging, florescence microscopy, etc. Afterpulsing is typical non ideal behavior of APDs, operated Geiger mode, which adversely affects any application measures the number or timing detection events. Several conflicting studies tried to model afterpulsing and link it fundamental semiconductor physics. Here we describe experiments performed on at least 2...
We present an experimental test of the Clauser-Horne-Shimony-Holt Bell inequality on photon pairs in a maximally entangled state polarization which value S=2.82759±0.00051 is observed. This comes close to Tsirelson bound |S|≤2sqrt[2], with S-2sqrt[2]=0.00084±0.00051. It also violates |S|≤2.82537 introduced by Grinbaum 4.3 standard deviations. violation allows us exclude that quantum mechanics only effective description more fundamental theory.
Models of quantum systems on curved space-times lack sufficient experimental verification. Some speculative theories suggest that properties, such as entanglement, may exhibit entirely different behavior to purely classical systems. By measuring this effect or thereof, we can test the hypotheses behind several models. For instance, predicted by Ralph and coworkers [T C Ralph, G J Milburn, T Downes, Phys. Rev. A, 79(2):22121, 2009, Pienaar, New Journal Physics, 16(8):85008, 2014], a bipartite...
Sources of entanglement are an enabling resource in quantum technology, and pushing the limits generation rate quality is a necessary pre-requisite towards practical applications. Here, we present ultra-bright source polarization-entangled photon pairs based on time-reversed Hong-Ou-Mandel interference. By superimposing four pair-creation possibilities polarization beam splitter, identical photons separated into two spatial modes without usual requirement for wavelength distinguishability or...
Concerted efforts are underway to establish an infrastructure for a global quantum internet realise spectrum of technologies. This will enable more precise sensors, secure communications, and faster data processing. Quantum communications front-runner with networks already implemented in several metropolitan areas. A number recent proposals have modelled the use space segments overcome range limitations purely terrestrial networks. Rapid progress design devices enabled their deployment...
Abstract Anonymity in networked communication is vital for many privacy-preserving tasks. Secure key distribution alone insufficient high-security communications. Often, knowing who transmits a message to whom and when must also be kept hidden from an adversary. Here, we experimentally demonstrate five information-theoretically secure anonymity protocols on eight user city-wide quantum network using polarisation entangled photon pairs. At the heart of these anonymous broadcasting, which...
Harnessing the unique properties of quantum mechanics offers possibility to deliver new technologies that can fundamentally outperform their classical counterparts. These only advantages when components operate with performance beyond specific thresholds. For optical metrology, biggest challenge impacts on thresholds is loss. Here we demonstrate how including an delay and switch in a feed-forward configuration stable efficient correlated photon pair source reduces detector efficiency...
Satellites are the efficient way to achieve global scale quantum communication (Q.Com) because unavoidable losses restrict fiber based Q.Com a few hundred kilometers. We demonstrate feasibility of establishing uplink with tiny 3U CubeSat (measuring just 10X10X32 cm^3 ) using commercial off-the-shelf components, majority which have space heritage. how leverage latest advancements in nano-satellite body-pointing show that our 4kg can provide performance comparable much larger 600kg satellite...
By exploiting the quantised nature of light, we demonstrate a sub-shot-noise scanning optical transmittance microscope. Our microscope demonstrates, with micron scale resolution, factor improvement in precision 1.76(9) estimation gained per probe photon relative to theoretical model, shot-noise-limited source an equivalent single-pass classical version same experiment using number photons detected 90% efficient detector. This would allow us observe photosensitive samples nearly twice...
Quantum key distribution (QKD) based on entangled photon pairs holds the potential for repeater-based quantum networks connecting clients over long distance. We demonstrate long-distance entanglement by means of polarisation-entangled through two successive deployed 96 km-long telecommunications fibres in same submarine cable. One each pair was detected directly after source, while other travelled fibre cable both directions a total distance 192 km and attenuation 48 dB. The observed...
Abstract The ability to know and verifiably demonstrate the origins of messages can often be as important encrypting message itself. Here we present an experimental demonstration unconditionally secure digital signature (USS) protocol implemented for first time, best our knowledge, on a fully connected quantum network without trusted nodes. We choose USS which is against forging, repudiation are transferrable. show feasibility signatures using only bi-partite entangled states distributed...
Abstract The information-theoretic unconditional security offered by quantum key distribution has spurred the development of larger communication networks. However, as these networks grow so does strong need to reduce complexity and overheads. Polarization-based entanglement are a promising approach due their scalability no for trusted nodes. Nevertheless, they only viable if birefringence all-optical fibres in network is compensated preserve polarization-based state. brute force would...
Abstract Quantum key distribution (QKD) provides a method of ensuring security using the laws physics, avoiding risks inherent in cryptosystems protected by computational complexity. Here, authors investigate feasibility satellite‐based quantum exchange low‐cost compact nano‐satellites. The first prototype system level aimed at Cube satellite scenario is demonstrated. It consists transmitter payload, ground receiver and simulated free space channel to verify timing synchronisation (T&S)...
The global interest in quantum networks stems from the security guaranteed by laws of physics. deployment means facing challenges scaling up physical hardware and, more importantly, all other network layers and optimally utilizing resources. Here, we consider two related protocols their experimental demonstrations on an eight-user test bed, discuss usefulness with aid example use cases. First, authentication-transfer protocol to manage a fundamental limitation communication—the need for...