npj Quantum Info: Flexible semi-device-independent randomness

A European wide collaboration: With colleagues in Czech Republic, Slovakia, Austria, Poland and Spain, theory and experiment came together for the development of a quantum random number generation framework that can be applied in a wide range of physical scenarios.

Our new paper “Semi-device independent random number generation with flexible assumptions” has been published in npj Quantum Information. Working along with theorists all over Europe, we formulated a framework for semi-device-independent quantum random number generation, and demonstrated the protocol with an experiment in the BBQ Lab. Our approach works with flexible assumptions and different levels of trust, allowing it to be implemented over a large number of practical situations.

This work was the result of an international collaboration that involved people in 6 different countries. Even though some of the co-authors haven’t even met in person, we developed theoretical methods and showed their experimental realisation. This is the power of science: joining people together, even during these difficult times!

AVS Quantum Science: Enhancing noise tolerance with high-dimensional entanglement

Our article “Is high-dimensional photonic entanglement robust to noise?” was featured on the cover of AVS Quantum Science’s first issue of 2021

Our paper “Is high-dimensional photonic entanglement robust to noise?” has been published as a Featured Article on AVS Quantum Science, and is now in the cover of the journal’s first issue of 2021!

Working in collaboration with the HWQuantum group, here at Heriot-Watt University, we show that the noise tolerance of high-dimensional entanglement can be significantly enhanced. While answering the question of “Is high-dimensional photonic entanglement robust to noise? involves the complex interplay between the characteristics of the state, the channel, and the detection system, we provide easily measurable experimental parameters that accurately predict system performance and noise bounds, so the optimum entanglement measurement strategy can be chosen. This works demonstrates the potential of high-dimensional entangled states in the realisation of entanglement-based communication systems under extreme noise conditions.

arXiv: Unscrambling Entanglement through a Complex Medium

Photonic high-dimensional entanglement in the spatial degree of freedom has recently emerged as a practical way to enhance the capacity of quantum information systems, as well as increase their robustness to noise. However, while qubit entanglement has been distributed over large distances through free-space and fibre, the transport of high-dimensional entangled states of light through highly complex media has never been demonstrated.

After many months of hard work, we achieved the transport of high-dimensional spatial-mode entanglement through a commercial multi-mode fibre for the first time. In our experiment, one photon from a bipartite spatially entangled state was sent through a two-metre piece of multi-mode fibre from Thorlabs. Interestingly, while entanglement was completely lost, the resulting “scrambled” correlations captured the behaviour of the multi-mode fibre in the form of its transmission matrix. This information allowed us to recover the entanglement by only manipulating the entangled partner photon that did not enter the fibre!

For more details, please read our preprint: N. H. Valencia, S. Goel, W. McCutcheon, H. Defienne, and M. Malik, “Unscrambling Entanglement through a Complex Medium”, arXiv:1910.04490 (2019), Link: https://arxiv.org/abs/1910.04490

Welcome Vatshal!

We are very happy to welcome our second PhD student Vatshal Srivastav, who joins us from India!

Vatshal comes to us after completing both his B.S and M.S. in Physics at the Indian Institute of Technology Kanpur (IITK), where he gained significant experience on theoretical models of qubits for quantum computing.

Welcome to the BBQ Lab, Vatshal!

Welcome Will!

Looking forward to all the new ideas from Will’s intricate mind!

We are delighted to welcome our first postdoc, Dr. Will McCutcheon, who joins us from Bristol, UK.

Will completed his PhD at the University of Bristol with Prof. John Rarity, followed by a two-year postdoc at Bristol Quantum Engineering Technology Laboratories.

We are very excited to add Will’s extensive knowledge and experience on both theoretical and experimental quantum information and photonics to the mix!