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:

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!