News

arXiv: Pixel Entanglement in 55 dimensions!

A 97-dimensional pixel hologram used in the experiment and two-photon correlation data

In a record-breaking result from our lab, we recently demonstrated the generation and certification of photonic high-dimensional entanglement with the highest quality, fastest measurement speed, largest dimensionality, and the most “entangled bits” of information till date!

We achieved this through several breakthroughs in theory and experiment, including a cleverly designed spatial-mode basis of macro-pixels and an efficient entanglement witness developed in collaboration with our colleagues in Austria and the Czech Republic. This result demonstrates that high-dimensional entanglement can indeed break out of the confines of an optical laboratory and enable practical, high-capacity quantum communication networks in the near future.

Preprint: N. H. Valencia,  V. Srivastav, M. Pivoluska, M. Huber, N. Friis, W. McCutcheon, and M. Malik, “High-Dimensional Pixel Entanglement: Efficient Generation and Certification,” arXiv:2004.04994 (2020).

Welcome Saroch!

We are excited to welcome the newest member of our group, Dr. Saroch Leedumrongwatthanakun! Originally from Thailand, Saroch recently completed his PhD in the group of Prof. Sylvain Gigan at the Laboratoire Kastler Brossel (LKB) in Paris.

Saroch joins us at a crazy time for science, albeit the world, but it won’t be long before we can put his expertise in complex quantum photonics into action!

Teleportation and a bag of chips

An optical microscope image of the Silicon chip used in the experiment.
Image credit: Llewellyn et al, doi: 10.1038/s41567-019-0727-x

In a recent collaboration spanning Bristol, Denmark, Austria, and China, we demonstrated the teleportation of quantum states of light across two millimetre-scale Silicon chips and the on-chip entanglement of four photons in a GHZ-entangled state. Together with the Huber group at IQOQI Vienna, our team developed efficient theoretical techniques for measuring the generated multi-photon entangled states. These results open the door towards CMOS-compatible quantum technology applications in networking and computation.

Publication: D. Llewellyn et al, “Chip-to-chip quantum teleportation and multi-photon entanglement in silicon,” Nature Physics 16, 148–153 (2020).

PRX: Entanglement beats the Noise

Artist’s depiction of entanglement surviving the onslaught of noise!
(Image credit: Harald Ritsch for IQOQI Vienna)

In our new paper on “Overcoming Noise in Entanglement Distribution” co-authored with colleagues in Austria, Finland, Germany, and Canada, we demonstrate how high-dimensional entanglement in the spatio-temporal degrees of freedom allows one to tolerate large amounts of noise that would generally lead to a loss of qubit, or two-dimensional entanglement. In other words, we certified entanglement with the laboratory lights on! This works demonstrates the potential for high-dimensional quantum states to not only enable high-capacity quantum networks, but also operate in realistic environmental conditions, such as in broad daylight or alongside classical data traffic. For more information, please read this APS synopsis.

Popular media coverage: Heriot-Watt press release, Wiener Zeitung, Orf.at.
Journal reference: Ecker et al, Phys. Rev. X 9, 041042 (2019), doi: 10.1103/PhysRevX.9.041042.

arXiv: Unscrambling Entanglement through a Complex Medium

Our first major result is now on the arXiv!

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

Congratulations Natalia! – 1st Prize!

” 1st prize for best poster goes to our wonderful Natalia Herrera Valencia! “

Nice one Natalia!!! Amazing work!!!

Natalia’s poster on “Unscrambling Entanglement Through A Complex Medium” won 1st Year Postgraduate Reseach Prize in IPaQS on Sept 11th.

The poster presented exciting new results she has obtained, demonstrating a remarkable feature of entanglement: even after one particle gets scrambled through a complex medium, we can observe the entanglement by carefully scrambling its partner!

For more details, please read our recent arXiv paper: 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!