Author: vatshal7885

We are pleased to announce the publication of ‘Characterizing and Tailoring Spatial Correlations in Multimode Parametric Down-Conversion’ in Physical Review Applied. In this article, we have developed a detailed theoretical model for the quantum state of two photons entangled in their transverse position and momentum. Our model incorporates the systems used for generating entanglement and measuring it, both of which play a significant role in what the final two-photon entangled state looks like. We introduce and demonstrate a simple and efficient method to quickly characterise the two-photon joint-transverse-momentum amplitude (JTMA) using scanned phase-only holograms. We use knowledge of the JTMA to precisely tailor discrete, high-dimensional entangled states of light in the Laguerre-Gaussian (LG) and Pixel bases. We expect our work to have wide-ranging applications in experiments on multi-mode SPDC, as well as for entanglement-based quantum technologies for communication, imaging, and computation.

In our latest work on arXiv, we experimentally demonstrate detection-loophole-free quantum steering with qudits under extreme conditions of loss and noise. This work was done in collaboration with the Quantum Information Theory Group at the University of Geneva.

We showcase the improvements over qubit-based systems by experimentally demonstrating detection loophole-free quantum steering in 53 dimensions through simultaneous loss and noise conditions corresponding to 14.2 dB loss equivalent to 79 km of telecommunication fibre and 36% of white noise. We further show how the use of high dimensions counter-intuitively leads to a dramatic reduction in total measurement time. Our work demonstrates that qudit-entanglement can transcend the limits imposed by a realistic and noisy environment, proving itself a critical ingredient for making device-independent quantum communication over long distances a reality.