Information processing with quantum photonic processors
Jelmer J. Renema · 2023
In recent years, photonics has become one of the key contenders in the race to build large-scale quantum computers. The prominence of photonics as a quantum information technology is underscored by the fact that it is one of only a handful of technology platforms which has achieved a quantum advantage, i.e., a large-scale quantum system which outperforms a classical supercomputer at some well-defined computational task [1 2]. In this talk, I will highlight several aspects of the research that my team is doing in this field, focusing on the fundamental science that is enabled by quantum photonic processors, i.e. large-scale, tunable interferometers which are necessary to give these proof-of-principle systems a degree of programmability. We have recently demonstrated [3] the world’s largest quantum photonic processor, i.e. fully tunable multimode optical interferometer, using silicon nitride photonic waveguides, and I will briefly introduce these devices. Large-scale photonic systems are an interesting novel testbed with which to explore the fundamental concepts and problems of quantum mechanics. Specifically, I will focus on two results obtained in this experimental platform: first, a result in quantum thermodynamics [4], where we experimentally show how to reconcile the apparent contradiction between quantum mechanics, which is time-reversible and information-preserving, and thermodynamics, which is neither, and secondly, a semi-device independent entanglement witness [5] suitable specifically for linear-optical systems. [1] Zhong et al, Science 370, 6523 (2020). [2] Zhong et al, arXiv:2106.15534. [3] Taballione et al, arXiv:2012.05673. [4] Somhorst et al, arXiv:2201.00049. [5] v.d Meer et al, arXiv:2112.00067.