Grant: Alliance Grants

In today's connected world, the ability to communicate securely is an ever-increasing concern. For certain organizations - financial institutions, governments, the military - it is a critical requirement, which is why immense resources are currently spent on developing new technologies so that individuals and organizations can communicate privately. However, there is always a caveat in implementing new communications technologies: the need to trust the device. What if the (supposedly secure) apparatus is not properly designed and those not implementing its quantum operations as expected? Or what if the device has been tampered with by an adversary?Device-independent quantum communication aims to solve these issues by providing secure communication guaranteed by the laws of physics even with untrusted devices. It is therefore, unsurprisingly, one of the ultimate goals of researchers working on quantum communication. But scaling these device-independent schemes to long distances is a significant challenge. We propose to solve this problem using photon precertification, an approach which relies on splitting photons carrying quantum information into pairs to mitigate the loss of long-distance transmission.To this most efficiently, photons should ideally be detected on the same devices which are used to split photons. However, current devices used to split photons do not typically use materials which are compatible with high-efficiency detectors. This international collaborative project aims to address this by demonstrating photon precertification using devices made from materials which are compatible with high-efficiency detectors. It will involve the design and characterization of novel nonlinear optical devices, followed by proof-of-principle demonstrations of photon precertification.