Quantum information processing and quantum communication are novel protocols that originate from the very fundamental and philosophical questions on superposition and entanglement raised since the early days of quantum mechanics. Strikingly, these new protocols offer capabilities beyond communication task possible with classical physics. One very important example is the secure key exchange based on the transmission of individual quantum signals between communication partners. The big vision and frontier in the field of quantum communication research is the development of a Quantum Internet, which establishes entanglement between many different users and devices. The basic idea is that similar to today’s internet, the Quantum Internet will readily transfer quantum bits, rather than today’s classical bits, between users near and far and over multiple different channels and could be used for secure communications, quantum computer networks and metrological applications. I will discuss recent advances on implementations and tools useful for generating and distributing photonic quantum entanglement over robust channels including. time-bin encoding and reference-frame-free protocols. I will also present an overview of the upcoming Canadian quantum communication satellite QEYSSAT.
CQT PhD Thesis Defense by Aitor Villar Zafra
Title: Building Entangled Photon Pair Sources for Quantum Key Distribution With Nano-Satellites Date/Time: 28-Aug, 01:00PM Venue: CQT Level 3 Conference Room, S15-03-17
Quantum entanglement, one of the most characteristic concepts of quantum physics, is the reason for many applications to feature a quantum advantage when compared to their classical counterparts. Applications in fields such as communication, computation, sensing and simulation can benefit from this remarkable property. A challenge to be addressed in order to deploy such applications around the globe is to distribute entanglement over inter-continental distances. While photons are excellent entanglement carriers, they do suffer from losses when travelling in optical fibers, and also require line-of-sight when flying in free-space from emitter to receiver, thus negating application-deployment over continental distances. In this context, to equip a nano-satellite with a source of entangled photons has the potential to render these limitations void, enabling continental distances in quantum applications. This thesis focuses on accelerating the development of a space-ready entangled photon source capable of performing Quantum Key Distribution from space. The source design is driven by the size, weight and power requirements typically encountered in nano-satellites. Experimental progress in terms of the pump preparation, the crystal geometry and the collection technique of the entangled photon source is presented. Additionally, preliminary scientific data from SpooQy-1, a quantum CubeSat aimed to demonstrate entanglement in space, is discussed.