Bell state measurements for quantum communication
AuthorValivarthi, Venkata Ramana Raju
Committee MemberBarclay, Paul
MetadataShow full item record
AbstractOver the last few decades, quantum key distribution (QKD) has gained a lot of attention due to its promise of establishing secret keys between authenticated users even in the presence of an eavesdropper who is only confined by the laws of nature. Secure key established by QKD in conjunction with one-time pad (OTP) encryption thus promises to end the long standing battle between code-makers and code-breakers. Spurred by its great promise, QKD has been the first quantum information technology to be commercialized and QKD systems are available from a number of vendors.However, these systems are still vulnerable to side-channel attacks as the components used in these systems don’t necessarily conform to the idealistic assumptions made in security proofs of QKD. Of the many components, single photon detectors have been identified as the most vulnerable component allowing, for instance, so-called ‘blinding attacks.’ In light of this, measurement device independent quantum key distribution (MDIQKD) protocol was proposed as a means to make QKD inherently immune to all possible detector side channel attacks, due to the particular property of the so-called Bell state measurement. The aim of this thesis is to develop techniques that will allow developing a cost- effective MDIQKD system that is suitable for quantum networks and to use these techniques to perform quantum teleportation on a metropolitan scale for the first time. More precisely this thesis describes the assessment of performance of MDIQKD using differ- ent hardware; the development of cost-effective MDIQKD system for quantum networks; the building of a practical quantum random generator (QRNG) suitable for high speed QKD systems; the demonstration of quantum teleportation on a metropolitan scale and the realization of an efficient Bell state analyzer for time-bin qubits that improves the efficiency of all quantum information processing tasks including MDIQKD and quantum teleportation. The above demonstrations constitute an important step towards realizing practical quantum internet.
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