Alladi Ramakrishnan Hall

Quantum computation with classical light: The Deutsch Algorithm / Process tomography via sequential measurements on a single quantum system

Benjamín Pérez and Humairah Bassa

Photonics and Mathematical Optics Group, Tecnológico de Monterrey, Mexico and School of Chemistry and Physics, University of KwaZulu-Natal, Durban - South Africa

Quantum computation with classical light: The Deutsch Algorithm
Speaker : Benjamín Pérez
Reference : Phys. Lett. A, vol. 379 (2015) 1675 -- 1680

We present an implementation of the Deutsch Algorithm using linear optical elements and laser light. We encoded two quantum bits in form of superpositions of electromagnetic fields in two degrees of freedom of the beam: its polarisation and orbital angular momentum. Our approach, based on a Sagnac interferometer, offers outstanding stability and demonstrates that optical quantum computation is possible using classical states of light.


Process tomography via sequential measurements on a single quantum system
Speaker : Humairah Bassa
Reference : arxiv.org/abs/1504.06000

The purpose of quantum process tomography (QPT) is to characterize a dynamical process such that one could predict the output state given a specific input state. In this talk I will describe a method for QPT which involves a discrete sequence of so-called unsharp measurements on a single qubit in order to determine the unknown dynamical parameters. This method is based on a technique for state estimation and monitoring (arxiv.org/pdf/quant-ph/0608097), which will be discussed as an introduction. I will then analyze the two equivalent formalisms that can be used to describe the QPT protocol. The numerical results will be examined.