Working with former Edinburgh colleagues Alexandru Gheorghiu and Elham Kashefi, Theodoros has published a review paper exploring existing techniques for the verification of quantum computation (DOI:10.1007/s00224-018-9872-3) in Theory of Computation.

Quantum computers offer the prospect of solving computational problems which would take an infeasible amount of time to solve with classical devices. For some of these, the solutions cannot be checked without solving the problem again - which would require use of and trust in a quantum computer. Through quantum verification techniques it becomes possible to test the performance of a quantum computer and even test whether a claimed quantum computer is genuine.

Along with an overview of the fundamental obstacle, a number of schemes which allow verification if the user has access to basic quantum apparatus, which allows them to confidently prepare a handful of simple states or to perform a few simple measurements, are discussed and compared in the review paper.