Introduction to Quantum Computation: What’s all the fuss about?

Google has recently revealed its 72-qubit quantum computer, named Bristlecone. Earlier, Intel released a 49-qubit chip called Tangle Lake. IBM also built a quantum computer with 50 qubits. D-Wave boasts about their quantum annealing systems with more than 2000 qubits. What’s all the fuss about?
Quantum computation is a novel way of information processing that allows, for certain classes of problems, exponential speedup over classical computation. Various models of quantum computation exist, such as the adiabatic, circuit, and measurement-based models, but operate very differently and may suit different physical realizations. I will give a pedagogical introduction to quantum computation. I will give an idea why quantum computers seem powerful and yet it is not easy to design quantum algorithms that outperform classical ones. But quantum computers can be used to simulate other quantum systems. I will also mention several recent examples of experiments on quantum simultations. This opens up many potential applications of quantum computers, in addition to other quantum alogrithmic pursuits. I will also discuss the idea of quantum error correction, as in order for the quantum computer to retain its coherence and resist errors. One of the characteristic trait of quantum mechanics is entanglement and during the execution of a quantum algorithm, entanglement is generated. Entanglement itself can also enable tasks that are otherwise impossible. If time permits I will briefly discuss my own research on how to exploit entanglement as a resource for quantum computation. This talk does not assume much background and should be accessible to physicists, mathematician, chemists, computer scientists and engineers.


Tzu-Chieh Wei obtained his PhD degree in Physics at the University of Illinois at Urbana-Champaign in 2004, working on quantum entanglement theory in many-body systems and theoretical quantum optics (especially entangled photons) and applications in quantum information processing. He continued as a postdoctoral researcher there and expanded his research to condensed matter and AMO physics, such as superconductivity, BEC, and optical lattices. He collaborated closely with experimental groups there. In 2007, he moved to the Institute for Quantum Computing at the University of Waterloo as a postdoctoral fellow, and further expanded his research to quantum computational complexity and quantum simulations. In 2009, he moved to the University of British Columbia and focused on measurement-based models of quantum computation and connection to condensed matter physics. In 2011, he moved to Stony Brook.


Tzu-Chieh Wei


Friday, May 4, 2018




IACS Seminar Room