Quantum Computing

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Description

This course seeks to provide an introduction to the basics of the quantum circuit model of quantum computing and (at the risk of mixing metaphors...) to some of the “classic” quantum algorithms.

 

  • Quantum mechanics: Bras, kets, qubits and all that - the state vector formalism for quantum mechanics (in strange physicists’ notation). I won’t cover the more general approach using density matrices.

  • Quantum circuit model of quantum computing: A pictorial way of representing the unitary operations and measurements carried out in a quantum computer.

  • Party tricks: Dense coding and teleportation - some (small) quantum circuits doing non-classical things.

  • Quantum advantage: Deutsch’s (and Deutch-Josza’s) algorithm - the first evidence that a quantum computer could do something a classical one couldn’t.

  • Finding a needle in a haystack: Grover’s algorithm - a quantum algorithm for unstructured database search that offers a square root speedup over a naive exhaustive classical search.

  • Breaking the code: Shor’s algorithm. What really got folk interested in the field - the prospect of breaking public key cryptography using the efficiency of quantum period- finding algorithms.

  • Solving linear systems and PDEs: The HHL algorithm - something that would be a very bad idea for solving a linear system classically turns out to be very effective in the quantum case.

  • Quantum Simulation: Feynman was one of the first to point out that quantum computers would be good simulators of quantum systems - some simple examples are discussed.