Fault-tolerant quantum computation input/output 

Overview

Quantum computers are powerful, but they are also extremely fragile. Even the smallest errors can break a computation. In this talk, Matthias Christandl explains how researchers are tackling this challenge by designing systems that can compute reliably despite noise. This is a key step toward making quantum computing work in practice and not just in theory.

Abstract

The qubit quality of available quantum devices is increasing, yet it is expected that individual qubit operations (gates) will remain noisy for the foreseeable future. The execution of a sizeable quantum algorithms (e.g. factoring numbers, simulating materials), therefore requires a software solution to the noise problem. In essence, one needs to simulate a virtual noiseless quantum processor with a physical noisy quantum device. Is this possible at all? Yes, says a foundational result from the 90s (if the gate noise is below a threshold). I will start by giving some key ideas and intuition behind this result.

In contrast to stand-alone single-core quantum computers, in many distributed scenarios (e.g. a multi-core quantum processor or the quantum internet) quantum processors need to pass qubits among each other, and have therefore quantum inputs, quantum outputs or even both. Just imagine the communication from one noisy quantum devices to another one via even noisier quantum communication channels. Also, such scenarios need to be secured against noise. It’s possible – I will explain how 😉

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