Course: Understanding Quantum Computers

Finally, we have the tools to understand quantum error correcting codes. We know what types of errors happen, and how to measure the parity of groups of qubits without destroying …

We have just seen the requirements for a technology useful for building a quantum computer (the DiVincenzo criteria). In this video, Professor Kae Nemoto of Japan’s National Institute of Informatics …

Error correcting codes generally identify errors by calculating the parity of a set of bits. Parity tells us whether the number of ones in a set of bits is even …

Grover’s algorithm consists of two parts: marking and diffusion. First, we will discuss a little more formally the structure introduced in the previous Step, then we will see some examples …

Of course, classical information is binary, so the only errors that can occur are bit flips: a 0 becomes a 1, or a 1 becomes a 0. But qubits are …

The most general quantum algorithm is Lov Grover’s search algorithm. Using entanglement and interference, it allows us to answer the question, “For what value of (x) does (f(x) = k), …

A couple of times so far in this course, we have alluded to the decoherence of quantum states caused by noise and imperfections in our control systems. We can mitigate …

Now that we have the basic concepts under our belt, we are ready to examine some of the important quantum algorithms in detail. *Note: You can find a PDF version …

Recently, we saw that the energy levels of atoms, either the simple energy levels or hyperfine splitting, can make an attractive qubit. But atoms are not usually found in isolation; …

In this Video, Professor James Whitfield describes quantum chemistry as being similar to crash test dummies: rather than solving lots of equations, some important quantum chemistry algorithms model the behavior …

Many materials are atoms arranged in a regular crystal. When an atom is missing, or is replaced with a different kind, that uniform arrangement is broken. The change in the …

Professor James Whitfield of Darmouth College returns help us lay the groundwork for quantum chemistry algorithms. He describes these algorithms as “model spectroscopy”, finding the important frequencies and energies in …

In an earlier Step, we visited the laboratory of Professor Yasunobu Nakamura at the University of Tokyo, and learned about using electric charge and magnetic flux as our qubit state …

Before quantum computers existed, quantum algorithms were defined either mathematically, in terms of the transitions on quantum states, or using a graphical circuit notation for individual gates. Nowadays, quantum computers …

An atom has a nucleus and electrons in orbitals around the nucleus. We can create artificial atoms known as quantum dots using our ability to manipulate electrical fields and create …