Canada 2020

# Justin Trudeau: “What quantum states allow for is much more complex information to be encoded into a single bit.”

**By: **Dana Wagner on

**Justin Trudeau**, Prime Minister and MP for Papineau, in a press conference on April 15, 2016

A few physicists agree Trudeau’s quantum computing 101 is accurate.

**FactsCan Score:**True

At an event to announce funding for the Perimeter Institute, a theoretical physics research centre in Waterloo, Justin Trudeau took a sarcastic question from a reporter about how quantum computing works.

The Prime Minister’s reply landed in the news and spread quickly on social media, because he actually answered the question, and succinctly too. We asked a few physicists how he did.

“Trudeau did an impressive job,” said Michele Mosca, deputy director of the Institute for Quantum Computing at the University of Waterloo. “It was pretty clear for a lay audience and nothing was wrong.”

Pedro Vieira, a chair in theoretical physics at the Perimeter Institute, agreed. “The explanation by the prime minister is actually great. I could phrase it differently but probably not better.”

Interesting challenge.

We asked Mosca, of the Institute for Quantum Computing, and Richard Laflamme of the same institute who also holds a research chair in quantum information, to explain their field using the same brevity as Trudeau – less than 100 words.

You judge who did it better:

**Justin Trudeau, prime minister**: “Very simply, normal computers work by either there’s power going through a wire or not, it’s 1 or a 0, they’re binary systems. What quantum states allow for is much more complex information to be encoded into a single bit. Regular computer bit is either a 1 or a 0, on or off, a quantum state can be much more complex than that because as we know things can be both particle and wave at the same times, and the uncertainty around quantum states allows us to encode more information into a much smaller computer.”

**Michele Mosca, mathematician**: “Our computers work by manipulating information stored in a collection of bits, where each bit can store one of two states which we label 0 and 1. For example, an electric current on or off. Quantum physics allows for bits to be in both the 0 and 1 states at the same time. By manipulating a large collection of quantum bits, a “quantum computer” can in a special way explore the countless configurations of 0s and 1s simultaneously. This allows them to solve some important computational problems that we thought would take essentially forever to solve on regular computers.”

**Raymond Laflamme, physicist**: “Today’s computers (called classical computers by physicists) manipulate information using bits. One bit is the basic unit of information that can be encoded in a system with two states described by 0 and 1. A computation is fundamentally the manipulation of a string of bits. At the microscopic level, classical physics fails and is replaced by Quantum Mechanics. Quantum Mechanics introduces new properties not seen at the macroscopic scale: the uncertainty principle, wave particle duality, the superposition principle. Quantum computing uses these new properties to compute in a way that is fundamentally more powerful.”

However Trudeau scores against a physicist, he scores full points for accuracy.