Researchers determine the performance of multi-dimensional bits

February 4, 2019, University of Vienna
Credit: CC0 Public Domain

What kinds of computers would be conceivable if physics worked differently? Quantum physicists Marius Krumm from the University of Vienna and Markus Müller from the Viennese Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences (ÖAW) are speculating about theoretical properties of future computers to offer interesting insights into quantum computing.

Standard computing uses logic based on bits: patterns of zeroes and ones. Quantum computers, on the other hand, work with . Conceptually, these are points on a three-dimensional ball. The represents zero and the represents one. Such a "qubit" can also take any place in-between (for example, on the equator) in the so-called superposition states.

In their current study, Krumm and Müller consider bits as points on a ball, too. But in contrast to the quantum bit, this ball is not limited to three dimensions. A few years ago, two quantum physicists from the University of Vienna and the Austrian Academy of Sciences proposed alternative physics in worlds with more than three . To check this idea, Krumm and Müller made two assumptions about how these bits are wired: First, they are processed via reversible gates like "AND" or "NOT." Second, they satisfy an intuitive property of classical and : knowing the single bits and how they are correlated provides a complete picture.

The surprising result is that even though these bits would be more complicated, computers based on them would have extremely limited capabilities. They would not be faster than quantum computers and could not even execute ordinary algorithms. In this sense, the third dimension and the quantum bit are special, and so is quantum computation—in a phrase coined previously by computer scientist Scott Aaronson, it is an "island in theoryspace."

Explore further: How does a quantum particle see the world?

More information: Marius Krumm et al, Quantum computation is the unique reversible circuit model for which bits are balls, npj Quantum Information (2019). DOI: 10.1038/s41534-018-0123-x

Related Stories

First proof of quantum computer advantage

October 18, 2018

For many years, quantum computers were not much more than an idea. Today, companies, governments and intelligence agencies are investing in the development of quantum technology. Robert König, professor for the theory of ...

A new kind of quantum computer

November 6, 2017

Quantum mechanics incorporates some very non-intuitive properties of matter. Quantum superposition, for example, allows an atom to be simultaneously in two different states with its spin axis pointed both up and down, or ...

The right squeeze for quantum computing

June 1, 2018

A new theoretical model involves squeezing light to just the right amount to accurately transmit information using subatomic particles. Scientists at Hokkaido University and Kyoto University report that this theoretical approach ...

Recommended for you

CMS gets first result using largest-ever LHC data sample

February 15, 2019

Just under three months after the final proton–proton collisions from the Large Hadron Collider (LHC)'s second run (Run 2), the CMS collaboration has submitted its first paper based on the full LHC dataset collected in ...

Gravitational waves will settle cosmic conundrum

February 14, 2019

Measurements of gravitational waves from approximately 50 binary neutron stars over the next decade will definitively resolve an intense debate about how quickly our universe is expanding, according to findings from an international ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.