Nav: Home

Faster than allowed by quantum computing?

February 01, 2019

Computers are an integral part of our daily lives. What has once been science fiction is now real technology in our pockets. But computers are physical objects. And as quantum computation has taught us, new insights into physics can sometimes lead to new types of computers.

What kinds of computers would be conceivable if physics worked differently? The 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) have addressed this question. Theoretical properties of such "science fiction computers" could give us interesting insights into quantum computing.

Bits and Qubits

The key elements of classical and quantum computers are the bits: alternatives of "yes" and "no", wired together in a circuit. On an ordinary laptop, these bits would have to be either 0 or 1. Quantum computers, on the other hand, work with quantum bits: we can think of these as points on a three-dimensional ball. The north pole represents 0 and the south pole 1. A "qubit" can also take any place in between (for example on the equator) - 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 does not need to be three-dimensional. A few years ago, two quantum physicists from the University of Vienna and the Austrian Academy of Sciences, Borivoje Daki? and ?aslav Brukner, have conjectured that these balls describe alternative physics in worlds with more than three spatial dimensions. To check this idea, Krumm and Müller have made two assumptions on 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 quantum computing: knowing the single bits and how they are correlated tells us everything there is to know.

The surprising result: even though their bits would be more complicated, these computers would have extremely limited capabilities. They would not be faster than quantum computers and could not even execute ordinary algorithms. In this sense, dimension three 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".
-end-
Publication in Nature Quantum Information:

Marius Krumm & Markus P. Müller: Quantum computation is the unique reversible circuit model for which bits are balls (2019)

DOI: 10.1038/s41534-018-0123-x

University of Vienna

Related Quantum Computing Articles:

A platform for stable quantum computing, a playground for exotic physics
Harvard University researchers have demonstrated the first material that can have both strongly correlated electron interactions and topological properties, which not only paves the way for more stable quantum computing but also an entirely new platform to explore the wild world of exotic physics.
Diversity may be key to reducing errors in quantum computing
In quantum computing, as in team building, a little diversity can help get the job done better, computer scientists have discovered.
'Valley states' in this 2D material could potentially be used for quantum computing
New research on 2-dimensional tungsten disulfide (WS2) could open the door to advances in quantum computing.
Sound of the future: A new analog to quantum computing
In a paper published in Nature Research's journal, Communications Physics, researchers in the University of Arizona Department of Materials Science and Engineering have demonstrated the possibility for acoustic waves in a classical environment to do the work of quantum information processing without the time limitations and fragility.
Imaging of exotic quantum particles as building blocks for quantum computing
Researchers have imaged an exotic quantum particle -- called a Majorana fermion -- that can be used as a building block for future qubits and eventually the realization of quantum computers.
Virginia Tech researchers lead breakthrough in quantum computing
A team of Virginia Tech chemistry and physics researchers have advanced quantum simulation by devising an algorithm that can more efficiently calculate the properties of molecules on a noisy quantum computer.
Limitation exposed in promising quantum computing material
Physicists have theorized that a new type of material, called a three-dimensional (3-D) topological insulator (TI), could be a candidate to create qubits for quantum computing due to its special properties.
New material shows high potential for quantum computing
A joint team of scientists at the University of California, Riverside, and the Massachusetts Institute of Technology is getting closer to confirming the existence of an exotic quantum particle called Majorana fermion, crucial for fault-tolerant quantum computing -- the kind of quantum computing that addresses errors during its operation.
A sound idea: a step towards quantum computing
Researchers at the University of Tsukuba and the University of Pittsburgh have developed a new method for using lasers to create tiny lattice waves inside silicon crystals that can encode quantum information.
Quantum computing boost from vapour stabilising technique
A technique to stabilise alkali metal vapour density using gold nanoparticles, so electrons can be accessed for applications including quantum computing, atom cooling and precision measurements, has been patented by scientists at the University of Bath.
More Quantum Computing News and Quantum Computing Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Accessing Better Health
Essential health care is a right, not a privilege ... or is it? This hour, TED speakers explore how we can give everyone access to a healthier way of life, despite who you are or where you live. Guests include physician Raj Panjabi, former NYC health commissioner Mary Bassett, researcher Michael Hendryx, and neuroscientist Rachel Wurzman.
Now Playing: Science for the People

#544 Prosperity Without Growth
The societies we live in are organised around growth, objects, and driving forward a constantly expanding economy as benchmarks of success and prosperity. But this growing consumption at all costs is at odds with our understanding of what our planet can support. How do we lower the environmental impact of economic activity? How do we redefine success and prosperity separate from GDP, which politicians and governments have focused on for decades? We speak with ecological economist Tim Jackson, Professor of Sustainable Development at the University of Surrey, Director of the Centre for the Understanding of Sustainable Propserity, and author of...
Now Playing: Radiolab

An Announcement from Radiolab