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:

Quantum experiments explore power of light for communications, computing
A team of quantum researchers from ORNL have conducted a series of experiments to gain a better understanding of quantum mechanics and pursue advances in quantum networking and quantum computing, which could lead to practical applications in cybersecurity and other areas.
In leap for quantum computing, silicon quantum bits establish a long-distance relationship
In an important step forward in the quest to build a quantum computer using silicon-based hardware, researchers at Princeton have succeeded in making possible the exchange of information between two qubits located relatively far apart -- about the length of a grain of rice, which is a considerable distance on a computer chip.
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.
More Quantum Computing News and Quantum Computing Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.