Home > Press > Paving the way for a faster quantum computer: Unordered quantum computation: Improved efficiency
![]() |
Quantum mechanics does not only allow superposition of quantum states but also superposition of quantum gates. It was shown that superimposing two quantum gates A and B, an unordered quantum computation can run more efficiently than a well-defined order quantum computation.
Copyright: Philip Walther Group, University of Vienna |
Abstract:
Since its conception, quantum mechanics has defied our natural way of thinking, and it has forced physicists to come to grips with peculiar ideas. Although they may be difficult to digest, quantum phenomena are real. What's more, in the last decades, scientists have shown that these bizarre quantum effects can be used for many astonishingly powerful applications: from ultra-secure communication to hacking existing secure communications, and from simulating complex quantum systems to efficiently solving large systems of equations.
One of the most exciting and most difficult proposed quantum technologies is the quantum computer. Quantum logic gates are the basic building blocks of a quantum computer, but constructing enough of them to perform a useful computation is difficult. In the usual approach to quantum computing, quantum gates are applied in a specific order, one gate before another. But it was recently realized that quantum mechanics permits one to "superimpose quantum gates". If engineered correctly, this means that a set of quantum gates can act in all possible orders at the same time. Surprisingly, this effect can be used to reduce the total number of gates required for certain quantum computations.
All orders at once
A team led by Philip Walther recently realized that superimposing the order of quantum gates, an idea which was theoretically designed by the group of Caslav Brukner, could be implemented in the laboratory. In a superposition of quantum gate orders, it is impossible - even in principle - to know if one operation occurred before another operation, or the other way around. This means that two quantum logic gates A and B can be applied in both orders at the same time. In other words, gate A acts before B and B acts before A. The physicists from Philip Walther's group designed an experiment in which the two quantum logic gates were applied to single photons in both orders.
The results of their experiment confirm that it is impossible to determine which gate acted first - but the experiment was not simply a curiosity. "In fact, we were able to run a quantum algorithm to characterize the gates more efficiently than any previously known algorithm," says Lorenzo Procopio, lead author of the study. From a single measurement on the photon, they probed a specific property of the two quantum gates thereby confirming that the gates were applied in both orders at once. As more gates are added to the task, the new method becomes even more efficient compared to previous techniques.
The Way Forward
This is the first time that a superposition of quantum gates has been implemented in the lab. At the same time, it was used to successfully demonstrate a new kind of quantum computing. The scientists were able to accomplish a computation with an efficiency that cannot be achieved within the old scheme of quantum computing. This work opens a door for future studies on novel types of quantum computation. Although its full implications are still unknown, this work represents a new, exciting way to connect theoretical research on the foundations of physics to experimental quantum computing.
###
Publication in "Nature Communications":
"Experimental Superposition of Orders of Quantum Gates"
Lorenzo M. Procopio, Amir Moqanaki, Mateus Araújo, Fabio Costa, Irati Alonso Calafell, Emma G. Dowd, Deny R. Hamel, Lee A. Rozema, Caslav Brukner, and Philip Walther
Nature Communications
DOI: 10.1038/ncomms8913
####
For more information, please click here
Contacts:
Philip Walther
43-142-772-9575
Copyright © University of Vienna
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related News Press |
Physics
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
News and information
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
Chip Technology
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Programmable electron-induced color router array May 14th, 2025
Enhancing power factor of p- and n-type single-walled carbon nanotubes April 25th, 2025
Ultrafast plasmon-enhanced magnetic bit switching at the nanoscale April 25th, 2025
Quantum Computing
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
Magnetism in new exotic material opens the way for robust quantum computers June 4th, 2025
Programmable electron-induced color router array May 14th, 2025
Discoveries
Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025
Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Announcements
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025
Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025
Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025
A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025
![]() |
||
![]() |
||
The latest news from around the world, FREE | ||
![]() |
![]() |
||
Premium Products | ||
![]() |
||
Only the news you want to read!
Learn More |
||
![]() |
||
Full-service, expert consulting
Learn More |
||
![]() |