Photo: INRS University Scientists have built a microchip that can generate two entangled qudits each with 10 states, for 100 dimensions total, more than what six entangled qubits could generate.
Instead of creating quantum computers based on qubits that can each adopt only two possible options, scientists have now developed a microchip that can generate qudits that can each assume 10 or more states, potentially opening up a new way to creating incredibly powerful quantum computers, a new study finds.
Classical computers switch transistors either on or off to symbolize data as ones and zeroes. In contrast, quantum computers use quantum bits, or qubitsthat, because of the bizarre nature of quantum physics, can be in a state ofsuperpositionwhere they simultaneously act as both 1 and 0.
The superpositions that qubits can adopt let them each help perform two calculations at once. If two qubitsare quantum-mechanically linked, orentangled,they can help perform four calculations simultaneously; three qubits, eight calculations; and so on. As a result, aquantum computer with 300 qubits could perform more calculations in an instant than there are atoms in the known universe, solving certain problems much faster than classical computers. However, superpositions are extraordinarily fragile, making it difficult to work with multiple qubits.
Most attempts at building practical quantum computers rely on particles that serve as qubits. However, scientists have long known that they could in principle use quditswith more than two states simultaneously. In principle, a quantum computer with two 32-state qudits, for example, would be able to perform as many operations as 10 qubits while skipping the challenges inherent with working with 10 qubits together.
Researchers used the setup pictured above to create, manipulate, and detect qudits. The experiment starts when a laser fires pulses of light into a micro-ring resonator, which in turn emits entangled pairs of photons.Because the ring has multiple resonances, the photons have optical spectrumswitha set of evenly spaced frequencies(red and blue peaks), a process known as spontaneous four-wave mixing (SFWM).The researchers were able to use each of thefrequencies to encode information, which means the photons act asqudits.Each quditis in a superposition of 10 possible states, extending the usual binary alphabet (0 and 1) of quantum bits.The researchers also showed they could perform basic gate operations on the qudits using optical filters and modulators, and then detect the results using single-photon counters.
Now scientists have for the first time created a microchip that can generate two entangled qudits each with 10 states, for 100 dimensions total, more than what six entangled qubits could generate. We have now achieved the compact and easy generation of high-dimensional quantum states, says study co-lead author Michael Kues, a quantum optics researcher at Canadas National Institute of Scientific Research, or INRS,its French acronym,in Varennes, Quebec.
The researchers developed a photonic chip fabricated using techniques similar to ones used for integrated circuits. A laser fires pulses of light into a micro-ring resonator, a 270-micrometer-diameter circle etched onto silica glass, which in turn emits entangled pairs of photons. Each photon is in a superposition of 10 possible wavelengths or colors.
For example, a high-dimensional photon can be red and yellow and green and blue, although the photons used here were in the infrared wavelength range, Kues says. Specifically, one photon from each pair spanned wavelengths from 1534 to 1550 nanometers, while the other spanned from 1550 to 1566 nanometers.
Using commercial off-the-shelf telecommunications components, the researchers showed they could manipulate these entangled photons. The basic capabilities they show are really what you need to do universal quantum computation, says quantum optics researcher Joseph Lukens at Oak Ridge National Laboratory, in Tennessee, who did not take part in this research. Its pretty exciting stuff.
In addition, by sending the entangled photons through a 24.2-kilometer-long optical fiber telecommunications system, the researchers showed that entanglement was preserved over large distances. This could prove useful for nigh-unhackable quantum communications applications, the researchers say.
What I think is amazing about our system is that it can be created using components that are out on the market, whereas other quantum computer technologies need state-of-the-art cryogenics, state-of-the-art superconductors, state-of-the-art magnets, saysstudy co-senior authorRoberto Morandotti, a physicistatINRSin Varennes. The fact that we use basic telecommunications components to access and control these states means that a lot of researchers could explore this area as well.
The scientists noted that current state-of-the-art components could conceivably generate entangled pairs of 96-state qudits, corresponding to more dimensions than 13 qubits. Conceptually, in principle, I dont see a limit to the number of states of qudits right now, Lukens, from Oak Ridge,says. I do think a 96-by-96-dimensional system is fairly reasonable, and achievable in the near future.
But he adds that several components of the experiment were not on the microchips, such as the programmable filters and phase modulators, which led to photon loss. Kues says that integrating such components with the rest of the chips and optimizing their micro-ring resonator would help reduce such losses to make their system more practical for use.
The next big challenge we will have to solve is to use our system for quantum computation and quantum communications applications, Kues says. While this will take some additional years, it is the final step required to achieve systems that can outperform classical computers and communications.
The scientists detailed their findings in the latest issue of the journal Nature.
IEEE Spectrums general technology blog, featuring news, analysis, and opinions about engineering, consumer electronics, and technology and society, from the editorial staff and freelance contributors.
Sign up for the Tech Alert newsletter and receive ground-breaking technology and science news from IEEE Spectrum every Thursday.
Connected quantum dots may form the building blocks of a solid-state quantum computer1Aug2004
A startup challenging Google and IBM sees opportunities for quantum computing in both the short term and long run 26Jun
By the end of 2017, Google hopes to make a 49-qubit chip that will prove quantum computers can beat classical machines 24May
Control of nuclear spin is key to a practical silicon quantum computer 18Apr2013
Freeing processors from doing the grunt work of communications accelerated the connected world 30Jun
Reading listings on the bulletin-board system was free, but posting cost a quarter 29Jun
HAX executives preview trends in hardware startups 26Jun
The massive 1 billion project has shifted focus from simulation to informatics 21Jun
Personalized medicine, self-driving cars, big data, AI, and machine learning will mainstream supercomputing 21Jun
For the first time since 1996, the U.S. holds none of the world’s top three supercomputers. An upgraded Swiss machine takes third 19Jun
Silicon Valleys top employers made big staffing changes, according to Silicon Valley Business Journal 15Jun
Neuroscience will give us what weve sought for decades: computers that think like we do 2Jun
Why the merger of the Raspberry Pi and CoderDojo foundations makes senseand why it doesnt 2Jun
Large-scale brainlike systems are possible with existing technologyif were willing to spend themoney 1Jun
Massive efforts to better understand the human brain will deliver on the original promise of computer science: machines that think like us 31May
Modeling computers after the brain could revolutionize robotics and big data 31May
Researchers in this specialized field have hitched their wagon to deep learnings star 29May
Artificial intelligence might endow some computers with self-awareness. Heres how wed know 25May
Fujitsus new cooling system promises easy server maintenance while using less power and taking up less space 18May
Scott Borg, director of the U.S. Cyber Consequences Unit, says hardware design engineers hold the future of cybersecurity in their hands 15May
- New silicon structure opens the gate to quantum computers - December 14th, 2017
- Microsoft offers developers a preview of its quantum ... - December 12th, 2017
- Quantum Computing Is the Next Big Security Risk | WIRED - December 8th, 2017
- Yale Professors Race Google and IBM to the First Quantum ... - November 16th, 2017
- IBM's processor pushes quantum computing ... - engadget.com - November 16th, 2017
- Quantum computing - news.microsoft.com - November 1st, 2017
- Intel Takes First Steps To Universal Quantum Computing - October 13th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - October 13th, 2017
- quantum computing - engadget.com - October 13th, 2017
- Quantum Computing | Intel Newsroom - October 13th, 2017
- What will you actually use quantum computing for? | ZDNet - October 11th, 2017
- Here's what quantum computing is and why it matters - October 6th, 2017
- Microsoft just upped its multi-million bet on quantum computing - ZDNet - September 7th, 2017
- Microsoft's Aussie quantum computing lab set to scale up next-gen ... - ARNnet - September 7th, 2017
- An Entirely New Type of Quantum Computing Has Just Been Invented - Futurism - September 7th, 2017
- Quantum computing event explores the implications for business - Cambridge Network - August 30th, 2017
- Quantum Computing Is Coming at Us Fast, So Here's Everything You Need to Know - ScienceAlert - August 27th, 2017
- How quantum mechanics can change computing - San Francisco ... - San Francisco Chronicle - August 25th, 2017
- Commonwealth Bank investing in Australia's first quantum computer company - Which-50 (blog) - August 25th, 2017
- How quantum mechanics can change computing - The Conversation US - August 23rd, 2017
- Introducing Australia's first quantum computing hardware company - Computerworld Australia - August 23rd, 2017
- IEEE Approves Standards Project for Quantum Computing ... - insideHPC - August 23rd, 2017
- $495.3 Million Quantum Computing Market 2017 by Revenue Source, Application, Industry, and Geography - Global ... - PR Newswire (press release) - August 18th, 2017
- Physicists Have Made Exotic Quantum States From Light - Futurism - August 16th, 2017
- Machine learning tackles quantum error correction - Phys.Org - August 15th, 2017
- Quantum Internet Is 13 Years Away. Wait, What's Quantum Internet? - WIRED - August 15th, 2017
- Blind quantum computing for everyone - Phys.org - Phys.Org - August 12th, 2017
- Quantum Computing Is Real, and D-Wave Just Open ... - WIRED - August 12th, 2017
- Quantum Computing Market Worth 495.3 Million USD by 2023 | 08 ... - Markets Insider - August 10th, 2017
- China uses a quantum satellite to transmit potentially unhackable data - CNBC - August 10th, 2017
- Physicists Take Big Step Towards Quantum Computing and ... - Universe Today - August 1st, 2017
- Why you might trust a quantum computer with secretseven over ... - Phys.Org - July 12th, 2017
- Quantum-computer node uses two different ion species - physicsworld.com - July 10th, 2017
- Quantum Computers vs Bitcoin How Worried Should We Be? - The Merkle - July 10th, 2017
- Quantum cheques could be a forgery-free way to move money - New Scientist - July 10th, 2017
- Technique for measuring and controlling electron state is a ... - UCLA Newsroom - July 9th, 2017
- Quantum Computers Made Even More Powerful with New microchip generating 'Qudits' - TrendinTech - July 8th, 2017
- Quantum Computing Record Broken - Wall Street Pit - July 8th, 2017
- Alkermes and IBM's quantum computing. Who'll be the big winner? Malcolm Berko - Durham Herald Sun - July 6th, 2017
- Google to Achieve "Supremacy" in Quantum Computing by the End of 2017 - Big Think - July 1st, 2017
- Quantum Computing Becomes More Accessible - Scientific American - July 1st, 2017
- Tektronix AWG Pulls Test into Era of Quantum Computing - Electronic Design - June 2nd, 2017
- Toward mass-producible quantum computers | MIT News - MIT News - June 2nd, 2017
- Purdue, Microsoft Partner On Quantum Computing Research | WBAA - WBAA - June 2nd, 2017
- IBM boosts power of quantum computing processors as it lays ... - www.computing.co.uk - May 22nd, 2017
- IBM makes leap in quantum computing power - ITworld - May 22nd, 2017
- The Bizarre Quantum Test That Could Keep Your Data Secure - WIRED - May 18th, 2017
- Molecular magnets closer to application in quantum computing - Next Big Future - May 15th, 2017
- Inside Microsoft's 'soup to nuts' quantum computing ramp-up - Computerworld Australia - April 29th, 2017
- Quantum computing is about to disrupt the government contracts market - Bloomberg Government (blog) - April 22nd, 2017
- Scientists: We Have Detected the Existence of a Fundamentally New State of Matter - Futurism - April 22nd, 2017
- What Sorts Of Problems Are Quantum Computers Good For? - Forbes - April 22nd, 2017
- quantum computing - WIRED UK - April 22nd, 2017
- What is Quantum Computing? Webopedia Definition - March 18th, 2017
- Here Is Everything You Need to Know About Quantum Computers - Interesting Engineering - March 18th, 2017
- Quantum Computing Market Forecast 2017-2022 | Market ... - March 18th, 2017
- Mathematician breaks down how to defend against quantum ... - Phys.Org - February 28th, 2017