Transistors are tiny switches that form the bedrock of modern computing; billions of them route electrical signals around inside a smartphone, for instance.
Quantum computers will need analogous hardware to manipulate quantum information. But the design constraints for this new technology are stringent, and today’s most advanced processors can’t be repurposed as quantum devices. That’s because quantum information carriers, dubbed qubits, have to follow different rules laid out by quantum physics.
Scientists can use many kinds of quantum particles as qubits, even the photons that make up light. Photons have added appeal because they can swiftly shuttle information over long distances, and they are compatible with fabricated chips. However, making a quantum transistor triggered by light has been challenging because it requires that the photons interact with each other, something that doesn’t ordinarily happen on its own.
Now, researchers at the University of Maryland’s A. James Clark School of Engineering and Joint Quantum Institute (JQI)–led by Professor of Electrical and Computer Engineering, JQI Fellow, and Institute for Research in Electronics and Applied Physics Affiliate Edo Waks–have cleared this hurdle and demonstrated the first single-photon transistor using a semiconductor chip. The device, described in the July 6 issue of Science, is compact; roughly one million of these new transistors could fit inside a single grain of salt. It is also fast and able to process 10 billion photonic qubits every second.
“Using our transistor, we should be able to perform quantum gates between photons,” says Waks. “Software running on a quantum computer would use a series of such operations to attain exponential speedup for certain computational problems.
The photonic chip is made from a semiconductor with numerous holes in it, making it appear much like a honeycomb. Light entering the chip bounces around and gets trapped by the hole pattern; a small crystal called a quantum dot sits inside the area where the light intensity is strongest. Analogous to conventional computer memory, the dot stores information about photons as they enter the device. The dot can effectively tap into that memory to mediate photon interactions–meaning that the actions of one photon affect others that later arrive at the chip.
“In a single-photon transistor the quantum dot memory must persist long enough to interact with each photonic qubit,” says Shuo Sun, lead author of the new work and postdoctoral research fellow at Stanford University who was a UMD grad student at the time of the research. “This allows a single photon to switch a bigger stream of photons, which is essential for our device to be considered a transistor.”
To test that the chip operated like a transistor, the researchers examined how the device responded to weak light pulses that usually contained only one photon. In a normal environment, such dim light might barely register. However, in this device, a single photon gets trapped for a long time, registering its presence in the nearby dot.
The team observed that a single photon could, by interacting with the dot, control the transmission of a second light pulse through the device. The first light pulse acts like a key, opening the door for the second photon to enter the chip. If the first pulse didn’t contain any photons, the dot blocked subsequent photons from getting through. This behavior is similar to a conventional transistor where a small voltage controls the passage of current through its terminals. Here, the researchers successfully replaced the voltage with a single photon and demonstrated that their quantum transistor could switch a light pulse containing around 30 photons before the quantum dot’s memory ran out.
Waks says that his team had to test different aspects of the device’s performance prior to getting the transistor to work. “Until now, we had the individual components necessary to make a single photon transistor, but here we combined all of the steps into a single chip,” he says.
Sun says that with realistic engineering improvements their approach could allow many quantum light transistors to be linked together. The team hopes that such speedy, highly connected devices will eventually lead to compact quantum computers that process large numbers of photonic qubits.
Learn more: Semiconductor quantum transistor opens the door for photon-based computing
[osd_subscribe categories=’quantum-computer’ placeholder=’Email Address’ button_text=’Subscribe Now for any new posts on the topic “QUANTUM COMPUTER’]
Receive an email update when we add a new QUANTUM COMPUTER article.
The Latest on: Quantum computer
[google_news title=”” keyword=”quantum computer” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Quantum computer
- 3 Quantum Computing Stocks That Could Be Multibaggers in the Making: April Editionon April 27, 2024 at 11:00 am
Quantum computing technology and applications across sectors are advancing rapidly; the market is predicted to grow over 32% from 2023 to 2030, attracting attention toward multibagger quantum ...
- How Quantum Computers Could Illuminate the Full Range of Human Genetic Diversityon April 26, 2024 at 10:26 am
Pangenomes that incorporate many people’s DNA could capture the breadth of human genetic diversity, and quantum computers may be a key enabler.
- Quantum computing in Colorado could get a multimillion-dollar investmenton April 26, 2024 at 9:00 am
Quantum computing in Colorado could get a massive boost in federal funding this year, to invest in startups, workforce development and laboratory space.
- The Top 3 Quantum Computing Stocks to Buy in April 2024on April 26, 2024 at 4:30 am
InvestorPlace - Stock Market News, Stock Advice & Trading Tips When the largest American bank, JPMorgan Chase (NYSE:JPM), starts investing ...
- 3 Quantum Computing Stocks to Buy on the Dip: April 2024on April 26, 2024 at 3:30 am
Quantum computing is poised to revolutionize various industries and greatly impact society due to its immense computational power. Unlike classical computers, quantum computers can perform complex ...
- Quantum Computing Meets Genomics: The Dawn of Hyper-Fast DNA Analysison April 26, 2024 at 2:13 am
A new project unites world-leading experts in quantum computing and genomics to develop new methods and algorithms to process biological data. Researchers aim to harness quantum computing to speed up ...
- Japan Tightens Export Controls on More Chip and Quantum Techon April 26, 2024 at 1:38 am
Japan said it plans to expand restrictions on exports of four technologies related to semiconductors or quantum computing, the latest in a global push to control the flow of strategic tech.
- Why Your Company Needs To Assess Its Quantum Computing Vulnerabilities Nowon April 25, 2024 at 7:22 am
Although current knowledge causes most companies to expect that cybersecurity vulnerability and threats from quantum computing will be way out in the future, those expectations are incorrect.
- 3 Quantum Computing Stocks to Buy Now: Q2 Editionon April 22, 2024 at 8:52 am
InvestorPlace - Stock Market News, Stock Advice & Trading Tips AI stocks have overshadowed other emerging technologies, including quantum ...
via Bing News