May 9, 2017 by Tom Abate Researchers are developing quantum computers based on light rather than electricity. At Stanford, new materials could be the key to progress in this field. Credit: iStock/Pobytov
For 60 years computers have become smaller, faster and cheaper. But engineers are approaching the limits of how small they can make silicon transistors and how quickly they can push electricity through devices to create digital ones and zeros.
That limitation is why Stanford electrical engineering Professor Jelena Vuckovic is looking to quantum computing, which is based on light rather than electricity. Quantum computers work by isolating spinning electrons inside a new type of semiconductor material. When a laser strikes the electron, it reveals which way it is spinning by emitting one or more quanta, or particles, of light. Those spin states replace the ones and zeros of traditional computing.
Vuckovic, who is one of the world's leading researchers in the field, said quantum computing is ideal for studying biological systems, doing cryptography or data mining in fact, solving any problem with many variables.
"When people talk about finding a needle in a haystack, that's where quantum computing comes in," she said.
Marina Radulaski, a postdoctoral fellow in Vuckovic's lab, said the problem-solving potential of quantum computers stems from the complexity of the laser-electron interactions at the core of the concept.
"With electronics you have zeros and ones," Radulaski said. "But when the laser hits the electron in a quantum system, it creates many possible spin states, and that greater range of possibilities forms the basis for more complex computing."
Capturing electrons
Harnessing information based on the interactions of light and electrons is easier said than done. Some of the world's leading technology companies are trying to build massive quantum computers that rely on materials super-cooled to near absolute zero, the theoretical temperature at which atoms would cease to move.
In her own studies of nearly 20 years, Vuckovic has focused on one aspect of the challenge: creating new types of quantum computer chips that would become the building blocks of future systems.
"To fully realize the promise of quantum computing we will have to develop technologies that can operate in normal environments," she said. "The materials we are exploring bring us closer toward finding tomorrow's quantum processor."
The challenge for Vuckovic's team is developing materials that can trap a single, isolated electron. Working with collaborators worldwide, they have recently tested three different approaches to the problem, one of which can operate at room temperature a critical step if quantum computing is going to become a practical tool.
In all three cases the group started with semiconductor crystals, material with a regular atomic lattice like the girders of a skyscraper. By slightly altering this lattice, they sought to create a structure in which the atomic forces exerted by the material could confine a spinning electron.
"We are trying to develop the basic working unit of a quantum chip, the equivalent of the transistor on a silicon chip," Vuckovic said.
Quantum dots
One way to create this laser-electron interaction chamber is through a structure known as a quantum dot. Physically, the quantum dot is a small amount of indium arsenide inside a crystal of gallium arsenide. The atomic properties of the two materials are known to trap a spinning electron.
In a recent paper in Nature Physics, Kevin Fischer, a graduate student in the Vuckovic lab, describes how the laser-electron processes can be exploited within such a quantum dot to control the input and output of light. By sending more laser power to the quantum dot, the researchers could force it to emit exactly two photons rather than one. They say the quantum dot has practical advantages over other leading quantum computing platforms but still requires cryogenic cooling, so it may not be useful for general-purpose computing. However, it could have applications in creating tamper-proof communications networks.
Color centers
In two other papers Vuckovic took a different approach to electron capture, by modifying a single crystal to trap light in what is called a color center.
In a recent paper published in Nano Letters, her team focused on color centers in diamond. In nature the crystalline lattice of a diamond consists of carbon atoms. Jingyuan Linda Zhang, a graduate student in Vuckovic's lab, described how a 16-member research team replaced some of those carbon atoms with silicon atoms. This one alteration created color centers that effectively trapped spinning electrons in the diamond lattice.
But like the quantum dot, most diamond color center experiments require cryogenic cooling. Though that is an improvement over other approaches that required even more elaborate cooling, Vuckovic wanted to do better.
So she worked with another global team to experiment with a third material, silicon carbide. Commonly known as carborundum, silicon carbide is a hard, transparent crystal used to make clutch plates, brake pads and bulletproof vests. Prior research had shown that silicon carbide could be modified to create color centers at room temperature. But this potential had not yet been made efficient enough to yield a quantum chip.
Vuckovic's team knocked certain silicon atoms out of the silicon carbide lattice in a way that created highly efficient color centers. They also fabricated nanowire structures around the color centers to improve the extraction of photons. Radulaski was the first author on that experiment, which is described in another NanoLetters paper. She said the net results an efficient color center, operating at room temperature, in a material familiar to industry were huge pluses.
"We think we've demonstrated a practical approach to making a quantum chip," Radulaski said.
But the field is still in its early days and electron tapping is no simple feat. Even the researchers aren't sure which method or methods will win out.
"We don't know yet which approach is best, so we continue to experiment," Vuckovic said.
Explore further: Simultaneous detection of multiple spin states in a single quantum dot
More information: Marina Radulaski et al. Scalable Quantum Photonics with Single Color Centers in Silicon Carbide, Nano Letters (2017). DOI: 10.1021/acs.nanolett.6b05102
Journal reference: Nano Letters
Provided by: Stanford University
Quantum dots are very small particles that exhibit luminescence and electronic properties different from those of their bulk materials. As a result, they are attractive for use in solar cells, optoelectronics, and quantum ...
Imagine communicating with your bank, the IRS or your doctor by way of an Internet that was perfectly secure. Your most private data would be protected with absolute certainty and, better yet, if any bad actor were to try ...
A City College of New York led-team headed by physicist Dr. Carlos Meriles has successfully demonstrated charge transport between Nitrogen-Vacancy color centers in diamond. The team developed a novel multi-color scanning ...
Scientists can now identify the exact location of a single atom in a silicon crystal, a discovery that is key to greater accuracy in the operation of tomorrow's silicon-based quantum computers.
When the quantum computer was imagined 30 years ago, it was revered for its potential to quickly and accurately complete practical tasks often considered impossible for mere humans and for conventional computers. But, there ...
What does the future hold for computing? Experts at the Networked Quantum Information Technologies Hub (NQIT), based at Oxford University, believe our next great technological leap lies in the development of quantum computing.
For 60 years computers have become smaller, faster and cheaper. But engineers are approaching the limits of how small they can make silicon transistors and how quickly they can push electricity through devices to create digital ...
For many, zinc oxide conjures images of bright stripes down lifeguards' noses. But for researchers in Concordia's Faculty of Arts and Science, ZnO is an exciting compound with important optical and electrical properties.
With the tap of your finger, your tablet comes to life thanks to tiny force sensors and accelerometers that contain piezoelectric materials.
If they're quick about it, "hot" electrons excited in a plasmonic metal can tunnel their way across a nanoscale gap to a neighboring metal. Rice University scientists said the cool part is what happens in the gap.
A team of researchers, led by the University of Minnesota, have discovered a new nano-scale thin film material with the highest-ever conductivity in its class. The new material could lead to smaller, faster, and more powerful ...
In normal conductive materials such as silver and copper, electric current flows with varying degrees of resistance, in the form of individual electrons that ping-pong off defects, dissipating energy as they go. Superconductors, ...
Please sign in to add a comment. Registration is free, and takes less than a minute. Read more
See the original post here:
New materials bring quantum computing closer to reality - Phys.org - Phys.Org
- Time Crystals Could be the Key to the First Quantum Computer - TrendinTech [Last Updated On: May 3rd, 2017] [Originally Added On: May 3rd, 2017]
- The Quantum Computer Revolution Is Closer Than You May Think - National Review [Last Updated On: May 3rd, 2017] [Originally Added On: May 3rd, 2017]
- Chinese scientists build world's first quantum computing machine - India Today [Last Updated On: May 3rd, 2017] [Originally Added On: May 3rd, 2017]
- Quantum Computing | D-Wave Systems [Last Updated On: May 3rd, 2017] [Originally Added On: May 3rd, 2017]
- Quantum computing utilizes 3D crystals - Johns Hopkins News-Letter [Last Updated On: May 4th, 2017] [Originally Added On: May 4th, 2017]
- Quantum Computing and What All Good IT Managers Should Know - TrendinTech [Last Updated On: May 4th, 2017] [Originally Added On: May 4th, 2017]
- World's First Quantum Computer Made By China 24000 Times Faster Than International Counterparts - Fossbytes [Last Updated On: May 4th, 2017] [Originally Added On: May 4th, 2017]
- China adds a quantum computer to high-performance computing arsenal - PCWorld [Last Updated On: May 6th, 2017] [Originally Added On: May 6th, 2017]
- Quantum computing: A simple introduction - Explain that Stuff [Last Updated On: May 6th, 2017] [Originally Added On: May 6th, 2017]
- What is Quantum Computing? Webopedia Definition [Last Updated On: May 6th, 2017] [Originally Added On: May 6th, 2017]
- Quantum Computing Market Forecast 2017-2022 | Market ... [Last Updated On: May 6th, 2017] [Originally Added On: May 6th, 2017]
- China hits milestone in developing quantum computer - South China Morning Post [Last Updated On: May 8th, 2017] [Originally Added On: May 8th, 2017]
- China builds five qubit quantum computer sampling and will scale to 20 qubits by end of this year and could any beat ... - Next Big Future [Last Updated On: May 8th, 2017] [Originally Added On: May 8th, 2017]
- Five Ways Quantum Computing Will Change the Way We Think ... - PR Newswire (press release) [Last Updated On: May 8th, 2017] [Originally Added On: May 8th, 2017]
- Quantum Computing Demands a Whole New Kind of Programmer - Singularity Hub [Last Updated On: May 9th, 2017] [Originally Added On: May 9th, 2017]
- Researchers Invent Nanoscale 'Refrigerator' for Quantum ... - Sci-News.com [Last Updated On: May 11th, 2017] [Originally Added On: May 11th, 2017]
- China's New Type of Quantum Computing Device, Built Inside a Diamond - TrendinTech [Last Updated On: May 11th, 2017] [Originally Added On: May 11th, 2017]
- Molecular magnets closer to application in quantum computing - Next Big Future [Last Updated On: May 11th, 2017] [Originally Added On: May 11th, 2017]
- New Materials Could Make Quantum Computers More Practical - Tom's Hardware [Last Updated On: May 11th, 2017] [Originally Added On: May 11th, 2017]
- Home News Computer Europe Takes Quantum Computing to the Next Level With this Billion Euro... - TrendinTech [Last Updated On: May 13th, 2017] [Originally Added On: May 13th, 2017]
- Researchers seek to advance quantum computing - The Stanford Daily [Last Updated On: May 13th, 2017] [Originally Added On: May 13th, 2017]
- quantum computing - WIRED UK [Last Updated On: May 13th, 2017] [Originally Added On: May 13th, 2017]
- Scientists Invent Nanoscale Refrigerator For Quantum Computers - Wall Street Pit [Last Updated On: May 14th, 2017] [Originally Added On: May 14th, 2017]
- D-Wave Closes $50M Facility to Fund Next Generation of Quantum Computers - Marketwired (press release) [Last Updated On: May 17th, 2017] [Originally Added On: May 17th, 2017]
- Quantum Computers Sound Great, But Who's Going to Program Them? - TrendinTech [Last Updated On: May 17th, 2017] [Originally Added On: May 17th, 2017]
- Quantum Computing Could Use Graphene To Create Stable Qubits - International Business Times [Last Updated On: May 18th, 2017] [Originally Added On: May 18th, 2017]
- Bigger is better: Quantum volume expresses computer's limit - Ars Technica [Last Updated On: May 18th, 2017] [Originally Added On: May 18th, 2017]
- IBM's Newest Quantum Computing Processors Have Triple the Qubits of Their Last - Futurism [Last Updated On: May 18th, 2017] [Originally Added On: May 18th, 2017]
- It's time to decide how quantum computing will help your business - Techworld Australia [Last Updated On: May 20th, 2017] [Originally Added On: May 20th, 2017]
- IBM makes a leap in quantum computing power - PCWorld [Last Updated On: May 20th, 2017] [Originally Added On: May 20th, 2017]
- IBM scientists demonstrate ballistic nanowire connections, a potential future key component for quantum computing - Phys.Org [Last Updated On: May 20th, 2017] [Originally Added On: May 20th, 2017]
- The route to high-speed quantum computing is paved with error - Ars Technica UK [Last Updated On: May 20th, 2017] [Originally Added On: May 20th, 2017]
- IBM makes leap in quantum computing power - ITworld [Last Updated On: May 22nd, 2017] [Originally Added On: May 22nd, 2017]
- Researchers push forward quantum computing research - The ... - Economic Times [Last Updated On: May 22nd, 2017] [Originally Added On: May 22nd, 2017]
- Quantum Computing Research Given a Boost by Stanford Team - News18 [Last Updated On: May 22nd, 2017] [Originally Added On: May 22nd, 2017]
- US playing catch-up in quantum computing - The Register-Guard [Last Updated On: May 22nd, 2017] [Originally Added On: May 22nd, 2017]
- Stanford researchers push forward quantum computing research ... - The Indian Express [Last Updated On: May 23rd, 2017] [Originally Added On: May 23rd, 2017]
- NASA Scientist Eleanor Rieffel to give a talk on quantum computing - Chapman University: Happenings (blog) [Last Updated On: May 23rd, 2017] [Originally Added On: May 23rd, 2017]
- Graphene Just Brought Us One Step Closer to Practical Quantum Computers - Futurism [Last Updated On: May 23rd, 2017] [Originally Added On: May 23rd, 2017]
- IBM Q Offers Quantum Computing as a Service - The Merkle [Last Updated On: May 23rd, 2017] [Originally Added On: May 23rd, 2017]
- How quantum computing increases cybersecurity risks | Network ... - Network World [Last Updated On: May 23rd, 2017] [Originally Added On: May 23rd, 2017]
- Quantum Computing Is Going Commercial With the Potential ... [Last Updated On: May 23rd, 2017] [Originally Added On: May 23rd, 2017]
- Is the US falling behind in the race for quantum computing? - AroundtheO [Last Updated On: May 26th, 2017] [Originally Added On: May 26th, 2017]
- Quantum computing, election pledges and a thief who made science history - Nature.com [Last Updated On: May 26th, 2017] [Originally Added On: May 26th, 2017]
- Top 5: Things to know about quantum computers - TechRepublic [Last Updated On: May 26th, 2017] [Originally Added On: May 26th, 2017]
- Google Plans to Demonstrate the Supremacy of Quantum ... - IEEE Spectrum [Last Updated On: May 26th, 2017] [Originally Added On: May 26th, 2017]
- Quantum Computing Is Real, and D-Wave Just Open ... - WIRED [Last Updated On: May 26th, 2017] [Originally Added On: May 26th, 2017]
- IBM to Sell Use of Its New 17-Qubit Quantum Computer over the Cloud - All About Circuits [Last Updated On: May 28th, 2017] [Originally Added On: May 28th, 2017]
- Doped Diamonds Push Practical Quantum Computing Closer to Reality - Motherboard [Last Updated On: May 28th, 2017] [Originally Added On: May 28th, 2017]
- For more advanced computing, technology needs to make a ... - CIO Dive [Last Updated On: May 30th, 2017] [Originally Added On: May 30th, 2017]
- Microsoft, Purdue Extend Quantum Computing Partnership To Create More Stable Qubits - Tom's Hardware [Last Updated On: May 30th, 2017] [Originally Added On: May 30th, 2017]
- AI and Quantum Computers Are Our Best Weapons Against Cyber Criminals - Futurism [Last Updated On: May 30th, 2017] [Originally Added On: May 30th, 2017]
- Toward mass-producible quantum computers | MIT News - MIT News [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- Purdue, Microsoft Partner On Quantum Computing Research | WBAA - WBAA [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- Tektronix AWG Pulls Test into Era of Quantum Computing - Electronic Design [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- Telstra just wants a quantum computer to offer as-a-service - ZDNet [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- D-Wave partners with U of T to move quantum computing along - Financial Post [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- MIT Just Unveiled A Technique to Mass Produce Quantum Computers - Futurism [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- Here's how we can achieve mass-produced quantum computers ... - ScienceAlert [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- Research collaborative pursues advanced quantum computing - Phys.Org [Last Updated On: June 1st, 2017] [Originally Added On: June 1st, 2017]
- Team develops first blockchain that can't be hacked by quantum computer - Siliconrepublic.com [Last Updated On: June 3rd, 2017] [Originally Added On: June 3rd, 2017]
- Quantum computers to drive customer insights, says CBA CIO - CIO - CIO Australia [Last Updated On: June 6th, 2017] [Originally Added On: June 6th, 2017]
- FinDEVr London: Preparing for the Dark Side of Quantum Computing - GlobeNewswire (press release) [Last Updated On: June 8th, 2017] [Originally Added On: June 8th, 2017]
- Scientists May Have Found a Way to Combat Quantum Computer Blockchain Hacking - Futurism [Last Updated On: June 9th, 2017] [Originally Added On: June 9th, 2017]
- Purdue, Microsoft to Collaborate on Quantum Computer - Photonics.com [Last Updated On: June 9th, 2017] [Originally Added On: June 9th, 2017]
- From the Abacus to Supercomputers to Quantum Computers - Duke Today [Last Updated On: June 12th, 2017] [Originally Added On: June 12th, 2017]
- Microsoft and Purdue work on scalable topological quantum computer - Next Big Future [Last Updated On: June 12th, 2017] [Originally Added On: June 12th, 2017]
- Are Enterprises Ready to Take a Quantum Leap? - IT Business Edge [Last Updated On: June 12th, 2017] [Originally Added On: June 12th, 2017]
- A Hybrid of Quantum Computing and Machine Learning Is Spawning New Ventures - IEEE Spectrum [Last Updated On: June 14th, 2017] [Originally Added On: June 14th, 2017]
- The Machine of Tomorrow Today: Quantum Computing on the Verge - Bloomberg [Last Updated On: June 14th, 2017] [Originally Added On: June 14th, 2017]
- KPN CISO details Quantum computing attack dangers - Mobile World Live [Last Updated On: June 15th, 2017] [Originally Added On: June 15th, 2017]
- Accenture, Biogen, 1QBit Launch Quantum Computing App to ... - HIT Consultant [Last Updated On: June 15th, 2017] [Originally Added On: June 15th, 2017]
- Angry Birds, qubits and big ideas: Quantum computing is tantalisingly close - The Australian Financial Review [Last Updated On: June 15th, 2017] [Originally Added On: June 15th, 2017]
- Consortium Applies Quantum Computing to Drug Discovery for Neurological Diseases - Drug Discovery & Development [Last Updated On: June 15th, 2017] [Originally Added On: June 15th, 2017]
- Accenture, 1QBit partner for drug discovery through quantum computing - ZDNet [Last Updated On: June 15th, 2017] [Originally Added On: June 15th, 2017]
- How to get ahead in quantum machine learning AND attract Goldman Sachs - eFinancialCareers [Last Updated On: June 15th, 2017] [Originally Added On: June 15th, 2017]
- Quantum computing, the machines of tomorrow - The Japan Times [Last Updated On: June 16th, 2017] [Originally Added On: June 16th, 2017]
- Toward optical quantum computing - MIT News [Last Updated On: June 17th, 2017] [Originally Added On: June 17th, 2017]
- Its time to decide how quantum computing will help your ... [Last Updated On: June 18th, 2017] [Originally Added On: June 18th, 2017]
- Israel Enters Quantum Computer Race, Placing Encryption at Ever-Greater Risk - Sputnik International [Last Updated On: June 19th, 2017] [Originally Added On: June 19th, 2017]