Navigation Links
Quantum computer built inside a diamond

Diamonds are forever or, at least, the effects of this diamond on quantum computing may be.

A team that includes scientists from USC has built a quantum computer in a diamond, the first of its kind to include protection against "decoherence" noise that prevents the computer from functioning properly.

The demonstration shows the viability of solid-state quantum computers, which unlike earlier gas- and liquid-state systems may represent the future of quantum computing because they can be easily scaled up in size. Current quantum computers are typically very small and though impressive cannot yet compete with the speed of larger, traditional computers.

The multinational team included USC Professor Daniel Lidar and USC postdoctoral researcher Zhihui Wang, as well as researchers from the Delft University of Technology in the Netherlands, Iowa State University and the University of California, Santa Barbara. Their findings will be published on April 5 in Nature.

The team's diamond quantum computer system featured two quantum bits (called "qubits"), made of subatomic particles.

As opposed to traditional computer bits, which can encode distinctly either a one or a zero, qubits can encode a one and a zero at the same time. This property, called superposition, along with the ability of quantum states to "tunnel" through energy barriers, will some day allow quantum computers to perform optimization calculations much faster than traditional computers.

Like all diamonds, the diamond used by the researchers has impurities things other than carbon. The more impurities in a diamond, the less attractive it is as a piece of jewelry, because it makes the crystal appear cloudy.

The team, however, utilized the impurities themselves.

A rogue nitrogen nucleus became the first qubit. In a second flaw sat an electron, which became the second qubit. (Though put more accurately, the "spin" of each of these subatomic particles was used as the qubit.)

Electrons are smaller than nuclei and perform computations much more quickly, but also fall victim more quickly to "decoherence." A qubit based on a nucleus, which is large, is much more stable but slower.

"A nucleus has a long decoherence time in the milliseconds. You can think of it as very sluggish," said Lidar, who holds a joint appointment with the USC Viterbi School of Engineering and the USC Dornsife College of Letters, Arts and Sciences.

Though solid-state computing systems have existed before, this was the first to incorporate decoherence protection using microwave pulses to continually switch the direction of the electron spin rotation.

"It's a little like time travel," Lidar said, because switching the direction of rotation time-reverses the inconsistencies in motion as the qubits move back to their original position.

The team was able to demonstrate that their diamond-encased system does indeed operate in a quantum fashion by seeing how closely it matched "Grover's algorithm."

The algorithm is not new Lov Grover of Bell Labs invented it in 1996 but it shows the promise of quantum computing.

The test is a search of an unsorted database, akin to being told to search for a name in a phone book when you've only been given the phone number.

Sometimes you'd miraculously find it on the first try, other times you might have to search through the entire book to find it. If you did the search countless times, on average, you'd find the name you were looking for after searching through half of the phone book.

Mathematically, this can be expressed by saying you'd find the correct choice in X/2 tries if X is the number of total choices you have to search through. So, with four choices total, you'll find the correct one after two tries on average.

A quantum computer, using the properties of superposition, can find the correct choice much more quickly. The mathematics behind it are complicated, but in practical terms, a quantum computer searching through an unsorted list of four choices will find the correct choice on the first try, every time.

Though not perfect, the new computer picked the correct choice on the first try about 95 percent of the time enough to demonstrate that it operates in a quantum fashion.


Contact: Robert Perkins
University of Southern California

Related biology technology :

1. Quantum control protocols could lead to more accurate, larger scale quantum computations
2. Single molecules in a quantum movie
3. A new class of electron interactions in quantum systems
4. Graphene quantum dots: The next big small thing
5. Smaller and more powerful electronics requires the understanding of quantum jamming physics
6. Quantum computing has applications in magnetic imaging, say Pitt researchers
7. Michael Cusumano, MITs Sloan Distinguished Professor of Management, Joins Quantum Leap Innovations Board of Directors
8. Pitt discoveries in quantum physics could change face of technology
9. In new quantum-dot LED design, researchers turn troublesome molecules to their advantage
10. UCSB physicists identify room temperature quantum bits in widely used semiconductor
11. New hybrid technology could bring quantum information systems
Post Your Comments:
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. Hoffmann, former senior ... the University of North Carolina Kenan-Flagler Business School effective June 27. ... Kenan-Flagler, with a focus on the school’s international efforts, leading classes and participating ...
(Date:6/24/2016)... June 24, 2016 Epic Sciences unveiled ... cancers susceptible to PARP inhibitors by targeting homologous ... (CTCs). The new test has already been incorporated ... multiple cancer types. Over 230 clinical ... response pathways, including PARP, ATM, ATR, DNA-PK and ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one of the ... brand, UP4™ Probiotics, into Target stores nationwide. The company, which has been manufacturing ... to its list of well-respected retailers. This list includes such fine stores as ...
(Date:6/23/2016)... 2016 Houston Methodist Willowbrook Hospital has ... Association to serve as their official health care ... Willowbrook will provide sponsorship support, athletic training services, ... coaches, volunteers, athletes and families. "We ... Association and to bring Houston Methodist quality services ...
Breaking Biology Technology:
(Date:6/15/2016)... 15, 2016 Transparency Market ... Recognition Market by Application Market - Global Industry Analysis Size ... to the report, the  global gesture recognition market ... and is estimated to grow at a CAGR ... 2024.  Increasing application of gesture recognition ...
(Date:6/9/2016)... , June 9, 2016 ... Police deploy Teleste,s video security solution to ensure the safety ... France during the major tournament Teleste, ... communications systems and services, announced today that its video security ... to back up public safety across the country. ...
(Date:6/3/2016)... , June 3, 2016 ... Management) von Nepal ... und Lieferung hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, ... führend in der Produktion und Implementierung von ... der Ausschreibung im Januar teilgenommen, aber Decatur ...
Breaking Biology News(10 mins):