Physicists develop method for quantum computers

February 8, 2013
An image depicting a network of collective qubits. Credit: Leibniz Universität Hannover

Quantum computers can solve certain problems much faster than their classical counterparts, but their realization on a scale relevent for practical applications has proven to be very difficult. However, this could change with a new method for solid state quantum computers devised by physicists from Leibniz Universität Hannover, Germany, and Harvard University. The scientists around Dr. Hendrik Weimer from the Institute for Theoretical Physics at Leibniz Universität report their results in the journal Physical Review Letters.

While controlling single ("qubits") is nowadays possible with high precision, the realization of large networks with many qubits remains an outstanding challenge. This is particularly relevant for devices based on magnetic impurities in systems, where the magnetic interaction between the qubits is too weak. However, the research team could now show that this obstacle could be solved by grouping about 100 impurities to form a single collective qubit. When an external magnetic field is chosen correctly, the magnetic properties of the impurities lose their individual characteristics and become indistinguishable due to their quantum nature. Such collective quantum states are known to show drastically increased interaction strengths, allowing to perform faster quantum logic operations between the collective qubits.

While the proposed method is applicable for a large class of solid state qubits, the scientists present a detailed analysis for nitrogen-vacancy defect centers in diamond, demonstrating the realizability of much larger quantum networks. "As few as 50 collective are enough for immediate applications in the simulation of strongly correlated quantum systems" Dr. Weimer explains.

Explore further: Turning down the noise in quantum data storage

More information: Hendrik Weimer, Norman Y. Yao, Mikhail D. Lukin. Collectively enhanced interactions in solid-state spin qubits, Physical Review Letters 110, 067601 (2013). dx.doi.org/10.1103/PhysRevLett.110.067601

Related Stories

Turning down the noise in quantum data storage

January 19, 2010

Researchers who hope to create quantum computers are currently investigating various methods to store data. Nitrogen atoms embedded in diamond show promise for encoding quantum bits (qubits), but the process of reading the ...

Physicists set guidelines for qubit candidates

May 4, 2010

(PhysOrg.com) -- To build a quantum computer, it's essential to be able to quickly and efficiently manipulate the quantum states of qubits. The qubits, which are the basic unit of quantum information, can be composed of many ...

Recommended for you

New device converts DC electric field to terahertz radiation

August 4, 2015

Terahertz radiation, the no-man's land of the electromagnetic spectrum, has long stymied researchers. Optical technologies can finagle light in the shorter-wavelength visible and infrared range, while electromagnetic techniques ...

The resplendent inflexibility of the rainbow

August 4, 2015

Children often ask simple questions that make you wonder if you really understand your subject. An young acquaintance of mine named Collin wondered why the colors of the rainbow were always in the same order—red, orange, ...

Magnetism at nanoscale

August 3, 2015

As the demand grows for ever smaller, smarter electronics, so does the demand for understanding materials' behavior at ever smaller scales. Physicists at the U.S. Department of Energy's Ames Laboratory are building a unique ...

Study calculates the speed of ice formation

August 3, 2015

Researchers at Princeton University have for the first time directly calculated the rate at which water crystallizes into ice in a realistic computer model of water molecules. The simulations, which were carried out on supercomputers, ...

Small tilt in magnets makes them viable memory chips

August 3, 2015

University of California, Berkeley, researchers have discovered a new way to switch the polarization of nanomagnets, paving the way for high-density storage to move from hard disks onto integrated circuits.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.