It’s the holy grail of quantum computing: how to create the key building blocks known as quantum bits — qubits — that exist in a solid-state system at room temperature.
A group of Harvard scientists, led by Professor of Physics Mikhail Lukin and including graduate students Georg Kucsko and Peter Maurer and postdoctoral researcher Christian Latta, say they have cracked the code regarding the cooling of quantum computers.
And they did it by turning to one of the purest materials on Earth: diamonds.
Using a pair of impurities in ultra-pure, laboratory-grown diamonds, the researchers announced earlier this week that preliminary results reveal the ability to create quantum bits and store information in them for nearly two seconds — an increase of nearly six magnitudes, say the scientists. The work, described in the June 8 issue of Science, is a critical first step in the eventual construction of a functional quantum computer that could one day allow for advanced computations.
“What we’ve been able to achieve in terms of control is quite unprecedented,” Harvard Professor of Physics Mikhail Lukin said. “We have a qubit, at room temperature, that we can measure with very high efficiency and fidelity. We can encode data in it, and we can store it for a relatively long time. We believe this work is limited only by technical issues, so it looks feasible to increase the life span into the range of hours. At that point, a host of real-world applications become possible.”
The research is the latest step towards creating quantum computers. A practical quantum computer with enough qubits available could complete in minutes calculations that would take ultrafast super-computers years, and your laptop perhaps millions of years to process. Such computers will harness the powers of atoms and sub-atomic particles (ions, photons, electrons) to perform memory and processing tasks, thanks to the strange sub-atomic properties of quantum mechanics, say scientists.
One challenge facing quantum computing is creating computers that can remain in a solid-state at room temperature. Most systems rely on complex and expensive equipment designed to trap an atom or electron in a vacuum, and then cool the entire system to nearly absolute zero, or −459.67° Fahrenheit. Researchers say the experiment is an essential finding for the evolution of the quantum computer, saying it will likely serve as cornerstone for additional research in the coming years.
“This research is an important step forward in research toward one day building a practical quantum computer,” graduate student Georg Kucskoo, who works in Lukin’s lab and is one of two first authors of the paper, said. “For the first time, we have a system that has a reasonable timescale for memory and simplicity, so this is now something we can pursue.”
The most current computers are possibly able to understand is a bit. Much like a light that can be switched on or off, a bit can have only one of two values: “1″ or “0″. For qubits, they can hold a value of “1” or “0” as well as both values at the same time. Described as superposition, this is what allows quantum computers to perform millions of calculations at once.
That said, this is not the first time scientists have turn to diamonds as a solution to the vexing problem of quantum computing. Scientists at the University of Southern California (USC) announced in April that were able to build a quantum computer system within a diamond that leveraged imperfections, the first of its kind.
The project comes as a number of research institutes have announced advances in studying quantum computing. Physicists at Purdue University and the University of New South Wales announced earlier this year that they have built a transistor from a single atom of phosphorous precisely placed on a bed of silicon. Meanwhile, scientists at IBM Research announced they achieved major advances in quantum computing device performance, establishing three new records for reducing errors in elementary computations and retaining the integrity of quantum mechanical properties in qubits.
The practical purposes of a quantum computer are nearly endless, say scientists. Quantum computers are expected to play an important role in future information processing since they can outperform classical computers at many tasks. Considering the challenges inherent in building quantum devices, it is conceivable that future quantum computing capabilities will exist only in a few specialized facilities around the world — much like today’s supercomputers. Quantum computers would also likely have the ability to produce advanced encryption and the ability to process massive computations.
Researchers at the California Institute of Technology and the Max-Planck-Institut für Quantenoptik also participated in the research. Funding was provided by the National Science Foundation, the Center for Ultracold Atoms, the Defense Advanced Research Projects Agency, Element 6, the Packard Foundation, the European Union, the Swiss National Science Foundation, and the Sherman Fairchild Foundation.