Progress in the fight against quantum dissipation

April 16, 2014
Progress in the fight against quantum dissipation
Scientists at Yale have confirmed a 50-year-old, previously untested theoretical prediction in physics and improved the energy storage time of a quantum switch by several orders of magnitude.

( —Scientists at Yale have confirmed a 50-year-old, previously untested theoretical prediction in physics and improved the energy storage time of a quantum switch by several orders of magnitude. They report their results in the April 17 issue of the journal Nature.

High-quality quantum switches are essential for the development of quantum computers and the quantum internet—innovations that would offer vastly greater information processing power and speed than classical (digital) computers, as well as more secure information transmission.

"Fighting dissipation is one of the main goals in the development of quantum hardware," said Ioan Pop, a postdoctoral researcher in applied physics at Yale and lead author of the paper. "A quantum switch needs to act reversibly without losing any energy. Our result is very encouraging for the development of superconducting acting as switches."

Superconducting quantum bits, or qubits, are artificial atoms that represent information in quantum systems. They also manipulate that information as they switch among states—such as "0," "1," or both simultaneously—under the influence of other qubits. But in switching states, they tend to lose energy, resulting in information loss.

In the Yale experiment, researchers demonstrated that a type of superconducting quantum bit can be immune to dissipation in presence of a quasiparticle—a microscopic entity that normally saps the energy of the qubit.

"We can engineer a system that is immune to quasiparticle dissipation," Pop said.

The researchers used an artificial fluxonium atom as their qubit.

The experiment confirms by direct measurement a theoretical prediction made by Nobel Prize-winning British physicist Brian Josephson in the 1960s, namely that quasiparticle dissipation should vanish under certain conditions. Josephson junctions are superconducting devices with properties well suited for building quantum processing systems.

The results open new frontiers in areas related to quantum information and quantum measurements, the researchers said, providing both a strategy for building dissipation-immune quantum systems and a specific new device that could be adapted for better measuring properties of quasiparticles and understanding their origin and dynamics.

Explore further: Physicists demonstrate the quantum von Neumann architecture

More information: The paper is titled "Coherent suppression of electromagnetic dissipation due to superconducting quasiparticles." DOI: 10.1038/nature13017

Related Stories

At Yale, quantum computing is a (qu)bit closer to reality

February 15, 2012

( -- Physicists at Yale University have taken another significant step in the development of quantum computing, a new frontier in computing that promises exponentially faster information processing than the most ...

New qubit control bodes well for future of quantum computing

January 14, 2013

(—Yale University scientists have found a way to observe quantum information while preserving its integrity, an achievement that offers researchers greater control in the volatile realm of quantum mechanics and ...

In quantum computing, light may lead the way

October 8, 2013

( —Light might be able to play a bigger, more versatile role in the future of quantum computing, according to new research by Yale University scientists.

Recommended for you

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...

Iron-gallium alloy shows promise as a power-generation device

September 29, 2015

An alloy first made nearly two decades ago by the U. S. Navy could provide an efficient new way to produce electricity. The material, dubbed Galfenol, consists of iron doped with the metal gallium. In new experiments, researchers ...

Invisibility cloak might enhance efficiency of solar cells

September 30, 2015

Success of the energy turnaround will depend decisively on the extended use of renewable energy sources. However, their efficiency partly is much smaller than that of conventional energy sources. The efficiency of commercially ...

Extending a battery's lifetime with heat

October 1, 2015

Don't go sticking your electronic devices in a toaster oven just yet, but for a longer-lasting battery, you might someday heat them up when not in use. Over time, the electrodes inside a rechargeable battery cell can grow ...


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.