Scientists working with a feature of light described by Albert Einstein as "spooky" have managed to link, or entangle, up to five particles in an advance that may lead to better measuring instruments and faster computers.
Israeli researchers said on Thursday their technique could be scaled up to create even larger quantum entanglements, in which light particles, or photons, exist in two possible states simultaneously.
The notion that photons can be connected in such a way that changing the state of one instantly affects another, even when they are miles apart, alarmed Einstein, who called it "spooky action at a distance".
But quantum physicists — who study the universe at the ultra-small level of atoms, photons and other particles — have already put it to work to improve data encryption and, they hope, to someday supercharge computers.
Entanglement also lies at the heart of other new areas of quantum research, including ultra-precise measurement and improved imaging.
"The applications are out there, although there is a big barrier between demonstrating these states and application because these quantum states are very fragile," Yaron Silberberg of the Weizmann Institute of Science in Israel said in a telephone interview.
Silberberg and colleagues reported their work in the journal Science, noting that previous entangled states had been limited to three photons.
Using the unique qualities of quantum light could help scientists build more accurate instruments for use in cosmology and to further miniaturise lithography, the precision etching technology used in making microchips, he said.
Multi-particle entangled states also open up new opportunities in the design of super-fast quantum computers, which may be used in the future to try out many possible solutions to a problem at once.
Conventional computers are based on binary "switches", or bits, which can either be switched on or off and can only do one thing at a time.
