Synopsis: Quantum guessing games

Multiplayer quantum games reveal a class of nonlocal correlations stronger than in either purely quantum or purely classical scenarios.
Synopsis figure
Illustration: Alan Stonebraker

Nonlocality—the entanglement of one object with another at a distance—is a powerful way to achieve quantum information processing. However, quantum mechanics is tethered by a “no-signaling” principle, that is, these correlations cannot be used to transmit information arbitrarily quickly from one point to another. In a paper in Physical Review Letters, Mafalda Almeida at the ICFO-Institut de Ciencies Fotoniques in Barcelona and colleagues at institutions in Spain, Switzerland, the UK, and Belgium follow multiplayer games that obey quantum rules to better understand how no-signaling correlations can, in and of themselves, govern the outcome.

Almeida et al. have concocted a multiplayer game they call “Guess Your Neighbor’s Input” in which N players arranged in a circle each receive a bit: 0 or 1. A player then guesses the input the neighbor on her right has received, and emits a bit equal to that guess. The distribution of possible input bits is known ahead of time, but the players do not otherwise communicate.

This game clearly hints that winning it requires signaling. And indeed, Almeida et al. find that the guesses are no more successful on average when quantum correlations between the bits govern the play, than with purely classical correlations—a case where quantum information processing buys no advantage. However, surprisingly, they observe that for certain correlations governed only by the no-signalling principle, the players can outperform both quantum and classical scenarios. The results spell out for the first time where quantum nonlocality leaves off and where a stronger set of correlations can be found in multipartite situations. – David Voss


Features

More Features »

Announcements

More Announcements »

Subject Areas

Quantum Information

Previous Synopsis

Atomic and Molecular Physics

Raman thermometer for fermions

Read More »

Next Synopsis

Atomic and Molecular Physics

Cavernous nanofibers

Read More »

Related Articles

Synopsis: Entangled Photon Source Ticks All Boxes
Quantum Physics

Synopsis: Entangled Photon Source Ticks All Boxes

A quantum-dot-based device combines all of the attributes necessary for producing a reliable source of entangled photons for quantum information applications.  Read More »

Viewpoint: Alkaline Atoms Held with Optical Tweezers
Quantum Information

Viewpoint: Alkaline Atoms Held with Optical Tweezers

Three separate groups demonstrate the trapping of two-electron atoms in arrays of optical tweezers, opening up new opportunities for quantum simulation and many-body studies. Read More »

Synopsis: A Possible Quantum Computing Boost 
Quantum Information

Synopsis: A Possible Quantum Computing Boost 

A hybrid quantum-classical computing algorithm could solve a basic computer science problem faster than a classical computer. Read More »

More Articles