Sunday, June 25, 2017

'Quantum gambling' could make betting fairer for all involved

From Wired, June 20:

'Quantum gambling' is a combination of game theory and quantum mechanics

Gambling only works if the playing field is fair between the two parties. However, because of the nature of it, both have something to gain or lose.

Historically, it has been difficult to ensure fair play in gambling for this reason, without getting a third party to step in to oversee things. Now, it seems quantum mechanics promises a solution.

A team of researchers in China and Bristol has developed a way for two parties to play a gambling game fairly, without the need for any third party to step in, using quantum mechanics. The authors think this area of ‘quantum gambling’ could one day be used in casinos.

"The fairness of our protocol does not rely on the integrity of any participant, but relies on the assumption that both parties are rational and would like to choose a strategy to maximise their own gains," Xiaoqi Zhou, co-author of the paper, told WIRED.

The strategy the researchers developed is a mixture of game theory and quantum information processing, and it could be adapted for use in casinos or lotteries.

“Surprisingly, by drawing from the classical and quantum game theory, we have found a protocol which enables two parties to create an unbiased gambling machine themselves to perform a fair gambling without introducing any third party,” the authors wrote in their paper.

The idea rests on a theoretical machine that can be constructed by two parties, named Alice and Bob. It uses properties of quantum mechanics, called Heisenberg’s uncertainty principle and quantum superposition.

Heisenberg’s uncertainty principle means the act of observing a particle creates certain changes in its behaviour. Specifically, it means we cannot know both the momentum and position of a particle to the same degree of certainty at once.

Quantum superposition means a particle can be in a combination of two different states at once.
In the gambling machine example, Alice starts out with two boxes, each hosting a particle. She knows what state both particles are in but depending on what she chooses, the states might decay before they reach Bob.

Bob then receives box B, and he will win if he can work out the state box B is in either by observing the particle, or by asking for box A and working it out from there.
Alice does not want Bob to guess what is in the boxes, but the rules of quantum mechanics make it difficult to work out what is best to do.

The authors calculated, using a large amount of maths, that the best strategies for both parties would take them to what is called a Nash equilibrium point. This is a point where “no player has anything to gain by unilaterally changing his or her own strategy”....MORE
Also by the same writer at Wired: