![Sketch of quantum Go machine. a, Experimental setup of the quantum stone box. The generated photon pairs can be tuned to maximally entangled states, non-maximally entangled states and product states to behave as difierent quantum stones, see Methods. b, The collapse measurement module. After the photons come into this module, they will be measured by the polarizing beam splitter (PBS) then the quantum state collapses to path 1 and 3 (or path 2 and 4). Four single photon detectors transfer the photon signals to electronic signals. c, The time-of-flight storage module. Four output channels from the collapse measurement module will be guided into this module. The collapse result information of each pair of the entangled photons can be acquired aer seing a proper coincidence time window, and recorded as an effective stored state in the time series data. We encode the signals coincidence in Channel 1 and 3 as "1", and Channel 2 and 4 as "0". d, Sketch of playing quantum Go with the quantum stones from the time series data. Two robot arms represent the two agents who help to execute the game of quantum Go together. They pick the quantum stones from the quantum stone box alternately and put every stone onto two intersections of the virtual board. When a quantum stone is put on an intersection that has neighbors, the game will get the collapse results from the time series data with a backdated measurement in the collapse measurement module. Credit: arXiv:2007.12186 [quant-ph]](https://swissquantumhub.com/wp-content/uploads/2020/08/5f2a8a4dd6cdd.jpg)
Using entangled photons to play “quantum Go”
A team of researchers affiliated with several institutions in China has developed a form of the board game Go using entanglement. The researchers created a version of quantum Go using entangled photons and found that