Physicists from Griffith University (Australia) and the National University of Singapore have developed a photonic quantum processor capable of simultaneously considering several scenarios for the development of a system in the future. The article of scientists was published in the journal Nature Communications.
Researchers have implemented a device that simulates several coin tosses, whose two possible states (heads and tails) may not be equally probable. It creates a superposition of all possible futures three steps ahead by encoding the quantum states of a single photon.
During the experiment, a photon with two different quantum states could arrive at one of 16 different futures. Finally, the quantum processor computed the probability distribution of the random process.
Information about the past was encoded in non-orthogonal states of photon polarization. Researchers have managed to reduce the amount of memory required to analyze stochastic processes, that is, to determine the future state of a system that is affected by various random factors. The experimentally determined probabilities of the outcome turned out to be close to the theoretically calculated values.
In previous works, superposition (quantum coherence) was maintained for only one simulation cycle, after which the corresponding information should be transferred to classical, not quantum memory. This dramatically increased the amount of memory required to calculate the probabilities of the outcome of a stochastic process.
