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Quantum computer will explore possible futures

Just as in the 1960s few people could imagine many uses for traditional computers, now we don’t know what a quantum computer can be used for.

Researchers at Nanyang Technological University in Singapore and Griffith University in Australia have constructed a prototype quantum computer that can generate all possible variations of the future.

According to the researchers, when we think about the future, we are faced with a wide range of possibilities. For example, given two choices for every minute, we have 14 million potential futures in less than 30 minutes. In less than a day, that number is greater than the sum of atoms in the Universe.

The research group notes that a quantum computer can explore all possible futures if those futures are placed in a quantum superposition, similar to that of Schrödinger’s famous cat.

According to this thought experiment, invented in 1935 by Austrian physicist Erwin Schrödinger to debunk one interpretation of quantum mechanics, a cat in a box containing food on one side and poison on the other is simultaneously in two possible states (alive or dead) until an observer opens the box and looks inside to see what happened. Without knowing it, according to this example, the observer determines the cat’s fate.

Based on this superposition of states, scientists have developed a quantum device that analyzes the behavior of photons, or quantum particles of light. Unlike classical particles, quantum particles can move in a quantum superposition involving different directions, that is, they move in different directions at the same time.

The phenomenon of a particle moving from point A to point B does not necessarily have to follow a single path. It can also move along all other possible paths connecting these points. Researchers from Australia and Singapore have extended and used this phenomenon to model the future.

What the researchers did was to assign a representation of the decision-making process to the photons of the device, depending on their location. That is, if a decision (such as whether to take the bus or the subway) is applied to a photon in superposition, the device can determine what will happen, whether to take the bus or the subway, depending on the paths the photon simultaneously takes in the device.

In this way, they have turned the device into a superposition of several potential futures that can be analyzed according to their probability of occurrence.

The machine already has one practical application: it measures how much our attitude toward a particular choice (riding the bus or subway) in the present affects the future.

However, the machine is not there for us to know what happens whether we take the bus or the subway. Because it is quantum in nature, it is only valid in the universe of elementary particles.

The researchers point out that while their current prototype is capable of generating 16 potential future scenarios simultaneously, the underlying quantum algorithm can scale possible statistical futures essentially without limit. Additionally, their constructed device requires much less operating memory for its calculations than a standard computer would require for such an operation. This means that quantum computers in the future will have much better performance than the ones we use today.

These findings are described in the article entitled „Interfering trajectories in experimental quantum-enhanced stochastic simulation” published in the journal Nature Communications, 09.08.2019(Authors: Ghafari F., Tischler N., Di Franco C., Thompson J., Gu M., Pryde G.J.) DOI: 10.1038/s41467-019-08951-2. Translation was done with the assistance of DeepL translator.