Is there a way to predict the future? Scientists use quantum physics in developing a powerful computer that allows them to predict all possible futures at any given moment.
There are many, many possible realities extending into the future.
Mile Gu, assistant professor from Nanyang Technological University in Singapore, points out that the number of possible futures continues to grow with every passing minute.
"For instance, even if we have only two possibilities to choose from each minute, in less than half an hour there are 14 million possible futures. In less than a day, the number exceeds the number of atoms in the universe," Gu explains in a press release from Phys.Org.
In a new study published in the journal Nature Communications, scientists develop a quantum device that can generate the different possible timelines that can exist in the future.
To understand how the scientists were able to do this, it's essential to know one of the most basic principles in quantum physics: quantum superposition.
What's Quantum Superposition?
In a nutshell, quantum superposition is when quantum particles exist in multiple states simultaneously.
MIT professor and physicist Allan Adams explains the concept of superposition with a version of the Stern-Gerlach experiment in which an electron only has two properties: color and hardness. In this reality, electrons can only be black or white, and they can only be hard or soft.
Though multiple experiments, scientists found that the two properties are entirely unrelated with the color saying nothing about the hardness and vice versa.
Furthermore, only one property can be observed at one time. An electron cannot be both hard and white or soft and black simultaneously. When the electron is measured for color, it collapses into a fixed color, and when it is measured for hardness, it collapses into a fixed hardness. However, measuring for one property "resets" the measurement for the other property.
The bottom line is that all quantum particles are in multiple quantum states at any given time. It is only when they're observed that they collapse into a fixed state.
The famous thought experiment known as "Schrodinger's Cat" demonstrates quantum superposition. In this situation, a cat in a box is neither alive nor dead but is in a superposition of both states until the box is opened and the cat is observed.
Since this behavior has no real world equivalent, many people find it a challenging concept to grasp.
Scientists Build Quantum Superposition Machine
In the new study, researchers from NTU Singapore and Griffith University in Australia figured that one way to generate multiple possible futures is by putting them in quantum superposition. This means that the subject or particle is in a superposition of a number of different potential futures, in the same way Schrodinger's Cat is in a superposition of both being alive and dead.
Dr. Jayne Thompson, who is one of the researchers on the Singapore team, says that the quantum device is inspired by physicist Richard Feynman, who is a Nobel Laureate.
"When Feynman started studying quantum physics, he realized that when a particle travels from point A to point B, it does not necessarily follow a single path," Thompson explains. "Instead, it simultaneously transverses all possible paths connecting the points. Our work extends this phenomenon and harnesses it for modelling statistical futures."
The scientists used a quantum computer to show the potential future outcomes of a decision process using the locations of photons. The quantum device is in a state of superposition of multiple outcomes, each one weighed by the probability of its occurrence.
The first of its kind, the quantum computer, has already shown that it can measure how bias toward a present choice affects the future.
"Our approach is to synthesise a quantum superposition of all possible futures for each bias." Farzad Ghafari, one of the members of the experimental team, says. "By interfering these superpositions with each other, we can completely avoid looking at each possible future individually."
For now, the quantum device can only generate 16 possible future outcomes, but the researchers say it can hypothetically be scaled to simulate infinite numbers of outcomes.