Physicists observe wormhole dynamics using a quantum computer
Artwork depicting a quantum experiment that studies traversable wormholes. Credit: inqnet/A. Mueller (Caltech)

For the first time, scientists have created a quantum experiment that allows them to study the dynamics of a theoretical wormhole. The experiment allows researchers to look at connections between theoretical wormholes and quantum physics, a prediction of quantum gravity. Two fundamental descriptions of nature that seem incompatible with each other are connected by a set of theories called quantum gravity.

Maria Spiropulu is the principal investigator of the U.S. Department of Energy Office of Science research program quantum communication channels for fundamental physics. A larger program of testing quantum gravity physics using a quantum computer is a result of this work. It does not substitute for direct probes of quantum gravity in the same way as other planned experiments that might probe quantum gravity effects in the future using quantum sensor, but it offers a powerful testbed to exercise ideas of quantum gravity.

Nature will publish the research on December 1st. The study's first authors are a graduate student at MIT and a former undergrad at Caltech who started this project for his bachelor's thesis.

There are bridges in space. Scientists have been studying their existence and properties for more than a century. Einstein's general theory of relativity states that gravity is a curvature of spacetime and that wormholes are tunnels through the fabric of space time. The term "wormhole" was first used by physicist John Wheeler in the 1950s.

There is a theory that wormholes and quantum physics may have a connection. According to the physicists, wormholes were equivalent to EPR after Albert Einstein, Boris Podolsky, and Nathan Rosen. The work established a link between the worlds of gravity and quantum physics. It was a very daring and poetic idea according to Spiropulu.

The ER = EPR idea was extended by his colleagues Ping Gao and Aron Wall. The scientists created a scenario in which negative repulsive energy held a wormhole open so that something could pass through from one end to the other. The researchers found that the description of a traversable wormhole is similar to quantum teleportation. Over long distances via optical fiber and over the air, the principles of quantumentanglement have been demonstrated in quantum teleportation.

wormholes and quantum teleportation are explored in the work. The Caltech-led team performed the first experiments that probed the idea that information traveling from one point in space to another can be described in a language other than gravity.

A key finding that inspired possible experiments occurred in 2015, when Caltech's Alexei Kitaev showed that a simple quantum system could exhibit the same duality as the model's quantum. Some theoretical ideas could be studied more deeply by doing experiments on quantum wormholes, according to researchers who worked on the model.

Researchers should be able to measure the properties of traversable wormholes with the help of two SYK models.

The physicists performed this type of experiment for the first time. They were able to observe the dynamics of the wormhole on a quantum device at the same time as they used a "baby" SYK model. The team used machine learning tools to reduce the SYK model to a simpler form.

Spiropulu says that they used learning techniques to prepare a simple quantum system that could be used in the current quantum architectures. We looked at the model we found on the quantum processor after we simplified the description of the quantum system. One characteristic of the model preserved the other metrics. We have plans for more tests to find out more about the model.

The researchers inserted a qubit into one of their systems and watched the information come from the other system. The information traveled from one quantum system to the other via quantum teleportation.

A traversable wormhole in the gravity picture was performed by us. We had to simplify the quantum system to the smallest example so that we could use it on the Sycamore quantum processor.

It took a long time to arrive at the results and we surprised ourselves with the result.

John Preskill is the director of the Institute for Quantum Information and Matter at Caltech. Using machine learning, they were able to make the system simple enough to mimic an existing quantum machine while keeping a reasonable caricature of what the gravitation picture predicts.

wormhole behavior is expected from the perspectives of gravity and quantum physics according to the physicists. The experimental process was shown to be similar to what might happen if quantum information traveled through a wormhole. The team tried to open the wormhole using either negative or positive energy. When the equivalent of negative energy was applied, they were able to observe key signatures of a traversable wormhole.

The high fidelity of the quantum processor was important. The signal would have been completely obscured if the error rate was higher. We would have ten times the signal if they were half the size.

The researchers want to extend this work to more complex quantum circuits. The team will continue to perform experiments on existing quantum computing platforms even though quantum computers are years away.

One of the most important questions in fundamental physics is the relationship between quantum entanglement, spacetime, and quantum gravity. We will keep going and take this small step to test these ideas on quantum hardware.

A quantum processer is being studied. Other authors include: David Kolchmeyer, formerly at Harvard and now a PhD student at MIT, and Hartmut Neven, formerly a PhD student at Caltech.

There is more information on Maria Spiropulu's work. The article can be found at

You can find more information at the Alliance for Quantum Technologies website.

Journal information: Nature