Something Out Of Nothing: New Approach Mimics Matter Creation Using Superfluid Helium

When matter and antimatter collide, they turn into pure energy. Energy can also spontaneously turn into matter and antimatter pairs. If this happens in a vacuum under a strong electric field, this is known as the Schwinger effect. Researchers have now found a way to simulate this fascinating phenomenon in a much easier way.

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There are ways to create a pair of particles, but they involve high-energy setups. Breakthroughs in the last few years have shown that we can look at some of these processes directly; this is not the case for the Schwinger effect. The electrical field required is just beyond what we can do in a lab. Researchers were looking for an analogous setup that could provide a similar behavior without having to provide an electric field 100 trillion times what you have in a typical household.

Physicists at the University of British Columbia (UBC) approached this problem with a truly peculiar quantum system: a thin film of superfluid helium. When helium is brought down to a temperature near absolute zero, a bunch of quantum behaviors start happening. One in particular is an excellent analogy for the production of electron and positron pairs.

“Superfluid Helium-4 is a wonder. At a few atomic layers thick it can be cooled very easily to a temperature where it's basically in a frictionless vacuum state,” co-author Dr Philip Stamp said in a statement.

“When we make that frictionless vacuum flow, instead of electron-positron pairs appearing, vortex/anti-vortex pairs will appear spontaneously, spinning in opposite directions to one another.” 

Quantum vortices have already been used to simulate black holes in the lab, and there are plenty of other cosmic phenomena waiting to be unlocked with them.

“We believe the Helium-4 film provides a nice analog to several cosmic phenomena,” added Dr Stamp. “The vacuum in deep space, quantum black holes, even the very beginning of the Universe itself. And these are phenomena we can’t ever approach in any direct experimental way.”

Despite the fact that they can be used to study wildly different phenomena, quantum vortices are not perfectly analogous. For example, they lose mass – something that matter-antimatter pairs do not. This kind of work provides insights into fundamental physics and also the physics of an extreme substance such as superfluid helium.

“These are real physical systems in their own right, not analogs. And we can do experiments on these,” Dr Stamp said.

The study is published in PNAS.