Cosmic Physics Innovation: Researchers Produce Particle-Antiparticle Pairs From a Vacuum

Cosmic physics simulated on the tabletop as graphene enables the Schwinger effect, forming particle-antiparticle pairs.

Researchers at The University of Manchester succeeded in observing the supposed Schwinger effect. The Schwinger effect is an evasive process that usually happens only in cosmic events. The group – based at the National Graphene Institute – accomplished to create particle-antiparticle pairs by applying high currents through specifically designed graphene-based devices.

Creating particle-antiparticle pairs

A vacuum is assumed to be an entirely empty space without any matter or elementary particles. Nonetheless, Nobel laureate Julian Schwinger predicted 70 years ago that intense electric or electromagnetic fields can deteriorate the vacuum and spontaneously generate elementary particles.

This demands truly cosmic-strength fields such as those around magnetars or generated temporarily throughout high-energy collisions of charged nuclei. It has actually been a long-lived objective of particle physics to research these theoretical predictions experimentally, and some are presently planned for high-energy colliders worldwide.

Now the research team– led by another Nobel laureate, Prof Sir Andre Geim, in collaboration with associates from the United Kingdom, Spain, United States, and Japan– has utilized graphene to mimic the Schwinger manufacturing of electron and positron pairs.

In the January 2022 issue of Science, they report uniquely designed devices such as slim constrictions and superlattices made from graphene, which enabled the scientists to acquire exceptionally strong electric fields in a simple tabletop setup. Spontaneous generation of electron and hole pairs was clearly observed (holes are a solid-state analog of positrons), and the process’ particulars coincided well with theoretical predictions.

The researchers observed another uncommon high-energy process that so far has no analogies in particle physics and astrophysics. They loaded their simulated vacuum with electrons and sped them up to the maximum velocity permitted by graphene’s vacuum, which is 1/300 of the speed of light. At this moment, something apparently impossible occurred: electrons appeared to become superluminous, giving an electric current greater than authorized by general rules of quantum condensed matter physics. The source of this effect was described as the spontaneous generation of additional charge carriers (holes). The theoretical description of this process supplied by the research group is different from the Schwinger one for the empty space.

Further particle-antiparticle pair investigation

” People generally study the electronic properties using tiny electric fields that permit easier analysis and theoretical description. We decided to push the strength of electrical fields as much as feasible using different experimental tricks not to blaze our devices,” claimed the paper’s first author Dr. Alexey Berduygin.

Co-lead author Dr. Na Xin included: “We just wondered what could occur at this extreme. To our shock, it was the Schwinger effect rather than smoke coming out of our set up.”

Dr. Roshan Krishna Kumar, another leading contributor, stated: “When we first saw the magnificent characteristics of our superlattice devices, we assumed ‘wow … it could be some type of new superconductivity’. Although the response strongly resembles that routinely observed in superconductors, we quickly found that the puzzling behavior was not superconductivity but something in astrophysics and particle physics. It is unexpected to see such parallels between distant disciplines.”

The research study is also vital for the advancement of future electronic devices based upon two-dimensional quantum materials. It establishes restrictions on wiring made from graphene that was currently recognized for its exceptional ability to sustain ultra-high electric currents.

Read the original article on Scitech Daily. Related “Introduction to Particle Physics“.

Reference: “Out-of-equilibrium criticalities in graphene superlattices” 27 January 2022, Science.
DOI: 10.1126/science.abi8627