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Sunday, October 24, 2021

UCLA, UC Davis, UC Irvine, Stanford researchers find evidence of Majorana particle

DAVIS WHALEN / AGGIE

New research may have implications for supercomputing

Researchers at UCLA, with the help of researchers from UC Davis, UC Irvine and Stanford, have found evidence of the Majorana particle. This particle acts as its own antiparticle and belongs to a class of fundamental particles: fermions.

The experiment was conducted by first constructing a “layer cake” of quantum materials from a superconductor and a magnetic topological insulator. A superconductor was used because it has zero electrical resistance and a topological insulator has the characteristic only along its surface and edges but not through its middle.

A magnetic field applied to the ‘layer cake’ induces pairs of Majorana fermions, which travel along the edges of the topological insulator,” said Kai Liu, a co-author of the study and a professor of physics at UC Davis. “Under certain conditions, the hybrid structure splits each pair, allowing one member to go through and deflecting the other, leading to conductance half as high as that for electrons. These half-steps were the signal confirming the presence of mobile Majorana fermions, predicted by Professor Shoucheng Zhang’s group at Stanford.”

Ettore Majorana, an Italian physicist, first proposed this particle in 1937, but it remained undiscovered until now. This particle’s connection to quantum computing directly linked this discovery to cybersecurity.

Quantum computers based on Majorana particles can be powerful and fault tolerant,” said Zhijie Chen, a third-year graduate student at UC Davis. “Because quantum computers are way more powerful than computers we have nowadays, encryption used by quantum computer is impossible for normal computers to break.”

Information in normal computers are stored in terms of bits, but in quantum computers, information is stored in terms of complex superpositions of quantum states called Qubits. There are two types of particles that make good candidates for Qubits: trapped quantum particles and topological structures like Majorana fermions.

“The advantage of the latter is that Majorana particles have zero charge and are thus less easy to influence than particles that do have charge like electrons,” said Edward Burks, a researcher and UC Davis alumnus. “Additionally, small perturbations and outside effects can degrade a trapped quantum particle state [and cause data loss], but it’s much more difficult to change a topology. So, if data could be stored in this form it could be more robust to external influence, creating a fault tolerant and safe data storage method.”

 

 

Written by: Kriti Varghese — science@theaggie.org

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