A 2017 report of the discovery of a particular kind of Majorana fermion—the chiral Majorana fermion, referred to as the “angel particle”—is likely a false alarm, according to new research. Majorana fermions are enigmatic particles that act as their own antiparticle and were first hypothesized to exist in 1937. They are of immense interest to physicists because their unique properties could allow them to be used in the construction of a topological quantum computer.
A team of physicists at Penn State and the University of Wurzburg in Germany led by Cui-Zu Chang, an assistant professor of physics at Penn State studied over three dozen devices similar to the one used to produce the angel particle in the 2017 report. They found that the feature that was claimed to be the manifestation of the angel particle was unlikely to be induced by the existence of the angel particle. A paper describing the research appears on January 3, 2020 in the journal Science.
“When the Italian physicist Ettore Majorana predicted the possibility of a new fundamental particle which is its own antiparticle, little could he have envisioned the long-lasting implications of his imaginative idea,” said Nitin Samarth, Downsbrough Department Head and professor of physics at Penn State. “Over 80 years after Majorana’s prediction, physicists continue to actively search for signatures of the still elusive “Majorana fermion” in diverse corners of the universe.”
Journal Reference:
Morteza Kayyalha, Di Xiao, Ruoxi Zhang, Jaeho Shin, Jue Jiang, Fei Wang, Yi-Fan Zhao, Run Xiao, Ling Zhang, Kajetan M. Fijalkowski, Pankaj Mandal, Martin Winnerlein, Charles Gould, Qi Li, Laurens W. Molenkamp, Moses H. W. Chan, Nitin Samarth, Cui-Zu Chang. Absence of evidence for chiral Majorana modes in quantum anomalous Hall-superconductor devices. Science, 2020; 367 (6473): 64 DOI: 10.1126/science.aax6361
Related Stories
Researchers identify new type of superconductor:
Until now, the history of superconducting materials has been a tale of two types: s-wave and d-wave.
Now, Cornell researchers—led by Brad Ramshaw, the Dick & Dale Reis Johnson Assistant Professor in the College of Arts and Sciences—have discovered a possible third type: g-wave.
[...] Physicists have theorized the existence of a third type of superconductor between these two so-called "singlet" states: a p-wave superconductor, with one quanta of angular momentum and the electrons pairing with parallel rather than antiparallel spins. This spin-triplet superconductor would be a major breakthrough for quantum computing because it can be used to create Majorana fermions, a unique particle which is its own antiparticle.
For more than 20 years, one of the leading candidates for a p-wave superconductor has been strontium ruthenate (Sr2RuO4), although recent research has started to poke holes in the idea.
Ramshaw and his team set out to determine once and for all whether strontium ruthenate is a highly desired p-wave superconductor. Using high-resolution resonant ultrasound spectroscopy, they discovered that the material is potentially an entirely new kind of superconductor altogether: g-wave.
"This experiment really shows the possibility of this new type of superconductor that we had never thought about before," Ramshaw said. "It really opens up the space of possibilities for what a superconductor can be and how it can manifest itself.
(Score: 5, Informative) by maxwell demon on Monday January 06 2020, @06:34PM (6 children)
This is not about a new particle (like those that you would look for at LHC) but about a quasiparticle (that is, a quantum state in a substance made out of ordinary atoms which behaves *as if* it were a particle; the most well-know quasiparticles are probably the holes in superconductors).
When Majorana intrroduced the possibility of those fermions, it was proposed as a possible type of an actual particle. Indeed, neutrinos have been proposed to potentially be Majorana fermions.
However the 2017 Majorana fermion was a quasiparticle. It is predicted to appear at the boundary of superconductors and topological insulators.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Monday January 06 2020, @07:10PM (3 children)
Who the hell felt they had to call it the "angel particle"? I assume someone wanted to pick up on the "God particle" thing and hope that it catches on with the popular press in a similar way.
(Score: 3, Touché) by Bot on Monday January 06 2020, @07:18PM
Your guardian angel is sad at your angelphobe remark.
Account abandoned.
(Score: 2) by stormwyrm on Tuesday January 07 2020, @12:55AM (1 child)
Numquam ponenda est pluralitas sine necessitate.
(Score: 0) by Anonymous Coward on Tuesday January 07 2020, @02:00PM
Actually, I think it was Leon Lederman's book where he jokingly suggested that as a title and the editor ran with it.
Higgs was known to refer to the Higgs as "the boson to which some have attached my name".
(Score: 2) by maxwell demon on Monday January 06 2020, @08:44PM (1 child)
Err … I just notice an embarrassing mistake:
I of course meant the holes in semiconductors.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Tuesday January 07 2020, @02:16PM
Perhaps you should specify that you mean "electron holes" as you can make real holes in semiconductors with nothing but a drill, making them plenty real.
(Score: 2) by stormwyrm on Tuesday January 07 2020, @12:27AM
Numquam ponenda est pluralitas sine necessitate.
(Score: 0) by Anonymous Coward on Tuesday January 07 2020, @11:46AM
if you go to beach with a semi calm ocean and after staring at the horizon you will start to see "quasi pariclesx too. ofc maybe it's just a optical illusion where the brain "imagines" or interprets crests and trouts of waves as flight path of a particle.
curious enough all paths seem to lead to the observers eyes / head ... always.