Researchers from the USA and India have proposed that Floquet Majorana fermions may improve quantum computing by controlling superconducting currents, potentially reducing errors and increasing stability.
In a study published in Physical Review Letters that was co-authored by [Babak Seradjeh], a Professor of Physics at Indiana University Bloomington, and theoretical physicists [Rekha Kumari] and [Arijit Kundu], from the Indian Institute of Technology Kanpur, the scientists validate their theory using numerical simulations.
In the absence of room-temperature superconductors — the Holy Grail of superconductivity, everybody put your thinking caps on! — the low temperatures required lead to expense (for cooling) and errors (due to decoherence) which need to be managed. Using the techniques proposed by the study, quantum information may be modeled non-locally and be spread out spatially in a material, making it more stable and less error prone, immune to local noise and fluctuations.
Majorana fermions are named after Italian physicist [Ettore Majorana] who proposed them in 1937. Unlike most particles, Majorana fermions are their own antiparticles. In the year 2000 mathematical physicist [Alexei Kitaev] realized Majorana fermions can exist not only as elementary particles but also as quantum excitations in certain materials known as topological superconductors. Topological superconductors differ from regular superconductors in that they have unique, stable quantum states on their surface or edges that are protected by the material’s underlying topology.
Superconductivity is such an interesting phenomenon, where electrical resistance all but vanishes in certain materials when they are very cold. Usually to induce a current in a material you apply a voltage, or potential difference, in order to create the electrical pressure that results in the current. But in a superconductor currents can flow in the absence of an applied voltage. This is because of a peculiar quantum tunneling process known as the “Josephson effect”. It is hoped that by tuning the Josephson current using a superconductor’s “chemical potential” that we discover a new level of control over quantum materials.
Ettore Majorana picture: Mondadori Collection, Public domain.
Numerical simulations are of course only valid if our equations describing reality are an accurate representation. Obviously it’s a reasonable hypothesis that is worth pursuing but it’s impossible to account for the unknown unknowns. At worst, an experiment will uncover an flaw in the simulation, at best, it will help identify the a fundamental misunderstanding, and somewhere in the middle it will work as expected.
Here comes Moireee…(and graphene)
Maybe, I still see that quantum computing, if it’s going to be practical will need to ditch the supercooling requirement.
Quantum computing’s always going to need extreme environments or massive error correcting. Seriously, what do you want? You’re literally trying to work at the fundamental limits of the universe. You thought it’d be easy?
We used to believe the atom was a fundamental, unsplitabble particle.
the question about its practicality is just whether it provides any unique capabilities to justify its expense. whatever that expense is hardly matters, if it doesn’t do anything unique at all.
i’ve just seen a bunch of hand waving of the form “collapsing a waveform function is a complicated result of superpositions therefore quantum computers can do huge prime factoring problems in O(1) time QED”. it ain’t true but if it was then there’s certainly a market that would pay any amount for such a computer.
I am kinda surprised that there are no known examples of custom-designed CPU chips that would work in liquid helium. Did I miss something?
Probably hard to beat for overclocking stunts.
But, for anything else, if someone needs to do a lot of computing in a short time, the money they could spend on exotic CPUs and helium cooling is probably better spent on additional ordinary CPUs.
How much power does that hypothetical CPU dissipate? Any more than a few milliwatts, you’ll be facing a pretty steep cost for the helium boiloff and/or cryocooler running cost. A watt of cooling at 4.2K cost $50,000 per year the last time I was looking at the bills (a couple of decades ago though).
Right, that’s why mass-produced CPUs won’t work. I meant the custom-designed ones, the ones that would emit as little heat as possible, which also means the machine-code has be absolute top-notch, only the commands needed, and ideally none of the pointers pointing to the pointers that point to the pointers (Windoz is know for these) or 64-bit ASCII codes with useless zero padding.
$50K per year is peanuts to average JP Morgan Chase or Geico. They spend billions in CEO stock options last I checked, so this is not something that average Fortune 500 would even sneeze at, unless it adds value to their stock price jacking/fixing.
I bet if Seymour Cray would be around he’d hire an eager bunch of University of Waterloo students and build a prototype right there, in Canada, no problem.