Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Thursday February 13 2020, @02:41PM   Printer-friendly
from the putting-a-new-spin-on-things dept.

In a paper published today in Nature Communications, UNSW quantum computing researchers describe how they created artificial atoms in a silicon 'quantum dot', a tiny space in a quantum circuit where electrons are used as qubits (or quantum bits), the basic units of quantum information.

Scientia Professor Andrew Dzurak explains that unlike a real atom, an artificial atom has no nucleus, but it still has shells of electrons whizzing around the centre of the device, rather than around the atom's nucleus.

[...] [Ph.D. student Ross] Leon, who ran the experiments, says the researchers were interested in what happened when an extra electron began to populate a new outer shell. In the periodic table, the elements with just one electron in their outer shells include Hydrogen and the metals Lithium, Sodium and Potassium.

"When we create the equivalent of Hydrogen, Lithium and Sodium in the quantum dot, we are basically able to use that lone electron on the outer shell as a qubit," Ross says.

"Up until now, imperfections in silicon devices at the atomic level have disrupted the way qubits behave, leading to unreliable operation and errors. But it seems that the extra electrons in the inner shells act like a 'primer' on the imperfect surface of the quantum dot, smoothing things out and giving stability to the electron in the outer shell."

[...] It is the spin of an electron that we use to encode the value of the qubit, explains Professor Dzurak.

[...] "When the electrons in either a real atom, or our artificial atoms, form a complete shell, they align their poles in opposite directions so that the total spin of the system is zero, making them useless as a qubit. But when we add one more electron to start a new shell, this extra electron has a spin that we can now use as a qubit again.

"Our new work shows that we can control the spin of electrons in the outer shells of these artificial atoms to give us reliable and stable qubits.

Journal Reference:
Leon, R.C.C., Yang, C.H., Hwang, J.C.C. et al. "Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot." Nat Commun 11, 797 (2020). DOI: 10.1038/s41467-019-14053-w


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 3, Interesting) by maxwell demon on Friday February 14 2020, @12:28PM

    by maxwell demon (1608) on Friday February 14 2020, @12:28PM (#958143) Journal

    It certainly looks interesting, however note that up to now they only did single-qubit operations. While those are of course important, the true power of quantum computation comes with two-qubit operations. Before they did that, I'd be careful about judging the promise.

    For example, with photons we can do single-qubit operations almost perfectly (they are just the standard linear optics operations, with the only genuine quantum devices involved being the single-photon sources and detectors). However to my knowledge, no one has yet managed to build a scalable general quantum computer from photonics.

    --
    The Tao of math: The numbers you can count are not the real numbers.
    Starting Score:    1  point
    Moderation   +1  
       Interesting=1, Total=1
    Extra 'Interesting' Modifier   0  
    Karma-Bonus Modifier   +1  

    Total Score:   3