
Artificial atoms create stable qubits for quantum computing - dnetesn
https://phys.org/news/2020-02-artificial-atoms-stable-qubits-quantum.html
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ganzuul
> Abstract

> Once the periodic properties of elements were unveiled, chemical behaviour
> could be understood in terms of the valence of atoms. Ideally, this
> rationale would extend to quantum dots, and quantum computation could be
> performed by merely controlling the outer-shell electrons of dot-based
> qubits. Imperfections in semiconductor materials disrupt this analogy, so
> real devices seldom display a systematic many-electron arrangement. We
> demonstrate here an electrostatically confined quantum dot that reveals a
> well defined shell structure. We observe four shells (31 electrons) with
> multiplicities given by spin and valley degrees of freedom. Various fillings
> containing a single valence electron—namely 1, 5, 13 and 25 electrons—are
> found to be potential qubits. An integrated micromagnet allows us to perform
> electrically-driven spin resonance (EDSR), leading to faster Rabi rotations
> and higher fidelity single qubit gates at higher shell states. We
> investigate the impact of orbital excitations on single qubits as a function
> of the dot deformation and exploit it for faster qubit control.

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pauljurczak
Nice work, but "infinitesimally small space of only around 10 nanometres in
diameter" really rubs me the wrong way. Well, at least they are not using
diameter of human hair as a unit of measure.

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numlock86
> Well, at least they are not using diameter of human hair as a unit of
> measure.

I recently heard a scientific talk mentioning that the earth is losing around
three slices of mortadella in helium every second ...

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pr_nik
In defense of academics resorting to such comparisons, making this tangible,
exciting, accessible, and generally common sense-compatible is all the rage
nowadays. The attention economy certainly rules the PR-side of academia and
success there can translate into cash for basic research. Not my idea, not my
style, but it's a thing.

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Koshkin
Problem is, those who might need this sort of comparisons never read such
articles. (Educated people already know what a nanometer is.)

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Animats
This is either Nobel Prize material or total bullshit. Which is it?

This could be a huge breakthrough in quantum computing. Or it could just be a
capacitor with delusions of grandeur. Don't know.

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peacockwank
lol, nah.

I did my own PhD thesis a couple years ago on donor atoms in silicon,
specifically selenium, forming hydrogen and helium like systems that "could"
have been useful for forming a qbit. tldr selenium has 2 more valence
electrons than silicon so when it is substitutionally doped into silicon then
you get a helium like system, which in some cases ends up hydrogen like when,
presumably, imperfections either local or remote cause enough disruption to
whisk away/capture one of the electrons, thus forming a hydrogen like system.
I didn't investigate the cause of the different molecular like complexes that
spring up when you dope silicon like this though, I only probed things with
light and did calculations relating to that probing, I didn't do any modelling
concerning the diffusion and behaviour of dopants which I kinda regret.

Then you can optically manipulate that remaining donor electron. It didn't
really work cause it's hard and the lifetimes of the donor electron systems
are not great (tens of ns to ~100ns for some of the systems).

It was then I realised that physics research is a dangerous thing to attempt
if you can't stomach the constant uncertainty and risk about your own personal
future, when you are found to be not good enough due to not publishing, so I
abandoned academia so I could massively reduce that stress and constant
anxiety and actually have a life.

So the tldr is that this is not bullshit at all, it is in-fact very
interesting and a promising line of work. But it's not going to make anyone's
career by itself, and without appropriate pumping of the importance of the
work and sufficient mentoring no-one who works on it as a grad student has a
future as a researcher.

So no, it's neither Nobel Prize material or total bullshit.

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imvetri
What original commenter is mentioning is "if this isn't bullshit, change the
text so that you could push it for Nobel" or publish it in a place where you
can find good recognition

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peacockwank
The exact person to whom my comment was a reply lol.

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the_dege
I wasn't able to find it referenced in the article and on the paper, is it at
room temperature or still near 0 °Kelvin?

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tagrun
The electron temperature should be around ~100mK

