Artificial atoms create stable qubits for quantum computing
phys.org
phys.org
> 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.
I recently heard a scientific talk mentioning that the earth is losing around three slices of mortadella in helium every second ...
This could be a huge breakthrough in quantum computing. Or it could just be a capacitor with delusions of grandeur. Don't know.
I think there's more than enough room in between bullshit and nobel prize.
This looks very promising, but as always the devil is in the details. The next steps are multiqubit gates, then linking those up into useful quantum circuits, and then hopefully doing actual quantum computations.
Personally I wouldn't expect a nobel prize until one of those last 2 steps. There's a lot of hurdles before then to run into some nasty problems.
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.
Anyway, it's neither. It's the experimental demonstration of an incremental improvement in silicon quantum dots. The idea is basically that instead of loading a single electron to a quantum dot and using its spin as the qubit, loading more electrons can actually lead to better coherence times (=higher fidelities) due to an increased resilience to charge noise (one of the most significant source of errors in these devices), and one can still use the spin of an "outer shell" (in analogy with atoms) as qubit.