Ask HN: Greatest breakthrough in your field?

Not my field, but quantum dots are incredible.

Quantum dots are of reversible polarity, a QD can absorb a photon of the same frequency it can release.

QD frequency response is a function of size, not composition: unlike traditional LEDs there's no need to discover the specific doping materials required for a given frequency.

Make the design bigger/smaller, and it will resonate with a proportionally higher/lower wavelength (respectively).

There are limitations, UV frequencies require very small dots and infrared relatively large, which presents manufacturing difficulties.

A lot of the current dots utilise rare earth metals in their composition, but less toxic and more readily available materials have been researched and found viable (though I'm not sure about difficulties reaching mass production).

So what can we do with them?

Absorb and emit light - think televisions, solar, heating, cooling, refrigeration, cameras, projectors.

Imagine a television with subzero blacks and active glare elimination.

The same panel (with infrared dots) could heat or cool the room.

You could have a television that can emit light across the whole of the visible spectrum.

Defective monitors could be adapted as solar panels (reverse the polarity).

The greatest breakthrough ever? I'd say the machine tool, a cutting tool made to follow a path by purely mechanistic guidance. There are a lot of things that were enabled once the dependence of the skill and dexterity of a person holding a tool were removed from the equation.

s/Breakthrow/Breakthrough/

A breakthrow in my field would be, like, literally throwing my desktop out the 4th floor window. Satisfying, but frowned upon.

I once worked on MRI conditional robotic devices. A difficulty in the field was how to actuate these robots. We worked on developing plastic electric (or photonic) motors. Although not quite there, it is a technology that once ready will help the field quite a bit: https://link.springer.com/chapter/10.1007/978-3-030-59773-3_...

The solution to the Dichotomy Conjecture for Constraint Satisfaction Problems [1] (also [2], but this proof is much more difficult). This gives a clear dividing line between the types of problems that are easy to solve exactly and the types of problems that are difficult to solve exactly, for a fairly large class of problems. I wouldn't even dare to dream that something like this could be done until I saw it happen!

[1] https://arxiv.org/pdf/1704.01914.pdf [2] https://arxiv.org/pdf/1703.03021.pdf

Facebook's excellent targeting changed the game for digital direct response ads. Before targeting was so bad only lowest common denominator ads (teeth whitening, weightloss, ringtones) could make money, now you can even advertise a niche b2b SaaS company effectively.

Telephone I can carry in my pocket.

So I don't have to be paged. Or walk to a phone (possibly distant) to find out what someone thinks is an important "issue". Or possibly just read a text or email when convenient.

And I can (hopefully) turn it off at night.