All you need to do, is figure out a way to use electro magnetic radiation to slow down particles.

It's just a small technical challenge.

There’s something called blast freezer, which is basically a freezer with fans inside, like what convection ovens have. It cools down food much faster than a standard freezer.

The problem is that cold is merely the absence of heat, you can't inject cold into something or generate cold, because there is no such thing as cold. It's kind of like how we can make a light bulb, but we can't make a dark bulb.

We have that, it's called a fridge, and then there's a freezer for making things frozen.

Yup. It’s called a refrigerator

Temperature is average kinetic energy. It is very easy to put kinetic energy into an object and much harder to take it out. Microwaves do it by shining a “light” tuned to microwave frequencies on objects. So you can imagine the problem is about as hard as shining a lamp on something and having it get colder. Laser-based cooling methods do exist but they’re quite expensive and mostly operate on the atomic scale. For now, the best way we know of to cool large items in bulk is to put them next to something that’s even colder—in short, a refrigerator.

Fridge?

Refrigerator

You can dump energy into something by blasting photons at it, because photons carry energy. You can't do the reverse because you'd need to use particles with negative energy. Either that, or you'd need to suck photons out of the food, but it doesn't work that way; things radiate photons at a specific frequency and intensity (called blackbody radiation) depending on how hot they are, and you can't make them emit more energy except by getting them hotter.

Refrigeration Tech here. See: Traulson Blast Chiller. I imagine there'd be a consumer version if enough people wanted them.

if you see a dark area you can turn on a flashlight to emit light towards the area and make it not-dark.

If you see a lit area and you want it unlit, there is no anti-flashlight you can point towards it to suck the light out.

Similar kind of thing, heat can only be given, not taken. heating stuff up is easy, but for cooling the best you can do in most cases is to make it easier for the thing to give you its heat (ex by the atmosphere colder), but you can't force it.

Laser cooling exists, but I don't suppose you can afford one or want your beer on 2°K

https://en.wikipedia.org/wiki/Laser_cooling

This is a bit like asking if we could build a flashlight that emits a beam of darkness I think

There are actually two ways to do this. One is a heat pump (like a small ac or an electric cooling plate) the issue is that it would heat up on the other side, so not great.

The other option is actually really interesting as just like a microwave it uses radio waves (in this case lasers) to cool things by shooting the atoms in a way that negates their current movment and slows them down.

In reductively simple terms heat is really easy to generate. In fact pretty much everything we do creates extra heat entirely on accident, so a device than make things hot on purpose is actually surprisingly simple. It's much harder to get rid of. The only economical way we've found of managing it is by using to phase change of refrigerants to pump it out of enclosed spaces, which is how refrigerators and air conditioners currently work. Everything else would be more complex, less efficient, or both. So if such a thing is even possible it would almost certainly be much more expensive

It's called a freezer and it just takes a bit longer.

Liquid nitrogen is kinda dangerous for consumer appliances.

The simple answer is entropy. It's much easier to poor a bunch of energy into something and have it express itself as heat than it is to retrieve spent energy out of an object. You can burn down a forest and make a lot of light and heat, but you can't spend light and heat to turn smoke into a dark, cold forest.

This is technically possible. The cosmic microwave background, i.e. space, is extremely cold (barely above absolute zero) so it basically acts as a heatsink you can pump infinite amounts of heat into. It turns out that if you can make the food radiate heat out into space and prevent it from absorbing more heat from sunlight, it's possible to cool it below ambient temperature. This is also a completely passive process so it requires no electricity or other form of active energy input.

The problem with this is that doing it with food might be impossible. At the moment, we can only really do it using objects with special coatings that have been optimized for this purpose.

Here's a couple interesting videos that explain how it works:

https://www.youtube.com/watch?v=KDRnEm-B3AI

https://www.youtube.com/watch?v=dNs_kNilSjk

Push heat into something is easier than pull heat out of something

There's commercial equipment called blast chillers but it still takes like 10-15 minutes

Cool question. I‘d imagine the easiest way I can at least think of is spraying it with liquid nitrogen. The challenge will be to get the nitrogen back in the bottle and keep it liquid in the meantime.

It is called liquid nitrogen and it is too expensive to store.

Flash freezing is how frozen foods are made.

Lemmy sure has gotten popular, bunch of comments that doesn't understand how microwaves work

Commercial kitchens sometimes have blast chillers and blast freezers. Some of the cooking shows use them.