cynar

Of course not, that would be immoral. They'll track trollies and baskets, then tag it to the till and your loyalty card. It would be a lot more consistent, and harder to dodge.

I can see multiple uses for the tech. Unfortunately, many are a but dystopian, but some are legitimately useful.

It was the initial description used in my 1st year physics degree course. Not sure if it has an explicit name. We also jumped fairly quickly from there to the maths.

Basically space time can stretch infinitely, and flows towards mass. Anything on that spacetime is drawn along. It's functionally identical to a standard force. Straight lines twist into spacetime spirals (aka orbits etc).

Physics has lots of interesting mental models for different things. Unfortunately, most are flawed, so dont lean on tgem too hard. What actually happens is way beyond what our monkey brains can interpret. The best we can do if follow the maths, and try and fit something to the end result.

It's worth noting that spacetime isn't static. Space "flows" into mass. It's akin to a treadmill, you need to constantly move "upwards" to stay in place.

This is also the reason that uniform gravity, and acceleration are identical. With acceleration, the "ground" is constantly moving upwards into new space, pushing you along. With gravity, space is constantly moving down through the floor, trying to push you into the floor. It's functionally the same thing.

Nukes and ICBMs are extremely complex devices. They also require extremely specialist servi e work to remain functional. Even worse, the only people who can actually check that work are the ones doing it.

Russia hasn't detonated a nuke in decades. I wouldn't be surprised if most of their arsenal are now duds. The money embezzled, while boxes were ticked. Similarly, I wouldn't be surprised if many of their ICBMs just wouldn't launch.

Russia's nuclear capabilities are likely a paper tiger, and Putin likely knows this. Until they try and use them, they are scary. If they try and they fail, they are in a VERY bad situation.

Putin is many things, but he's not stupid. It would take a LOT more pressure from nato for him to even consider using nukes.

You could detect decoherence in the system, that doesn't indicate a human observer, however.

That process is, however, used to protect cryptographic keys, transfered between banks. A hostile observer collapses the state early. The observer gets the key instead of the 2nd bank, which is extremely conspicuous to both banks.

I've still got about 100 or so of them. I was mass printing them as part of a coordinated project. We basically managed to saturate the local area with them. Once demand suddenly stopped, I was left with the next batch ready to go. I've still to find a good use for them.

We can observe the end result. E.g. observing the screen only, and you get wavelike behaviour. When you also observe the slit, the wavelike behaviour disappears, and it seems particle like.

Both end in an observation, 1 has an extra observation.

Depends on how you are observing it photons impart energy and momentum. The true, detailed explanation is a lot more convoluted, it's all wave interactions, in the complex plane. However, digesting that into something a layman can follow is difficult.

The main point I was trying to get across is that there is no such thing as an independent, external measurement. Your measurement systems minimum interaction is no longer negligible. How that is done varies, but it always changes the target and becomes part of the equations.

We know how it works, we just don't yet understand what is going on under the hood.

In short, quantum effects can be very obvious with small systems. The effects generally get averaged out over larger systems. A measurement inherently entangled your small system with a much larger system diluting the effect.

The blind spot is that we don't know what a quantum state IS. We know the maths behind it, but not the underlying physics model. It's likely to fall out when we unify quantum mechanics with general relativity, but we've been chipping at that for over 70 years now, with limited success.

Observer here doesn't mean the same as the layman meaning. It's anything that interacts with the system while it's developing.

Interestingly, it actually can be used for a presence detector, at least in a sense. You can use it to transfer cryptographic information. If no-one is listening in, about half your sent numbers are wrong, but you can agree on what ones. However, if someone is listening in, all your data gets randomised.

They actually now use this system to transfer information between banks. They send a random stream of 0s and 1s over a fibre optic cable. They then send (semi publicly) which bits made it properly. If someone spliced into the fibre, they would get the encryption data, but the target bank would not! They know instantly that something is wrong.

For those confused, it's worth noting the difference between observed as a layman concept and as a quantum mechanical one.

In QM, to observed is to couple the observer to the "system" being observed. Think of it like "observing" your neighbour, over a fence using a BB gun. When you hit flesh, you know where your neighbour is. Unfortunately, the system has now been fundamentally changed. In a classical system, you could turn down the power, until your neighbour doesn't notice the hits. Unfortunately, QM imposes fundamental limits on your measurements (heisenburg and his uncertainty principal). In order to observe your neighbour accurately, you need to hit them hard enough that the will also feel it and react differently.

QM behaves in a similar way. Initially, the system is just a single particle, and is not very restrained. This allows it to behave in a very wave like manner. When you observe it, the system now includes the whole observation system, as this coupling propagates, more and more atoms etc get linked. The various restraints cause an effect called decoherence. The system behaves ever more like a classical physical system.

In short, a quantum mechanical "observer" is less sneaky watching, and more hosing down with a machine gun and watching the ricochets.