Ciro Santilli @cirosantilli  40

A single line in the emission spectrum.

So precise, so discrete, which makes no sense in classical mechanics!

Has been the leading motivation of the development of quantum mechanics, all the way from the:

You need a secondary password that when used leads to an empty inbox with a setting set where message are deleted after 2 days.

This way, if the attacker sends a test email, it will still show up, but being empty is also plausible.

Of course, this means that any new emails received will be visible by the attacker, so you have to find a way to inform senders that the account has been compromised.

So you have to find a way to inform senders that the account has been compromised, e.g. a secret pre-agreed canary that must be checked each time as part of the contact protocol.

A suggested at Physics from Symmetry by Jakob Schwichtenberg (2015) chapter 3.9 "Elementary particles", it appears that in the Standard Model, the behaviour of each particle can be uniquely defined by the following five numbers:

E.g. for the electron we have:

Once you specify these properties, you could in theory just pluck them into the Standard Model Lagrangian and you could simulate what happens.

Setting new random values for those properties would also allow us to create new particles. It appears unknown why we only see the particles that we do, and why they have the values of properties they have.

Initially light was though of as a wave because it experienced interference as shown by experiments such as:

But then, some key experiments also start suggesting that light is made up of discrete packets:and in the understanding of the 2020 Standard Model the photon is one of the elementary particles.

This duality is fully described mathematically by quantum electrodynamics, where the photon is modelled as a quantized excitation of the photon field.

Initially there were mathematical reasons why people suspected that all boson needed to have 0 mass as is the case for photons a gluons, see Goldstone's theorem.

However, experiments showed that the W boson and the Z boson both has large non-zero masses.

So people started theorizing some hack that would fix up the equations, and they came up with the higgs mechanism.

Can be contrasted with baryons as mentioned at baryon vs meson vs lepton.

Centralized system that still attempts some level of privacy.

In it, a central bank issue tokens that are stored offline in your cell phone, a bit like cash bank notes.

When you take those tokens, a corresponding amount gets removed from your bank account, a bit like cash bank notes.

When a transaction is made, tokens are put into a spent token list via central API, and cannot be double spent thereafter. The corresponding ammount is then added to the bank account of the receiver. This also means that offline transactions are not possible.

When emitting, the bank signs the token with their private key. When spending, the bank checks that signature.

How do we prevent the bank from logging which token goes to which user besides trusting that they are running the software we whink they are running? Notably, couldn't timing be used to identify that?

The main ones as of 2020 are: