Newbie question. AFAIK, each US banknote has a unique serial number. Is the same true for bitcoin? Does each bitcoin have a unique identifier, regardless who owns it? Does each satoshi have a unique identifier?
This is true only for cash banknotes, but most of the dollars in circulation now is virtual and digital numbers on screen, so there is no real identifiers there.
There is no such thing in bitcoin, but you can identify history and origin of coins on blockchain, that is why governments and regulators can blacklist bitcoin addresses and connected coins.
This is not quite true. There is a unique identifer even from when the bitcoin is minted in the Coinbase block.
When a block is found, say 50 BTC as an example, then each satoshi doesn't have a unique identifier however once those 50 BTC are spent then they have unspent outputs which have a hash. So if someone sends that 50 BTC to 1 person, there is 1 UTXO, but if its sent to 50 BTC then there are 50 different unspent outputs.
And those get all spents and the trial goes on and on and eventually different blocks are combined with one another and its difficult to trace them but its still there.