Universal wrapped tokens

Question

Some wrapped tokens like wETH exist on many blockchains like Ethereum, Polygon, Arbitrum etc. This is a little bit confusing since these all have the same name and icon but they are definitely not the same thing. Is there any efficient way to swap wETH on let's say polygon with wETH on Ethereum? I have seen that you can use different Bridges like a Polygon-Ethereum Bridge to turn Polygon wETH to actual ETH and then you can turn the Eth into wETH on the Ethereum network. But this seems inefficient I was wondering whether there is a direct/efficient way of doing this? On polygon's bridge I was not able to find wETH on Ethereum side although wBTC does exist.

Is there any concept of universal wrapped tokens (meaning the wrapped tokens are the same thing even though they might be on different blockchains) available maybe in other blockchains?

Answer 1

The real WETH only exists on Ethereum mainnet. The WETH in other blockchains are just a synthetic representation, usually backed by a bridge collateral. For a transfer the real WETH is locked in the Ethereum side, and identical amount is minted on the other chain.

The bridge efficiency depends on how it is designed. If the bridge a run by a centralized entity it will be more performant, that a decentralized bridge that uses a challenge/response scheme to validate transfers.

Building efficient decentralized bridges is a research topic.