what is the state of the art algorithm to encrypt credit card data
In practical cryptography, you do not use state-of-the-art, the newest and shiniest algorithms, but instead something required or recommended by the appropriate standards.

In PCI, AES, Triple-DES, SHA-1, RSA etc. are fairly common. PCI is bit slow to adopt  new cryptographic standards. This is for part that payment industry uses devices (like cards) with relatively underpowered processing units.

If you want something that is state-of-the-art, and practical, you may enjoy e.g. cr.yp.to, but those algorithms are likely not accepted by some of the PCI standards.



For encrypting credit card data stored on disc, one modern fancy combination would be  AES-256 with FPE.