Atomic Dynamics on the Attoscecond Scale

Advances in ultrashort-pulse technology have made it possible to generate electromagnetic pulses with duration $\tau_P$ as short as few hundred attoseconds. $\tau_P$ thus approaches the orbital period $\tau_0$ of a classical atomic electron. This advance holds the promise to map out electronic dynamics inside atoms in real time. It poses a considerable challenge to theory to identify observables and novel information that can be accessed and mapped out by attosecond pulses. We will review recent progress with the help of a few examples including time- resolved atomic resonances and double ionization of helium.