You want to access the user provider the authentication uses.
$provider = Auth::getProvider();
The provider will be based on how your authentication is configured.
It'll be the provider for the driver you set up in the your
app/config/auth.php. See Changing Your Authentication Driver.
If you're using the
database configuration driver, the provider will be
Illuminate\Auth\DatabaseUserProvider. If you're using the
eloquent configuration driver the provider will be
If you set up a custom authentication driver, the user provider will be whatever you set up.