acta physica slovaca is an internationally recognised physics journal originally established in 1950. Since 1998 listed in Current Contents. Since 2006, acta physica slovaca publishes review and tutorial articles. Papers written by specialists in a given field are intended to be accessible also to non-specialists and PhD students. Although the printed version of the journal is available, all issues are free to download from the journal's web page. We hope that the new issues of acta physica slovaca will be useful and interesting for readers.