[1] Warsaw Univ Technol, Fac Phys, Ul Koszykowa 75, PL-00662 Warsaw, Poland
[2] Univ Washington, Dept Phys, Seattle, WA 98195 USA
[3] Consiglio Nazl Ric CNR INO, Ist Nazl Ott, I-50019 Sesto Fiorentino, Italy
[4] Newcastle Univ, Joint Quantum Ctr JQC Durham Newcastle, Sch Math Stat & Phys, Newcastle Upon Tyne NE1 7RU, England