Dielectric constant of glasses: first observation of a two-dimensional   behavior
  The 1kHz real part $\chi'$ of the dielectric constant of a structural glass was measured at low temperature $T$ down to 14 mK. Reducing the sample thickness $h$ to 10 nm suppresses the usual minimum of $\chi'$ for measuring fields $E<.5 $ MV/m. This contradicts the Two Level System (TLS) model but is well accounted for by including TLS-TLS interactions where excitations delocalize between TLS's through a $E$-induced mechanism recently designed: for small $h$'s this interaction is reduced, which explains the two-dimensional behavior of $\chi'(T)$. Hence, interactions play a key role in standard thick samples. 
F. Ladieu (CEA/Saclay, Drecam/LPS, France), J. Le Cochec (CEA/Saclay,   Drecam/LPS, France), P. Pari (CEA/Saclay, Drecam/Spe...