Experimental signature of a topological quantum dot.

Topological insulator nanoparticles (TINPs) host topologically protected Dirac surface states, just like their bulk counterparts. For TINPs of radius <100 nm, quantum confinement on the surface results in the discretization of the Dirac cone. This system of discrete energy levels is referred to as a topological quantum dot (TQD) with energy level spacing on the order of Terahertz (THz), which is tunable with material-type and particle size. The presence of these discretized energy levels in turn leads to a new electron-mediated phonon-light coupling in the THz range, and the resulting mode can be observed in the absorption cross-section of the TINPs. We present the first experimental evidence of this new quantum phenomenon in Bi2Te3 topological quantum dots, remarkably observed at room temperature.

Gay Voice: Stable Marker of Sexual Orientation or Flexible Communication Device?

Listeners rely on vocal features when guessing others' sexual orientation. What is less clear is whether speakers modulate their voice to emphasize or to conceal their sexual orientation. We hypothesized that gay individuals adapt their voices to the social context, either emphasizing or disguising their sexual orientation. In Study 1 (n = 20 speakers, n = 383 Italian listeners and n = 373 British listeners), using a simulated conversation paradigm, we found that gay speakers modulated their voices depending on the interlocutor, sounding more gay when speaking to a person with whom they have had an easy (vs. difficult or no) coming out. Although straight speakers were always clearly perceived as heterosexual, their voice perception also varied depending on the interlocutor. Study 2 (n = 14 speakers and n = 309 listeners), comparing the voices of young YouTubers before and after their public coming out, showed a voice modulation as a function of coming out. The voices of gay YouTubers sounded more gay after coming out, whereas those of age-matched straight control male speakers sounded increasingly heterosexual over time. Combining experimental and archival methods, this research suggests that gay speakers modulate their voices flexibly depending on their relation with the interlocutor and as a consequence of their public coming out.

Hydrogen Bonding Features in Cholinium-Based Protic Ionic Liquids from Molecular Dynamics Simulations.

We explore the structure of a series of protic Ionic Liquids based on the choline cation and amino acid anions. In the series, the length and the branching of the amino acid alkyl chain varies. Ab initio molecular dynamics, X-ray diffraction measurements, and infrared spectra have been used to provide a reliable picture of the short-range structure and of the short-time dynamic process that characterize the fluids. We have put special emphasis on the peculiar and complicated network of hydrogen bonds that stem from the amphoteric nature of the anion moiety. The use of ab initio molecular dynamics allows us to calculate the "exact" charge density of the system and hence to obtain fairly accurate infrared spectra that, in turn, have been used to assign the experimental ones.