Islands in an electron sea Artistic impression of bound states in the continuum, which are represented by the red and blue peaks in a sea of free electrons. (Courtesy: Raquel Queiroz/Columbia University)"> Islands in an electron sea Artistic impression of bound states in the continuum, which are represented by the red and blue peaks in a sea of free electrons. (Courtesy: Raquel Queiroz/Columbia University)

Bound states in the continuum (BICs) – static waves that remain isolated from propagating waves at similar energies – have been observed in electronic systems for the first time. This is analogous to a well-established phenomenon in optics, which has been exploited in lasers, sensors and directional antennas.…