Mølmer

Mølmer is a Danish surname. In scientific contexts, the name is associated with contributions in quantum optics and quantum information, most notably through Klaus Mølmer and the eponymous Mølmer–Sørensen gate.

Klaus Mølmer is a Danish theoretical physicist known for work in quantum optics and quantum information theory. He is one of the developers associated with the Mølmer–Sørensen gate, a widely used two-qubit entangling gate in trapped-ion quantum computing. The gate is described in terms of laser-induced, spin-dependent forces that couple the internal states of two ions to a shared motional mode, enabling entanglement while minimizing sensitivity to the ions’ initial motional state under appropriate conditions. The design emphasizes robust performance in practical ion-trap experiments and has become a standard tool in quantum information processing with trapped ions.

The Mølmer–Sørensen gate is implemented with bichromatic laser fields that drive sideband transitions, producing an effective spin–spin interaction. When correctly configured and driven, the motion returns to its initial state at the end of the gate operation, leaving the two ions in an entangled state. The gate is one of several entangling operations used in trapped-ion platforms and illustrates the influence of Mølmer’s work on contemporary quantum computation research.

In addition to this gate, the surname Mølmer appears in scientific literature primarily through references to Klaus Mølmer and related theoretical contributions.