Cold molecules: techniques and applications

Yuval Shagam

Břetislav Friedrich, John M. Doyle

Abstract Brrrr! Cold molecule and cold atom research are juxtaposed and the challenges in cooling and trapping molecules are recounted. Both indirect and direct techniques of producing cold and slow molecules (such as buffer‐gas cooling and magnetic trapping, see picture) are described. Advanced techniques of manipulating cold or slow molecules are reviewed and ongoing work with cold molecules is outlined. magnified image Herein, we aim to show why the work on translationally (and otherwise) cold molecules has sparked so much inspiration—and anticipation—in both the physics and chemistry communities. We begin by discussing the basic features of cold molecules as implied by their de Broglie wavelengths, large compared with molecular dimensions. We juxtapose cold molecule and cold atom research and recount the challenges that had to be met if molecules were to be cooled and trapped. Subsequently, both the indirect and direct techniques of producing cold and slow molecules are described in some detail, and their applicability to various classes of molecules is discussed. Advanced techniques of manipulating cold or slow molecules are illustrated by the examples of DC and AC trapping and storage. Finally, ongoing and future work with cold and/or trapped molecules is outlined. This includes precision spectroscopy, chemical reaction dynamics, simulations of few‐ and many‐body physics, quantum computing, and tests of fundamental physics.

Thomas E. Wall

Molecules can be used to test fundamental physics. Such tests often require cold molecules for detailed spectroscopic analysis. Cooling internal degrees of freedom provides a high level of state-selectivity, with large populations in the molecular states of interest. Cold translational motion allows slow, bright beams to be created, allowing long interaction times. In this tutorial article we describe the common techniques for producing cold molecules for high-precision spectroscopy experiments. For each technique we give examples of its application in experiments that use molecular structure to probe fundamental physics, choosing one experiment in particular as a case study. We then discuss a number of new techniques, some currently under development, others proposed, that promise high flux sources of cold molecules applicable to precise spectroscopic tests of fundamental physics.

Edvardas Narevicius

Masatoshi Kajita

Martin Zeppenfeld, Thomas Gantner, Rosa Glöckner +6 more

Cold and ultracold molecules enable fascinating applications in quantum science. We present our toolbox of techniques to generate the required molecule ensembles, including buffergas cooling, centrifuge deceleration and optoelectrical Sisyphus cooling. We obtain excellent control over both the motional and internal molecular degrees of freedom, allowing us to aim at various applications.