Cold molecules and molecular ions for quantum information and vice versa

Jordi Mur-Petit

Filippo Troiani, Elisa Molinari, Ulrich Hohenester

A doped semiconductor double-quantum-dot molecule is proposed as a qubit realization. The quantum information is encoded in the electron spin, thus benefiting from the long relevant decoherence times; the enhanced flexibility of the molecular structure allows one to map the spin degrees of freedom onto the orbital ones and vice versa and opens the possibility for high-finesse (conditional and unconditional) quantum gates by means of stimulated Raman adiabatic passages.

Qing Liu, Wenli Li, Chenyue Pan +4 more

Over the past two decades, a chip-based atom double well has matured as a powerful art with many applications in modern science. However, its molecular counterpart, which holds potential for higher precision and broader science, has been little studied. In this paper, we propose a scheme for chip-based electrostatic double-well potential for polar molecules. The structure consists of two square wires and three square electrodes deposited on an insulating chip. By adjusting the applied voltages, versatile operations on the double well can be easily realized, such as precisely changing the depth and height of the double well, dynamically deforming the double-well potential to a single well and vice versa, and adjusting the double well from symmetric to asymmetric. We have developed numerical and analytical methods to verify the feasibility of our scheme with both light ($^{15}\mathrm{ND}_{3}$) and heavy ($^{202}\mathrm{Hg}^{19}\mathrm{F}$) polar molecules. The microscopic integrated double-well potential presents a promising platform for confined molecule interferometry. Also, it provides new perspectives for the study of cold collisions, sympathetic cooling, quantum information processing, and quantum simulation.

P. Zoller

Sadhan K. Adhikari

The dynamics of stability and collapse of a trapped atomic Bose-Einstein condensate (BEC) coupled to a molecular one is studied using the time-dependent Gross-Pitaevskii (GP) equation including a nonlinear interaction term which can transform two atoms into a molecule and vice versa. We find an interesting oscillation of the number of atoms and molecules for a BEC of fixed mass. This oscillation is a consequence of continuous transformation in the condensate of two atoms into a molecule and vice versa. For the study of collapse an absorptive contact interaction and an imaginary quartic three-body recombination term are included in the GP equation. It is possible to have a collapse of one or both components when one or more of the nonlinear terms in the GP equation are attractive in nature, respectively.

P. Zoller