Controlling ultracold RbCs molecules for applications in quantum technology

Simon L. Cornish Department of Physics, Durham University, South Road, Durham DH1 3LE, UK

Ultracold polar molecules are an exciting new platform for quantum technologies. The combination of rich internal structure of vibration and rotation, controllable long-range dipole-dipole interactions and strong coupling to applied electric and microwave fields has inspired many applications. These include sensitive imaging of electromagnetic fields, quantum simulation of strongly interacting many-body systems, the study of quantum magnetism, quantum metrology and molecular clocks and quantum computation.

In Durham, we study ultracold ground-state RbCs molecules formed by associating Rb and Cs atoms using a combination of magnetoassociation and STIRAP [1]. This talk will report our progress on controlling the molecules for applications in quantum technology. Specifically, we will discuss how we have mastered the ac Stark shift due to the trapping light [2] to demonstrate robust storage qubits in the molecule [3] and will describe the development of magic traps that support long rotational coherences [4]. Finally, we will describe new experiments that produce single molecules in optical tweezers starting from a single Rb and a single Cs atom [5]. Together these results demonstrate the key elements of a quantum processor based upon ultracold RbCs molecules.

Figure 1. Robust storage qubit in ultracold RbCs molecules showing long-lived coherence.

[1] P.K.Molony et al., “Creation of Ultracold RbCs Molecules in the Rovibrational Ground State”, Phys. Rev. Lett. 113, 255301 (2014).

[2] P.D.Gregory et al., “ac Stark effect in ultracold polar RbCs molecules”, Phys. Rev. A 96, 021402(R) (2017).

[3] P.D.Gregory et al., “Robust storage qubits in ultracold polar molecules”, Nature Physics 17, 1149-1153 (2021).

[4] Q.Guan et al., “Magic conditions for multiple rotational states of bialkali molecules in optical lattices”, Phys. Rev. A 103, 043311 (2021).

[5] R.V.Brooks et al., “Preparation of one Rb and one Cs atom in a single optical tweezer”, New J. Physics 23, 065002 (2021).