Strongly interacting spins underlie many intriguing phenomena and applications1–4
ranging from magnetism to quantum information processing. Interacting spins
combined with motion show exotic spin transport phenomena, such as superfluidity
arising from pairing of spins induced by spin attraction5,6. To understand these
complex phenomena, an interacting spin system with high controllability is desired.
Quantum spin dynamics have been studied on different platforms with varying
capabilities7–13. Here we demonstrate tunable itinerant spin dynamics enabled by
dipolar interactions using a gas of potassium-rubidium molecules confined to
two-dimensional planes, where a spin-1/2 system is encoded into the molecular
rotational levels. The dipolar interaction gives rise to a shift of the rotational
transition frequency and a collision-limited Ramsey contrast decay that emerges from
the coupled spin and motion. Both the Ising and spin-exchange interactions are
precisely tuned by varying the strength and orientation of an electric field, as well as
the internal molecular state. This full tunability enables both static and dynamical
control of the spin Hamiltonian, allowing reversal of the coherent spin dynamics.
Our work establishes an interacting spin platform that allows for exploration of
many-body spin dynamics and spin-motion physics using the strong, tunable dipolar
interaction.
Strongly interacting spins underlie many intriguing phenomena and applications1–4
ranging from magnetism to quantum information processing. Interacting spins
combined with motion show exotic spin transport phenomena, such as superfluidity
arising from pairing of spins induced by spin attraction5,6. To understand these
complex phenomena, an interacting spin system with high controllability is desired.
Quantum spin dynamics have been studied on different platforms with varying
capabilities7–13. Here we demonstrate tunable itinerant spin dynamics enabled by
dipolar interactions using a gas of potassium-rubidium molecules confined to
two-dimensional planes, where a spin-1/2 system is encoded into the molecular
rotational levels. The dipolar interaction gives rise to a shift of the rotational
transition frequency and a collision-limited Ramsey contrast decay that emerges from
the coupled spin and motion. Both the Ising and spin-exchange interactions are
precisely tuned by varying the strength and orientation of an electric field, as well as
the internal molecular state. This full tunability enables both static and dynamical
control of the spin Hamiltonian, allowing reversal of the coherent spin dynamics.
Our work establishes an interacting spin platform that allows for exploration of
many-body spin dynamics and spin-motion physics using the strong, tunable dipolar
interaction.