Section: New Results

Confining the state of light to a quantum manifold by engineered two-photon loss

Participants: Zaki Leghtas and Mazyar Mirrahimi

Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can become a resource for the generation and protection of quantum states. This notion can be generalized to the confinement of a system into a manifold of quantum states, consisting of all coherent superpositions of multiple stable steady states. In a collaboration with the team of Michel H. Devoret at Yale university, we have confined the state of a superconducting resonator to the quantum manifold spanned by two coherent states of opposite phases and have observed a Schrödinger cat state spontaneously squeeze out of vacuum before decaying into a classical mixture. As suggested by our earlier work  [93] , this experiment points toward robustly encoding quantum information in multidimensional steady-state manifolds and should lead to significant hardware shortcuts for quantum error correction and fault-tolerant quantum computation.

This experimental work was published in Science [18] .