Experimental realization of a stabilized pair coherent state in 3D cQED storage cavities.

Preparing steady one-mode cat states in microwave cavities has led to applications like error-corrected bosonic logical qubits. A two-mode entangled state such as a pair coherent state│ξ, Δ〉= Σ_n  C(ξ, n, Δ)│n+Δ, n〉, where ξ is a complex number, Δ is the photon number difference and coefficients C(ξ, n, Δ) have sub-Poissonian distribution, when used as a cat code for autonomous error correction promises significant advantages over one-mode cat-qubit. There is extensive theoretical research proposing the generation and stabilization of a pair coherent state from four-wave mixing and spontaneous emission that has not been realized experimentally yet. In this work, we prepare a stabilized pair coherent state in high-quality superconducting microwave storage cavities. The state is created from the vacuum and stabilized by engineering a two-photon exchange interaction of the cavities with the reservoir aid by four-wave mixing. In this talk, I will present our implementation of the dissipative process and show tomography results that prove the coherence in the prepared pair coherent state for long enough time before it decays into a classical mixture.