2024/12/19 by Luo, Haoyuan, Mahmoodian, Sahand · 2 citations
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2412.14798
Optical Schrödinger cat states are non-Gaussian states with applications in quantum technologies, such as for building error-correcting states in quantum computing. Yet the efficient generation of high-fidelity optical Schrödinger cat states is an outstanding problem in quantum optics. Here, we propose using squeezed superpositions of zero and two photons, |θ⟩ = cos(θ/2)|0⟩ + sin(θ/2)|2⟩, as ingredients for protocols to efficiently generate high-fidelity cat states. We present a protocol using linear optics with success probability P\gtrsim 50% that can generate cat states of size |α|2=5 with fidelity F>0.99. The protocol relies only on detecting single photons and is remarkably tolerant of loss, with 2% detection loss still achieving F>0.98 for cats with |α|2=5. We also show that squeezed θ states are ideal candidates for nonlinear photon subtraction using a two-level system with near deterministic success probability and fidelity F>0.98 for cat states of size |α|2=5. Schemes for generating θ states using quantum emitters are also presented. Our protocols can be implemented with current state-of-the-art quantum optics experiments.