Deterministic single-photon sources are indispensable core devices for quantum information technology, yet high-performance implementation remains a long-standing bottleneck for linear optical quantum computing. We propose a feasible scheme for deterministic single-photon emission based on a
△-type three-level atom coupled to a single-mode cavity, driven by two classical external fields, which is adaptable to both strong and ultrastrong cavity-atom coupling regimes. Under continuous-wave driving, the system achieves excellent single-photon characteristics: the normalized equal-time second-order correlation function reaches
g(2)(0)∼10−6, with a photon indistinguishability of
98.73% and a state purity of
99.95% in the strong coupling regime, while the ultrastrong coupling regime further suppresses
G(2)(0)∼10−8, yielding an indistinguishability of
99.10% and a purity of
99.99%. For pulsed driving in the ultrastrong coupling regime, the source realizes superior performance, with an emission efficiency, indistinguishability, and purity of
99.96%,
98.98%, and
99.99% under resonant conditions, and
100%,
95.91%, and
99.93% under detuned conditions, respectively. The near-ideal optical performance of the proposed scheme provides a viable route for constructing high-quality deterministic single-photon sources, which offers a promising solution to the limitations of conventional single-photon devices and facilitates the further development of quantum information science and fundamental quantum optical research.
We propose the effective simulation of light-matter ultrastrong-coupling phenomena with strong-coupling systems. Recent theory and experiments have shown that the single-atom quantum Rabi model can be simulated by the Jaynes-Cummings model with two additional classical drives. Here, we show that quantum nonlinear optical phenomena, relying on the counter-rotating terms of the Rabi model, can be implemented by the Jaynes-Cummings and Tavis-Cummings models with only a single classical drive. We analyze three examples: a single atom exciting two photons, frequency conversion, and a single photon exciting two atoms.
We propose the effective simulation of light-matter ultrastrong-coupling phenomena with strong-coupling systems. Recent theory and experiments have shown that the quantum Rabi Hamiltonian can be simulated by a Jaynes-Cummings system with the addition of two classical drives. This allows one to implement nonlinear processes that do not conserve the total number of excitations. However, parity is still a conserved quantity in the quantum Rabi Hamiltonian, which forbids a wide family of processes involving virtual transitions that break this conservation. Here, we show that these parity-nonconserving processes can be simulated and that this can be done in an even simpler setup: a Jaynes-Cummings-type system with the addition of a single classical drive. By shifting the paradigm from simulating a particular model to simulating a particular process, we are able to implement a much wider family of nonlinear coherent protocols than in previous simulation approaches, doing so with fewer resources and constraints. We focus our analysis on three particular examples: a single atom exciting two photons, frequency conversion, and a single photon exciting two atoms.