Hybrid photon blockade with hyperradiance in two-qubit cavity QED system

Abstract

We investigate a hybrid photon blockade (HPB) scheme in a driven two-qubit cavity QED system arising from the combination of eigenenergy-level anharmonicity (ELA) and quantum destructive interference (QDI). By tuning the detuning of a single qubit and pumping field, we identify precise parametric regimes that fully integrate the advantages of high brightness in ELA-based conventional photon blockade and strong antibunching in QDI-based unconventional photon blockade. Interestingly, these regimes are accompanied by hyperradiance, indicating that inter-emitter correlations give rise to enhanced collective emission. The HPB mechanism exhibits parametric generality across varying coupling asymmetries and remains accessible via detuning control, offering a feasible route for generating high-quality single-photon source in diverse quantum platforms.

Figures (3)

• Figure 1: (a) Schematic diagram of the driven two-qubit cavity QED system. qubit 1 and qubit 2 are coupled to a single-mode cavity with coupling strengths $g_{1}$ and $g_{2}$ with the same spontaneous decay rate $\gamma$ , while the cavity decays at rate $\kappa$. The frequency detuning between the qubits is defined as $\delta$. (b) Dressed-state spectrum versus the qubit detuning $\delta$. Green (blue) solid curves denote the single- (two-) excitation subspaces. (c) Interfering transition pathways in the excitation process. The three colored arrows represent three sets of QDI channels.
• Figure 2: (a) Mean photon number $\langle a^\dagger a \rangle$, (b) second-order correlation function $g^{(2)}(0)$, and (c) radiance witness $R$ as functions of the normalized detunings $\Delta/g_{1}$ and $\delta/g_{1}$. The dashed lines denote the three QDI channels identified in Fig.\ref{['fig_1']}(a), while The dot-dashed lines delineate the blockade regions governed by the ELA mechanism. (d) Photon number distribution $P(n)$ in the Fock state for the three blockade regimes highlighted in (b). Here, we set the parameters to $g_{1}=g_{2}=10\kappa$, and $\eta/\kappa=0.1$.
• Figure 3: Characteristics of HPB under varying coupling asymmetries. (a) Three-dimensional trajectories of the HPB points in the $(\Delta/g_1, \delta/g_1, g_{2}/g_{1})$ parameter space. (b) mean photon number $\langle a^\dagger a \rangle$, (c) equal-time second-order correlation function $g^{(2)}(0)$, and (d) radiance witness $R$. The green and purple solid lines correspond to the primary and secondary HPB series, respectively, which are colored to match the two QDI channels identified in Fig.\ref{['fig_1']}(c). Here, we set $K = g_{2}/g_{1}$. All other system parameters remain identical to those used in Fig.\ref{['fig_2']}.