Tunable Single- and Multiphoton Bundles in Cavity-Coupled Atomic Arrays

Abstract

We propose an experimentally accessible scheme for realizing tunable nonclassical light in cavity-coupled reconfigurable atomic arrays. By coherently controlling the collective interference phase, the system switches from single-photon blockade to high-purity multiphoton bundle emission, unveiling a hierarchical structure of photon correlations dictated by atom-number parity and cavity detuning. The scaling of photon population identifies the transition between superradiant and subradiant regimes, while parity- and phase-dependent spin correlations elucidate the microscopic interference processes enabling coherent multiphoton generation. This work establishes a unified framework connecting cooperative atomic interactions to controllable nonclassical photon statistics and introduces a distinct interference-enabled mechanism that provides a practical route toward high-fidelity multiphoton sources in scalable cavity QEDs.

Figures (5)

• Figure 1: (a) Schematic of cavity-coupled reconfigurable atomic array, highlighting dipole-forbidden $^1S_0 \leftrightarrow {^3P_1}$ transition of $^{88}$Sr. (b) Phase $\phi$ dependence of anharmonic energy spectrum for different atom numbers $N$.
• Figure 2: Distributions of (a) $n_s$ and (b) $g^{(2)}_1(0)$ on the $\Delta-\phi$ plane for $N=5$. The white dashed curves indicate the analytic dressed-state splitting at $\Delta=\Delta_{1,\pm}$. The phase $\phi$ dependence of $n_s$ (solid line) and $g^{(2)}_1(0)$ (dashed line) for (c) $\Delta=|\Delta_{1,\pm}|$ and (d) $\Delta=0$ at $N=5$ and 6, respectively. Color shading encodes the magnitude of $n_s$ and $g^{(2)}_1(0)$.
• Figure 3: (a) ${\cal S}$ as functions of $\Delta$ and $\phi$ for $N=5$. Solid lines are contour lines and the white dashed line shows vacuum Rabi splitting $\Delta_{1+}$ at blue sideband. (b) $n_s$ versus $N$ for $\phi=0$ and $\Delta/g=3,\,6,\,12,\, {\rm and}\, 20$. The black dashed line serves as a guide for $n_s\sim N^2$.
• Figure 4: $N$ dependence of $n_s$ (red lines) and $g^{(2)}_1$ (green lines) for (a) $\phi=0$ and (b) $\phi=\pi$ at $\Delta=|\Delta_{1\pm}|$, and (c) $[\phi, \Delta]=[\pi, 0]$, respectively. The dashed lines indicate power-law fits: $n_s=0.07 N^{0.56}$ in (a) and $n_s=0.09 N^{-0.8}$ in (b).
• Figure 5: (a)-(d) Time interval $\tau$ dependence of $g^{(2)}_1 (\tau)$ (solid lines) and $g^{(2)}_n (\tau)$ (dashed lines) for $N=2$, 3, 4, and 6, respectively. The inset displays the steady-state photon distribution $p(q)$. Spatial profiles of (e) correlations $C^{z}_{1,j}$ and (f) spin magnetism $\langle\hat{\sigma}^z_j\rangle$ as function of lattice site $j$ for different $N$. The other parameters are $\phi=\pi$ and $\Delta=0$.