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arXiv · 2406.09100

Emergence of superradiance in dissipative dipolar-coupled spin systems

Saptarshi Saha·Yeshma Ibrahim·Rangeet Bhattacharyya
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Abstract

In the superradiance phenomenon, a collection of non-interacting atoms exhibits collective dissipation due to interaction with a common radiation field, resulting in a non-monotonic decay profile. This work shows that dissipative dipolar-coupled systems exhibit an identical collective dissipation aided by the nonsecular part of the dipolar coupling. We consider a simplified dipolar network where the dipolar interaction between the spin-pairs is assumed to be identical. Hence the dynamics remain confined in the block diagonal Hilbert spaces. For a suitable choice of the initial condition, the resulting dynamics require dealing with a smaller subspace which helps extend the analysis to a larger spin network. To include the nonsecular dipolar relaxation, we use a fluctuation-regulated quantum master equation. We note that a successful observation of superradiance in this system requires a weak system-bath coupling. Moreover, we find that for an ensemble of N spins, the maximum intensity of the radiation exhibits a nearly quadratic scaling (N^2), and the dipolar relaxation time follows an inverse square proportionality (1/N^2); these two observations help characterize the emergence of superradiance. Our results agree well with the standard results of pure spin superradiance observed experimentally in various systems.

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Saptarshi Saha, Yeshma Ibrahim, Rangeet Bhattacharyya. 2024-06-13. Emergence of superradiance in dissipative dipolar-coupled spin systems. https://arxiv.org/abs/2406.09100

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