Spontaneous Emission Near Superconducting Bodies

TL;DR

This paper investigates how superconducting bodies significantly enhance the spin-flip lifetime of nearby atoms compared to normal conductors, analyzing temperature, thickness, and impurity effects with both numerical and analytical methods.

Contribution

It provides an exact numerical formulation for spin-flip lifetime near superconductors and compares it with an analytical approximation, highlighting the effects of temperature, thickness, and impurities.

Findings

Superconductors increase spin-flip lifetime by orders of magnitude below T_c.

Excellent agreement between numerical and analytical results.

Impurities and strong-coupling effects do not significantly affect the lifetime.

Abstract

In the present paper we study the spontaneous photon emission due to a magnetic spin-flip transition of a two-level atom in the vicinity of a dielectric body like a normal conducting metal or a superconductor. For temperatures below the transition temperature T_c of a superconductor, the corresponding spin-flip lifetime is boosted by several orders of magnitude as compared to the case of a normal conducting body. Numerical results of an exact formulation are also compared to a previously derived approximative analytical expression for the spin-flip lifetime and we find an excellent agreement. We present results on how the spin-flip lifetime depends on the temperature T of a superconducting body as well as its thickness H. Finally, we study how non-magnetic impurities as well as possible Eliashberg strong-coupling effects influence the spin-flip rate. It is found that non-magnetic impurities as well as strong-coupling effects have no dramatic impact on the spin-flip lifetime.