We analyze the magnetic dipole contribution to atom-surface dispersion forces. Unlike its electrical counterpart, it involves small transition frequencies that are comparable to thermal energy scales. A significant temperature dependence is found near surfaces with a nonzero dc conductivity, leading to a strong suppression of the dispersion force at $T > 0$. We use thermal response theory for the surface material and discuss both normal metals and superconductors. The asymptotes of the free energy of interaction and of the entropy are calculated analytically over a large range of distances. Near a superconductor, the onset of dissipation at the phase transition strongly changes the interaction, including a discontinuous entropy. We discuss the similarities with the Casimir interaction between two surfaces and suggest that precision measurements of the atom-surface interaction may shed light upon open questions around the temperature dependence of dispersion forces between lossy media.
Haakh, H., Intravaia, F., Henkel, C., Spagnolo, S., Passante, R., Power, B., et al. (2009). Temperature dependence of the magnetic Casimir-Polder interaction. PHYSICAL REVIEW A, 80, 062905-1-062905-15 [10.1103/PhysRevA.80.062905].
Temperature dependence of the magnetic Casimir-Polder interaction
SPAGNOLO, Salvatore;PASSANTE, Roberto;
2009-01-01
Abstract
We analyze the magnetic dipole contribution to atom-surface dispersion forces. Unlike its electrical counterpart, it involves small transition frequencies that are comparable to thermal energy scales. A significant temperature dependence is found near surfaces with a nonzero dc conductivity, leading to a strong suppression of the dispersion force at $T > 0$. We use thermal response theory for the surface material and discuss both normal metals and superconductors. The asymptotes of the free energy of interaction and of the entropy are calculated analytically over a large range of distances. Near a superconductor, the onset of dissipation at the phase transition strongly changes the interaction, including a discontinuous entropy. We discuss the similarities with the Casimir interaction between two surfaces and suggest that precision measurements of the atom-surface interaction may shed light upon open questions around the temperature dependence of dispersion forces between lossy media.File | Dimensione | Formato | |
---|---|---|---|
2009pra80-062905.pdf
Solo gestori archvio
Dimensione
366.91 kB
Formato
Adobe PDF
|
366.91 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.