content_image/420448.jpg content_image/420460.jpg content_image/420461.jpg content_image/420444.jpg content_image/420464.jpg content_image/420445.jpg content_image/420443.jpg content_image/420446.jpg content_image/420447.jpg content_image/420462.jpg content_image/420463.jpg content_image/420458.jpg content_image/420459.jpg content_image/420465.jpg
Performing integration over momentum space for the spherical Fermi surfaces in the limit γ$_{0}$k$_{F}$ ≪ ε$_{F}$ , we ob- tain 

The corresponding gyrotropy conductivity is 

## IV. GYROTROPY CONDUCTIVITY IN THE SUPERCONDUCTING STATE 

To find the gyrotropy conductivity in the supercon- ducting phase with the cubic symmetry, one needs to perform summation and integration in the eqn. (20) us- ing G and F in the superconducting phase. The integral in eqn. (20) consists of two terms 

<img src='content_image/420448.jpg'>

where 

<img src='content_image/420460.jpg'>

and 

<img src='content_image/420461.jpg'>

Transforming the summation into an equivalent con- tour integration $^{16}$, eqn. (30) can be written as 

<img src='content_image/420444.jpg'>

<img src='content_image/420464.jpg'>

<img src='content_image/420445.jpg'>

<img src='content_image/420443.jpg'>

Here, the Green functions are 

<img src='content_image/420446.jpg'>

and 

<img src='content_image/420447.jpg'>

where 

and k$_{±}$ = k ± q / 2. Taking into account 

<img src='content_image/420462.jpg'>

<img src='content_image/420463.jpg'>

after integration with respect to ω $^{′}$, we can rewrite eqn. (32) as: 

<img src='content_image/420458.jpg'>

<img src='content_image/420459.jpg'>

<img src='content_image/420465.jpg'>

Here we have ignored the shifts in the arguments of the phase factors: t$_{λ}$ ( k ± q / 2 ) ≈ t$_{λ}$ ( k ) leading to the small corrections of the order of γ$_{0}$k$_{F}$ /ε$_{F}$ to the main terms. 

For the second term under integral in the eqn. (29) we 

