Dipolon Theory of Muon Spin Relaxation Rate in High Temperature Superconductors

We have utilized the dipolon theory [1-4] to explain the muon spin relaxation rate (MSRR) in $YBa_2Cu_3O_{7-\delta}$. Earlier, we predicted first of all two new high energy kinks which were observed later on. Following the dipolon theory we use the four momenta space diagrams in the dressed particle picture for scattering of quasiparticles (QPs) by dipolons involving the QP Green's function, the dipolon propagator and screened electron-dipolon vertex to derive the self-energy $\Sigma^{e-dip}(p)$ and the mean lifetime of scattering of QPs by dipolons required to calculate the penetration depth $\lambda$ \ and MSRR. We also incorporate scatterings by vacancies and phonons. The calculated values [5] of MSRR as a function of $T_c$ agree very well with experiments.
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(2) R. R. Sharma, Physica {\bf C 439}, 47 (2006).
(3) R. R. Sharma, Physica {\bf C 468}, 190 (2008).
(4) R. R. Sharma, "Dipolon Theory of Kink Structure ...", in "Superconducting ...", Ed. K. N. Courtlandt,
P. 81-100, Nova Sc, Pub., Inc., New York, 2009.
(5) R. R. Sharma, "Theory of Dipolon ...", Physipoetics Press,Lake Barrington, IL, 2021.