The kondo screening cloud
A dissertation submitted in fulfillment of the requirements for the degree of Master of Science in Physics at the University of the Witwatersrand. November 7th, 2016 === The spin-1=2 Kondo model describes an antiferromagnetic exchange interaction between an impurity spin and the spin-density of...
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| Format: | Others |
| Language: | en |
| Published: |
2017
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| Online Access: | Panos, Brandon Leigh (2017) The kondo screening cloud, University of Witwatersrand, Johannesburg, <http://wiredspace.wits.ac.za/handle/10539/22745> http://hdl.handle.net/10539/22745 |
| Summary: | A dissertation submitted in fulfillment of the requirements for the degree of
Master of Science in Physics
at
the University of the Witwatersrand. November 7th, 2016 === The spin-1=2 Kondo model describes an antiferromagnetic exchange
interaction between an impurity spin and the spin-density of a Fermi gas.
Although the thermodynamics of this system have been resolved, there are
still some unanswered questions regarding its spatial features. The spatial
region of correlation between the impurity spin and the spin-density of
the Fermi gas is referred to as the Kondo screening cloud. For the case of
anisotropic couplings, the cloud consists of four distinct components. In
this dissertation we use the bosonization technique to derive both an exact
numeric and an approximate analytic expression for the forward scattering
longitudinal cloud at the Toulouse point. The expressions are then extended
to incorporate the effects of a time-independent external magnetic field. The
non-magnetic case displays universal scaling behavior, while the addition
of an external magnetic field only slightly spoils the scaling in the vicinity
of the crossover length (B)
K , but remarkably not deep inside or outside the
cloud. === MT2017 |
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