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TT: Fachverband Tiefe Temperaturen

TT 58: SC: Vortex Dynamics, Vortex Phases, Pinning

TT 58.6: Vortrag

Donnerstag, 17. März 2011, 18:45–19:00, HSZ 301

Influence of dissipation on flux patterns in type-II superconductors — •Constantin Tomaras and Stefan Kehrein — Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, Theresienstr. 37, D- 80333 München, Germany

Topological quantum field theories constitute the present frontier of theoretical physics [1]. Quite the oldest example is the theory of superconductivity, where the appropriate topological charge is just the number of condensed gauge bosons. We formulate a non-equilibrium BCS theory (d≥2) in presence of a continuous measurement of the local order parameter Δ_BCS=⟨Ψ_↓^†Ψ_↑^†⟩. This allows for local annihilation of pairs of vortices with opposing winding number, while the global phase (∼number of particles-number of holes) is conserved. Depending on the initial flux pattern, the constraint yields to domain wall formation and eventually a percolation transition. Our theory is in agreement with the seminal paper of Toussiant and Wilczek [2], and relevant for recent Hall probe microscopy experiments [3].
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