Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...
Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...
Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...
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Posters Tuesday February 5<br />
Poster 40:<br />
Magnetic field effects on the finite-frequency noise and ac conductance of a<br />
Kondo quantum dot out of equilibrium<br />
Sarah Müller<br />
We present analytic results for the finite-frequency current noise and the<br />
nonequilibrium ac conductance for a Kondo quantum dot in presence of a<br />
magnetic field. We determine the line shape close to resonances and show<br />
that while all resonances in the ac conductance are broadened by the transverse<br />
spin relaxation rate; the noise at finite field additionally involves the<br />
longitudinal rate as well as sharp kinks resulting in singular <strong>der</strong>ivatives. Our<br />
results provide a consistent theoretical description of recent experimental<br />
data [Phys. Rev. Lett. 108, 046802 (2012)] for the emission noise at zero<br />
magnetic field, and we propose the extension to finite field for which we<br />
present a detailed prediction.<br />
Poster 41:<br />
Electron entanglement in Cooper pair beam splitter with magnetic fields<br />
Stephan Weiss<br />
We develop a theory that suggests the efficient manipulation of entangled<br />
electrons provided by a Cooper pair beam splitter. The splitting of coherent<br />
electrons forming a spin singlet is present if the superconductor is tunnel<br />
coupled to a double quantum dot [1]. In or<strong>der</strong> to probe entanglement, we<br />
allow for an inhomogeneous and, in general, non-collinear magnetic field in<br />
both dots. If the DQD-SC system is embedded in a transport setup, non-local<br />
current and noise properties are obtained within the real-time diagrammatic<br />
method [2]. As a small parameter we use the hybridization between splitter<br />
and normal leads. The tunnel coupling to the superconductor is taken into<br />
account non-perturbatively. Furthermore, we provide a detailed investigation<br />
of the violation of Bell’s inequality for various parameter regimes.<br />
[1] J. Eldridge, M. Governale, and J. König, Phys. Rev. B 82 184507, (2010).<br />
[2] M. Governale, M. Pala, and J. König, Phys. Rev. B 77 134513, (2008).<br />
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