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TT: Fachverband Tiefe Temperaturen

TT 7: Transport: Quantum Coherence and Quantum Information Systems – Theory (jointly with HL, MA)

TT 7.13: Vortrag

Montag, 16. März 2015, 12:45–13:00, H 3005

Spin dynamics using the Majorana representation: validity, path integral and higher correlators — •Pablo Schad1, Boris N. Narozhny1,2, Gerd Schön3, Yuriy Makhlin4,5, and Alexander Shnirman11Institut für Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany — 2National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse 31, 115409 Moscow, Russia — 3Institut für Theoretische Festkörperphysik und Institut für Nanotechnologie, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany — 4Landau Institute for Theoretical Physics, acad. Semyonov av., 1a, 142432, Chernogolovka, Russia — 5Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Russia

We present a method to calculate higher spin correlators via the Majorana fermion representation of spin operators. We show explicitly that the Majorana representation does not require any projection procedure. Previously found identities [1,2] between spin and Majorana fermion correlation functions are extended. As an example we consider a spin-1/2 coupled to an isotropic, ohmic bath. We formulate a path-integral approach, which is valid at B=0 in contrast to perturbation theory, find the saddle-point solution and discuss fluctuations. We demonstrate that spin correlators in the high-temperature regime can be obtained using saddle-point Green’s functions.


[1] A. Shnirman and Y. Makhlin,

Phys. Rev. Lett. 91, 207204 (2003).

[2] W. Mao, P. Coleman, C. Hooley, and D. Langreth,

Phys. Rev. Lett. 91, 207203 (2003).

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DPG-Physik > DPG-Verhandlungen > 2015 > Berlin