Dr Sam T. Carr

Institut fur Theorie der Kondensierten Materie
Universitat Karlsruhe

Room: 10-08
Tel: ++49 721 608-7006
Email: carr@tkm.uni-karlsruhe.de

List of Publications

  1. M. P. Schneider, S. T. Carr, I. V. Gornyi and A. D. Mirlin, Weak localization and magnetoresistance in a two-leg ladder model, arXiv:1207.6337 (2012), (submitted to Phys. Rev. B)
  2. J. M. Fellows, S. T. Carr, C. A. Hooley and J. Schmalian, Unbinding of giant vortices in states of competing order, arXiv:1205.1333 (2012), (submitted to Phys. Rev. Lett.)
  3. J. M. Fellows and S. T. Carr, Superfluid, solid, and supersolid phases of dipolar bosons in a quasi-one-dimensional optical lattice, Phys. Rev. A 84, 051602(R) (2011).
  4. S. T. Carr, D. A. Bagrets and P. Schmitteckert, Full counting statistics in the self-dual interacting resonant level model, Phys. Rev. Lett. 107, 206801 (2011).
  5. S. T. Carr, B. N. Narozhny and A. A. Nersesyan, The effect of a local perturbation in a fermionic ladder, Phys. Rev. Lett. 106, 126805 (2011).
  6. S. T. Carr, J. Quintanilla and J. J. Betouras, Lifshitz transitions and crystallization of fully-polarised dipolar Fermions in an anisotropic 2D lattice, Phys. Rev. B 82, 045110 (2010).
  7. S. T. Carr, J. Quintanilla and J. J. Betouras, Deconfinement and quantum liquid crystalline states of dipolar fermions in optical lattices, Int. J. Mod. Phys. B 23, 4074 (2009) (proceedings of conference CMT32 in Loughborough).
  8. J. Quintanilla, S. T. Carr and J. J. Betouras, Meta-nematic, smectic and crystalline phases of dipolar fermions in an optical lattice, Phys. Rev. A 79, 031601(R) (2009).
  9. S. T. Carr, Strong correlation effects in single wall carbon nanotubes, Int. J. Mod. Phys. B 22, 5235 (2008), (invited review article).
  10. S. T. Carr, A. O. Gogolin and A. A. Nersesyan, Interaction induced dimerization in zigzag single wall carbon nanotubes, Phys.Rev. B 76 245121 (2007).
  11. S. T. Carr, B. N. Narozhny and A. A. Nersesyan, Spinless fermionic ladders in a magnetic field: Phase diagram, Phys. Rev. B 73 195114 (2006).
  12. B. N. Narozhny, S. T. Carr and A. A. Nersesyan, Fractional charge excitations in fermionic ladders, Phys. Rev. B 71 161101 (2005).
  13. S. T. Carr and A. M. Tsvelik, Spectrum and correlation functions of a quasi-one-dimensional quantum Ising model, Phys. Rev. Lett. 90, 177206 (2003).
  14. S. T. Carr and A. M. Tsvelik, Superconductivity and Charge Density Wave in a Quasi-One-Dimensional Spin Gap System, Phys. Rev. B 65, 195121 (2002).

You can also find all these articles on the arXiv: Full list of articles on arXiv or at ResearcherID

DPhil Thesis

Non-perturbative solutions to quasi-one-dimensional strongly correlated systems

Abstract - In this thesis, we deal with quasi-one-dimensional field theories by which we mean strongly anisotropic higher dimensional models. One way to solve such quasi-one-dimensional models is to split them into a one-dimensional part and a weaker inter-chain perturbation on this. The one-dimensional model can then be solved exactly by techniques such as bosonisation or integrability, and the weak inter-chain part can be treated perturbatively by using the Random Phase Approximation (RPA), or beyond this. This allows us to comment on concepts such as dimensional crossover, and by treating the one-dimensional fluctuations exactly, we access phases not accessible by conventional perturbation theory. In this thesis, we report results for three such models: the first is a model of non-BCS superconductivity where a spin-gap in the one dimensional chains leads to pairing, even for repulsive interactions. We look at the interplay between a superconducting and a charge density wave ground state. The second model is that of a Mott insulator, where we are specifically looking at the effects of a magnetic field on the model. We look at the density of states as the angle of the magnetic field is varied. The third system is the quantum Ising model, a generic model of two-state systems, where we calculate the correlation functions in the ordered phase. All three models are motivated by reference to real materials with a strong structural anisotropy.

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