Moscow Institute of Physics and Technology

Theoretical nanophysics laboratory

Visiting address:

Laboratory building, room 122
Moscow Institute of Physics and Technology
Dolgoprudny, Russia

contact e-mail address: (head M.V.Feigel'man, deputy head I.V.Zagorodnev)

Research topics
  • Mesoscopic electronic systems
  • Superconducting hybrid structures
  • Quantum phase transitions
  • Spintronics
  • 2DEG and quantum Hall effect
  • Quantum magnetism and topological order
  • Physics of quantum computation
Recent quantum-nanophysics seminars
Scientific Council of the Landau Institute, Friday, June 23, 2017, Landau Institute, 11:30 am

Ivan Protopopov

Transport in a disordered ν=2/3 fractional quantum Hall junction

Electric and thermal transport properties of a ν=2/3 fractional quantum Hall junction are analyzed. We investigate the evolution of the electric and thermal two-terminal conductances, G and G_Q, with system size L and temperature T. This is done both for the case of strong interaction between the 1 and 1/3 modes (when the low-temperature physics of the interacting segment of the device is controlled by the vicinity of the strong-disorder Kane-Fisher-Polchinski fixed point) and for relatively weak interaction, for which the disorder is irrelevant at T=0 in the renormalization-group sense. The transport properties in both cases are similar in several respects. In particular, G(L) is close to 4/3 (in units of e2/h) and G_Q to 2 (in units of πT/6?) for small L, independently of the interaction strength. For large L the system is in an incoherent regime, with G given by 2/3 and GQ showing the Ohmic scaling, G_Q\sim 1/L, again for any interaction strength. The hallmark of the strong-disorder fixed point is the emergence of an intermediate range of L, in which the electric conductance shows strong mesoscopic fluctuations and the thermal conductance is G_Q=1. The analysis is extended also to a device with floating 1/3 mode, as studied in a recent experiment [A. Grivnin et al, Phys. Rev. Lett. 113, 266803 (2014)].

Referativnyi seminar, Friday, June 16, 2017, ITF, 3:00 pm

Leon Ogorodnikov

Coherent quantum phase slip

Referativnyi doklad po rabote