Spinless Fermionic ladders in a magnetic field

宏光 堀, Shoji Yamamoto

H. Frahm, C. Rödenbeck

Sam T. Carr, B. N. Narozhny, A. A. Nersesyan

The system of interacting spinless fermions hopping on a two-leg ladder exhibits a series of quantum phase transitions when subjected to an external magnetic field. At half-filling, these are either U(1) Gaussian phase transitions between two phases with distinct types of long-range order or Berezinskii-Kosterlitz-Thouless transitions between ordered and gapless phases.

Frédéric Mila

宏光 堀, Shoji Yamamoto

In terms of spinless fermions via the Jordan-Wigner transformation along a snake-like path and spin waves modified so as to restore the sublattice symmetry, we investigate static and dynamic properties of two-leg antiferromagnetic Heisenberg ladders. The specific heat is finely reproduced by the spinless fermions, whereas the magnetic susceptibility is well described by the modified spin waves. The nuclear spin-lattice relaxation rate is discussed in detail with particular emphasis on its novel field dependence.

Joy Prakash Das, Girish S. Setlur