Bosonization in two-dimensional field theory

Edward Witten

Edi Halyo

Two dimensional conformal field theories, can be described by their pseudo Goldstone bosons when the conformal symmetry is spontaneously and anomalously broken. We show that the Schwarzian action of these bosons leads to the Cardy formula without using modular invariance. As a result, the Cardy formula applies to conformal field theories on a cylinder and chiral theories in one dimension. This also explains why the Cardy--Verlinde formula for theories on $S^1 \times S^{d-2}$ can be written in the form of the Cardy formula of an effective two dimensional theory.

Edward Witten

Alexios P. Polychronakos

We propose the bosonization of a many-body fermion theory in D spatial dimensions through a noncommutative field theory on a (2D-1)-dimensional space. This theory leads to a chiral current algebra over the noncommutative space and reproduces the correct perturbative Hilbert space and excitation energies for the fermions. The validity of the method is demonstrated by bosonizing a two-dimensional gas of fermions in a harmonic trap.

Kun Yang

We use high dimensional bosonization to derive an effective field theory that describes the Pomeranchuck transition in two-dimensional Fermi liquids. The bosonization approach explicitly retains all low-energy degrees of freedom of the system. The resultant theory has dynamical exponent z=2 at tree level and upper critical dimension d_c=2, thus in 2D the system is at the upper critical dimension. These results differ from those of an earlier study based on integrating out fermions.