Entanglement spectrum of a topological phase in one dimension (2009)
Pollmann, Frank, Berg, Erez, Turner, Ari M., Oshikawa, Masaki
We show that the Haldane phase of S=1 chains is characterized by a double degeneracy of the entanglement spectrum. The degeneracy is protected by a set of symmetries (either the dihedral group of...
Symmetry protection of topological order in one-dimensional quantum spin systems (2009)
Pollmann, Frank, Berg, Erez, Turner, Ari M., Oshikawa, Masaki
We discuss characterization and stability of the topological order of the Haldane phase. We find that an odd-$S$ Haldane phase has a robust topological order protected by any one of the following...
Striped superconductors: How the cuprates intertwine spin, charge and superconducting orders (2009)
Berg, Erez, Fradkin, Eduardo, Kivelson, Steven A., Tranquada, John
Recent transport experiments in the original cuprate high temperature superconductor, {La$_{2-x}$Ba$_x$CuO$_4$}, have revealed a remarkable sequence of transitions and crossovers which give rise to a...
Theory of the striped superconductor (2008)
Berg, Erez, Fradkin, Eduardo, Kivelson, Steven A.
We define a distinct phase of matter, a "pair density wave" (PDW), in which the superconducting order parameter $\phi$ varies periodically as a function of position such that when averaged over the...
Rise and fall of hidden string order of lattice bosons (2008)
Berg, Erez, Torre, Emanuele G. Dalla, Giamarchi, Thierry, Altman, Ehud
We investigate the ground state properties of a newly discovered phase of one dimensional lattice bosons with extended interactions (see E. G. Dalla Torre et al., Phys. Rev. Lett. \textbf{97}, 260401...
Superconductivity in zigzag CuO chains (2007)
Berg, Erez, Geballe, Theodore H., Kivelson, Steven A.
Superconductivity has recently been discovered in Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$ with a maximum $T_c$ of about 15K. Since the CuO planes in this material are believed to be insulating, it...
Evolution of the Fermi surface in phase fluctuating d-wave superconductors (2007)
One of the most puzzling aspects of the high $T_c$ superconductors is the appearance of Fermi arcs in the normal state of the underdoped cuprate materials. These are loci of low energy excitations...
Dynamical layer decoupling in a stripe-ordered, high T_c superconductor (2007)
Berg, Erez, Fradkin, Eduardo, Kim, Eun-Ah, Kivelson, Steven A., Oganesyan, Vadim, Tranquada, John, ...
In the stripe-ordered state of a strongly-correlated two-dimensional electronic system, under a set of special circumstances, the superconducting condensate, like the magnetic order, can occur at a...
Hidden order in 1D Bose insulators (2006)
Torre, Emanuele G. Dalla, Berg, Erez, Altman, Ehud
We investigate the phase diagram of spinless bosons with long range (~ 1/r^3) repulsive interactions, relevant to ultracold polarized atoms or molecules, using DMRG. Between the two conventional...
Singlet Excitations in Pyrochlore: A Study of Quantum Frustration (2002)
Berg, Erez, Altman, Ehud, Auerbach, Assa
The highly frustrated Heisenberg antiferromagnet on Checkerboard and Pyrochlore lattices is subject to strong quantum fluctuations. This problem is amenable to the Contractor Renormalization (CORE)...