Related papers: A planar extrapolation of the correlation problem …
We discuss a many-electron Hamiltonian with Hubbard-like repulsive interaction and linear coupling to the phonon branches, having the Cu-O plane of the superconducting cuprates as a paradigm. A canonical transformation extracts an effective…
Pairing occurs in conventional superconductors through a reduction of the electronic potential energy accompanied by an increase in kinetic energy, indicating that the transition is driven by a pairing potential. In the underdoped cuprates,…
We consider a class of time dependent finite energy multi-soliton solutions of the U(N) integrable chiral model in $(2+1)$ dimensions. The corresponding extended solutions of the associated linear problem have a pole with arbitrary…
The leading superconducting instabilities of the two-dimensional extended repulsive one-band Hubbard model within spin-fluctuation pairing theory depend sensitively on electron density, band and interaction parameters. We map out the phase…
The Hubbard model with an additional bond-charge interaction $X$ is solved exactly in one dimension for the case $t=X$ where $t$ is the hopping amplitude. In this case the number of doubly occupied sites is conserved. In the sector with no…
We study extremal correlation functions of chiral primary operators in the large-N SU(N) ${\cal N} = 2$ superconformal QCD theory and present new results based on supersymmetric localization. We discuss extensively the basis-independent…
We study the SO(4)x SU(2) invariant Q-deformation of Euclidean N=(1,1) gauge theories in the harmonic superspace formulation. This deformation preserves chirality and Grassmann harmonic analyticity but breaks N=(1,1) to N=(1,0)…
We compute the planar limit, as all-order power series in the 't Hooft coupling, of various integrated 4-point functions of chiral primary operators of ${\cal N}=4$ SU(N) super Yang-Mills, and of moment map operators of ${\cal N}=2$ SU(N)…
It has been proposed to abandon the requirement that parallel transporters in gauge theories are unitary (or pseudoorthogonal). This leads to a geometric interpretation of Vierbein fields as parts of gauge fields, and nonunitary parallel…
The superselection sectors of two classes of scalar bilocal quantum fields in D>=4 dimensions are explicitly determined by working out the constraints imposed by unitarity. The resulting classification in terms of the dual of the respective…
In this thesis, we theoretically examine the pairing mechanisms and the identification of the pairing symmetry of unconventional superconductors whose normal states are correlated, multiband, or topological. In the first part, we…
We consider a symplectic extrapolation of the Hubbard model of N fold replicated electrons and solve this model exactly in two special cases, at N=infinity in the bosonic sector and for any N on a dimer of two points. At N=infinity we find…
We propose gauge theory/gravity duality involving conformal theories based on U(N+k|k) gauge groups. We show that to all orders in 1/N these non-unitary theories based on supergroups are indistinguishable from the corresponding unitary…
We study non-planar corrections in two special $\mathcal N=2$ superconformal $SU(N)$ gauge theories that are planar-equivalent to $\mathcal N=4$ SYM theory: two-nodes quiver model with equal couplings and $\mathcal N=2$ vector multiplet…
We consider the extension of the Standard electroweak Model through an $SU(2)$ quadruplet of scalars with hypercharge either $3/2$ or $1/2$ (with an additional reflection symmetry in the latter case). We establish, through $\textit{exact…
Recent scanning tunneling spectroscopy experiments have provided evidence that dopant impurities in high- Tc superconductors can strongly modify the electronic structure of the CuO2 planes nearby, and possibly influence the pairing. To…
We consider extended versions of the Hubbard model which contain additional interactions between nearest neighbours. In this letter we show that a large class of these models has a superconducting ground state in arbitrary dimensions. In…
The pairing symmetry in the electron mechanism for superconductivity is explored when charge fluctuations coexist with spin fluctuations. The extended Hubbard model is adopted to obtain, with the fluctuation exchange approximation, a phase…
The Hubbard on-site repulsion $U$ between opposite spin electrons on the same atomic orbital is widely regarded to be the most important source of electronic correlation in solids. Here we extend the Hubbard model to account for the fact…
We exhibit explicitly the intertwiner operator for the monodromy matrices of the recent proposed SU(N) Hubbard model [5]. This produces a new family of non-additive R-matrices and generalizes an earlier result by Shastry [2].