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By modifying the conventional one-electron hopping behavior, we study effects of an occupation-dependent hopping on the ground state of the half-filled one-dimensional pair-hopping model. At weak coupling, the use of bosonization and renormalization-group analysis techniques helps to derive the phase diagram. Such unusual hopping is shown to drive a spin-gap transition and to introduce a new region where the triplet superconducting instability dominates for positively small pair-hopping interaction. • We extend 1D Penson-Kolb model where the one-electron hopping is modified. • The phase diagram is analytically obtained at weak coupling and at half filling. • The occupation-dependent hopping induces additional instabilities. • The relevant backward scatter processes drive a spin-gap transition. • The triplet superconducting instability dominates for positively small pair-hopping. [ABSTRACT FROM AUTHOR]

Highlights • We extend the 1D t – U – J x y model up to NNN easy-plane anisotropy. • We derive quantum phase diagram at weak coupling and at half filling. • The effects of the frustration on the phase diagram is highlighted. • The mechanism for the realization of two spin-gapped phases is clarified. Abstract At weak coupling, we investigate the frustrated Hubbard chain including nearest-neighbor and next-nearest-neighbor antiferromagnetic exchange with easy-plane anisotropy J 1 x y and J 2 x y. At half filling, we obtain three different phases in the J 1 x y – J 2 x y plane: a transverse spin density wave phase, a bond order wave phase and a Luther–Emery metallic phase characterized by the coexistence of singlet superconductivity and charge density wave correlations. The frustrating exchange J 2 x y accounts for the spin-gapped phases. [ABSTRACT FROM AUTHOR]

The experimental advances in cold fermion gases motivates the investigation of a one-dimensional (1D) correlated electronic system by incorporating a four-body coupling. Using the low-energy field theory scheme and focusing on the weak-coupling regime, we extend the 1D Penson–Kolb–Hubbard (PKH) model at half filling. It is found that the additional four-body interaction may significantly modify the quantum phase diagram, favoring the presence of the superconducting phase even in the case of two-body repulsions. [ABSTRACT FROM AUTHOR]

We study a one-dimensional anisotropic extended Hubbard model, where the inter-site density ( V ) and exchange ( J ) interactions are spin-dependent. Use of bosonization and renormalization helps investigate phase diagram. At half filling, the ground state characterizes insulating phases. The spin-dependent repulsion leads to a bond-spin-density-wave (BSDW) phase. The antiferromagnetic exchange enhances the bond-order-wave (BOW) phase while weakens the charge-density-wave (CDW) phase. When J > 4 V , the BSDW and CDW phases disappear. Away from half filling, the ground state exhibits superconducting behavior. The anisotropic interactions have an important effect on the phase structures. [ABSTRACT FROM AUTHOR]

At half filling, we study analytically a one-dimensional correlated electronic system modeled by an extended Penson–Kolb–Hubbard (PKH) chain with the occupation-dependent hopping. The modification of the electron hopping amplitude is exhibited to induce the additional correlated-hopping interactions. At weak coupling, we use the field theory to obtain ground-state phase diagram, including the SDW, BCDW, BSDW, SS and TS phases for U > 0. The induced three-body attractive interaction accounts for the superconductivity absent in the usual PKH model. • We study a 1D extended PKH model with the occupation-dependent hopping. • The modified one-electron hopping leads to the correlated-hopping interactions. • The induced three-body attraction accounts for the superconducting phases. • The study supplements the understanding of quantum properties of the 1D physics. [ABSTRACT FROM AUTHOR]

By introducing a modulation parameter ( ξ ), we study the one-dimensional correlated system with modulated hopping, on-site ( U ) and nearest-neighbor ( V ) repulsions in the weak-coupling regime. The induced three-body attraction changes topology of the conventional phase diagram. Besides the usual CDW and SDW phases, a BSDW phase exists for | U − 2 V | < 8 t ξ 2 / π . In the absence of V , an insulator–metal transition takes place, and the TS phase is realized for ξ > π U / 8 t . Phenomenologically, the general quantum phase diagram including insulating and superconducting phases is discussed. [ABSTRACT FROM AUTHOR]

The ground-state properties of a 1D modified Penson–Kolb–Hubbard model characterized by alternating Hubbard interaction at odd and even sites are discussed by the bosonization scheme and the renormalization group analysis. At quarter filling, the quantum phase diagram consists of the charge-density-wave, spin-density-wave and singlet-superconductivity instabilities. The insulating phases come from the relevant umklapp process induced by the unequal on-site repulsion. The results provide a further understanding of occurrence of the umklapp process in 1D correlated electron systems. • We study the 1D modified PKH model with unequal on-site interactions. • The alternating on-site repulsion induces relevant umklapp process at quarter filling. • The study supplements understanding of quantum properties of 1D correlated systems. [ABSTRACT FROM AUTHOR]

Abstract: The one-dimensional half-filled extended Hubbard model with on-site repulsion (U) and nearest-neighbor interactions including Coulomb repulsion (V) and exchange (J) is studied in the weak-coupling regime. We present a theoretical argument for the occurrence of bond-located phases. The bond–charge–density–wave (BCDW) is realized for and bond–spin–density–wave (BSDW) occurs for . [Copyright &y& Elsevier]