2 M ar 1 99 7 SO ( 4 ) symmetry and off - diagonal long - range order in the Hubbard bilayer
نویسنده
چکیده
Yang's η pairing operator is generalized to explore off-diagonal long-range order in the Hubbard bilayer with an arbitrary chemical potential. With this operator and a constraint condition on annihilation and creation operators, we construct explicitly eigenstates which possess simultaneously three kinds of off-diagonal long-range order, i.e., the intralayer one and the interlayer one for on-site pairing, and that for interlayer nearest-neighbor pairing. As in the simple Hubbard model there is also an SO(4) symmetry, with the the generators properly defined. A sufficient condition leads to at least one of the above three kinds of off-diagonal long-range order. A constraint relation among different kinds of off-diagonal long-range order is also given. There exists a triplet of collective modes if the U(1) symmetry of a subgroup is spontaneously broken.
منابع مشابه
ar X iv : c on d - m at / 9 40 40 42 v 1 1 4 A pr 1 99 4 Supersolids in the Bose – Hubbard Hamiltonian
We use a combination of numeric and analytic techniques to determine the ground state phase diagram of the Bose–Hubbard Hamiltonian with longer range repulsive interactions. At half filling one finds superfluidity and an insulating solid phase. Depending on the relative sizes of near–neighbor and next near–neighbor interactions, this solid either follows a checkerboard or a striped pattern. In ...
متن کاملar X iv : c on d - m at / 9 60 31 41 v 1 2 1 M ar 1 99 6 March 1996 A remark on off - diagonal long - range order
In this work, we study some general property of a strongly correlated electron system defined on a lattice. Assuming that the lattice system exhibits off-diagonal long-range order, we show rigorously that this assumption would lead to Meissner effect. This generalizes previous results of continuous case to a lattice electron system.
متن کاملابررسانای d- موجی، پادفرومغناطیس و مایع اسپینی در ابررساناهای آلی شبه دوبعدی
The self-energy-functional approach is a powerful many-body tool to investigate different broken symmetry phases of strongly correlated electron systems. We use the variational cluster perturbation theory (also called the variational cluster approximation) to investigate the interplay between the antiferromagnetism and d-wave superconductivity of κ-(ET)2 X conductors. These compounds are desc...
متن کاملHubbard Models with Superconducting Quantum Symmetry
where a†iσ , aiσ are fermionic operators for electrons of spin σ ∈ {↑, ↓} at site i of the lattice, niσ ≡ a † iσaiσ, and 〈i, j〉 denotes nearest neighbor sites i 6= j. The model is given in grand canonical form; μ fixes the average number 〈 ∑ i,σ niσ〉 of electrons. The first term is a local on-site interaction; for u > 0 it describes a repulsive Coulomb interaction, for u < 0 it yields an effect...
متن کاملSpontaneous Symmetry Breaking, Off-diagonal Long-range Order, and Nucleation of Quantum State
Spontaneous symmetry breaking is determined by quantum mechanical measurement, and is classified to two types according to whether Hamiltonian commutes the relevant observable, the average of which is the order parameter. A supplement regarding phases is given to the expansion postulate and validate ensemble description of many-particle systems. Interference between many-particle states, macros...
متن کامل