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The Bose-Hubbard dimer Hamiltonian is a simple yet effective model for describing tunneling phenomena of Bose-Einstein condensates. One of the significant mathematical properties of the model is that it can be exactly solved by Bethe ansatz…

Exactly Solvable and Integrable Systems · Physics 2008-04-24 Jon Links , Katrina E. Hibberd

We develop an explicit description of a time-dependent response of fermionic condensates to perturbations. The dynamics of Cooper pairs at times shorter than the energy relaxation time can be described by the BCS model. We obtain a general…

Superconductivity · Physics 2009-11-10 Emil A. Yuzbashyan , Boris L. Altshuler , Vadim B. Kuznetsov , Victor Z. Enolskii

Mean field approximation treats only coherent aspects of the evolution of a Bose Einstein condensate. However, in many experiments some atoms scatter out of the condensate. We study an analytic model of two counter-propagating atomic…

Other Condensed Matter · Physics 2009-11-10 P. Zin , J. Chwedenczuk , A. Perez , K. Rzazewski , M. Trippenbach

We describe a method to derive, from first principles, the long-distance asymptotic behavior of correlation functions of integrable models in the framework of the algebraic Bethe ansatz. We apply this approach to the longitudinal spin- spin…

Mathematical Physics · Physics 2009-09-25 N. Kitanine , K. K. Kozlowski , J. M. Maillet , N. A. Slavnov , V. Terras

The pairing gap plays a fundamental role in the nuclear many-body problem and many large scale and accurate mass formula fits suggest the smooth nuclear mass dependence $\Delta \sim 6(1)~ A^{-1/3}~{\rm MeV}$ in the liquid drop model which…

Nuclear Theory · Physics 2017-06-30 E. Ruiz Arriola , S. Szpigel , V. S. Timoteo

The condensate of the Bardeen-Cooper-Schrieffer (BCS) pair in the ground state, which may contain information on both topology and spin pairing, promises the superconductivity of the system. In this paper, we study a singlet-triplet spin…

Strongly Correlated Electrons · Physics 2023-09-29 E. S. Ma , K. L. Zhang , Z. Song

We consider two particular 1D quantum many-body systems with local interactions related to the root system $C_N$. Both models describe identical particles moving on the half-line with non-trivial boundary conditions at the origin, and they…

Mathematical Physics · Physics 2009-11-10 Martin Hallnäs , Edwin Langmann

By using the intertwiner and face-vertex correpondence relation, we obtain the Bethe ansatz equation of eight vertex model with open boundary condtitions in the framework of algebraic Bethe ansatz method. The open boundary condition under…

High Energy Physics - Theory · Physics 2010-01-15 Heng Fan , Bo-yu Hou , Kang-jie Shi , Zhong-xia Yang

We derive the coordinate space wave function for the inhomogeneous six-vertex model from the Algebraic Bethe Ansatz. The result is in agreement with the result first obtained long time ago by Yang and Gaudin in the context of the problem of…

Mathematical Physics · Physics 2011-04-07 A. A. Ovchinnikov

We construct commuting transfer matrices for models describing the interaction between a single quantum spin and a single bosonic mode using the quantum inverse scattering framework. The transfer matrices are obtained from certain…

Other Condensed Matter · Physics 2008-11-26 L. Amico , H. Frahm , A. Osterloh , G. A. P. Ribeiro

The exact solution of the one-dimensional super-symmetric t-J model under generic integrable boundary conditions is obtained via the Bethe ansatz methods. With the coordinate Bethe ansatz, the corresponding R-matrix and K-matrices are…

Mathematical Physics · Physics 2015-06-18 Xin Zhang , Junpeng Cao , Wen-Li Yang , Kangjie Shi , Yupeng Wang

We solve the $A_{2n}^{(2)}$ vertex model with all kinds of diagonal reflecting matrices by using the algebraic Behe ansatz, which includes constructing the multi-particle states and achieving the eigenvalue of the transfer matrix and…

High Energy Physics - Theory · Physics 2010-02-03 G. L. Li , K. J. Shi , R. H. Yue

We introduce a variational approach for the Quantum Inverse Scattering Method to exactly solve a class of Hamiltonians via Bethe ansatz methods. We undertake this in a manner which does not rely on any prior knowledge of integrability…

Exactly Solvable and Integrable Systems · Physics 2015-06-03 A. Birrell , P. S. Isaac , J. Links

We discuss the influence of boundary conditions on the continuum limit of the six-vertex model by deriving a variational principle for the associated height function with arbitrary fixed boundary conditions. We discuss its consequences…

Statistical Mechanics · Physics 2007-05-23 P. Zinn-Justin

Some features of integrable lattice models are reviewed for the case of the six-vertex model. By the Bethe ansatz method we derive the free energy of the six-vertex model. Then, from the expression of the free energy we show analytically…

Statistical Mechanics · Physics 2007-05-23 Tetsuo Deguchi

The quantum $\tau_2$-model with generic site-dependent inhomogeneity and arbitrary boundary fields is studied via the off-diagonal Bethe Ansatz method. The eigenvalues of the corresponding transfer matrix are given in terms of an…

Mathematical Physics · Physics 2016-12-21 Xiaotian Xu , Kun Hao , Tao Yang , Junpeng Cao , Wen-Li Yang , Kangjie Shi

An integrable version of the supersymmetric U model with open boundary conditions and an impurity situated at one end of the chain is introduced. The model is solved through the algebraic Bethe ansatz method and the Bethe ansatz equations…

Strongly Correlated Electrons · Physics 2009-10-31 A. Foerster , K. E. Hibberd , J. R. Links , I. Roditi

Using ideas from BCS descriptions of systems of fermions, a covariant extension of the relativistic Fermi gas model is presented as a way to incorporate correlation effects in nuclei. The model is developed for the BCS nuclear ground state…

Nuclear Theory · Physics 2010-01-22 M. B. Barbaro , R. Cenni , T. W. Donnelly , A. Molinari

I study the technique of Algebraic Bethe Ansatz for solving integrable models and show how it works in detail on the simplest example of spin 1/2 XXX magnetic chain. Several other models are treated more superficially, only the specific…

High Energy Physics - Theory · Physics 2007-05-23 L. D. Faddeev

We test the canonical BCS wave functions for fixed number of electrons for the attractive Hubbard model. We present results in one dimension for various chain lengths, electron densities, and coupling strengths. The ground-state energy and…

Superconductivity · Physics 2009-10-31 K. Tanaka , F. Marsiglio