Monodromy Matrix Elements Research Articles

Action of the monodromy matrix elements in the generalized algebraic Bethe ansatz

В рамках обобщенного алгебраического анзаца Бете рассматривается спиновая цепочка $XYZ$. Вычислено действие элементов матрицы монодромии на векторы Бете, результат которого представляется в виде линейной комбинации новых векторов Бете. Также вычислено кратное действие калибровочно-преобразованных элементов матрицы монодромии на превекторы Бете. Результаты выражены через статистическую сумму восьмивершинной модели.

Action of the monodromy matrix elements in the generalized algebraic Bethe ansatz

Action of the monodromy matrix elements in the generalized algebraic Bethe ansatz

Actions of the monodromy matrix elements onto -invariant Bethe vectors

Multiple actions of the monodromy matrix elements onto off-shell Bethe vectors in the -invariant quantum integrable models are calculated. These actions are used to describe recursions for the highest coefficients in the sum formula for the scalar product. For simplicity, detailed proofs are given for the case. The results for the supersymmetric case can be obtained similarly and are formulated without proofs.

Bethe Vectors for Orthogonal Integrable Models

We consider quantum integrable models associated with $\mathfrak{so}_3$ algebra. We describe Bethe vectors of these models in terms of the current generators of the $\mathcal{D}Y(\mathfrak{so}_3)$ algebra. To implement this approach we use isomorphism between $R$-matrix and Drinfeld current realizations of the Yangians and their doubles for classical types $B$, $C$, and $D$ series algebras. Using these results we derive the actions of the monodromy matrix elements on off-shell Bethe vectors. We show that these action formulas lead to recursions for off-shell Bethe vectors and Bethe equations for on-shell Bethe vectors. The action formulas can also be used for calculating the scalar products in the models associated with $\mathfrak{so}_3$ algebra.

Bethe Vectors for Composite Models with gl(2|1) and gl(1|2) Supersymmetry

Supersymmetric composite generalized quantum integrable models solvable by the algebraic Bethe ansatz are studied. Using a coproduct in the bialgebra of monodromy matrix elements and their action on Bethe vectors, formulas for Bethe vectors in the composite models with supersymmetry based on the super-Yangians $Y[\mathfrak{gl}(2|1)]$ and $Y[\mathfrak{gl}(1|2)]$ are derived.

GL(3) -Based Quantum Integrable Composite Models. I. Bethe Vectors

We consider a composite generalized quantum integrable model solvable by the nested algebraic Bethe ansatz. Using explicit formulas of the action of the monodromy matrix elements onto Bethe vectors in the GL(3)-based quantum integrable models we prove a formula for the Bethe vectors of composite model. We show that this representation is a particular case of general coproduct property of the weight functions (Bethe vectors) found in the theory of the deformed Knizhnik-Zamolodchikov equation.

The factorized F-matrices for arbitrary [formula omitted] integrable vertex models

We discuss the F-matrices associated to the R-matrix of a general N-state vertex model whose statistical configurations encode N−1U(1) symmetries. The factorization condition is shown for arbitrary weights being based only on the unitarity property and the Yang–Baxter relation satisfied by the R-matrix. Focusing on the N=3 case we are able to conjecture the structure of some relevant twisted monodromy matrix elements for general weights. We apply this result providing the algebraic expressions of the domain wall partition functions built up in terms of the creation and annihilation monodromy fields. For N=3 we also exhibit a R-matrix whose weights lie on a del Pezzo surface and have a rather general structure.

The monodromy matrix in the F-basis for arbitrary six-vertex models

We present the expressions for the monodromy matrix elements of the six-vertex model in the F-basis for arbitrary Boltzmann weights. The results rely solely on the property of unitarity and Yang–Baxter relations, avoiding any specific parameterization of the weights. This allows us to write complete algebraic expressions for the inner products and the underlying domain wall partition functions in the case of arbitrary rapidities. We then apply our results for the trigonometric six-vertex model in the presence of inhomogeneous electric fields and obtain a determinant formula for the respective on-shell scalar products.

Renormalization of the frozen Gaussian approximation to the quantum propagator

The frozen Gaussian approximation to the quantum propagator may be a viable method for obtaining "on the fly" quantum dynamical information on systems with many degrees of freedom. However, it has two severe limitations, it rapidly loses normalization and one needs to know the Gaussian averaged potential, hence it is not a purely local theory in the force field. These limitations are in principle remedied by using the Herman-Kluk (HK) form for the semiclassical propagator. The HK propagator approximately conserves unitarity for relatively long times and depends only locally on the bare potential and its second derivatives. However, the HK propagator involves a much more expensive computation due to the need for evaluating the monodromy matrix elements. In this paper, we (a) derive a new formula for the normalization integral based on a prefactor free HK propagator which is amenable to "on the fly" computations; (b) show that a frozen Gaussian version of the normalization integral is not readily computable "on the fly"; (c) provide a new insight into how the HK prefactor leads to approximate unitarity; and (d) how one may construct a prefactor free approximation which combines the advantages of the frozen Gaussian and the HK propagators. The theoretical developments are backed by numerical examples on a Morse oscillator and a quartic double well potential.

Algebraic Bethe ansatz for [formula omitted] invariant integrable models: The method and general results

In this work we have developed the essential tools for the algebraic Bethe ansatz solution of integrable vertex models invariant by a unique U ( 1 ) charge symmetry. The formulation is valid for arbitrary statistical weights and respective number N of edge states. We show that the fundamental commutation rules between the monodromy matrix elements are derived by solving linear systems of equations. This makes possible the construction of the transfer matrix eigenstates by means of a new recurrence relation depending on N − 1 distinct types of creation fields. The necessary identities to solve the eigenvalue problem are obtained exploring the unitarity property and the Yang–Baxter equation satisfied by the R-matrix. The on-shell and off-shell properties of the algebraic Bethe ansatz are explicitly presented in terms of the arbitrary R-matrix elements. This includes the transfer matrix eigenvalues, the Bethe ansatz equations and the structure of the vectors not parallel to the eigenstates.

A prefactor free semiclassical initial value series representation of the propagator.

A new class of prefactor free semiclassical initial value representations (SCIVR) of the quantum propagator is presented. The derivation is based on the physically motivated demand, that on the average in phase space and in time, the propagator obey the exact quantum equation of motion. The resulting SCIVR series representation of the exact quantum propagator is also free of prefactors. When using a constant width parameter, the prefactor free SCIVR propagator is identical to the frozen Gaussian propagator of Heller [J. Chem. Phys. 75, 2923 (1981)]. A numerical study of the prefactor free SCIVR series is presented for scattering through a double slit potential, a system studied extensively previously by Gelabert et al. [J. Chem. Phys. 114, 2572 (2001)]. As a basis for comparison, the SCIVR series is also computed using the optimized Herman-Kluk SCIVR. We find that the sum of the zeroth order and the first order terms in the series suffice for an accurate determination of the diffraction pattern. The same exercise, but using the prefactor free propagator series needs also the second order term in the series, however the numerical effort is not greater than that needed for the Herman-Kluk propagator, since one does not need to compute the monodromy matrix elements at each point in time. The numerical advantage of the prefactor free propagator grows with increasing dimensionality of the problem.

Hamiltonian formulation of self-induced transparency theory without slowly varying envelope approximation

It was shown that the propagation of an ultrashort light pulse in resonance absorbing medium under self-induced transparency conditions can be described by the theory which allows Hamiltonian formulation where corresponding Poisson brackets are non-ultralocal and the restrictions of a slowly varying envelope approximation are lifted. By employing the representation of zero curvature, a compact form of fundamental Poisson brackets for a monodromy matrix was found to satisfy the requirements of the generalized Hamiltonian formulation of completely integrable systems. An explicit form of PB amongst monodromy matrix elements, canonical variables of an angle-action type and integrals of motion can then be derived by a standard procedure. Semi-classical quantization of this model can also be done. The model considered extends the list of completely integrable non-ultralocal models.

COLORED EXTENSIONS OF GLq(2) QUANTUM GROUP AND RELATED NONCOMMUTATIVE PLANES

An infinite-dimensional quantum group, containing the standard GLq(2) and GLp,q(2) cases as different subalgebras, is constructed by using a colored braid group representation. It turns out that all algebraic relations occurring in this “colored” quantum group can be expressed in the Heisenberg-Weyl form, for a nontrivial choice of corresponding basis elements. Moreover a novel quadratic algebra, defined through Kac-Moody-like generators, is obtained by making some power series expansion of related monodromy matrix elements. The structure of invariant noncommutative planes associated with this “colored” quantum group has also been investigated.

Semiclassical wavepacket propagation in a hydrogen atom

A description of a new time dependent semiclassical theory for propagating wave packets is given in terms of Monodromy matrix elements. The nonlinear classical phase space aids in the obtainment of the semiclassical autocorrelation function, which for the case of a Coulomb potential is compared to its quantum analog.