We investigate the algebraic structure of the supersymmetric t-J model in one dimension. We prove that the Bethe ansatz states are highest weight vectors of an spl(2,1) superalgebra. By acting with shift operators we construct a complete set of states for this model. In addition we analyse the multiplet structure of the anti-ferromagnetic ground state and some low lying excitations. It turns ou...

The spectroscopic studies of transition metal complexes of iron. metal complexes, are characterized by XRD, FTIR, H NMR, Mössbauer and VSM (vibrating sample magnetometer) measurements, are reported in the present paper. The XRD analysis reveals the crystalline nature of all the compounds. Mössbauer study interprets paramagnetic nature of complexes at room temperature. VSM measurements also reve...

Two dimensional anti-ferromagnetic solid He adsorbed on graphite, so called 4/7 phase, is a strongly frustrated quantum spin system and the ground state is considered to be a gapless spin liquid. To clarify the magnetic behavior, the magnetization curve has been investigated below 1 mK in high magnetic fields, using NMR over the wide frequency region up to 360 MHz. The magnetization is found to...

In recent work,N = 2 supersymmetry has been proposed as a tool for the analysis of itinerant, correlated fermions on a lattice. In this paper we extend these considerations to the case of lattice fermions with spin 1/2 . We introduce a model for correlated spin-1/2 fermions with a manifest N = 4 supersymmetry, and analyze its properties. The supersymmetric ground states that we find represent h...

In the title anti-ferromagnetic material, (C(7)H(12)N(2))[ReCl(6)], the Néel temperature is observed at 5 K. The salt is stabilized by an extensive network of N-H⋯Cl and C-H⋯Cl hydrogen bonds, where hydrogen-bonded anion chains and characteristic cation-anion motifs are present. Similar systems play an important role in crystal engineering as hydrogen bonds that can transmit magnetic inter-acti...

In this paper we illustrate new techniques for bounding the mixing rates of certain Markov chains. Whereas previous techniques have required extensive insight into the combinatorics of the problem in question, we provide a more heuristic method. We apply this to several hard combinatorial problems including graph colouring and Twice-SAT, as well as problems from statistical physics, such as the...

We introduce a formula for the disagreement function which is used to control a recently proposed dynamics of the Ising spin system. This leads to four different phases of the Ising spin chain in a zero temperature. One of these phases is doubly degenerated (anti-and ferromagnetic states are equally probable). On the borders between the phases two types of transitions are observed: infinite deg...

We introduce the notion of optimal target vector, and describe how it creates a link between supervised and unsupervised learning. We exploit this notion to construct Ising models, for dichotomic clustering, whose couplings are (i) both ferroand anti-ferromagnetic (ii) depending on the whole data-set and not only on pairs of samples. The effectiveness of the method is shown in the case of the w...