Yangian Symmetry and Quantum Inverse Scattering Method for the One-Dimensional Hubbard Model

We develop the quantum inverse scattering method for the one-dimensional Hubbard model on the infinite interval at zero density. $R$-matrix and monodromy matrix are obtained as limits from their known counterparts on the finite interval. The $R$-matrix greatly simplifies in the considered limit. The new $R$-matrix contains a submatrix which turns into the rational $R$-matrix of the XXX-chain by an appropriate reparametrization. The corresponding submatrix of the monodromy matrix thus provides a representation of the Y(su(2)) Yangian. From its quantum determinant we obtain an infinite series of mutually commuting Yangian invariant operators which includes the Hamiltonian.Comment: 14 pages, LaTeX, no figures, minor change

The Hubbard chain: Lieb-Wu equations and norm of the eigenfunctions

We argue that the square of the norm of the Hubbard wave function is proportional to the determinant of a matrix, which is obtained by linearization of the Lieb-Wu equations around a solution. This means that in the vicinity of a solution the Lieb-Wu equations are non-degenerate, if the corresponding wave function is non-zero. We further derive an action that generates the Lieb-Wu equations and express our determinant formula for the square of the norm in terms of the Hessian determinant of this action.Comment: 11 pages, Late

Asymptotic form of two-point correlation function of the XXZ spin chain

Correlation functions of the XXZ spin chain in the critical regime is studied at zero-temperature. They are exactly represented in the Fredholm determinant form and are related with an operator-valued Riemann-Hilbert problem. Analyzing this problem we prove that a two-point correlation function consisting of sufficiently separated spin operators is expressed by power-functions of the distance between those operators.Comment: 9 pages, LaTeX2e (+ amssymb, amsthm); Proof of Lemma 1 is revise

SU(2)xSU(2) Invariant Scattering Matrix of the Hubbard Model

We consider the one-dimensional half-filled Hubbard model. We show that the excitation spectrum is given by the scattering states of four elementary excitations, which form the fundamental representation of $SU(2)\times SU(2)$. We determine the exact two-particle Scattering matrix, which a solution of the Yang-Baxter equation and reflects the $SO(4)$ symmetry of the model. The results for repulsive and attractive Hubbard model are related by an interchange of spin and charge degrees of freedom.Comment: 29 pages, jyTeX (macro included - just TeX the file) ITP-SB-93-45, BONN-HE-93-3

A note on density correlations in the half-filled Hubbard model

We consider density-density correlations in the one-dimensional Hubbard model at half filling. On intuitive grounds one might expect them to exhibit an exponential decay. However, as has been noted recently, this is not obvious from the Bethe Ansatz/conformal field theory (BA/CFT) approach. We show that by supplementing the BA/CFT analysis with simple symmetry arguments one can easily prove that correlations of the lattice density operators decay exponentially.Comment: 3 pages, RevTe

Odyssey Towards a Sirenic Thinking: An Attempt at a Self-Criticism of the Listening Paradigm Within Sound Studies

This text departs from a contradictory claim in deaf studies and sound studies: both disciplines describe a hierarchical regime of the sensible – visuocentrism and audiocentrism – which they try to counter with conceptualisations as “acoustemology” or “deaf gain.” However, as we argue, they both thereby erect what they claim to overcome: a sensual regime that privileges one sense over another and a restricted conception of subjectivity deriving from it. First, we draw a philosophical line in the critique of sensual regimes. Then we propose a figure for the transcendence of the separation of the sensible: in re-reading of the myth of Odysseus and the sirens, we engage various examples from literature, art, and acoustics to describe sirens as a mythological and technical archetype of the transcendence of the sensual regime, as well as reified subjectivity. The question, then, is not how to escape the sirens, but how they can be approached. It is necessary, we argue, for sound studies to develop a critical self-consciousness of its own restricted concepts in order to move from sonic thinking towards a sirenic thinking

Integro-Difference Equation for a correlation function of the spin-12{1\over2} Heisenberg XXZ chain

We consider the Ferromagnetic-String-Formation-Probability correlation function (FSFP) for the spin-$1\over 2$ Heisenberg XXZ chain. We construct a completely integrable system of integro-difference equations (IDE), which has the FSFP as a $\tau$-function. We derive the associated Riemann-Hilbert problem and obtain the large distance asymptotics of the FSFP correlator in some limiting cases.Comment: 14 pages, latex+epsf, 1 figur

Krankheit gestalten

Moulagen - plastische Krankheitsdarstellungen - waren wichtige Dokumentations- und Lehrobjekte der Medizin. Die Moulagenbildner*innen galten in der Medizingeschichte oft als skurrile Außenseiter*innen, deren Arbeit von alchemistisch anmutender Geheimnistuerei umgeben war. Henrik Eßler widmet sich erstmals der Berufsgeschichte dieser unterschätzten Spezialist*innen. Dabei stellt er einerseits die Bedeutung der Moulage heraus, die weit über eine »naturgetreue« Nachbildung hinausging. Andererseits rückt er die Stellung der Moulagenbildner*innen im wissenschaftlichen Arbeitsprozess in ein neues Licht: Sie waren nicht nur ausführendes Organ, sondern Kooperationspartner*innen im Forschungszusammenhang