Magic in the spectra of the XXZ quantum chain with boundaries at Delta=0 and Delta=-1/2

Jan de Gier; Alexander Nichols; Pavel Pyatov; Vladimir Rittenberg

doi:10.1016/j.nuclphysb.2005.09.005

Home/Archive/arXiv

arXiv · hep-th/0505062

Magic in the spectra of the XXZ quantum chain with boundaries at Delta=0 and Delta=-1/2

Jan de Gier·Alexander Nichols·Pavel Pyatov·Vladimir Rittenberg

View original source ↗Read source document ↗Export metadata ↓

Abstract

We show that from the spectra of the U_q (sl(2)) symmetric XXZ spin-1/2 finite quantum chain at Delta=-1/2 (q=e^{pi i/3}) one can obtain the spectra of certain XXZ quantum chains with diagonal and non-diagonal boundary conditions. Similar observations are made for Delta=0 (q=e^{pi i/2}). In the finite-size scaling limit the relations among the various spectra are the result of identities satisfied by known character functions. For the finite chains the origin of the remarkable spectral identities can be found in the representation theory of one and two boundaries Temperley-Lieb algebras at exceptional points. Inspired by these observations we have discovered other spectral identities between chains with different boundary conditions.

Explore related subjects

hep-th cond-mat.stat-mech

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Jan de Gier, Alexander Nichols, Pavel Pyatov, Vladimir Rittenberg. 2005-08-12. Magic in the spectra of the XXZ quantum chain with boundaries at Delta=0 and Delta=-1/2. https://doi.org/10.1016/j.nuclphysb.2005.09.005

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Analytic approaches to anisotropic holographic superfluids in asymptotically hyperscaling violation geometry

We explore anisotropic holographic superfluidity and find analytic solutions near critical point where superfluid/normalfluid phase transition appears in a holographic dual fluid system. In arXiv:hep-th/1109.4592, the authors obtained such an analytic solution in 5-dimensional Einstein-SU(2)Yang-Mills system, and it is asymptotically AdS$_5$. What is more in this note is that we get analytic solutions near the critical point in 3- and 4- dimensional Einstein-Scalar-U(1)$\times$SU(2)Yang-Mills systems, which become asymptotically hyperscaling violation geometry. We also get leading order back reactions to the background geometry, which clearly shows spatial anisotropy of the bulk geometry. To explore the properties of the spacetime, we compute holographic entanglement entropy and confirm that the superfluid/normalfluid phase transition must occur at the critical point.

hep-th↗

arXiv2026

Bootstrapping transport in the Drude-Kadanoff-Martin model

The Drude-Kadanoff-Martin model is a simple low energy and long wavelength description of charge transport, parameterised by the current relaxation timescale $τ$, charge diffusivity $D$ and charge compressibility $χ$. We obtain sharp constraints on these parameters in terms of the microscopic energy and length scales of any underlying lattice model with local and bounded interactions. Our primary tools are upper bounds on the retarded Green's function for the charge density in such a setting. We first note that the Drude-Kadanoff-Martin model cannot pertain at microscopic energy scales because it is inconsistent with the exponential suppression of spectral weight at the highest frequencies in a lattice model. Secondly, under the assumption that the low energy dynamics is captured by the model, we obtain a lower bound on the collective mean free path $\ell \equiv \sqrt{τD}$. This bound is shown to imply a version of the Mott-Ioffe-Regel bound: systems with $\ell$ much shorter than the lattice length scale cannot have conventional Drude peaks, in the sense of being captured by the DKM model.

hep-th↗

arXiv2026

Gravitational form factors of the proton in the improved holographic QCD model

We compute the gluonic contribution to the gravitational form factors of the proton using the improved holographic QCD model, in which the proton is described in terms of bulk Dirac fermions. Model parameters are constrained using lattice and phenomenological input, allowing us to obtain estimates for the gravitational form factors and to compare them with results from other approaches. Using the extracted form factors, we analyze mechanical properties of the proton, including pressure and shear distributions. We obtain estimates for the mechanical and mass radii of the proton, $ρ_{\text{mech}} \approx 0.63$ fm, $ρ_{\text{mass}} \approx 0.65$ fm, and compare these values with radius estimates from other nonperturbative studies.

hep-th↗