E_{8} Spectra of Quasi-One-Dimensional Antiferromagnet BaCo_{2}V_{2}O_{8} under Transverse Field.

We report ^{51}V NMR and inelastic neutron scattering (INS) measurements on a quasi-1D antiferromagnet BaCo_{2}V_{2}O_{8} under transverse field along the [010] direction. The scaling behavior of the spin-lattice relaxation rate above the Néel temperatures unveils a 1D quantum critical point (QCP) at H_{c}^{1D}≈4.7 T, which is masked by the 3D magnetic order. With the aid of accurate analytical analysis and numerical calculations, we show that the zone center INS spectrum at H_{c}^{1D} is precisely described by the pattern of the 1D quantum Ising model in a magnetic field, a class of universality described in terms of the exceptional E_{8} Lie algebra. These excitations are nondiffusive over a certain field range when the system is away from the 1D QCP. Our results provide an unambiguous experimental realization of the massive E_{8} phase in the compound, and open a new experimental route for exploring the dynamics of quantum integrable systems as well as physics beyond integrability.

Quantum quenches in the sine-Gordon model: A semiclassical approach.

We compute the time evolution of correlation functions after quantum quenches in the sine-Gordon model within the semiclassical approximation, which is expected to yield accurate results for small and slow quenches producing slow quasiparticles with low density. We demonstrate this by reproducing results of a recent form-factor calculation of the relaxation of expectation values [B. Bertini, D. Schuricht, and F. H. L. Essler, J. Stat. Mech. (2014) P100351742-546810.1088/1742-5468/2014/10/P10035]. Extending these results, we find that-in the universal limit of vanishingly small quasiparticle velocities-the expectation values of most vertex operators do not decay to zero. We give analytic expressions for the relaxation of dynamic correlation functions and show that they have diffusive behavior for large timelike separation.

Correlations after quantum quenches in the XXZ spin chain: failure of the generalized Gibbs ensemble.

We study the nonequilibrium time evolution of the spin-1/2 anisotropic Heisenberg (XXZ) spin chain, with a choice of dimer product and Néel states as initial states. We investigate numerically various short-ranged spin correlators in the long-time limit and find that they deviate significantly from predictions based on the generalized Gibbs ensemble (GGE) hypotheses. By computing the asymptotic spin correlators within the recently proposed quench-action formalism [Phys. Rev. Lett. 110, 257203 (2013)], however, we find excellent agreement with the numerical data. We, therefore, conclude that the GGE cannot give a complete description even of local observables, while the quench-action formalism correctly captures the steady state in this case.

Expectation values in the Lieb-Liniger Bose gas.

We present a novel method to compute expectation values in the Lieb-Liniger model both at zero and finite temperature. These quantities, relevant in the physics of one-dimensional ultracold Bose gases, are expressed by a series that has a remarkable behavior of convergence. Among other results, we show the computation of the three-body expectation value at finite temperature, a quantity that rules the recombination rate of the Bose gas.

Cytological investigation of biopsy performed in sarcoidosis.

One of the most frequent appearance of sarcoidosis is the enlargement of mediastinal lymph-nodes. The clinical picture first of all must be distinguished from the malignant processes and seldom from lymph-node tuberculosis. At our clinic material was obtained for cytological examination in two ways: through mediastinoscopy in the course of which we had opportunity of histological evaluation too and by means of transbronchial thin-needle puncture respectively and only cytological examination was performed with this material. We carried out investigations in 155 patients sent to our clinic on account of the suspicion of sarcoidosis. According to the course of disease or rather other examinations 123 out of 155 patients suffered from sarcoidosis and in 112 of these cases that is in 91% the diagnosis was verified by the help of cytological examination. In the smears epithelioid cell groups were generally found in large number but Langhans' giant cells could be produced only in 21 cases. In 70 of 123 patients mediastinoscopy and in 53 transbronchial thin-needle biopsy was accomplished. Through cytological investigation of material obtained mediastinoscopically we attained nearly 100% positivity rate and 80% by the help of thin-needle biopsy. Although forasmuch as the transbronchial puncture does not need special intervention because it can be carried out in the course of routine bronchoscopy we think the application of the procedure reasonable not only in finding metastasis if it involves the hypertrophy of mediastinal lymph-nodes. In this way we spare the patient from further examinations. The cytological finding, of course, must be always fitted in clinical picture but on the basis of our experience the close cooperation between the clinician and cytologist assures the avoidance of wrong diagnosis.