We investigated the thermodynamic property of the heavy fermion superconductor UTe 2 in pulsed high magnetic fields. The superconducting transition in zero field was observed at T c =1.65 K as a sharp heat capacity jump. Magnetocaloric effect measurements in pulsed-magnetic fields obviously detected a thermodynamic anomaly accompanied by a first-order metamagnetic transition at µ 0 H m =36.0 T when the fields are applied nearly along the hard-magnetization b-axis. From the results of heat capacity measurements in magnetic fields, we found a drastic diverging electronic heat capacity coefficient of the normal state γ N with approaching H m . Comparing with the previous works via the magnetic Clausius-Clapeyron relation, we unveil the thermodynamic details of the metamagnetic transition. The enhancement of the effective mass observed as the development of γ N indicates that quantum fluctuation strongly evolves around H m ; it assists the superconductivity emerging even in extremely high fields.1 arXiv:1907.03033v1 [cond-mat.str-el]

We report a high-resolution terahertz spectroscopic study of quantum spin dynamics in the antiferromagnetic Heisenberg-Ising spin-chain compound BaCo2V2O8 as a function of temperature and longitudinal magnetic field. Confined spinon excitations are observed in an antiferromagnetic phase below TN ≃ 5.5 K. In a field-induced gapless phase above Bc = 3.8 T, we identify many-body string excitations as well as low-energy fractional psinon/antipsinon excitations by comparing to Bethe-Ansatz calculations. In the vicinity of Bc, the high-energy string excitations are found to be dynamically dominant over the fractional excitations.

In this work, a tetraphenylethene-coumarin hybrid fluorophore (TPE-Cou) that contains a Schiff base form is designed and synthesized. A combination of plentiful optical properties and chemical reactivity towards thiols allows TPE-Cou to work as an excellent turn-on probe of thiols with a wide linear range, revealing the great potential of this dye as a quantitative fluorescence indicator. By means of NMR and optical spectrum analyses, a mechanistic picture at the molecular level has been drawn to illustrate how this dye works as a bio-thiol-sensitive fluorescent probe.

No abstract