Jožef Stefan Institute

About: Jožef Stefan Institute is a facility organization based out in Ljubljana, Slovenia. It is known for research contribution in the topics: Liquid crystal & Dielectric. The organization has 3828 authors who have published 12614 publications receiving 291025 citations.

Dynamics of photoinduced charge-density-wave to metal phase transition in K0.3MoO3.

Abstract: We present the first systematic studies of the photoinduced phase transition from the ground charge density wave (CDW) state to the normal metallic state in the prototype quasi-1D CDW system K0.3MoO3. Ultrafast nonthermal CDW melting is achieved at the absorbed energy density that corresponds to the electronic energy difference between the metallic and CDW states. The results imply that on the subpicosecond time scale when melting and subsequent initial recovery of the electronic order takes place the lattice remains unperturbed.

Pair-breaking and superconducting state recovery dynamics in MgB2.

Abstract: We present studies of the photoexcited quasiparticle dynamics in ${\mathrm{M}\mathrm{g}\mathrm{B}}_{2}$ where, using femtosecond optical techniques, Cooper pair-breaking dynamics (PBD) have been temporally resolved for the first time. The PBD are strongly temperature and photoexcitation intensity dependent. Analysis of the PBD using the Rothwarf-Taylor equations suggests that the anomalous PBD arises from the fact that in ${\mathrm{M}\mathrm{g}\mathrm{B}}_{2}$ photoexcitation is initially followed by energy relaxation to high frequency phonons instead of, as commonly assumed, $e\mathrm{\text{\ensuremath{-}}}e$ thermalization. Furthermore, the bare quasiparticle recombination rate and the probability for pair breaking by phonons have been determined.

Study of the $Z_c^+$ channel using lattice QCD

Abstract: Recently experimentalists have discovered several charged charmoniumlike hadrons ${Z}_{c}^{+}$ with unconventional quark content $\overline{c}c\overline{d}u$. We perform a search for ${Z}_{c}^{+}$ with mass below 4.2 GeV in the channel ${I}^{G}({J}^{PC})={1}^{+}({1}^{+\ensuremath{-}})$ using lattice QCD. The major challenge is presented by the two-meson states $J/\ensuremath{\psi}\ensuremath{\pi}$, ${\ensuremath{\psi}}_{2S}\ensuremath{\pi}$, ${\ensuremath{\psi}}_{1D}\ensuremath{\pi}$, $D{\overline{D}}^{*}$, ${D}^{*}{\overline{D}}^{*}$, ${\ensuremath{\eta}}_{c}\ensuremath{\rho}$ that are inevitably present in this channel. The spectrum of eigenstates is extracted using a number of meson-meson and diquark-antidiquark interpolating fields. For our pion mass of 266 MeV we find all the expected two-meson states but no additional candidate for ${Z}_{c}^{+}$ below 4.2 GeV. Possible reasons for not seeing an additional eigenstate related to ${Z}_{c}^{+}$ are discussed. We also illustrate how a simulation incorporating interpolators with a structure resembling low-lying two-meson states seems to render a ${Z}_{c}^{+}$ candidate, which is however not robust after further two-meson states around 4.2 GeV are implemented.