Paul Scherrer Institute

About: Paul Scherrer Institute is a facility organization based out in Villigen, Switzerland. It is known for research contribution in the topics: Neutron & Large Hadron Collider. The organization has 9248 authors who have published 23984 publications receiving 890129 citations. The organization is also known as: PSI.

Persistence of magnetic excitations in La2−xSrxCuO4 from the undoped insulator to the heavily overdoped non-superconducting metal

Abstract: The interplay between magnetism and superconductivity in copper oxide superconductors has been a topic of intense research. Now, a systematic resonant inelastic X-ray scattering study of strontium-doped lanthanum cuprate shows that high-energy magnetic excitations persist over a wide doping range.

Measurement of jet fragmentation in PbPb and pp collisions at root s(NN)=2.76 TeV

Abstract: The jet fragmentation function of inclusive jets with transverse momentum p_T above 100GeV/c in PbPb collisions has been measured using reconstructed charged particles with p_T above 1GeV/c in a cone of radius 0.3 around the jet axis. A data sample of PbPb collisions collected in 2011 at a nucleon-nucleon center-of-mass energy of √sNN = 2.76 TeV corresponding to an integrated luminosity of 150μb^(−1) is used. The results for PbPb collisions as a function of collision centrality and jet transverse momentum are compared to reference distributions based on pp data collected at the same center-of-mass energy in 2013, with an integrated luminosity of 5.3pb^(−1). A centrality-dependent modification of the fragmentation function is found. For the most central collisions, a significant enhancement is observed in the PbPb/pp fragmentation function ratio for charged particles with p_T less than 3GeV/c. This enhancement is observed for all jet p_T bins studied.

New Measurement of the Fe 60 Half-Life

Abstract: We have made a new determination of the half-life of the radioactive isotope $^{60}\mathrm{Fe}$ using high precision measurements of the number of $^{60}\mathrm{Fe}$ atoms and their activity in a sample containing over ${10}^{15}$ $^{60}\mathrm{Fe}$ atoms. Our new value for the half-life of $^{60}\mathrm{Fe}$ is $(2.62\ifmmode\pm\else\textpm\fi{}0.04)\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{ }\mathrm{yr}$, significantly above the previously reported value of $(1.49\ifmmode\pm\else\textpm\fi{}0.27)\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{ }\mathrm{yr}$. Our new measurement for the lifetime of $^{60}\mathrm{Fe}$ has significant implications for interpretations of galactic nucleosynthesis, for determinations of formation time scales of solids in the early Solar System, and for the interpretation of live $^{60}\mathrm{Fe}$ measurements from supernova-ejecta deposits on Earth.

Attosecond nonlinear polarization and light–matter energy transfer in solids

Abstract: Petahertz-bandwidth metrology is demonstrated in the measurement of nonlinear polarization in silica. Recent years have seen an increased interest in light–matter interactions in solid-state systems at ultrafast timescales. Ferenc Krausz and colleagues study the nonlinear polarization of silica in response to intense infrared light fields with a spectroscopy method in the attosecond time range. The method makes it possible to unravel details of the reversible and irreversible energy exchange between infrared light and electrons and points to the feasibility of using light-based switching techniques for signal processing in solid-state devices above 100 terahertz. Electric-field-induced charge separation (polarization) is the most fundamental manifestation of the interaction of light with matter and a phenomenon of great technological relevance. Nonlinear optical polarization1,2 produces coherent radiation in spectral ranges inaccessible by lasers and constitutes the key to ultimate-speed signal manipulation. Terahertz techniques3,4,5,6,7,8 have provided experimental access to this important observable up to frequencies of several terahertz9,10,11,12,13. Here we demonstrate that attosecond metrology14 extends the resolution to petahertz frequencies of visible light. Attosecond polarization spectroscopy allows measurement of the response of the electronic system of silica to strong (more than one volt per angstrom) few-cycle optical (about 750 nanometres) fields. Our proof-of-concept study provides time-resolved insight into the attosecond nonlinear polarization and the light–matter energy transfer dynamics behind the optical Kerr effect and multi-photon absorption. Timing the nonlinear polarization relative to the driving laser electric field with sub-30-attosecond accuracy yields direct quantitative access to both the reversible and irreversible energy exchange between visible–infrared light and electrons. Quantitative determination of dissipation within a signal manipulation cycle of only a few femtoseconds duration (by measurement and ab initio calculation) reveals the feasibility of dielectric optical switching at clock rates above 100 terahertz. The observed sub-femtosecond rise of energy transfer from the field to the material (for a peak electric field strength exceeding 2.5 volts per angstrom) in turn indicates the viability of petahertz-bandwidth metrology with a solid-state device.