Probing warm dense lithium by inelastic X-ray scattering

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Abstract

One of the grand challenges of contemporary physics is understanding strongly interacting quantum systems comprising such diverse examples as ultracold atoms in traps, electrons in high-temperature superconductors and nuclear matter1. Warm dense matter, defined by temperatures of a few electron volts and densities comparable with solids, is a complex state of such interacting matter2. Moreover, the study of warm dense matter states has practical applications for controlled thermonuclear fusion, where it is encountered during the implosion phase3, and it also represents laboratory analogues of astrophysical environments found in the core of planets and the crusts of old stars4,5. Here we demonstrate how warm dense matter states can be diagnosed and structural properties can be obtained by inelastic X-ray scattering measurements on a compressed lithium sample. Combining experiments and ab initio simulations enables us to determine its microscopic state and to evaluate more approximate theoretical models for the ionic structure.

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Figure 1: Experimental configuration.
Figure 2: Radiation hydrodynamic simulations.
Figure 3: Best-fit analysis.
Figure 4: Calibrated scattering spectra.
Figure 5: Ion-ion structure factors.

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Acknowledgements

This work was partially supported by EPSRC grants and by the Science and Technology Facilities Council of the United Kingdom. Additional support from the US DOE and the Lawrence Livermore National Laboratory is also acknowledged. We thank the Vulcan operation, engineering and target fabrication groups for their support during the experiment.

Author information

E.G.S., G.G., B.B., R.J.C., F.Y.K., M.M.N., A.P., R.L.W. and D.R. carried out the Vulcan experiment. E.G.S., G.G., S.H.G., P.N., A.P., D.P., M.R. and M.S. carried out preparatory experiments and diagnostics development at the Lawrence Livermore National Laboratory. E.G.S., G.G., F.Y.K. and D.R. analysed the data. E.G.S., G.G. and D.O.G. wrote the paper. The simulations were carried out by D.O.G., J.V. and K.W. C.S. and G.G. designed targets used in the experiment. R.R.F., S.H.G., M.K., O.L.L., D.N., M.R. and L.v.W. provided additional experimental and theoretical support. G.G., S.H.G. and D.R. conceived the project in this paper.

Correspondence to G. Gregori.

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