Measuring Unruh radiation from accelerated electrons
The European Physical Journal C Springer Science and Business Media LLC 84:5 (2024) 475
Abstract:
<jats:title>Abstract</jats:title><jats:p>Detecting thermal Unruh radiation from accelerated electrons has presented a formidable challenge due not only to technical difficulties but also for lack of conceptual clarity about what is actually seen by a laboratory observer. We give a summary of the current interpretations along with a simpler heuristic description that draws on the analogy between the Unruh effect and radiation from a two-level atomic system. We propose an experiment to test whether there is emission of thermal photons from an accelerated electron.</jats:p>
Multimessenger measurements of the static structure of shock-compressed liquid silicon at 100 GPa
Physical Review Research 6, 023144 (2024)
Abstract:
The ionic structure of high-pressure, high-temperature fluids is a challenging theoretical problem with applications to planetary interiors and fusion capsules. Here we report a multimessenger platform using velocimetry and in situ angularly and spectrally resolved x-ray scattering to measure the thermodynamic conditions and ion structure factor of materials at extreme pressures. We document the pressure, density, and temperature of shocked silicon near 100 GPa with uncertainties of 6%, 2%, and 20%, respectively. The measurements are sufficient to distinguish between and rule out some ion screening models.
Multimessenger measurements of the static structure of shock-compressed liquid silicon at 100 GPa
Physical Review Research American Physical Society (APS) 6:2 (2024) 023144
Speed of sound in methane under conditions of planetary interiors
Physical Review Research American Physical Society (APS) 6:2 (2024) l022029
Speed of sound in methane under conditions of planetary interiors
Physical Review Research 6, L022029 (2024)
Abstract:
We present direct observations of acoustic waves in warm dense matter. We analyze wave-number- and energy-resolved x-ray spectra taken from warm dense methane created by laser heating a cryogenic liquid jet. X-ray diffraction and inelastic free-electron scattering yield sample conditions of 0.3 ± 0.1 eV and 0.8 ± 0.1 g/cm-3, corresponding to a pressure of ~13 GPa. Inelastic x-ray scattering was used to observe the collective oscillations of the ions. With a highly improved energy resolution of ~50 meV, we could clearly distinguish the Brillouin peaks from the quasielastic Rayleigh feature. Data at different wave numbers were utilized to derive a sound speed of 5.9 ± 0.5 km/s, marking a high-temperature data point for methane and demonstrating consistency with Birch's law in this parameter regime.