Search Results
Competing Inversion-Based Lasing and Raman Lasing in Doped Silicon
2018, Pavlov, S. G., Deßmann, N., Redlich, B., van der Meer, A. F. G., Abrosimov, N. V., Riemann, H., Zhukavin, R. Kh., Shastin, V. N., Hübers, H.-W.
We report on an optically pumped laser where photons are simultaneously generated by population inversion and by stimulated Raman scattering in the same active medium, namely crystalline silicon doped by bismuth (SiBi). The medium utilizes three electronic levels: ground state [|1
Quantum fluctuations of charge order induce phonon softening in a superconducting cuprate
2021, Huang, H.Y., Singh, A., Mou, C.Y., Johnston, S., Kemper, A.F., van den Brink, J., Chen, P.J., Lee, T.K., Okamoto, J., Chu, Y.Y., Li, J.H., Komiya, S., Komarek, A.C., Fujimori, A., Chen, C.T., Huang, D.J.
Quantum phase transitions play an important role in shaping the phase diagram of high-temperature cuprate superconductors. These cuprates possess intertwined orders which interact strongly with superconductivity. However, the evidence for the quantum critical point associated with the charge order in the superconducting phase remains elusive. Here we show the short-range charge orders and the spectral signature of the quantum fluctuations in La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) near the optimal doping using high-resolution resonant inelastic X-ray scattering. On performing calculations through a diagrammatic framework, we discovered that the charge correlations significantly soften several branches of phonons. These results elucidate the role of charge order in the LSCO compound, providing evidence for quantum critical scaling and discommensurations associated with charge order.
Synthetic gravitational horizons in low-dimensional quantum matter
2021, Morice, C., Moghaddam, A., Chernyavsky, D., van Wezel, J., van den Brink, J.
We propose a class of lattice models realizable in a wide range of setups whose low-energy dynamics exactlyreduces to Dirac fields subjected to (1+1)-dimensional [(1+1)D] gravitational backgrounds, including (anti-)deSitter space-time. Wave packets propagating on the lattice exhibit an eternal slowdown for power-law position-dependent hopping integralst(x)∝xγwhenγ 1, signaling the formation of black hole event horizons. Forγ<1 instead the wave packets behave radically different and bounce off the horizon. We show that the eternalslowdown relates to a zero-energy spectral singularity of the lattice model and that the semiclassical wave packetstrajectories coincide with the geodesics on (1+1)D dilaton gravity, paving the way for new and experimentallyfeasible routes to mimic black hole horizons and realize (1+1)D space-times as they appear in certain gravitytheories.