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Showing 1 to 20 of 46 for “"collective modes"”.
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Ultrafast terahertz spectroscopy and control of collective modes in semiconductors
… of semiconductor physics and in particular of collective mode excitations in semiconductors. We detect and analyze THz radiation emitted by these collective modes to reveal the underlying physics of many-body interactions. We review a design, implementation and characterization of our ultrafast …
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Collective modes of semiconductors and unconventional metals with intertwined orders
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-05-01
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Dynamic polarizability and collective modes in narrow-band electron systems
… of these systems. Strong interactions alter the collective charge dynamics in a number of interesting ways, in particular by stiffening the frequency-momentum dispersion of surface plasmons and making it much stronger than that of the underlying narrow-band carriers. Strongly dispersing plasmons …
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Modeling protein flexibility using collective modes of motion: Applications to drug design
… representation that captures the dominant modes of motions of proteins. For a medium-sized protein this corresponds to reducing a problem with a few thousand degrees of freedom to one with less than fifty. Although there is inevitably some loss in accuracy, we show that we can approximate …
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NUCLEAR COLLECTIVE MODES AT FINITE TEMPERATURE AS A PROBE OF NUCLEAR STRUCTURE AND DYNAMICS
The framework of this Thesis is the study of nuclear structure and reaction dynamics through gamma-spectroscopy measurements in fusion-evaporation reactions. The gamma emission associated with the Dynamical Dipole (DD) mode and the Giant Dipole Resonance (GDR) is a very good tool to study the role …
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Electronic collective modes in two dilute conductors with momentum-resolved electron energy-loss spectroscopy
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo terms
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Evolution of the distribution of high energy nuclei and induced collective modes in plasmas
… single-particle effects and interactions with collective modes in the plasma will be considered. Part of this research will focus on the distribution of high energy nuclei undergoing motion in unperturbed orbits. This work utilizes appropriate symmetry properties and conservation laws, …
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Collective modes in strongly correlated electron systems measured with momentum-resolved electron energy-loss spectroscopy
… about the bosonic emergent particles, or the collective modes, of a material. Momentum-resolved electron energy-loss spectroscopy (M-EELS) can measure χ(q,ω) of strongly correlated materials at the low energy scales of interest. The ability to measure the momentum-dependence of the collective …
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Transport processes in well confined high temperature plasmas and collective modes in their partially ionized edged region
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1998.
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Carrier momentum relaxation in highly doped polar semiconductors and semiconductor heterostructures
… such structures. In doped polar semiconductors, collective excitations of the carriers (plasmons) and the atoms (polar phonons) couple. These coupled collective excitations affect the electrical conductivity, here quantified through the carrier mobility. In scattering events, the carriers and the …
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Phase-Coherent Drag of Plasmons in a 2D Flowing Fermi Liquid
Collective modes in electron fluids feature phase-coherent drag response under a background carrier flow, resembling the optical Fizeau drag of photons by a moving medium. Time reversal breaking due to Fermi surface polarization by the flow results in nonreciprocity: collective modes acquire a ±𝑘 …
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Ultrafast Terahertz Spectroscopy of Collective Excitations in Correlated Materials
… complex ground state phases. The lowest-energy collective excitations of a particular ground state serve as a fingerprint of the phase of matter, and revealing such collective modes can therefore provide crucial information for understanding the underlying microscopic interactions. A powerful …
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Interference of Intensity Noise in a Multimode Nd:YAG Laser
… is where there is cancellation of one or more collective modes of oscillation, which are distinct from the longitudinal modes, in the total output. Commonly lasers are studied experimentally to discriminate between models used to describe them. They are convenient since many external influences …
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Controlling and probing nonlinear collective mode dynamics in quantum materials
… In particular, the excitation of low-energy collective modes in solids—such as lattice vibrations (phonons) and spin precessions (magnons)—to large amplitudes opens fundamentally new pathways for controlling and probing material properties that are otherwise inaccessible under thermal …
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Ultrafast Terahertz Spectroscopy for the Manipulation and Elucidation of Correlated Quantum Materials
… a strong spectral weight here and many of the collective modes of insulating phases, such as phonons or magnons, occur at these energies as well. Specifically, the collective modes of two van der Waals antiferromagnets are excited coherently with the use of ultrafast optical pulses. In the …
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Cold, dense quark matter
… pattern of different quark matter phases, the collective modes associated with spontaneous chiral symmetry breaking, a possible realization of quark-hadron continuity in the color-flavor locked (CFL) quark superfluid, and the implications of these issues to quark matter equations of state, and …
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A viscoelastic hydrodynamic approach to the density fluctuations in classical liquids
… relaxation tensor by viscoelastic models, the collective modes responsible for the density and current fluctuations could be derived accordingly at small wavenumbers. Based on the examinations of two fundamental viscoelastic models, namely, the Kelvin-Voigt model and the Maxwell model, it is …
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Topological phenomena in ultracold atomic gases
… semiclassical dynamics of a wavepacket and the collective modes of an ultracold gas. We also study theoretically the dynamics of skyrmion-antiskyrmion pairs in a Bose Einstein condensate. Firstly, we propose a general method by which experiments can map the Berry curvature across the Brillouin …
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Elementary excitations in heavy-fermion superconductors
… superconductors. Finally, we study hydrodynamic collective modes associated with the rotational degrees of freedom of the p-wave or d-wave order parameter, called spin-orbit modes. These modes result in anomalous electron paramagnetic resonance and neutron scattering. In addition, they couple to …
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Universality in the Equilibration of Quenched Yukawa One Component Plasmas
… are observed, possibly indicating coupling to collective modes. Universality is demonstrated by showing that 1/Γ(t) curves taken at similar κ collapse onto the same curve when plotted vs. ω_{pi}t. We also compare our results to molecular dynamics (MD) simulations. The utility of the …
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