| 1. |
- Ferrario, M., et al.
(author)
-
IRIDE : Interdisciplinary research infrastructure based on dual electron linacs and lasers
- 2014
-
In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 740, s. 138-146
-
Journal article (peer-reviewed)abstract
- This paper describes the scientific aims and potentials as well as the preliminary technical design of RUDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, technological and industrial applications. IRIDE will be a high intensity "particles factory", based on a combination of high duty cycle radio-frequency superconducting electron linacs and of high energy lasers. Conceived to provide unique research possibilities for particle physics, for condensed matter physics, chemistry and material science, for structural biology and industrial applications, IRIDE will open completely new research possibilities and advance our knowledge in many branches of science and technology. [RIDE is also supposed to be realized in subsequent stages of development depending on the assigned priorities.
|
|
| 2. |
- Basini, Martina, 1985-, et al.
(author)
-
Terahertz ionic Kerr effect : Two-phonon contribution to the nonlinear optical response in insulators
- 2024
-
In: Physical Review B. - 2469-9950 .- 2469-9969. ; 109:2
-
Journal article (peer-reviewed)abstract
- The THz Kerr effect measures the birefringence induced in an otherwise isotropic material by a strong THz pulse driving the Raman-active excitations of the systems. Here we provide experimental evidence of a sizable Kerr response in insulating SrTiO3 due to infrared-active lattice vibrations. Such a signal, named the ionic Kerr effect, is associated with the simultaneous excitation of multiple phonons. Thanks to a theoretical modeling of the time, polarization, and temperature dependence of the birefrengence, we can disentangle the ionic Kerr effect from the off-resonant electronic excitations, providing an alternative tunable mechanism to modulate the refractive index on ultrashort timescales via infrared active phonons.
|
|
| 3. |
- Maccari, Ilaria, et al.
(author)
-
Interplay of spin waves and vortices in the two-dimensional XY model at small vortex-core energy
- 2020
-
In: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 102:10
-
Journal article (peer-reviewed)abstract
- The Berezinskii-Kosterlitz-Thouless (BKT) mechanism describes universal vortex unbinding in many two-dimensional systems, including the paradigmatic XY model. However, most of these systems present a complex interplay between excitations at different length scales that complicates theoretical calculations of nonuniversal thermodynamic quantities. These difficulties may be overcome by suitably modifying the initial conditions of the BKT flow equations to account for noncritical fluctuations at small length scales. In this work, we perform a systematic study of the validity and limits of this two-step approach by constructing optimised initial conditions for the BKT flow. We find that the two-step approach can accurately reproduce the results of Monte Carlo simulations of the traditional XY model. To systematically study the interplay between vortices and spin-wave excitations, we introduce a modified XY model with increased vortex fugacity. We present large-scale Monte Carlo simulations of the spin stiffness and vortex density for this modified XY model and show that even at large vortex fugacity, vortex unbinding is accurately described by the nonperturbative functional renormalization group.
|
|
| 4. |
- Maccari, Ilaria, et al.
(author)
-
Transport signatures of fragile glass dynamics in the melting of the two-dimensional vortex lattice
- 2023
-
In: Physical Review B. - 2469-9950 .- 2469-9969. ; 107:1
-
Journal article (peer-reviewed)abstract
- In a two-dimensional superconducting vortex lattice, the melting from the solid to the isotropic liquid can occur via an intermediate phase that retains orientational correlations. The effect of such correlations on transport and their interplay with the quenched disorder remain open questions. We perform magnetotransport measurements in a wide range of temperatures and magnetic fields on a weakly pinned two-dimensional vortex system in amorphous MoGe films. While at high fields, where quenched disorder dominates, we recover the typical strong-glass behavior of a vortex liquid, at low fields the resistivity shows a clear crossover to a fragile vortex glass. Our findings, supported by numerical simulations, suggest that this is a signature of heterogeneous dynamics that arises from the presence of orientational correlations.
|
|
