Search results for " MODELLI E METODI MATEMATICI"
showing 10 items of 263 documents
All N=(8,0) AdS3 solutions in 10 and 11 dimensions
2021
We classify AdS(3) solutions preserving N = (8, 0) supersymmetry in ten and eleven dimensions and find the local form of each of them. These include the AdS(3)xS(6) solution of [1] and the embeddings of AdS(3) into AdS(4)xS(7), AdS(5)xS(5), AdS(7)/Z(k)xS(4) and its IIA reduction within AdS(7). More interestingly we find solutions preserving the superconformal algebras f4, su(1,1|4), osp(4*|4) on certain squashings of the 7-sphere. These solutions asymptote to AdS(4)xS(7) and are promising candidates for holographic duals to defects in Chern-Simons matter theories.
Can a mathematical model of mass extinctions do without environmental noise?: Comment on "Knowledge gaps and missing links in understanding mass exti…
2023
No abstract available
Universal freezing of quantum correlations within the geometric approach
2015
Quantum correlations in a composite system can be measured by resorting to a geometric approach, according to which the distance from the state of the system to a suitable set of classically correlated states is considered. Here we show that all distance functions, which respect natural assumptions of invariance under transposition, convexity, and contractivity under quantum channels, give rise to geometric quantifiers of quantum correlations which exhibit the peculiar freezing phenomenon, i.e., remain constant during the evolution of a paradigmatic class of states of two qubits each independently interacting with a non-dissipative decohering environment. Our results demonstrate from first …
Greenberger-Horne-Zeilinger-state Generation in Qubit-Chains via a Single Landau-Majorana-Stückelberg-Zener π/2-pulse
2022
A protocol for generating Greenberger-Horne-Zeilinger states in a system of (Formula presented.) coupled qubits is proposed. The Hamiltonian model assumes (Formula presented.) -wise interactions between the (Formula presented.) qubits and the presence of a controllable time-dependent field acting upon one spin only. The dynamical problem is exactly solved thanks to the symmetries of the Hamiltonian model. The possibility of generating GHZ states simulating our physical scenario under both adiabatic and non-adiabatic conditions is within the reach of the experimentalists. This aspect is discussed in detail.
H2 Molecule Driven by a Laser Field
2008
We study the single and double ionization yields and the dissociation dynamics of a one-dimensional two-electron molecule exposed to a laser pulse of intensity IL in the range 1013 − 1015 W/cm2 and photon energy hω¯L =3.18 eV. The calculations are carried out in the case of both fixed and movable nuclei. At low IL the ionization curves have a power law shape In that is interrupted by a knee at higher intensity.
Harmonic Spectra in H2⁺ in the Presence of a Laser Field
2008
Angular harmonic dependence from a 3D-H2+ Molecular Ion
2012
The time-dependent Schroedinger equation of a H2+ molecular ion in the presence of a linearly polarized laser field is numerically solved by means of a split-operator parallel code. The electron, driven by the laser electric field, emits electromagnetic radiation whose HHG spectrum (shown in Figure 1) can be finely controlled by changing the angle between the laser electric field and the molecular axis. The numerical results confirm that the structure of the spectra strongly depends on this angle. In particular the correlation between the laser orientation (with respect to the molecular axis) and the intensity of various harmonic peaks are displayed in Figure 2.
Laser induced ultrafast H2+ dinamic and attosecond generation
2012
We examine the possibility that a H2+ molecular ion driven by a linearly polarized laser field can be considered as a source of attosecond pulses. The emisseion is investigated taking into account the role of the internuclear distance and by changing the angle between the laser field and the molecular axis. We find that the attosecond pulses emission happens when the electron cloud is over one nucleus; on the contrary, when the elctron is travelling between the two nuclei the attosecond emission do not take place.