Zobrazeno 1 - 10
of 50
pro vyhledávání: '"Grecchi, Vincenzo"'
Autor:
Giachetti, Riccardo, Grecchi, Vincenzo
We consider a family of quantum Hamiltonians $H_\hbar=-\hbar^2\,(d^2\!/dx^2) +V(x)$, $x\in\mathbb{R},$ $\hbar>0,$ where $V(x)=i(x^3-x)$ is an imaginary double well potential. We prove the existence of infinite eigenvalue crossings with the selection
Externí odkaz:
http://arxiv.org/abs/1607.00190
Autor:
Giachetti, Riccardo, Grecchi, Vincenzo
We consider a \textit{PT}-symmetric cubic oscillator with an imaginary double well. We prove the existence of an infinite number of level crossings with a definite selection rule. Decreasing the positive parameter $\hbar$ from large values, at a valu
Externí odkaz:
http://arxiv.org/abs/1506.01637
Autor:
Giachetti, Riccardo, Grecchi, Vincenzo
We make a nodal analysis of the processes of level crossings in a model of quantum mechanics with a PT-symmetric double well. We prove the existence of infinite crossings with their selection rules. At the crossing, before the PT-symmetry breaking an
Externí odkaz:
http://arxiv.org/abs/1410.8460
Autor:
Grecchi, Vincenzo, Martinez, André
We prove the simplicity and analyticity of the eigenvalues of the cubic oscillator Hamiltonian,$H(\beta)=-d^2/dx^2+x^2+i\sqrt{\beta}x^3$,for $\beta$ in the cut plane $\C_c:=\C\backslash (-\infty, 0)$. Moreover, we prove that the spectrum consists of
Externí odkaz:
http://arxiv.org/abs/1201.2797
We consider the vibrational energy levels of the first two electronic states of the molecule ion $H_2^+$. The Born-Oppenheimer method applied to the case of the Stark effect on a $H_2^+$-like molecule gives existence of sharp resonances localized in
Externí odkaz:
http://arxiv.org/abs/1009.4675
Autor:
Giachetti, Riccardo, Grecchi, Vincenzo
Publikováno v:
J.Phys.A44:095308,2011
We consider the one-dimensional Dirac equation for the harmonic oscillator and the associated second order separated operators giving the resonances of the problem by complex dilation. The same operators have unique extensions as closed PT-symmetric
Externí odkaz:
http://arxiv.org/abs/1005.3633
Autor:
Grecchi, Vincenzo, Sacchetti, Andrea
In this paper we review some known results on the motion of Bloch Oscillators in the crystal momentum representation. We emphasize that the acceleration theorem, as usually stated by most of the authors, is incomplete, but in the case of pure Bloch s
Externí odkaz:
http://arxiv.org/abs/quant-ph/0506057
Autor:
Grecchi, Vincenzo, Sacchetti, Andrea
Here, we show how the molecular structure appears and becomes stable for supercritical physical conditions. In particular we consider, for the ammonia molecule in a gas, a simple model based on a standard non-linear double-well Schroedinger equation
Externí odkaz:
http://arxiv.org/abs/math-ph/0210062
Autor:
Giachetti, Riccardo1 riccardo.giachetti@unifi.it, Grecchi, Vincenzo2 vincenzo.grecchi@unibo.it
Publikováno v:
International Journal of Theoretical Physics. Nov2015, Vol. 54 Issue 11, p3889-3899. 11p.
Autor:
Grecchi, Vincenzo1 vincenzo.grecchi@unibo.it, Martinez, André1 andre.martinez@unibo.it
Publikováno v:
Communications in Mathematical Physics. Apr2013, Vol. 319 Issue 2, p479-500. 22p.