AREA 3QUANTUM METHODOLOGIES FOR BEAMS AND CONDENSATES

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16 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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AREA
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QUANTUM METHODOLOGIES FOR BEAMS AND CONDENSATES


S. De Nicola*,
Renato Fedele
,

C. Stornaiolo*, V. G. Vaccaro

During 2004, the group has collaborated with the following foreign scientists: Prof. Dan
Anderson, Prof. Mietek Lisak (Department of Elect
romagnetics, Chalmers University of
Technology, Göteborg, Sweden), Prof. Dusan Jovanovic (Institute of Physics, Belgrade,
Serbia & Montenegro), Prof. Margarita A. Man’ko, Prof. Vladimir I. Man’ko (Lebedev
Physical Institute, Moscow, Russia), Prof. Hans Sch
amel (Physikalisches Institut, Universität
Bayreuth, Germany), Prof. Padma K. Shukla (Institut für Theoretische Physik, Ruhr
-
Univerität, Bochum, Germany),

Controlling potential for solitons in Bose
-
Einstein condensates (BEC)

We have developed a method for

filtering and controlling different kinds of soliton states of
the Bose
-
Einstein Condensate (BEC). The analysis has been carried out by considering the
3D Gross
-
Pitaevskii (GP) equation with appropriate confining potential wells. This idea
could be realiz
ed by recently developed techniques of optically induced potentials as well as
the ones involving lithographically fabricated circuit patterns which provide electromagnetic
guides and microtraps for ultracold neutral systems of atoms in BEC experiments. Bo
th these
techniques seem to provide practically arbitrary trap potential well profiles. We expect to
study the controlled nonlinear 3D BEC dynamics, trying to find coupled transverse and
longitudinal configurations.

Localized and/or coherent structures

We
have introduced a new type of tomographic probability distribution which contains
complete information on density matrix (wave function) related to Fresnel transform of the
complex wave function. In particular, we
have

tr
ied to clarify the relation with

sy
mplectic
tomographic probability distribution as well as to give the multimode generalization of the
Fresnel tomography.


Program for 2005


We are going to

reach the following objectives:


Controlling potential method

We will try to develop a unified descr
iption of modulational instability (condensed matter,
nonlinear optics and particle accelerators). The 3D aspects of BECs (such as, oscillatory
breathers, elongation) or 3D effects related to the nonlinear propagation of both radiation and
particle beams/b
unches (such as, beam self focusing/defocusing, filamentation instability,
bunch lengthening/shortening) will be taken into account. In particular:

1.

We will develop the 3D statistical approach to modulational instability (SAMI) for BECs
on the basis of the
experimental techniques that make possible controlled soliton states
of the system by using microtraps for ultracold neutral system of atoms as well as by
using suitably shaped laser beams (optically induced potentials, extremely versatile for
the producti
on of "exotic" potentials).

2.

Controlling potential method that has been used to provide 3D controlled BECs state
will be applied to optical beams, by taking into account the very recently
-
proposed
techniques of manipulating the refractive index of integrate
d optical fiber. It is expected
to find 3D solutions that couple the longitudinal soliton states with the nonclassical
transverse state of light.

3.

Controlling potential method that has been used to provide 3D controlled BECs state
will be also applied to ch
arged
-
particle beams, by taking into account the very advanced
techniques of controlling and guiding of charged
-
particle beams/bunches (kickers, RFQ
techniques, superconductig cavities, etc.). Within the framework of TWM, it is expected
to find 3D solution
s that couple the longitudinal soliton states with the "quantumlike"
transverse state of a high intensity high
-
energy charged
-
particle beams/bunches.


Coherent instabilities

Within the framework of the Madelung fluid picture provided by the Thermal Wave Mo
del,
a hydrodynamical description of coherent instabilities that take place in the longitudinal
dynamics of a charged
-
particle coasting beam in a high
-
energy accelerating machine will be
carried out. We expect to find the coherent instability charts in the

complex plane of the
longitudinal coupling impedance beyond the deterministic approach to modulational
instability, extending the analysis to a non
-
monochromatic coasting beam with a given
thermal equilibrium distribution, thought as a statistical ensembl
e of monochromatic
incoherent coasting beams ("white" beam). In this hydrodynamical framework, it is expected
to predict the phenomenon of Landau damping without using any kinetic equation governing
the phase space evolution of the system.


Responsability
roles in national projects

-

The group belongs to a national network HALODYST devoted to the use and development
of quantum methodologies to study collective and stochastic effects in beam physics and
particle accelerators, financially supported by INFN (l
ocal coordinator: R. Fedele)

-

S. De Nicola is responsible of Unità Operativa di Napoli within the framework of the
national project FIRB “Microdispositivi Fotonici in nimbato di Litio”, financially supported
by the Italian Ministry of University and Rese
arch (MIUR).