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G. Orlandini ECT, March 16, 2007
Research Activity at the Physics Departmentof
the University of Trento
G. Orlandini ECT, March 16, 2007
9 Experimental Laboratories (33)
1 Theoretical and Computational Physics Unit: (15)
Staff: 49 Faculty 32 technicians
List of the experimental groups and Laboratories:
Atomic and Molecular Beam Laboratory (4)
Bioorganic Chemistry Laboratory (4)
Biophysics Laboratory (1)
Experimental Gravitation and Low Temperature Physics Laboratory (4)
IdEA (Hydrogen, Energy, Environment) Laboratory (6)
Nanoscience Laboratory (3)
Optical Spectroscopy Laboratory (4)
XRay Synchrotron radiation (3)
The Research activity at the Physics Department is organized into
G. Orlandini ECT, March 16, 2007
Computer simulation of classical systems Computer simulation of classical systems (R. Vallauri)(R. Vallauri)
Cold atoms, BEC Cold atoms, BEC (F. Dalfovo, S. Giorgini, L. Pitajevski, S.Stringari)(F. Dalfovo, S. Giorgini, L. Pitajevski, S.Stringari)
Theory of fund. int.: cosmology and physics of black holes Theory of fund. int.: cosmology and physics of black holes (G. Cognola, L. Vanzo, S. Zerbini)(G. Cognola, L. Vanzo, S. Zerbini)
Neural network methods for high energy physics analysis Neural network methods for high energy physics analysis (I. Lazzizzera)(I. Lazzizzera)
Chiral regime of QCD in the instanton picture Chiral regime of QCD in the instanton picture (P. Faccioli, M. Traini)(P. Faccioli, M. Traini)
Quantum Monte Carlo for many-body systems Quantum Monte Carlo for many-body systems
(E. Lipparini, F. Pederiva P. Faccioli) (E. Lipparini, F. Pederiva P. Faccioli) NPNP
NewNew:: Protein folding with Protein folding with nuclear theorynuclear theory techniques techniques Structure and reactions of few-nucleon systems Structure and reactions of few-nucleon systems
(W. Leidemann, G.Orlandini)(W. Leidemann, G.Orlandini)
Research Activities of the Theoretical and Computational Physics Unit:
G. Orlandini ECT, March 16, 2007
Chiral Regime of QCD in the Instanton Picture
The Interacting Instanton Liquid Model is used to explore how the non analytic scaling of hadronic observables predicted by chiral perturbation theory emerges from microscopic quark gluon dynamics.
The question of what properties of light hadrons are not strongly influenced by confinement and can be understood in terms of just the interactions associated to Spontaneous Chiral Symmetry Breaking is also addressed (e..g. narrow a1 and rhomeson resonances can be generated by instantoninduced chiral forces, even in the absence of confinement )
* M.Cristoforetti, P.Faccioli and M. Traini, Phys. Rev. D in press* M.Cristoforetti, P.Faccioli, M. Traini and J.W.Negele, Phys.Rev. D in press
G. Orlandini – ECT March 16, 2007
Quantum Monte Carlo for many-nucleon Quantum Monte Carlo for many-nucleon systemssystems
Development of efficient Quantum Monte Carlo algorithms (based on HubbardStratonovich transform) for nuclear Hamiltonians > exact computation of ground state ground state energies of nuclear matterenergies of nuclear matter11 and nuclei up to nuclei up to 4040CaCa with a AV6’ interaction.
In progress: addition of threebody and spinorbit terms.
Equation of state of symmetric nuclear matter modeled with the AV6’ potential computed with AFDMC and compared with BHF and FHNC calculations
1. S. Gandolfi, F. Pederiva, K.E. Schmidt, S. Fantoni, Phys. Rev. Lett., in press.
In progress: Development of a Quantum Monte Carlo algorithm for exact solution of a ChPT ChPT HamiltonianHamiltonian, including therefore explicitly subsubnuclear degrees of freedomnuclear degrees of freedom (π field), while keeping the nucleons as particle degrees of freedom.
nucleus E E/A Eexp Eexp/A
44He He 27.20(5) 6.8 28.296 7.074 27.20(5) 6.8 28.296 7.074 88He 23.6(5 2.95 31.408 3.926He 23.6(5 2.95 31.408 3.9261616O 100.7(4) 6.2 127.619 7.98 O 100.7(4) 6.2 127.619 7.98 4040Ca 272(2) 6.8 342.051 8.55 Ca 272(2) 6.8 342.051 8.55 ∞ ∞ 12.8(1) 12.8(1)
G. Orlandini – ECT March 16, 2007
Protein Folding with Nuclear Theory techniques:
STARTING OBSERVATION: protein folding problem is characterized by•Strong correlations and hardcores•Strong stochastic Fluctuations
Nuclear Physics methods may be useful
NEW APPROACH: Stochastic FokkerPlanck Eq. for protein diffusion is rewritten as a Schroedinger equation in imaginary time and the folding transition probability is represented & studied with path integral methods
Understanding protein folding using standard Molecular Dynamics is strongly limitedby computational difficulties (one would need to simulate O(1012) elementary time steps)
RESULTS: it has been shown that, in this way, one can compute in atomistic detail the most probable protein folding trajectory using available computers
* P.Faccioli, M.Sega, F.Pederiva and H.Orland, Phys. Rev. Lett. 97, 108101 (2006)* M.Sega, P.Faccioli, F.Pederiva, G Garberoglio and H.Orland, submitted to PRL.
G. Orlandini – ECT March 16, 2007
Research activity: “Structure and reactions of few-nucleon systems”
ab initio calculations of perturbation induced reactions with light nuclei, also for A > 3
specialized in:
G. Orlandini – ECT March 16, 2007
the ab initio calculation of a cross section beyond continuum threshold (few MeV) requires such a knowledge
present situation: most calculations focus on structure (bound state properties) Very little is known about continuum wave functions: VERY complicated many(few) body scattering problem! at present the problem has no viable solution for A>3
however,
Our contribution to the solution of the problem:
The Lorentz Integral Transform method (LIT)V.D.Efros, W.Leidemann and G.O. PLB 338 (1994) 130
G. Orlandini ECT, March 16, 2007
TRENTO GROUP:
W. Leidemann
G. Orlandini
Sonia Bacca (ex PhD, now at GSI)Sara Della Monaca (PhD)Mario Marchisio (ex PhD)Alessio Paris (MSc)Sofia Quaglioni (ex PhD, now at LLL)
POSTDOCS
A. Khugaev C. Reiss* M. Schwamb (also ECT)
LONG TERM COLLABORATORS
V.D. Efros (Moscow)* N. Barnea (Jerusalem, ex postdoc ECT) E.L. Tomusiak (Victoria) Doron Gazit (PhD, Jerusalem) H. Arenhövel ( Mainz)
G. Orlandini – ECT March 16, 2007
The LIT methodThe LIT method it is an it is an ab initioab initio method method for for continuumcontinuum dynamics calculationsdynamics calculations however,however, oneone does notdoes not calculate continuum statescalculate continuum states oneone doesdoes calculate calculate matrix elementsmatrix elements to continuum to continuum
states states (> (> cross sections)cross sections) it is general enough to be applied to strong as well it is general enough to be applied to strong as well
as e.m. reactions as e.m. reactions the applications so far have been for the applications so far have been for electroweak electroweak
reactions on light nuclei.reactions on light nuclei.
G. Orlandini – ECT March 16, 2007
reduces the reduces the continuumcontinuum problem to a problem to a bound statebound state problemproblem
needs needs onlyonly a “good” method for a “good” method for bound statebound state calculationscalculations
applies both to applies both to inclusiveinclusive reactions (straightforward!) reactions (straightforward!) and to and to exclusiveexclusive ones ones
has beenhas been benchmarked benchmarked in “directly solvable” systems in “directly solvable” systems A=2,3A=2,3
G. Orlandini – ECT March 16, 2007
L(σ)= ∫ dω T(ω ) K(ω,σ)
bound state method
matrix element of interest
Integral Transform method
G. Orlandini – ECT March 16, 2007
L(σ)= ∫ dω T(ω ) K(ω,σ)
bound state method
matrix element of interest
Lorentzian function
Lorentz Integral Transform method
G. Orlandini – ECT March 16, 2007
from H.Kamada et al. (18 auhors 7 groups) PRC 64 (2001) 044001
AB INITIO BOUND STATE CALCULATIONS BE of 4He (exp. 28.296 MeV)
G. Orlandini – ECT March 16, 2007
Effective Interaction in the Hyperspherical Harmonics basis
EIHH
N. Barnea, W. Leidemann, and G. Orlandini, Phys. Rev. C 61, 054001 (2000); N. Barnea, W. Leidemann, and G. Orlandini, Nucl. Phys. A {\bf 693}, 565 (2001).
G. Orlandini – ECT March 16, 2007
reaction involving 4body continuum states:
G. Orlandini – ECT March 16, 2007Gazit et al PRL 96 (2006) 112301
4He
OLD data: (γ , n) Berman et al. '80 + (γ , p) Feldman et al. '90
Total Photoabsorption Cross Section of 4He
D.Gazit et al. PRL 96 (2006) 112301
Theory: LIT + EIHH
G. Orlandini – ECT March 16, 2007Gazit et al PRL 96 (2006) 112301
NEW data:
Nilsson et al. MAXLAB Lund (2005)
Shima et al. Osaka (2005)
4He
OLD data: (γ , n) Berman et al. '80 + (γ , p) Feldman et al. '90
Total Photoabsorption Cross Section of 4He
D.Gazit et al. PRL 96 (2006) 112301
G. Orlandini – ECT March 16, 2007
LIT+ EIHH
potential dependence (larger energy range)
G. Orlandini – ECT March 16, 2007
66-Body total photodisintegration-Body total photodisintegration
Theory:
LIT+ EIHH 6Li
6He
classical GT mode
soft mode
S.Bacca et al. PRL89(2002)052502S.Bacca et al. PRL89(2002)052502
G. Orlandini – ECT March 16, 2007
comparison with experiment
6Li6He
from S.Bacca et al. PRL 89 (2002) 052502
G. Orlandini – ECT March 16, 2007
77-Body total photodisintegration-Body total photodisintegration
'75
'75
S.Bacca et al.PLB 603 (2004) 159
G. Orlandini – ECT March 16, 2007
Nuclear Theory is now “ahead” of Nuclear Experiment
More experimental activity in low energy nuclear physics badly needed !
G. Orlandini ECT, March 16, 2007
Research Activities of the Theoretical and Computational Physics Unit:
G. Orlandini ECT, March 16, 2007
Computer simulation of classical Computer simulation of classical systems systems
WaterWater interacting with interacting with lipid membraneslipid membranes
phospholipidsphospholipids
gangliosidesgangliosides
WaterWater under high pressure under high pressure
structurestructure
dynamics dynamics
−
−
M. Sega, G. Garberoglio, P. Brocca, and L. Cantu' J. Phys. Chem. B 111 p. 24842489 (2007)
G. Orlandini – ECT March 16, 2007
Theory of fundamental interactions:cosmology and physics of black holes
Dark energy problem
Investigation of the so called modified gravity models. (they generalize Einstein gravity in a natural geometrical way) . In particular: phenomenology of these models stability with respect to the de Sitter accelerated spacetime.
Derivation of Hawking radiation within “tunneling methods” A variant of the original ParikWilczek method has been introduced.Now known in literature as the “HamiltonJacobi Method” Advantages: covariance and the extension to higher dimensional rotating black holes. M. Angheben, M. Nadalini, L. Vanzo and S. Zerbini, JHEP 0505:014 (2005)M. Nadalini, L. Vanzo and S. Zerbini, J. Physics A Math. Gen. 39, 6601 (2006).
G. Cognola, E. Elizalde, S. Nojiri, S. D. Odintsov, S. Zerbini. JCAP 0502:010 (2005)
