Dr. Jasmina Dugic, Facultatea de Stiinte, Universitatea Nis (Serbia)
Title: Large-molecules conformational stability and transitions: a decoherence approach
The molecules configuration is generally considered in chemistry as a ‘classical’ variable. In biochemistry, some configurations (conformations) are considered substantial e.g. for the operations in the energy transport or molecular recognition. The famous ‘Levinthal’s paradox’ (the protein folding problem) is therefore typically considered classically – by the standard statistical mechanics methods. Despite the significant progress, the resolution of the problem is not yet at hand. Here I will sketch a solution-in-principle based on the occurrence of decoherence, treating the molecular configurations as a quantum mechanical variable subject to nontrivial environmental influence.
Dr. S. Stoica, DFT
Faza 2/2011 a proiectului PN 09370106,
avand titlul: “Studiul fenomenelor fizice prin metode teoretice si computationale in domenii de frontiera”, Director proiect S. Stoica
Titlul fazei: “Reactii cu schimb de sarcina in nuclee cu A=64 cu aplicatii in astrofizica”
Rezumat.
Obiectivul fazei este de a testa predictiile teoretice pentru tariile tranzitiilor GT care sunt utilizate pentru a genera rate de captura
electronica ce au relevanta in evolutia stelelor. Rezultatele experimentale obtinute in reactia (t, 3H) la ciclotronul de la NSCL-Michigan, vor fi comparate cu calculele effectuate cu codul de ShM NUSHELL, folosind interactii efective in patura pf GXPF1A si KB3G. Mai departe sunt calculate ratele de captura electronica (EC) pe starea fundamental a 64Zn relevante pentru descrierea evolutiei stelare si discutat dezacordul dintre datele experimentale si cele teoretice.
Theodor Sandulescu, Fizician, cercetator stiintific, Institutul de Oncologie din Bucureşti
Titlu: "Efectul interactiunii structurilor biologice cu campul electromagnetic in oncologie"
Rezumat:
Exista posibilitatea unei legaturi biunivoce intre structuri cheratinice (par, unghii, etc;) si organismul de la care au fost prelevate. Se constata efectul radiatiilor electromagnetice de inalta frecventa (GHz) asupra structurii cheratinice, rezultand eliminarea tumorilor la sobolanii Wistar grefati cu hepatom malign, distanta intre proba iradiata si sobolan fiind de aproximativ 50 m, iar procentul vindecarii aproximativ 60%. Se avanseaza ipoteza unei terapii de acest fel si in tratamentul afectiunilor maligne la om.
Dr. Dragos-Victor Anghel
Department of Theoretical Physics, Horia Hulubei National Institute
for Physics and Nuclear Engineering
Titlul: "Glassy properties of mesoscopic systems and disordered crystals"
Rezumat:
The low temp erature acoustic and thermal prop erties of amorphous, glassy materials are remarkably similar and they can b e explained to a large extent by assuming that the material contains a large numb er of dynamic defects. These dynamic defects are tunneling systems and are modeled by an ensemble of two-level systems (TLS) [1, 2]. Crystals with defects{with a large enough amount of disorder{exhibit also glass-like prop erties, but these prop erties are not so universal and, even more, they are not isotropic. In Ref. [3] we prop osed a mo del for the interaction of two-level systems with arbitrary strain elds, which we then applied to calculate the thermal properties and phonon scattering in nanoscopic membranes at low temp eratures [4]. Here we shall show how we apply the same mo del calculate the interaction between TLSs in amorphous materials and to explain the anisotropy of the glass-like prop erties of disordered crystals and [5, 6, 7, 8]
References
[1] W. A. Phillips, J. Low Temp. Phys. 7 , 351 (1972).
[2] P. W. Anderson, B. I. Halp erin, and C. M. Varma, Phil. Mag. 25, 1 (1972).
[3] D. V. Anghel, T. Kuhn, Y. M. Galp erin, and M. Manninen, Phys. Rev. B 75, 064202 (2007).
[4] T. Kuhn, D. V. Anghel, Y. M. Galp erin, and M. Manninen, Phys. Rev. B 76, 165425 (2007).
[5] D. V. Anghel and D. V. Churo chkin, Phys. Rev. B 78, 94202 (2008).
[6] D. V. Anghel and D. Churo chkin, Europhys. Lett. 83, 56004 (2008).
[7] D. V. Anghel and D. V. Churo chkin, J. Pyhs.: Conf. Series 150 , 012002 (2008).
[8] D. V. Anghel, Rom. J. Phys. 54 , 65 (2009).
Titlul: Proprietati vitroase ale sistemelor mesoscopice. (Faza 2/2011 - Proiect Nucleu PN 09 37 01 02/2009,
Responsabil faza: Dr. Dragos Anghel)
Rezumat:
Se va studia interactia dintre sistemele cu doua nivele in solide vitroase, folosindu-se un model nou de interactiune. Se vor determina proprietatile fizice ale solidelor vitroase, in mod special in sisteme mesoscopice, prin investigarea efectelor de dimensiune finita.
Prof. Vladimir Gerdjikov
Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences, Sofia, Bulgaria
Titlul: "On the soliton interactions and complete integrability of a class of vector nonlinear Schroedinger equations"
Rezumat: The N- soliton interactions of the classes of vector (VNLS) equations related to the BD.I-type symmetric spaces SO(2r+1)/SO(2)xO((2r-1) are analyzed. The VNLS models are known to describe Bose-Einstein condensates provided the scattering lengths of atoms are specifically chosen and an one-dimensional approximation is possible. We prove that these VNLS models can be treated as an infinite dimensional completely integrable Hamiltonian structures. To this end we derive the explicit form of its action-angle variables.
Prof. Liviu Movileanu1,2
1Department of Physics, Syracuse University, 201 Physics Bldg., Syracuse, New York 13244-1130, USA
2Syracuse Biomaterials Institute, Syracuse University, 121 Link Hall, Syracuse, New York 13244, USA
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Titlul: "Engineered Nanopores for Single-molecule Science"
Abstract:
A nanopore may act as an amazingly versatile single-molecule probe that can be employed to reveal several important biophysical features of biomolecules. The underlying principle of nanopore probe techniques is outrageously simple: the application of a voltage bias across an electrically insulated membrane enables the measurement of a tiny picoamp-scale transmembrane current through a single hole of nanometer size, called a nanopore. Each molecule, translocating through the nanopore, produces a distinctive current blockade, the nature of which depends on its biophysical properties as well as the molecule-nanopore interaction. Such an approach proves to be quite powerful, because single small molecules and biopolymers are examined at very high spatial and temporal resolutions. I will discuss our recent work that provided a mechanistic understanding of the forces that drive translocation through a nanopore. These measurements facilitate the detection and exploration of the conformational fluctuations of single molecules and the energetic requirements for their transition from one state to another.
Dl. Vahid Mirzaei,
Universitatea Mashad Iran
Titlul: "Ternary fission of 252CF within the liquid drop model" , Raport de stagiu in cadrul IFIN-HH
Rezumat:
S-a investigat procesul de fisiune ternara. Au fost comparati timpii de viata obtinuti in fisiunea spontana a 252Cf pentru sisteme binare si ternare.
Dr M. Mirea, DFT IFIN
Titlul: "Masa efectiva cranking dependenta de energia de excitare."
Raport proiect IDEI 512
S-a obtinut o noua formula pentru masa efectiva cranking pornindu-se de la ecuatiile de imperechere dependente de timp. Cu acest formalism
se poate evidentia dependenta inertiei nucleare de energia de disipare. In aproximatia adiabatica, utilizand formalismul BCS, formula obtinuta se reduce la formula cranking clasica.
Dr. Cezar Condeescu, DFT
"D-brane models and non-perturbative vacuum destabilization"
Abstract.
Some general properties of models with magnetized/intersecting D-branes will be presented. In this context we consider non-perturbative effects generated by Euclidean brane instantons. We analyze the process of string vacuum destabilization due to instanton induced superpotential couplings which depend linearly on charged fields. These non-perturbative instabilities result in potentials for the D-brane moduli and lead to processes of D-brane recombination, motion and partial moduli stabilization at the non-perturbative vacuum. Phenomenological applications include breaking hidden sector gauge groups, open string moduli stabilization and supersymmetry breaking. The results suggest that breaking supersymmetry by Polonyi-like models in string theory is more difficult than expected.
Dr. Calin Lazaroiu, DFT
"String theory, D-branes, topological defects and higher categories"
Abstract.
Two-dimensional topological field theories with D-branes and/or with one-dimensional defects admit an axiomatic description which connects them to the formalism of ordinary and higher category theory.
Dr. Catalina Renata Jora
Grupul de Fizica Teoretica, Universitatea Autonoma din Barcelona (Spania)
Titlu: "An implementation of the permutation symmetry into the electroweak theory"
Abstract:
Recent experimental data suggest that the leptonic mixing matrix, one of the chief unsolved problems in elementary particle physics, is very close to the so-called "tribimaximal form". Such a structure is natural in the context of permutation symmetry. Inspired by this we implement the S3 group as a zeroth order approximation into the electroweak theory and S2 subgroups of it as first order and second order perturbations.
IPN, Université Paris-Sud, Orsay
Titlul: "Determination of local energy density functionals from Brueckner-Hartree-Fock calculations"
Rezumat:
"The Skyrme-type energy density functionals (EDF) are very widely used for building mean field models of nuclear matter and finite nuclei. Their parameters are usually directly determined by fitting nuclear observables. In this work we attempt to obtain these parameters by relating them to Brueckner-Hartree-Fock (BHF) results obtained in infinite nuclear matter with realistic two-body and three-body forces. These ab initio constraints are supplemented by additional constraints on binding energies of selected nuclei. In this way we can build new Skyrme-type EDF which have a microscopic, ab initio foundation. These EDF can describe properties of finite nuclei (ground states and giant resonances) at a quantitative level comparable with that of phenomenological Skyrme forces."
Dr. Sabin Stoica
Raport Faza nr. 1/2011 in cadrul proiectului PN 09 37 01 06/2009
“Studiul fenomenelor fizice prin metode teoretice si computationale in domenii de frontiera”
Abstract:
In lipsa unor masuratori directe experimentale, valorile constantei de cuplaj a axionilor si a masei lor pot fi constranse la un interval de valori prin considerente astrofizice si cosmologice. Limite inferioare pentru constanta de cuplaj a axionilor cu nucleonii se pot obtine si din cunoasterea ratelor de emisie a axionilor din stele neutronice, in procesul de racire a acestora. Obiectul fazei il constituie obtinerea de valori cat mai precise pentru ratele de emisie ale axionilor in stele neutronice din procese de bremsstrahlung nucleonic, prin includerea intr-un mod consistent a efectelor nucleare provenite din utilizarea unui potential nucleon-nucleon cu schimb de unul si doi pioni (OPEP si TPEP) in aproximatia Born.
Dr. Paula Gina Isar, Institute for Space Sciences, ISS, Bucharest, Institute of Nuclear Physics KIT Karlsruhe
Titlul: "Ultra High Energy Cosmic Rays Physics: Status and Perspective"
Rezumat: Cosmic particles can reach breathtaking energies, far beyond reachable energies at manmade accelerators. Worldwide, different types of detectors have been deployed to facilitate their observations in different media (air, water, ice). However, items like, "from where do they come from, how do they survive to reach ground at such enormous energies, what can we learn from them", are only a few of the addressed questions in Ultra High Energy Cosmic Rays Physics. Status and perspective of this research field will be outlined in the talk.
I. Silisteanu, A.I. Budaca, faza proiect nucleu
Titlul fazei: Studiul dinamicii reactiilor nucleare si al mecanismelor de producere si dezintegrare a elementelor supragrele.
Abstract
The alpha-decay is considered from the viewpoint of the many body features of internal nuclear motion and the theory of resonance reactions. The alpha-half-lives are derived from clustering and scattering amplitudes given by self-consistent nuclear models for the nuclear shell structure and reaction dynamics. Calculations are performed for superheavy nuclei with Z=102-120 using: only the measured E values, microscopic (shell model) or macroscopic (one body) cluster formation amplitudes and, resonance scattering amplitudes. Theoretical results for half-lives are compared to data and empirical estimates.
ALGEBRAIC METHODS OF MANY-BODY SYSTEMS
Boyka Aneva Bulgarian Academy of Sciences
Sandpile models describing systems with self-organized criticality have received a lot of attention due to the wide range of applications in diverse areas. Despite of their simplicity, due to the large number of elements there are difficulties in obtaining complete analytical solutions. However, the establishment of the Abelian property in the critical height models enhanced the derivation of some important results in the stationary state. In particular, the deterministic sandpile models were analytically solved by applying an Abelian algebra approach. It has been shown that they belong to a special universality class whose critical exponents are exactly known. Directed sandpile models with stochastic dynamics were studied as well. Numerical calculations have shown that they belong to a different universality class. A new approach to the analytical treatment of directed avalanches has recently been suggested. It is based on the study of directed Abelian algebras on two-dimensional acyclic lattices. We have applied this approach by using a simpler toppling rule which is more convenient for theoretical study to find the maximum current of particles at a given time and the maximum value of the height of each site.
Titlul: Tratarea matriciala a sistemelor optice si a fasciculelor laser
Rezumat:
Lucrarea prezinta o teorie inchegata si cu rezultate originale, in primul ordin de aproximatie, a sistemelor optice si a fasciculelor laser, folosind matrici reale 2x2 si 4x4. Un sistem optic realizabil fizic e reprezentat de o matrice simplectica, cu elemente reale, iar un fascicul laser e reprezentat de o matrice reala, pozitiv definita si simetrica. Tratarea acopera marea majoritate a cazurilor intalnite in practica. Se abordeaza atat sistemele optice cat si fasciculele ca sisteme fizice si se aplica concepte de baza din teoria sistemelor pentru a dezvolta teoria propagarii si modificarii fasciculelor prin sisteme optice, cum sunt: analiza, sinteza, clasificarea si identificarea sistemelor. Teoria prezentata permite atat intelegerea aprofundata a proprietatilor sistemelor optice si a fasciculelor laser, cat si dezvoltarea de concepte noi, cu aplicatii directe in obtinerea unor sisteme optice noi si in caracterizarea si masurarea unor tipuri noi de fascicule. In particular, se prezinta o metoda generala de sinteza a oricarui sistem optic fizic realizabil, precum si invarianti generalizati ai fasciculelor la propagarea acestora prin sisteme optice si o clasificare intrinseca si geometrica a fasciculelor laser.
Titlul: A single-particle model for two-body systems and applications
Rezumat:
We develop a consistent single-particle model of two-body systems at the classical, quantum non-relativistic and quantum relativistic levels. The
model is based on the replacement of the two-body potential by two suitable single-particle potentials which demand the splitting of the Hamilton function in two similar single-particle Hamilton functions corresponding to the real particles in external potentials. The equations of motion are individually solved and, in order to yield the image of a bound system, the solutions are required to satisfy some constraints derived from Newton's laws. As a result, the system is represented by two real particles with correlated coordinates, individually bound to a centre of forces which coincides with the centre of mass and the sum of particle energies in the rest frame is equal to the energy of the particle with the reduced mass in the old representation. The quantization procedure is individually applied to the single-particle systems: the individual position and momentum variables are replaced by the corresponding operators and the particles are being assigned individual wave functions which satisfy similar Schroedinger equations. The wave function of the bound system is a suitable product of individual wave functions and the sum of the eigenvalues of the single-particle Hamiltonians is equal to the eigenvalue of the Hamiltonian associated with the particle with the reduced mass if the arguments of the solution to the two-body problem satisfy a constraint similar to the classical one. The model is easily extended to a relativistic level by replacing the kinetic terms in the individual Schroedinger Hamiltonian with free Dirac or Klein-Gordon Hamitonians. In this form the model enabled us to obtain the generic expressions of meson electromagnetic and semi-leptonic form factors as
sums of the individual contributions of the quark and of the antiquark.
Dr. Liliana Micu, DFT IFIN-HH
Titlul: A single-particle model for two-body systems and applications
Rezumat:
We develop a consistent single-particle model of two-body systems at the classical, quantum non-relativistic and quantum relativistic levels. The
model is based on the replacement of the two-body potential by two suitable single-particle potentials which demand the splitting of the Hamilton function in two similar single-particle Hamilton functions corresponding to the real particles in external potentials. The equations of motion are individually solved and, in order to yield the image of a bound system, the solutions are required to satisfy some constraints derived from Newton's laws. As a result, the system is represented by two real particles with correlated coordinates, individually bound to a centre of forces which coincides with the centre of mass and the sum of particle energies in the rest frame is equal to the energy of the particle with the reduced mass in the old representation. The quantization procedure is individually applied to the single-particle systems: the individual position and momentum variables are replaced by the corresponding operators and the particles are being assigned individual wave functions which satisfy similar Schroedinger equations. The wave function of the bound system is a suitable product of individual wave functions and the sum of the eigenvalues of the single-particle Hamiltonians is equal to the eigenvalue of the Hamiltonian associated with the particle with the reduced mass if the arguments of the solution to the two-body problem satisfy a constraint similar to the classical one. The model is easily extended to a relativistic level by replacing the kinetic terms in the individual Schroedinger Hamiltonian with free Dirac or Klein-Gordon Hamitonians. In this form the model enabled us to obtain the generic expressions of meson electromagnetic and semi-leptonic form factors assums of the individual contributions of the quark and of the antiquark.
