Solutii analitice ale unor clase de ecuatii transcendentale ale mecanicii cuantice cu aplicatii in nanofizica
Victor Barsan
DFT / IFIN-HH
Abstract:
Sunt prezentate metode de rezolvare ale unor ecuatii transcendentale ale fizicii teoretice, in general ecuatii pentru valorile proprii ale energiei unei particule nerelativiste. Exemplele considerate se refera la functiile infasuratoare pentru electroni in banda de conductie la heterointerfete semiconductoare, la energiile starilor stationare ale unui electron intr-un punct cuantic de diferite arhitecturi, la benzile de energie ale unui fir cuantic format dintr-o succesiune de puncte cuantice cilindrice, etc. Este discutat potentialul aplicativ al acestor rezultate.
Precision predictions for testing the Standard Model at low and intermediate energies
Irinel Caprini
DFT / IFIN-HH
Abstract:
The Higgs boson of the standard model (SM) was discovered at the LHC, but no direct evidence of beyond the standard model physics has been found so far. In this context, more and more efforts are concentrated on searches for indirect evidence of new physics, through deviations from the SM predictions in precisely measured observables. I illustrate this approach with three examples from low and intermediate energies, where discrepancies between experiment and the SM calculations or differencies between the theoretical treatments exist. These are: the muon g-2, the omega-pi electromagnetic form factor and the strong coupling extracted from hadronic decays of the tau lepton. In each case I present methods proposed recently to improve the theoretical predictions.
Giant dipole oscillations and ionization of heavy atoms by intense
electromagnetic fields
Prof. Marian Apostol
DFT/IFIN-HH
Abstract:
The ”empirical” binding energy -16 Z7/3eV of heavy atoms (atomic number Z>>1) is computed by a linearized version of the Thomas-Fermi model, including a Hartree-type correction. The computations are carried out by means of a variational approach. Exchange energy and corrections to the exchange energy are also estimated. This is an updated result. It is shown that giant dipole oscillations of the electrons may be induced in heavy atoms by external electromagnetic fields in the range of moderate X-rays, which, in intense fields, may lead to ionization. There are examined anharmonicities in the giant dipole oscillations, which lead to frequeny shifts and high-order harmonics. Transitions to excited states and ionization of "peripheral" electrons are also investigated in the quasi-classical approximation for heavy atoms.
How can physical and mathematical approaches help explain fundamental problems in biology
Diana Rus
DFCTI / IFIN-HH
Abstract:
By combining methods from statistical mechanics, stochastic processes, statistical mathematics - data mining approach, mathematical biology, I’m trying to understand and find answers to fundamental questions routed in complex biological processes. In this talk I will present different models that involve approaches that are mathematical and physical driven. The processes that I will try to understand will range from epigenetic phenomena to stochastic approaches for understanding protein-protein interactions, to modeling the impact of antibacterial drugs on bacteria population dynamics. Besides if time will permit I will shortly present the future projects in which I’m about to get involved.
References:
• Diana David-Rus, Swagatam Mukhopadhyay, Joel L.Lebowitz, Anirvan Sengupta “Inheritance of epigenetic choromatin silencing”, Journal of Theoretical Biology, Volume 258, Issue 1, 7
May 2009, Pages 112-120
• Diana David-Rus “ Stochastic approaches in protein synthesis-degradation-the two interacting protein case, Digest Journal of Nanomaterials and Biostructures vol 8, Issue 3, July 2013, pp 1051-1059
• Diana David-Rus “ Mathematical framework of epigenetic DNA methylation in gene body Arabidopsis”, Digest Journal of Nanomaterials and Biostructures, vol 8, Issue.1, January 2013, pp 227-237
Pairing correlations in finite-systems within models preserving the particle number symmetry
Danilo Gambacurta
GANIL
Abstract:
Pairing correlations play a crucial role in several features of different kinds of physical systems. In particular, in nuclear systems, properties like binding energies and odd-even effects, superfluid phenomena and pair transfer mechanisms can be accurately explained only by including this kind of correlations. From a theoretical point of view, the standard description of these features is done by using BCS or HFB models which allow to describe in a simple way pairing effects. However, due to the explicit breaking of the particle number, these theories present some limitations which can be cured by using particle number projection techniques. In this talk we will show the merits of these techniques and their efficiency in the study of different properties. We will start by introducing a beyond BCS-HFB method where the effect of four quasi-particle states is included perturbatively and by restoring subsequently the particle number, an extremely good description of ground state properties is achieved [1]. We will then show the need of restoring the good particle number also in the study of excited states and in the description of pair transfer probabilities in superfluid systems [2]. After that, a full Variation After Projection at finite temperature (VAP-FT) approach which allows a proper description of the thermodynamics properties of finite systems is applied to analyze and discuss the issue of the pairing phase transition in finite systems [3]. The VAP-FT method will be employed to analyze the influence of pairing correlations on the specific heat for the 161,162Dy and 171,172Yb isotopes [4]. Finally, the role of the proton-neutron pairing will be analyzed by using a method which combines self-consistent mean-field method and shell-model techniques. Preliminary results in Z=N nuclei in the pf shell will be discussed, paying particular attention to the study of the competition between particle like pairing, neutron-proton pairing and deformation[5].
[1]D. Lacroix and D. Gambacurta Phys. Rev. C 86, 014306 (2012)
[2]D. Gambacurta and D. Lacroix Phys. Rev. C 85, 064320 (2012)
[3]D. Gambacurta and D. Lacroix Phys. Rev. C 85, 044321 (2012)
[4]D. Gambacurta, D. Lacroix and N. Sandulescu, Phys. Rev. C, 88, 034324 (2013)
[5]D. Gambacurta and D. Lacroix,``Deformation effect on the coexistence between
neutron-proton and particle like pairing in N=Z medium mass nuclei'', to be
submitted
Suppression of entanglement of two-mode Gaussian open systems
Tatiana Mihaescu
Absolventa a Facultatii de Fizica / DFT
Abstract:
We study the evolution of the entanglement of two independent bosonic modes embedded in a thermal environment, in the framework of the theory of open quantum systems. As a measure of entanglement we use the logarithmic negativity. For a non-zero temperature of the thermal reservoir the initial entangled Gaussian states become always separable in a finite time. For both initial squeezed vacuum states and squeezed thermal states we calculate the time of entanglement sudden death and analyze its dependence on temperature, squeezing parameter and mean thermal photon numbers.
Introduction to entanglement measures
Geoge Cristian Ivan
Absolvent al Facultatii de Fizica / DFT
Abstract:
We discuss the motivation for entanglement measures and present their implications for the study of quantum information. We will see how the usefulness of entanglement emerges because it allows us to overcome the LOCC constraint and present some of the measures, such as: the entanglement cost, entanglement of formation, distillable entanglement and relative entropic measures.
Pairing, quarteting and and Wigner energies in N = Z nuclei
Nicolae Sandulescu
DFT/IFIN-HH
Seminar de faza NUCLEU 09 37 01 02, 2/2014
Descrierea corelatiilor de pairing proton-neutronice izovectoare si izoscalare in nuclee cu N=Z
Abstract:
The common treatment of proton-neutron pairing in N=Z nuclei relies on Cooper pairs and mean-field BCS-type models. However, the nuclear interaction can induce, through the isospin conservation, quartet correlations of alpha type which might compete with the Cooper pairs. In fact, it can be shown that for any isovector pairing interactions the ground state of N=Z systems is accurately described not by Cooper pairs but in terms of collective quartets [1,2,3]. Cooper pairs and quartets can however coexist in isospin asymmetric systems with N>Z. In this case the ground state of the isovector pairing Hamiltonian can be described with high precision as a condensate of alpha-like quartets to which it is appended a condensate of Cooper pairs built with the excess neutrons [2]. Using the quartet approach it will be shown that the izovector pairing correlations are able to provide a good description of experimental data on symmetry and Wigner energies [4], which is not the case for BCS-like calculations.
1.N. Sandulescu, D. Negrea, J. Dukelski, C. W. Johnson Phys. Rev. C85, 061303 (R) (2012)
2. N. Sandulescu, D. Negrea, C. W. Johnson Phys. Rev. C86, 041302 (R) (2012)
3. M. Sambataro and N. Sandulescu Phys Rev. C88, 061303 (R)(2013)
4. D. Negrea and N. Sandulescu Phys. Rev. C90, 024322 (2014)
Multiphoton interference - first, second, and higher orders
Prof. Gunnar Bjork
Royal Institute of Technology, Stockholm, Suedia
Abstract:
For the common man, the word laser is intimately connected with the word coherence and interference. The irony is that the most commonly seen interference, amplitude interference, or in scientific terms "first order interference", does not distinguish laser light from, e.g., thermal light or any other source of classical light. It is only when one looks at the intensity interference, that is "second order interference", one can distinguish laser light from thermal light. In the talk I will discuss interference of different orders and how to produce higher order interferences from measurement post-selection. I will also show how one can engineer different non-sinusoidal interference patters such as rectangle and saw-tooth patterns.
The quest for the kings of quantumness
Prof. Luis Lorenzo Sanchez Soto
University of Madrid, Spain
Abstract:
We capitalize on a multipolar expansion of the polarization density matrix, in which multipoles appear as the successive moments of the Stokes variables. When all the multipoles up to a given order K vanish, we can properly say that the state is Kth-order unpolarized, as it lacks of any polarization information to that order. First-order unpolarized states coincide with the corresponding classical ones, whereas unpolarized to any order tally with the quantum notion of fully invariant states. In between these two extreme cases, there is a rich variety of situations that are explored here and show that they are the most quantum states.
Description of the chiral bands in 188,190Os
Seminar de faza nr 1/2014 Nucleu - ELI
A. A. Raduta si C. M. Raduta
DFT/IFIN-HH
Abstract
To a phenomenological core described by the Generalized Coherent State Model a set of interacting particles are coupled. Among the particle-core states one identifies a finite set which have the property that the angular momenta carried by the proton and neutron quadrupole bosons and the particles respectively, are mutually orthogonal. The magnetic properties of such states are investigated. All terms of the model Hamiltonian satisfy the chiral symmetry except for the spin-spin interaction. There are four bands of two quasiparticle-core dipole states type, which exhibit properties which are specific for magnetic twin bands. Application is made for the isotopes 188, 190Os. The proposed theory is the first on the market devoted to the chiral bands in even-even nuclei.
Quest for laser driven experiments at ELI-NP
Dr. Daniel Ursescu
Laser activities leader @ ELI-NP / IFIN-HH
Abstract
The ELI-NP (Extreme Light Infrastructure -Nuclear Physics) facility, currently under construction in Magurele, Romania, will make possible experiments with lasers peak powers of 100TW, 1PW and 10PW and corresponding intensities up to the range of 10^23W/cm2. The initial laser driven experiments are grouped in four main research directions: laser driven nuclear physics, studies of strong field quantum electrodynamics, combined laser-gamma beam experiments and applications related to materials in radiation fields. The facility will thus take advantage of the ultrashort time scales of secondary radiation pulses and the relatively broadband spectrum of radiation, complementary to the traditional nuclear physics research laboratories.
Constrangeri asupra parametrilor de masa ai neutrinilor deduse din analiza dezintegrarii beta duble
- raport de faza Nucleu PN 09 37 0102/2009 -
Andrei Neacsu
DFT/IFIN-HH
Obiective:Se vor obtine noi constrangeri asupra parametrilor de masa ai neutrinilor din analiza modului de dezintegrare beta dubla fara neutrini in cazul mai multor nuclee de interes experimental. Vor fi folosite, pe de o parte, cele mai recente masuratori ale timpilor de viata raportate in literatura si, pe de alta parte, noi valori pentru marimile teoretice care intra in componenta formulelor timpilor de viata: factori de faza si elemente de matrice nucleare. Noile constrangeri vor folosi atat la intelegerea sensibilitatii experimentelor actuale pentru masurarea dezintegrarii beta dubla fara neutrini, cat si la estimarea mai precisa a posibilitatii experimentelor viitoare de a investiga zona de "ierarhie inversa" pentru masa neutrinilor.
Abstract:
In cadrul fazei a fost efectuat un studiu al dezintegrarii beta duble (0νββ) care ne poate furniza informatii valoroase asupra proprieatilor neutrinilor, in mod deosebit, masa absoluta a neutrinului electronic. Pentru aceasta, am actualizat contrangerile prezente asupra paramerilor de masa ai neutrinilor, obtinuti din analiza dezintegrarii beta dubla a nucleelor de inters experimental. Folosim cele mai noi rezultate petru factorii de faza (phase space factors - PSFs) si elemente de matrice nucleare (nuclear matrix elements - NMEs), precum si limitele experimentale de viata cunoscute. In cazul PSFs, folosim valori obtinute cu o metoda imbunatatita raportata foarte recent. Pentru NMEs utilizam valori selectionate din literatura pentru fiecare caz in parte, beneficiind de consensul la care s-a ajuns in comunitatea stiintifica privind anumite ingrediente incluse in calculul acestora. Asadar, incercam sa micsoram variatia valorilor NMEs calculate prin diferite metode si, astfel, sa reducem incertitudinile in obtinerea limitelor pentru masa neutrinului de tip Majorana. Rezultatele noastre pot fi utile pentru a avea o imagine actualizata asupra senzitivitatilor asociate experimentelor 0νββ pentru diferit izotopi si pentru a estima cu mai mare precizie intervalul de valori pentru masele neutrinilor care pot fi explorate in experimentele viitoare de dezintegrare beta dubla.
Strictly finite-range nuclear potentials
Tamas Vertse
ATOMKI - Debrecen, Hungary
Abstract:
Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. S-matrix pole trajectories are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cut-off Woods–Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse Phys. Rev. C77, 037302 (2008). and the SS potential of Sahu and Sahu Int. J. Mod. Phys. E21, 1250067 (2012). The parameters of these latter were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a bench-mark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this bench-mark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.
A CRITICAL ANALYSIS OF THE RELATIVISTIC UNIVERSE
Stephen J. Crothers
Queensland, Australia
ABSTRACT
The black hole and the big bang contradict one another and so they are necessarily mutually exclusive. For instance, every alleged black hole universe pertains to a universe that is eternal but every alleged big bang universe is of finite age (~13.8 billion years). The black hole claimed to be predicted by General Relativity. It is surprisingly easy to prove that this is not true. Similarly it is very often claimed that Newton’s theory of gravitation also predicts the black hole, but this too is very easily proven to be erroneous – the Michell-Laplace dark body bears none of the alleged characteristics of a black hole. Despite numerous claims for discovery of black holes in their millions, nobody has ever actually found one. In addition it is not very difficult to prove that General Relativity violates the usual conservation of energy and momentum and is therefore in conflict with experiment on a fundamental level. The Cosmic Microwave Background (CMB) is a mainstay of big bang cosmology. However, no monopole signal has ever been detected outside the influence of Earth, for the very reason that Earth is the actual source of the signal. The COBE, WMAP and Planck satellites will be discussed in detail. None of these satellites have actually determined the temperature of the Universe or detected anisotropies in the so-called CMB. This has direct bearing on recent reports that the BICEP2 telescope has detected Einstein gravitational waves in polarisations of the ‘CMB’. Finally, breaking news concerning the invalidity of Kirchhoff’s Law of Thermal Emission will be presented and evidence that the Sun is condensed matter, not a gas.
Construction of the mutually unbiased bases
Iulia Ghiu
Universitatea Bucuresti, Facultatea de Fizica
Abstract:
Mutually unbiased bases are an important tool in many applications of quantum information theory. We present a new algorithm for finding the mutually unbiased bases for two-qubit systems. We derive a system of four equations in the Galois field GF(4) and show that the solutions of this system are sufficient for obtaining the most general set of mutually unbiased bases. Further we study the connection between mutually unbiased bases and mutually orthogonal extraordinary supersquares, a wider class of squares which does not contain only the Latin squares.
Geometric and Quantum Methods in Gravity and Particle Physics
Off-Diagonal Deformations of Kerr Black Holes in Einstein and Modified Massive Gravity
Dr. Sergiu Vacaru
Universitatea Al. I. Cuza, Iasi
Abstract:
- In the first part, it is reviewed S. Vacaru’s scientific activity in connection with Geometric and Quantum Methods in Gravity and Particle Physics. O. Vacaru’s praticipation is in the framwork of the International Masterclass program for highschool students and related to the program for visiting researchers at CERN, see http://www.physicsmasterclasses.org/.
-
We find general parametrizations for generic off-diagonal spacetime metrics and matter sources in general relativity, GR, and modified gravity theories when the field equations decouple with respect to certain types of nonholonomic frames of reference. This allows us to construct various classes of exact solutions when the coefficients of fundamental geometric/physical objects depend on all spacetime coordinates via corresponding classes of generating and integration functions and/or constants. Such (modified) spacetimes can be with Killing and non-Killing symmetries, describe nonlinear vacuum configurations and effective polarizations of cosmological and interaction constants. We reproduce the Kerr solution and show how to deform it nonholonomically into new classes of generic off-diagonal solutions depending on 3-8 spacetime coordinates. There are analyzed certain examples of exact solutions determined by contributions of new type of interactions and sources in massive gravity and/or modified f(R,T) gravity. We conclude that considering generic off-diagonal nonlinear parametric interactions in GR it is possible to mimic various effects in massive and/or modified gravity, or to distinguish certain classes of "generic" modified gravity solutions which can not be encoded in GR.
String Theory: The Quest for Phenomenological Predictions
Lilia Angulova
Perimeter Institute, Canada
String Theory is a very promising candidate for a unifying description of all interactions in nature. However, it still faces important challenges on the road to phenomenological predictions. In recent years there has been a lot of progress in solving these problems. In addition, it was realized that certain string-theoretic solutions have an unexpected application for the study of strongly coupled gauge theories. I will make an overview ofthe recent, phenomenologically motivated, theoretical progress in string theory. Finally, I will briefly mention some new results of mine in this area.
Nuclear proton distributions explored by relativistic resonance fluorescence
Octavian Postavaru
DFT / IFIN-HH
Abstract:
Resonance fluorescence of laser-driven atoms is studied in the relativistic regime by solving the time-dependent Dirac equation in a two-level model. Electron spin and retardation of the electron-photon interaction give rise to phenomena such as splitting of sideband peaks and modification of the Rabi frequencies not explainable in a non-relativistic theory. The approach based on the Dirac equation allows for investigating highly relativistic ions and, consequently, provides a sensitive means to determine parameters of nuclear charge distributions by applying coherent light with x-ray frequencies.
Galilei 450: Motive pentru a sarbatori aniversarea nasterii lui Galilei (15 februarie 1564)
Gheorghe Stratan
IFIN-HH
Abstract: Seminarul este dedicat realizarilor lui Galilei din Astronomie, Fizica, Matematica, Arhitectura Militara, Medicina, Filosofie, Teologie, Critica Literara, etc. Materialul vizual este bazat pe fotografii proprii, luate dupa cartile din Biblioteca Filialei din Cluj a Academiei Romane, unde autorul a identificat multe carti in editie princeps ale autorilor importanti de la Copernic la Newton. Seminarul prezinta si parerile catorva mari oameni de stiinta din trecut si prezent despre sarbatorit.
Subiectul a fost prezentat sub diferite forme (expozitii, seminare, lectii magistrale) in 18 centre din 6 tari.
Singular General Relativity. Relativity and the Quantum
Cristi Stoica
Abstract:
This seminary presents my research interests, and some results.
My PhD thesis is titled "Singular General Relativity" [1], and it is based on several articles, in which I develop the geometry of singular metrics [2], and apply it to the singularities of General Relativity. I present briefly the results concerning the big bang singularities [3,7,9] and the black hole singularities [4,5,6,8,9]. In the following, I intend to continue my research on possible implications of these results to Quantum Gravity, and possible experimental signatures [10]. In addition, I am interested for several years in the foundations of Quantum Mechanics. The main idea is that, although causality seems to be very different in Relativity as compared to Quantum Mechanics, in fact they have much in common. This is connected to an ontological view on the wavefunction which I entertain, as part of an interpretation of QM. The partial results obtained so far were communicated in [11,12,13,14,15].
[1] C. Stoica Singular General Relativity, PhD Thesis, arXiv:math.DG/1301.2231
[2] C. Stoica On Singular Semi-Riemannian Manifolds, To appear in Int. J. Geom. Methods Mod. Phys., arXiv:math.DG/1105.0201.
[3] C. Stoica On the Weyl Curvature Hypothesis, Annals of Physics, 338:186–194, November 2013, arXiv:gr-qc/1203.3382.
[4] C. Stoica Schwarzschild Singularity is Semi-Regularizable, Eur. Phys. J. Plus, 127(83):1-8, 2012, arXiv:gr-qc/1111.4837.
[5] C. Stoica Analytic Reissner-Nordstrom Singularity, Phys. Scr., 85(5):055004, 2012, arXiv:gr-qc/1111.4332.
[6] C. Stoica Kerr-Newman Solutions with Analytic Singularity and no Closed Timelike Curves, To appear in U.P.B. Sci. Bull., Series A, arXiv:gr-qc/1111.7082.
[7] C. Stoica Beyond the Friedmann-Lemaitre-Robertson-Walker Big Bang singularity, Commun. Theor. Phys., 58(4):613-616, March 2012, arXiv:gr-qc/1203.1819.
[8] C. Stoica Spacetimes with Singularities, An. St. Univ. Ovidius Constanta, 20(2):213-238, July 2012, arXiv:gr-qc/1108.5099.
[9] C. Stoica Einstein Equation at Singularities, To appear in Cent. Eur. J. Phys., arXiv:grqc/1203.2140.
[10] C. Stoica Quantum Gravity from Metric Dimensional Reduction at Singularities, arXiv:gr-qc/1205.2586.
[11] C. Stoica Flowing with a Frozen River, Foundational Questions Institute, "The Nature of Time" essay contest, community runners-up, 2008. http://fqxi.org/community/forum/topic/322 [fqxi.org]
[12] C. Stoica Modern Physics, Determinism, and Free-Will, Noema, Comitetul Roman pentru istoria si filosofia stiintei si tehnicii, Academia Romana, XI:431-456, 2012, http://www.noema.crifst.ro/doc/2012_5_01.pdf [www.noema.crifst.ro]
[13] C. Stoica Global and local aspects of causality in quantum mechanics, In TM 2012 - The Time Machine Factory [unspeakable, speakable] on Time Travel in Turin, EPJ Web of Conferences, volume 58, page 01017, September 2013.
[14] C. Stoica The Tao of It and Bit, Foundational Questions Institute, "It from Bit or Bit from It?" essay contest, fourth prize, 2013. http://fqxi.org/community/forum/topic/1627 [fqxi.org]
[15] O. C. Stoica Quantum measurement and initial conditions, arXiv:quant-ph/1212.2601.
