PT microseminar (archive 2006)

Informal seminar of Doppler Institute
on quantum theory and related topics and methods,
taking place, usually, on the territory of the
Department of Theoretical Physics of the
Nuclear Physics Institute in Rez


The complete list of the talks during 2006



Date and time: 14. 12. (10.30)
Speaker: Martin Jilek (FJFI)
Title: On a Levin's paper about broken waveguides
See: Daniel Levin,
On the spectrum of the Dirichlet Laplacian on broken strips,
J. Phys. A: Math. Gen. 37 No 1 (9 January 2004) L9-L11


Date: unusual: Wednesday, December 13
Time: 10:30 a. m.
Speaker: Roland Lombard (IPN Orsay)
Title and abstract: The size of the He atom
The mean square radius of the He atom is not an experimental datum. The best variational wave functions determine this quantity with numerous digits. We study this problem by means of the Bertlmann-Martin inequality and its generalizations. It gives an estimate with an approximated error of the order of 10 %. Comparison will be made between the results obtained by the two methods.


Place: unusual: Hradec Kralove University, Svobody 331/2, room C7
Date and time: unusual: Friday, December 8, 11:45 a. m.
Speaker: Tamas Fulop (NPI & DI)
Title and abstract: Singular potentials in Quantum Mechanics
Comprehensive review lecture for 2nd Int. Workshop DI "Spectra, Algorithms and Data Analysis".


Place: unusual: Hradec Kralove University, Svobody 331/2, room C7
Date and time: unusual: Friday, December 8, 9:25 a. m.
Speaker: Vit Jakubsky (NPI & DI)
Title and abstract: Non-Hermitian operators in Quantum Mechanics
Comprehensive review lecture for 2nd Int. Workshop DI "Spectra, Algorithms and Data Analysis".


Date (time): 30. 11. (10.30)
Speaker: Milos Tater (NPI & DI)
Title: Asymptotic analysis of spectra of QES Schrodinger operators
Abstract: We study asymptotic distribution of eigenenergies of the algebraic part of spectra and properties of roots of the corresponding eigenpolynomials. Setting of this degenerate exactly-solvable operators in the general scheme is presented.

Date (time): 23. 11. (10.30)
Speaker: Vit Jakubsky (NPI & DI)
Title: Thermodynamics of pseudo-Hermitian systems in equilibrium
Abstract: Physical quantities can be derived without an explicit evaluation of the spectra and without an explicit construction of the metric operator.

Date (time): 16. 11. (10.30)
Speaker: Sudhir R. Jain (Utrecht University)
Title: Resonances
Abstract: I discuss a study on quantum resonances for simple systems for which analytic results are possible, based on the concept of time-delay. The same ideas are then shown to work for extraction of unflavoured baryon resonances and some exotic systems. From these studies ensue some simple relations describing the density of resonances; we bring them out in the light of adiabatic invariance and Weyl-like laws.

Date: 26. 10. 2006 (10.30)
Speaker: Hynek Bila (NPI & DI)
Title: Dirac Equation and its Symmetries III.
Abstract: The review lecture ctd.

Date (time): Thursday 19. 10. 2006 (10.30)
Speaker: Andrey Sokolov (Sankt Petersburg State University)
Title: Factorization of non-linear supersymmetry in one-dimensional Quantum Mechanics
Abstract: Possible factorizations of supersymmetric (SUSY) transformations in one-dimensional Quantum Mechanics into chains of elementary Darboux transformations with non-singular coefficients and hermitian intermediate Hamiltonians are investigated. The classification of irreducible (almost) isospectral transformations and theorems about factorization of SUSY transformations are presented.

Date: 2. 10. (exceptionally, Monday)
Time: 10.30, as usual
Speaker: Alexander Turbiner (UNAM, Mexico)
Title: Anharmonic oscillator and double-well potential: approximating eigenfunctions
Abstract: A simple uniform approximation of the logarithmic derivative of the ground state eigenfunction for both the quantum-mechanical anharmonic oscillator and the double-well potential given by $V= m^2 x^2+g x^4$ at arbitrary $g \geq 0$ for $m^2>0$ and $m^2<0$, respectively, is presented. It is shown that if this approximation is taken as unperturbed problem it leads to an extremely fast convergent perturbation theory. The case of sextic oscillator is briefly mentioned. It is shown that quartic and sextic oscillators are two totally different problems.

Date: 15. 9. 2006 (exceptionally Friday, 10.30)
Speaker: Pedro Freitas (University of Lisbon)
Title: What we do not know about eigevalues
Abstract: What you always wanted to know but felt afraid to ask

Date: 14. 9. 2006 (10.30)
Speaker: Vit Jakubsky (NPI & DI)
Title: Partition functions and PT symmetry
Abstract: Impressions over the dissertation by A. Ivanov.

Date (time): 24. 8. 2006 (14.00)
Speaker: Frieder Kleefeld (DI & NPI)
Title: (Not only) on the paper by Duc Tai Trinh, II
Abstract: cf. J. Phys. A: Math. Gen. 38 (2005) 3665, continuation.

Date (time): 17. 8. (10.30)
Speaker: Peter G. L. Leach (Durban, University KwaZulu Natal)
Title: c-isochronous oscillators and the challenge of consistent quantisation
Abstract: Francesco Calogero introduced a class of oscillators containing a parameter c, which we call c-isochronous oscillators, to demonstrate that the ground-state energy was dependent upon the form of the Hamiltonian used even though classically the different forms are related by canonical transformations. This seems to be an affront to the physical nature of the system which should be independent of the mathematical mode of description. We propose a mathematical solution based upon the algebraic properties of the Schroedinger Equation.

Date: 22. 6. 2006 (10.30)
Speaker: Christian Tanguy (Paris)
Title: Open problems in the network reliability theory
Abstract: A few simple algebraically tractable sample networks and the related combinatorial analysis and matrix recurrences up to dimension 13.

Date: 1. 6. 2006 (10.30)
Speaker: Frieder Kleefeld (Erlangen)
Title: On a paper by Duc Tai Trinh
Abstract: cf. J. Phys. A: Math. Gen. 38 (2005) 3665.

Date: 25. 5. 2006 (10.30)
Speaker: Vit Jakubsky (NPI & DI)
Title: Proca problem once more
Abstract: Revision of a paper discussed.

Date: 18. 5. 2006 at 10.30 (MHD Dpt. of FZ Rossendorf this time, exceptionally of course).
Speaker: Miloslav Znojil (NPI & DI)
Title: Energy-dependent Hamiltonians
Abstract: A brief review.

Date: 11. 5. 2006 (10.30)
Speaker: Jaroslav Smejkal (UCF CVUT)
Title: Proca fields, classical and quantum
Abstract: Hamilton-Jacobi formulation, Heisenberg picture and all that

Date: 18. 5. 2006 (10.15)
Speaker: Petr Siegl (FJFI & DI)
Title: PT-symmetric version of supersymmetry II
Abstract: Conception and contents of the BSc thesis.

Date: 4. 5. 2006 (exceptionally at 9.00, DI/KM of FJFI CVUT, Trojanova 13, Prague)
Speaker: Petr Siegl (FJFI & DI)
Title: PT-symmetric version of supersymmetry
Abstract: Preliminary version of the BSc thesis

Date: 20. 4. 2006 (10.30)
Speaker: Milos Tater (NPI & DI)
Title: Spectra of certain non-Hermitian Hamiltonians with polynomial potentials in 2D
Abstract: Presentation of a numerical study.

Date: 13. 4. 2006 (10.30)
Speaker: Hynek Bila (NPI & DI)
Title: Dirac Equation and its Symmetries II.
Abstract: The review lecture ctd.

Date: 6. 4. 2006 (exceptionally at 15.00, in Brehova 7, room 111, an open-to-public part of the exam)
Speaker: Vit Jakubsky (NPI & DI)
Title: Introduction to dissertation
Abstract: A concise review of a bunch of papers.

Date: 3. 4. 2006 [Monday, 11.15]
Speaker: Vit Jakubsky (NPI & DI)
Title: Pre-introduction to dissertation
Abstract: Preparatory version of the state-exam presenting a sample of the speaker's PhD-research results

Date: 30. 3. 2006 (10.30)
Speaker: Miloslav Znojil (NPI & DI)
Title: PT-SUSY and exact solvability
Abstract: Discussion club on the project submitted to GA CR [followed by its brief presentation to the (parallel) session of the Sci. Council of NPI].

Date: 23. 3. 2006 (10.30)
Speaker: Petr Siegl (FJFI & DI)
Title: SUSY Quantum Mechanics
Abstract: A brief sketch of basic ideas.

Date: 16. 3. 2006 (10.30)
Speaker: Hynek Kovarik (Stuttgart)
Title: Trace formulas in one dimension
Abstract: Short guide to certain spectral-function estimates.

Date: 9. 3. 2006 (11.00)
Speaker: Hynek Bila (NPI & DI)
Title: Green's functions and WKB
Abstract: A review series, part II: Bender's papers on PT symmetry.

Date: 6. 3. 2006 (10.30)
Speaker: Petr Siegl (FJFI & DI)
Title: Discretizations with instabilities: PT square well example
Abstract: The instability of the equidistant-grid version of the Weideman's - Weigert's discretization method of solving Schroedinger equation disqualifies its use for the numerical evaluation of the exceptional points.

Date: 27. 2. 2006 (13.15)
Speaker: Hynek Bila (NPI & DI)
Title: Dirac Equation and its Symmetries.
Abstract: A review lecture, part I.

Date: 20. 2. 2006 (13.15)
Speaker: Miloslav Znojil (NPI & DI)
Title: What I heared in Polubny
Abstract: Brief information about the 14th Student's Winter School

Date: 13. 2. 2006 (15.15)
Speaker: David Krejcirik (NPI & DI)
Title: The simplest PT-symmetric model?
Abstract: Pre-publication discussion club.

Date: 23. 1. 2006 (exceptionally in Polubny):
Speaker: Miloslav Znojil (NPI & DI)
Title: Calogero-type models
Abstract: Review lecture based on the paper
``Low-lying spectra in anharmonic three-body oscillators with a strong short-range repulsion",
M. Znojil, J. Phys. A: Math. Gen. 36 No 38 (26 September 2003) 9929-9941, arXiv quant-ph/0307239.

Date: 16. 1. 2006 (13.15)
Speaker: Vit Jakubsky (NPI & DI)
Title: Proca equation as a pseudo-Hermitian problem
Abstract: Pre-publication discussion.



Reminder:

the list of subjects included
  • analytic and algebraic methods
  • constructive Quantum Mechanics
  • exactly solvable problems
  • perturbation expansions
  • non-Hermitian quantum models
  • computer tricks
  • relativistic equations and so on.

the secretaries of the microseminar were Vit Jakubsky and Miloslav Znojil

return upwards