microseminar

informal seminar of Doppler Institute

on quantum theory and related topics and methods,

usually on Thursdays, usually at 10.45 a.m., 20 minutes + discussion

usually in lecture hall S3
of the University of Hradec Kralove

occasionally also in the seminar room (second floor) of the
Department of Theoretical Physics
of the Nuclear Physics Institute in Rez

       note: external interested speakers are always warmly welcome.





     FORTHCOMING SESSIONS:







Place: lecture hall S3
of the Department of Physics (UHK) in Hradec Kralove
Date:


     Thursday, November 4th, 2021

Time (unusual):                11:00 a.m. (duration: ad hoc)
Speaker:


     Petr Seba (UHK)

Title:


Applications of repetitive ballistographic data


Abstract:               
Mathematically processed ballistography signals are used to evaluate various clinically significant markers routinely used in the human diagnostics.









Place: lecture hall S3
of the Department of Physics (UHK) in Hradec Kralove
Date:


     Thursday, December 2nd, 2021

Time:                10:45 a.m. (duration: 20 minutes + questions)
Speaker:


     Marzieh Baradaran (UHK)

Title:


t. b. a.


Abstract:               
t. b. a.









Place: lecture hall S3
of the Department of Physics (UHK) in Hradec Kralove
Date:


     Thursday, January 6th, 2022

Time:                10:45 a.m. (duration: 20 minutes + questions)
Speaker:


     Jiri Lipovsky (UHK)

Title:


Spectral determinants


Abstract:               
We introduce a generalization of the notion of the determinant from matrices to operators with infinitely many eigenvalues, which uses the spectral zeta function. We show how to compute it for simple operators and sketch the main difficulties in its definition, especially the dependence of the spectral determinant on the branch cut of the logarithm appearing in the definition of the spectral zeta function.

This is joint work with P. Freitas based on the paper [1].

[1] P. Freitas, J. Lipovsky, Spectral determinant for the damped wave equation on an interval, Acta Physica Polonica A 136 (2019), 817-823 [arXiv: 1908.06862 [math-ph]].









Place: lecture hall S3
of the Department of Physics (UHK) in Hradec Kralove
Date:


     Thursday, February 3rd, 2022

Time:                10:45 a.m. (duration: 20 minutes + questions)
Speaker:


     Jan Kriz (UHK)

Title:


t. b. a.


Abstract:               
t. b. a.









Place: lecture hall S3
of the Department of Physics (UHK) in Hradec Kralove
Date:


     Thursday, March 3rd, 2022

Time:                10:45 a.m. (duration: 20 minutes + questions)
Speaker:


     Anton Galaev (UHK)

Preliminary title:


A note on some field equations.


Preliminary abstract:               
The talk will be about the relationship between the notions of holonomy and field equations.








Place: lecture hall S3
of the Department of Physics (UHK) in Hradec Kralove
Date:


     Thursday, March 31st, 2022

Time:                10:45 a.m. (duration: 20 minutes + questions)
Speaker:


     Iveta Semoradova (NPI Rez)

Preliminary title:


Diverging eigenvalues in domain truncations of Schroedinger operators with complex potentials.


Preliminary abstract:               
Domain truncations of Schroedinger operators with complex potentials are known to be spectrally exact. However, several examples suggest that additional eigenvalues escaping to infinity seem to be a generic feature. We find conditions on the presence of such eigenvalues and obtain their asymptotic expansions. Our approach also yields asymptotic formulas for diverging eigenvalues in a strong coupling regime for the imaginary part of the potential.






     ARCHIVE:





Place (unusual!): University of Hradec Kralove, Faculty of Science, Department of Physics, Building S, laboratory S19 on the second floor
Date and time: Tuesday, October 12th, 2021, 10:45 a.m.
Speaker: Andrii Khrabustovskii
(UHK)
Title and abstract: Construction of self-adjoint differential operators with prescribed spectral properties
The objective of the talk is to illustrate how one can construct domains or potentials such that the essential or discrete spectrum of Laplace- and Schroedinger-type operators coincides with a predefined subset of the real line. Another aim is to emphasize that the spectrum of a differential operator on a bounded domain or bounded interval is not necessarily discrete, e.g., eigenvalues of infinite multiplicity or continuous spectrum may be present.

The talk is based on resent works with J. Behrndt (TU Graz).





Place (unusual!): University of Hradec Kralove, Faculty of Science, Department of Physics, Building S, ground floor, room Nr. S13
Date and time: Thursday, September 16th, 2021, 10:30 a.m.
Speaker: Miloslav Znojil
(UHK)
Title and abstract: Alice in the wanderland of algebraic geometry, and behind quantum catastrophes
A compact reparametrization of the Arnold polynomial potentials of arbitrary degree (known from the classical theory of catastrophes) is introduced and shown useful in quantum phenomenology. Main attention is paid to the specific unstable-localization dynamical regime. In this regime a systematic determination of the observable density distributions proves feasible via 1/N approximation yielding a qualitative classification and approximate description of a new type of quantum phase transitions, tractable as the (avoided) level crossings or, alternatively, as a manifestation of the existence of a fairly close complex exceptional point.





Place: University of Hradec Kralove, Faculty of Science, Department of Physics, Building S, 1st floor, room Nr. 72549
Date and time: Thursday, June 17th, 2021, 10:30 a.m.
Speaker: Miloslav Znojil
(UHK)
Title and abstract: From Cizek and Dyson to Bender
In the first microseminar organized in UHK the Bender-inspired formulation of quantum mechanics (a.k.a. PT-symmetric quantum mechanics) will be briefly reviewed. With emphasis on the history of the field, five related paradoxes will be formulated. (1) People never noticed the overlap of the theory with the Jiri Cizek's coupled cluster method in which one calculates the real spectrum using realistic Hamiltonians in non-Hermitian representation. (2) Only too late people noticed the overlap of the theory with an analogous Freeman Dyson's recipe. (3) Frequent misunderstandings were evoked by the Bender's claim that his Hamiltonians were non-Hermitian. At present, it is clear that they are only non-Hermitian in an unphysical, auxiliary, irrelevant Hilbert space. In this sense, their proper name should have been quasi-Hermitian Hamiltonians. (4) The main inspiration of the Bender's new theory was the Bessis' imaginary cubic interaction model. In 2012, in a paper by Siegl and Krejcirik, this particular model was proved not to fit the theory. (5) Subsequently, the initial orientation of the theory on the so called closed quantum systems has changed. Today, most people apply the concept of PT symmetry to open quantum systems.
Photo of whiteboard:






The archive of the older microseminars:



The list of talks during 2016 - 2020


The list of talks during 2012 - 2015


The list of talks during 2008 - 2011


The list of the talks during 2008


A compactified list of the speakers during 2008


The list of the talks during 2007


A compactified list of the speakers during 2007


The list of the talks during 2006


A compactified list of the speakers during 2006



PS: in parallel, nested seminars of the similar type may be also sought on the webpages of our local

microconferences

devoted to the analytic an algebraic methods in physics




Info for interested speakers:

send email to Miloslav Znojil
propose a talk
(Thursdays on 10.30 or 10:45 are preferable)
on any subject related to
  • mathematical physics
  • analytic and algebraic methods
  • constructive Quantum Mechanics
  • exactly solvable problems
  • perturbation expansions
  • non-Hermitian quantum models
  • computer tricks
  • relativistic equations
  • and so on.

you should book your term of talk: not later than 2 or 3 days in advance
your talk's length should be 20 minutes
time for subsequent questions: unlimited


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