Past Events 2016

December 2016

28. - 30. December 2016

 

WORKSHOP

The 7th International Workshop "Symmetry in Integrable Systems" (SIS'16)

Where:Leibniz Universität Hannover, venue
When:Talks will begin in the morning of 28th and end at noon on 30th December. 

 

The annual International Workshop "Supersymmetry in Integrable Systems" will be held at the Leibniz University of Hannover this year. 

The topics are:

  • Classical and quantum integrable systems
  • Supersymmetric mechanics
  • PT-symmetric systems
  • Applications in field theory and condensed matter

The program consist of five 45-minute talks and fifteen 30-minute talks. 

For further information please visit the workshops website.

6. - 7. December 2016

 

WORKSHOP

"Communication, conflict management and visibility for women in science"

December 6th - 7th, 2016


Seehotel Faehrhaus
Auf dem Hohen Ufer 8
26160 Bad Zwischenahn

Directions

6. December 2016

 

BREMEN - OLDENBURG RELATIVITY SEMINAR

Where:ZARM, University of Bremen, Room 1280 
When:14:00
Speaker:Marko Toroš, Department of Physics University of Trieste
Title:Quantum Mechanics beyond Galileo" Time and Place
Abstract:We will discuss some problems related to combing relativity and quantum mechanics. We will first introduce Foldy's framework for quantum mechanics in Minkowski space-time. We will present some new results within the theory of relativistic open quantum systems. In particular, we will discuss dynamical maps, Lorentz covariance and non-inertial reference frames. In addition, we will also look at the implications for fundamental non-unitary modifications of quantum mechanics.

5. December 2016

 

PHD DEFENSE

Where:Jacobs University Bremen, seminar room 50, Research Building III (R III)
When: 14:15
PhD Candidate: Fech Scen
Dissertation title:Generalized Geometry Approaches to Gravity

To locate the building "Research 3", please see the campus map.

If you take the main entrance of the building, the seminar room is only a few feets straight on. 

You will notice the sign direction on the glass door.

2. December 2016

 

BREMEN - OLDENBURG RELATIVITY SEMINAR

Where:ZARM, University of Bremen, Room 1730 
When:14:00
Speaker:Anna Hedegaard Lukawska
Title:Correlation of cosmological observables in the effective field theory of inflation
Abstract:The temperature fluctuations in early universe are encoded in statistical properties of the CMB anisotropies. If the fluctuations follow a Gaussian statistics, then the connected three-point correlation function, four-point, and higher order correlation functions referred to as non-Gaussianities, are all vanishing, and all statistical information is given by the two-point correlation function. So far there are neither high statistical significance detections of a non-zero value for the three-point nor higher-order correlation functions. However, if non-Gaussianities of the primordial fluctuations are there, the correlations can provide valuable information on inflation. I will introduce this topic and present a study I have done on how big non-Gaussianities can be generated by single field models using the effective field theory of inflation.

1. December 2016

 

BREMEN - OLDENBURG RELATIVITY SEMINAR

Where:University of Oldenburg, Campus Wechloy, Room W2 3-349
When:16:15
Speaker:Albert Samoilenko, Department of Theoretical Physics and Astrophysics, Belarusian State University, Minsk 
Title:Gauged Baby Skyrme Model with and without Chern-Simons Term
Abstract:The properties of the multisoliton solutions of the U(1) gauged modification of the 2+1 dimensional planar Skyrme model with and without Chern-Simons term are investigated numerically. Coupling to the Chern-Simons term allows for existence of the electrically charged solitons which may also carry magnetic fluxes. Two particular choices of the potential term are considered: (i) the weakly bounded potential and (ii) the double vacuum potential. In the absence of the gauge interaction in the former case the individual constituents of the multisoliton configuration are well separated, while in the latter case the rotational invariance of the configuration remains unbroken. We analyze the dependency of the structure of the solutions, the energies, angular momenta, electric and magnetic fields of the configurations on the gauge coupling constant g, and the electric potential. It is found that, generically, the coupling to the Chern-Simons term strongly affects the usual pattern of interaction between the skyrmions, in particular the electric repulsion between the solitons may break the multisoliton configuration into partons. On the other hand, in the strong coupling limit the coupling to the gauge field results in effective recovering of the rotational invariance of the configuration and both the magnetic flux and the electric charge of the solutions become quantized, although they are not topological numbers. 

November 2016

Change of room

Now: TAB Building, Entrance E, Second floor, Room: 2.63 

28 November 2016

Replacement Seminar

 

BREMEN - OLDENBURG RELATIVITY SEMINAR

Where:ZARM, University of Bremen, TAB Building, Entrance E, Second floor, Room: 2.63 
When:14:30
Speaker:Andrea Fuster, Eindhoven University of Technology
Title:Finsler gravitational waves
Abstract:In this work we present a Finslerian version of the well-known gravitational pp-waves, which generalizes the very special relativity (VSR) line element. Our Finsler pp-waves are an exact solution of Finslerian Einstein’s equations in vacuum.


22. November 2016

 
RTG Colloquium

Where:   Jacobs University Bremen, Conference Room, Campus Center      Directions

When:
  
  22.11.2016,  10:30 - 17:15 hrs

Speaker:
  
  Iva Lovrekovic (Vienna) and Dorothea Bahns (Göttingen)

 

 

Program
10:30 - 11:00
  Student´s Seminar: Patric Hölscher (Bielefeld):
  "Intodruction to conformal gravity"

11:00 - 11:30

  Students´ Meeting

11:30 - 12:00

  Women´s Assembly

12:00 - 12:30

  Coffee break
12:30 - 13:00
  Journals´ Club: Lucas Gardai Collodel (Oldenburg):
  "Relativistic Archimedeslaw for fast  moving bodies
  and the general-relativistic resolution of the 'submarine paradox'
  George E. A. Matsas, Phys. Rev. D 68, 027701 (2003)

13:00 - 14:15

  Lunch break / board meeting

14:15 - 15:15

  Dr. Iva Lovrekovic 
(Vienna) "Conformal Gravity" (Abstract)

15:15 - 15:45

  Coffee break
15:45 - 16:45
  Prof. Dr. Dorothea Bahns
 (Göttingen)
  “On a notion of Volume in a Noncommutative World”

16:45 - 17:15

  Coffee break and discussions

Evening 

  Dinner in downtown Bremen

 
Download Program

21. November 2016

 

PHYSICAL COLLOQUIUM

Where:University of Oldenburg, W2-1-148
When: 21.11.16, 4.15 p.m.
Speaker: Dr. Erik Curiel (Munich Center for Mathematical Philosophy, Germany) 
Topic:Can Black Holes be described by Thermodynamics?
Abstract: Serious problems have been raised about the idea that black holes "really are thermodynamical objects", for instance: that the Zeroth Law for black holes, constancy of surface gravity, is not equivalent to the deepest formulation of the Zeroth Law for ordinary thermodynamics, transitivity of equilibrium; that black?hole area is neither an extensive nor an additive quantity, as ordinary thermodynamical entropy is; that a lack of a general, localized expression for gravitational energy makes it difficult to construct a thermodynamical internal energy for black holes; and several more along the same lines.    The fundamental concern is that the mere fact that the relevant black?hole quantities satisfy formal analogues of the Laws of ordinary thermodynamics does not by itself guarantee that enough of the structure of ordinary thermodynamics is thereby recovered.    There is much more to thermodynamics, after all, than just the four Laws.    Transitivity of equilibrium, for instance, normally grounds the construction of the state space of an ordinary thermodynamical system and the arguments that isolated systems spontaneously approach equilibrium.    I argue in this talk that all these problems can be answered, and that black?hole can meaningfully be treated as thermodynamical objects.

 Please download the invitation here

 

 

 

17 - 18 November 2016

V Postgraduate Meeting on Theoretical Physics

Where:Oviedo University (Spain)
What:Following the spirit of the previous editions, the aim of the meeting is to allow Ph.D. students and young postdocs to present their research in an informal environment. As usual, speakers will be selected from the participants who apply to give a talk. We expect talks to cover a wide range of topics in theoretical physics. 
We will also have a poster session. 
Speaker 1:J. de Boer, University of Amsterdam
Speaker 2:Carlos Hoyos, University of Oviedo

There is no registration fee. Unfortunately, we will not be able to provide financial support for travel or accommodation expenses.

Registration is already open and will close by October 15th.

16. November 2016

Physics Colloquium

Where:Jacobs University, Lecture Hall in Research III Campusring 3
 
When: 17:15 – 18.15h
 
Speaker: Prof. Dr. Johann Kroha (Professor of Theoretical Physics, Physikalisches Institut, Universität Bonn) Additional Information  
 
Topic:Particle Creation in Coupled Bose-Einstein Condensates and in the Early Universe   
 
Abstract: Common knowledge tells that many-body systems come to thermodynamic equilibrium by coupling to a heat reservoir. In classical physics, even ideally isolated, macroscopic systems thermalize due to the equivalence of the microcanonical and the canonical ensembles. However, in quantum dynamics it is a fundamental problem how an isolated quantum many-body system can eventually come to rest from an initial nonequilibrium state, and whether the final state is a thermal one. The problem arises because the time evolution of a quantum system is unitary, that is, a single (pure) quantum state will remain pure for all times and can never reach a thermal state. Contrary to this theorem, one typically observes quantum many-body systems behave in a thermal way. This paradox has recently become more and more pressing, as isolated quantum systems can be realized in ultracold atomic gases with unprecedented control. This problem is also central for the evolution of the universe as an ideally isolated system. It is closely related to the creation of elementary particles. In this talk we will review some attempts at resolving the thermalization paradox. As a prototype of an isolated quantum system we will then consider an atomic Bose-Einstein condensate performing Josephson oscillations in a double-well potential trap. We will show that this system thermalizes by a complex dynamics, covered by three different time regimes: an initial period of undamped Josephson oscillations, an intermediate period of avalanche-like creation of bosonic quasiparticles out of the condensate and a slow thermalization regime induced by quasiparticle collisions [1<journals.aps.org/<wbr />prl/abstract/10.1103/<wbr />PhysRevLett.116.225304>]. We will draw a detailed analogy to the dynamics of elementary particle creation and thermalization during and after the inflationary phase of the early universe.

Additional Information 

For further information please contact:
Prof. Dr. Stefan Kettemann, Professor of Physics, Physics & Earth Sciences
Email: s.kettemann(at)jacobs-university.de
Tel: +49 421 200-3521
Homepage: http://skettemann.user.jacobs-university.de

All are welcome!

 

 

Change of date
Now:
28. November, 14:30, ZARM University of Bremen, Room 1730

 

08 November 2016

BREMEN - OLDENBURG RELATIVITY SEMINAR

Where:ZARM, University of Bremen, Room 1280
When:14:30
Speaker:Andrea Fuster, Eindhoven University of Technology
Title:Finsler gravitational waves
Abstract:In this work we present a Finslerian version of the well-known gravitational pp-waves, which generalizes the very special relativity (VSR) line element. Our Finsler pp-waves are an exact solution of Finslerian Einstein’s equations in vacuum.

3 - 6 November 2016

Deutsche Physikerinnen Tagung

Wo:Hamburg
Was:Die Physikerinnentagung ist eine physikalische Fachtagung, die von der Deutschen Physikalischen Gesellschaft e.V. (DPG) und deren Arbeitskreis Chancengleichheit (AKC) organisiert wird. Ziel ist neben dem fachlichen Austausch die Vernetzung von Physikerinnen aller Qualifikationen - von der Bachelor-Studentin bis zur Professorin und Industriephysikerin. Außerdem werden zahlreiche Anknüpfungspunkte in Industrie und Wirtschaft aufgezeigt und Kontakte zu lokalen und internationalen Unternehmen ermöglicht.

Weitere Informationen sind auf der Tagungshomepage zu finden.

Die Anmeldung ist ab dem 22.07.2016 geöffnet. Bis zum 23.09.2016 können Beiträge (Vorträge, Poster) angemeldet werden. Dabei sind im Rahmen einer Quote auch Beiträge von Männern erwünscht. 

October 2016

31. October 2016

Physical Colloquium 

Where:University of Oldenburg, W2-1-148
When: 31.10.16, 4.15 p.m.
Speaker:Dr. Felipe Guzman (ZARM, Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation,  Universität Bremen, Germany) 
Topic:Laser measurement science and an overview of its groundbreaking applications
Abstract:Coherent light enables length measurements of exquisite sensitivity that lie at the core of fascinating observations in fundamental and quantum physics, astrophysics, geodesy and measurement science. In particular, observations from the Laser Interferometer Gravitational-Wave Observatory (LIGO) over the past year not only confirmed crucial gravitational physics effects, but have now also officially launched the era of Gravitational Wave Astronomy and Multi-Messenger observations. Similar laser-interferometric measurements have been demonstrated and are now flying on LISA Pathfinder, exceeding expectations and paving the way for a spaceborne Gravitational Wave Observatory that will allow us to survey the gravitational universe otherwise inaccessible to us from ground. Moreover, GRACE follow-on will continue to provide valuable information about fluctuations of the Earth’s gravitational field to the geophysical and climatology science community starting early 2018, whose observations will be greatly enhanced by interspacecraft laser gradiometric measurements. In the area of cavity optomechanics and novel compact and integrated photonics, the combination of low-loss devices and optomechanically coupled coherent light field is enabling us to reach unprecedented measurement accuracies at the quantum sensing limit, which is revolutionizing the state-of-the-art in several areas of measurement science. I will discuss the advances in coherent light measurements and some of its recent results and upcoming groundbreaking applications to the science community.

 

 

 

 

4 - 7 October 2016

RTG Models of Gravity, Renewal Conference  

Black Holes, Neutron Stars and the structure of space-time  

Where: University of Oldenburg 
When:04-07 October 2016

Further information at this site.

September 2016

26 - 30 September 2016, University of Bremen

Summer School "Relativistic accretion: theoretical models and their application to observations"

The Research Training Group (RTG) „Models of Gravity“ organises a summer school on relativistic accretion in September, 26-30, at the University of Bremen, Germany. The main foci of the school are the analytical models, current state of observational data from accretion discs around astrophysical black holes and Active Galactic Nuclei (AGN), and the application of the theoretical models for determination of the properties of astrophysical compact objects from observations.

Confirmed Speakers:

Marek A. Abramowicz, N. Copernicus Astronomical Center, Warsaw, Poland.

Wolfgang J. Duschl, Christian-Albrechts-Universität, Kiel, Germany.

Vladimir Karas, Charles University, Prague, Czech Republic.

Odele Straub, LUTH, Observatoire de Paris, France

 Main Lectures: 

Vladimir Karas: Introduction to Active Galactic Nuclei 

  • Basic facts and ideas about active galactic nuclei 
  • Relevant radiation processes and their time scales
  • Accretion versus ejection: formation of cosmic jets
  • Large-scale magnetic fields around galactic nuclei 

Marek Abramowicz: Analytic foundations of the theory of black hole accretion discs

  • Circular motion in the Kerr geometry 
  • The Shakura-Sunyaev flux formula
  • Shakura-Sunyav and Novikov-Thorne equations
  • Thick discs (Polnish doughnuts) 
  • Advection: slim discs and adafs
  • Transonic accretion 

Specialized afternoon lectures: 

Wolfgang J. Duschl: tba

Odele Straub: Deducing black hole properties from observations 

 

Registration and Payment

Participation fee: €70 (4 lunches - Tue-Fr - included)

Registration deadline: Monday, 29 August 2016 

Registration

Please transfer the amount of € 70,00 to the following bank account:

ZARM FAB mbH

IBAN: DE 29 2905 0000 1012643046

BIC: BRLADE22XXX

Bremer Landesbank

Subject: 91162, [your last name, your first name]

After the payment transaction is completed (e.g. the amount shows on our account) you will receive a receipt from us via email which functions as an invoice and participant´s confirmation.

26 – 30 September 2016

66th INTERNATIONAL ASTRONAUTICAL CONGRESS - 2016 IAF EMERGING SPACE LEADERS GRANT PROGRAMME

Where:Guadalajara, Mexico
What:The International Astronautical Federation (IAF) is pleased to announce its *2016 Emerging Space Leaders Grant Programme* that provides opportunities for students and young professionals to participate in the annual International Astronautical Congress.

The young people selected to take part in the 2016 Emerging Space Leaders Grant Programme will participate in the 67^th International Astronautical Congress (IAC) scheduled to take place in Guadalajara, Mexico from 26 – 30 September 2016. The individuals selected will also participate in other activities held the week prior to and during the Congress such as the UN/IAF Workshop, the Space Generation Congress (SGC) or the Young Professionals Workshop and the Cross-Cultural Communications and Presentation Workshop.

Students and Young Professionals between the ages of *21 and 35 on 1 January 2016* with space-related career interests are encouraged to apply for the programme. Up to fourteen students and young professionals will be selected by the IAF to participate in the 2016 programme. 

*Application Deadline: 6 February 2016 15:00 Paris Time / UTC + 1:00 * *For detailed information, application process and requirements please download our "2016 IAF Emerging Space Leaders Grant Programme Handbook

19 - 22 September 2016

NEB-17 Recent Developments in Gravity

Where:St. John resort, Mykonos, Greece
Speakers: among others A. Ashtekar, R. Loll, R. Wald

More information

12 September 2016

BREMEN - OLDENBURG RELATIVITY SEMINAR

Where:University of Bremen, ZARM, Rm 1730
When:16:15 hrs
Speaker:Rico Berner, TU Berlin
Title:Kinematic constraints in parametrized nonlinear electrodynamics
Abstract:The aim of the talk is to give a concise introduction to the parametrization approach by Kucha and present its application to nonlinear electrodynamics. We show how the motion of physical fields, in particular the electromagnetic potential, is connected with the choice of a space and time decomposition of the background spacetime manifold. The relation of the field dynamics and its kinematic description is derived. With regard to generally covariant theories, the arising kinematic constraints are investigated for the class of nonlinear electrodynamics. We address the problem of finding the explicit form of the super-Hamiltonian constraint and reduce it to the problem of solving two nonlinear equations. By this, a plug-and-play approach to find the whole set of constraints for an arbitrary theory of nonlinear electrodynamics is provided and applied to selected examples.

5- 16 September 2016, Wolfersdorf, Thüringen

Foundations and new methods in theoretical physics

This school gives up to 35 PhD students of theoretical physics the opportunity  of becoming familiar with a selection of modern aspects and methods in theoretical and mathematical physics. Basic knowledge of quantum field theory, general relativity and group theory is assumed. Lectures and exercises will be conducted on: 

Lecture Program: 

C. Bender, (Washington University, St. Louis):
"Convergent and divergent series in physics"

M. Henneaux, (Université Libre de Bruxelles):
"Quantisation of gauge theories"

E. Poppitz, (University of Toronto):
"Confinement, Yang-Mills, and Super-Yang-Mills"

S. Weinzierl, (University of Mainz):
"Scattering amplitudes"

S. El-Showk, (CERN Geneve):
"Conformal bootstrap"

For electronic application and further information please go to

more information

The deadline is 30 June, and further instructions (list of participants, suggested literature) will appear starting July. Participants cover their travel and a school fee of 150 Euro; lodging and food (without drinks) are provided by the school. In 2002, the school's location moved from Saalburg to the hotel Am Kellerberg in the village of Trockenborn-Wolfersdorf, about 20 km southeast of Jena in the foothills of the Thüringer Wald. 

August 2016

28 August - 10 September 2016

Helmholtz International Summer School - Cosmology, strings, and new physics 

Where:Dubna, Russia
What:The Helmholtz International School "Cosmology, strings, and new physics" organized by the Bogoliubov Laboratory of Theoretical Physics, JINR, in the framework of the program DIAS-TH will be held on 28 August - 10 September, 2016 in Dubna, Russia. 

Topics:
  • Advances in supersymmetric gauge theories 
  • Higher Spin Theories
  • Gravity, (super)symmetries, integrability
  • Cosmology and high energy physics
  • Inflationary cosmology and alternatives
  • Dark energy and modified gravity
The arrival day is August 28, 2016. The departure day is September 10, 2016.

The expected number of participants is 60. Undergraduate, postgraduate students and young postdocs are invited to apply for participation. 

The lectures will be supplemented by evening discussion sessions. Short reports of the students will be encouraged as well.  

 more information 

21 - 28 August 2016, Belgrade 

QSPACE Summer school 2016

Quantum Structure of Spacetime and Gravity 

The school consists of lectures accompanied by tutorial sessions, as well as some slots reserved for student presentations. The aim is to provide the students with the necessay background to pursue original research in these and related topics. Students and postdocs from countries participating in COST QSPACE Action are eligible for financial support. 

Lecture Program:

Francois David (Institute for Theoretical Physics, Paris):
"Random matrices"

Catharine Meusburger (Friedrich-Alexander University, Erlangen):
"3D gravity"

Peter Schupp (Jacobs University, Bremen):
"Geometry with fluxes" 

Harold Steinacker (University of Vienna, Vienna):
"Fuzzy spaces and applications"

Dimitri Vassilevich (Federal University ABC, Sao Paulo):
"Spectral triples and related" 

more information

July 2016

28 July 2016

RTG Students' Colloquium

Where:University of Bremen, ZARM
When:14:00 hrs
Speaker 1:Michael Fennen, University of Bremen
Speaker 2:Ivan Kolar, University of Prague
Speaker 3:Andreas Schreiber, MPI für Astronomie
Speaker 4:Antonia M. Frassino, FIAS, University of Frankfurt

Further information will follow soon. 

14 July 2016

Berufsperspektive: Profession an einer Hochschule

Vortrag und Workshops

Wo:HWR Berlin, Campus Schöneberg, Haus B, Raum B 3.01 Badensche Straße 52, 10825 Berlin 
Wann:17:00 hrs

Program

8 - 13 July 2016

Foundations of quantum theory, International School of Physics "Enrico Fermi"

Where:Varenna, Comer See, Italy

Deadline for application: 5th of May 2016

Participation fee: 300 Euro (VAT included) for attendance, board, lodging and Proceedings

Please click here for further information

6 July 2016

RTG Colloquium

Where:University of Bremen, ZARM, Room 1730
When:11:00-16:00 hrs
11:00 - 11:30Students' Seminar
M.Sc. Vojtech Witzany, ZARM, University of Bremen
"Carter-Lichnerowicz form of perfect fluid equations and accretion in the Kerr spacetime"
11:30 - 11:45 Coffee Break 
11:45 - 12:15 Journals' Club 
M.Sc. Stephan Reimers
, University of Oldenburg 
"An Example of a New Type of Cosmological Solutions of Einstein's Field Equations of Gravitation", K.Gödel
12:15 - 13:45Lunch break for students / Board Meeting with Lunch
13:45 - 14:45Dr. Gesine Grosche, PTB, Braunschweig  
"Interferometric optical fibre links for long-distance frequency > transfer with 10^(-18) resolution" 
14:45 - 15:00 Coffee Break 
15:00 - 16:00Dr. Monika Moscibrodzka, Department of Astrophysics, IMAPP. Radboud University Nijmegen
"General relativistic magneto hydrodynamics simulations of black hole in the Galactic center: confronting theory with astronomical observations" 
17:30 Early Dinner

4 - 7 July 2016

Noncommutative geometry, quantum symmetries and quantum gravity II 

XXXVII Max Born Symposium hosting 2016 WG3 Meeting of COST Action MP 1405 

Where:Wrcolaw, Poland
Speakers: among others G. Amelino-Camelia, J. Lewandowski

More information 

June 2016

24 June 2016

BREMEN-OLDENBURG RELATIVITY SEMINAR

- Field Theory, Gravity, Relativity - 

Where:University of Oldenburg, Room W2 3-349
When:11:15 hrs
Speaker:Anastasia Golubtsova, Laboratory of Theoretical Physics JINR, Dubna
Title:"Holographic Wilson loops in Lifshitz-like backgrounds"
Abstract:In this talk we discuss the evolution of Wilson loops in Lifshitz-likebackgrounds which can describe anisotropic quark-gluon plasma using theholographic approach. We evaluate the Wilson loops in both static andtime-dependent cases. The anisotropic time-dependent plasma is dual toLifshitz-Vaidya background, while we use a black brane in theLifshitz-like spacetime for a finite temperature plasma in equilibrium.To probe the system we calculate Wilson loops oriented in differentspatial directions. We find that anisotropic effects in the Lifshitz-likebackgrounds are more visible for the Wilson loops lying in thetransversal direction unlike the Wilson loops partially oriented inthe longitudinal one.

16 June 2016

Physikalisches Kolloquium  

Wo:Universität Bremen, Hörsaal H3, Gebäude NW 1, Otto-Hahn-Allee
Wann:16 hrs
Sprecher/in:Prof. Dr. Manfred Stöckler
Titel: "EPR, Schrödingers Katze, Bellsche Ungleichung: das Rätsel der Nicht-Lokalität der Quantenmechanik"
Abstract:Eigentlich wollten Einstein, Podolsky und Rosen in ihrem Gedankenexperiment aus dem Jahre 1935 die Unvollständigkeit der Quantentheorie zeigen. Heute ist diese Arbeit aber interessant, weil darin die Nicht-Lokalität der Quantentheorie eine zentrale Rolle spielt. Im EPR-Paradoxon wird ein Zustandstyp verwendet, den wir heute verschränkt nennen. Er wurde dann von Schrödinger analysiert und zur Formulierung des Gedankenexperiments mit der Katze benutzt. Seit den sechziger Jahren konzentriert sich die Diskussion um die Nicht-Lokalität im Anschluss an einen Beweis von J.S. Bell auf die Besonderheiten der Korrelationen von Messungen an verschränkten Systemen mit weit voneinander entfernten Messgeräten. Diese belegen, dass (entgegen einer zentralen Prämisse von Einstein) die Quantentheorie nicht lokal ist, und darüber hinaus, dass jede beliebige Theorie, die die gleichen Korrelationen wie die Quantenmechanik vorhersagt, nicht lokal sein kann. 

Mittlerweile sind die von der Quantentheorie vorhergesagten Korrelationen empirisch hoch bestätigt. Damit ist das von EPR aufgeworfene Problem aber nicht gelöst, weil es keine dynamische Erklärung für den Messprozess an verschränkten Systemen zu geben und die Nicht-Lokalität der Quantentheorie der Relativitätstheorie zu widersprechen scheint. Die genaue Bedeutung der Nicht-Lokalität, insbesondere die Frage, ob sich daraus ein Konflikt mit der Relativitätstheorie ergibt, haben in der Philosophie der Physik eine bis heute offene Kontroverse ausgelöst. Der Sprecher berichtet über einschlägige Einsichten, Missverständnisse und mehr oder weniger verzweifelte Lösungsvorschläge.

16 June 2016 

Talk by a world-leading expert in relativistic geodesy

Where:Leibniz Universität Hannover, Institut für Erdmessung, Room 404
When:10:00 hrs
Speaker:Prof. Sergei Kopeikin, University of Missouri
Title:"Cosmological effects in the localized astronomical systems: myth or reality?"

14 June 2016

BREMEN-OLDENBURG RELATIVITY SEMINAR

- Field Theory, Gravity, Relativity - 

Where:University of Bremen, ZARM, Room 1280
When:14:30 hrs
Speaker:Dr. Dennis Raetzel, University Potsdam
Title:"How light gravitates: a brief exploration"
Abstract:As Einstein's equations tell us that all energy is a source of gravity, light must gravitate. However, because changes of the gravitational field propagate with the speed of light, the gravitational effect of light differs significantly from that of massive objects. In particular, the gravitational force induced by a light pulse is due only to its creation and annihilation and decays with the inverse of the distance to the pulse. 

We can expect the gravitational field of light to be extremely weak. However, the properties of light are premisses in the foundations of modern physics: they were used to derive special and general relativity and are the basis of the concept of time and causality in many alternative models. Studying the back-reaction of light on the gravitational field could give new fundamental insights to our understanding of space and time as well as classical and quantum gravity. 

In this talk, a brief overview is given of the gravitational field of light pulses in the framework of general relativity. A glimpse is caught of the gravitational interaction of two single photons which turns out to depend on the degree of their polarization entanglement. 

7 June 2016

Talks at ZARM 

Where:ZARM, University of Bremen 
Speaker: by Dr. Steffen Aksteiner 
Title:"Symbolic computer algebra and applications in linearized gravity"
Abstract:The symbolic computer algebra package xAct for Mathematica is an efficient tool for abstract differential geometric calculations. The speaker will review basic features of xAct and some of its applications in General Relativity. In the second part of the talk I will present more advances xAct tools based on spinors to elaborate the special geometry of the Kerr spacetime. Important consequences of the special geometry are symmetries and conservation laws for fields on the Kerr spacetime, including Maxwell and linearized gravity. 

3 June 2016

Erben-Vererben

Wo:GW 2, Raum B 3009, Universität Bremen
Wann:10:15-12:15 Uhr

2 June 2016

Theory colloquium  

Where:University of Oldenburg, W2 1-143
When:14:15 hrs
Speaker:Prof. Dr. Wolfgang Duschl (Kiel) 
Title:The Evolution of Active Galactic Nuclei - Individually and as an Ensemble
Abstract:Quasars, and Active Galactic Nuclei (AGN, for short) in general, are among the most efficient energy sources in the Universe. They balance their energy budget by liberating potential energy through accretion of matter into super-massive black holes. Due to their high luminosity, they are ideal test bodies which can be observed almost throughout the entire Universe's history.

As ever so often in astrophysics, we are confronted with the problem of exceedingly long evolutionary timescales of individual objects which are not accessible to direct observation.

In the talk, the speaker will adress several problems related to the evolution of individual objects as well as that of entire ensembles of AGN, an example being, for instance, the processes limiting the mass growth of black holes.   

May 2016

26 May 2016

Prof. Stephen Hawking spricht an der Leibniz Universität

Where:Leibniz Universität Hannover, Lichthof, Welfengarten 1
Live-Übertragung in die Hörsäle Audimax, Großer Physikhörsaal und E001 
When: 18:00 hrs
LanguageEnglish
Tickets:Kostenlos. Kartenausgabe am Donnerstag, 19., sowieso Freitag, 20. Mai 2016, jeweils von 14 bis 19 Uhr an der Leibniz Universität Hannover, Lichthof. 

Da Stephen Hawkings Gesundheitszustand eine kurzfristige Absage von Veranstaltungen erforderlich machen kann, wird der Stand tagesaktuell unter www.uni-hannover.de veröffentlicht.  

More information

23 - 26 May 2016

The first observation of a binary black hole merger: Status and future prospects

Where:Albert Einstein Institute, Hannover, Germany
What:The presentations at the meeting will cover all aspects of the detection and the science associated with the gravitational wave event. The meeting is targeted towards a general physics audience. It should be particularly valuable to graduate students and non-experts who might be interested in a broad introduction to the subject.

More information and registration 

19 May 2016

Theory Colloquium 

Where:University of Oldenburg, W2 1-143
When:14:15 hrs
Speaker:Dr. Christian Pfeifer, University of Bremen, University of Hannover
Title:"The Potential in General Linear Electrodynamics: Causal Structure, Propagators and Quantization"
Abstract:From an axiomatic point of view, the fundamental input for a theory of electrodynamics are Maxwell's equations dF=0 (or F=dA) and dH=J, and a constitutive law H=# F, which relates the field strength 2-form F and the excitation 2-form H. In this talk we consider general linear Electrodynamics, the theory of Electrodynamics which is defined through a liner constitutive law. The best known application of this theory is the effective description of Electro-dynamics inside (linear) media including for example birefringence. We will analyze the classical theory of the electromagnetic potential A thoroughly before we use methods familiar from mathematical quantum field theory in curved spacetimes to quantize it. Our analysis of the classical theory contains the inversion of the principal symbol of the field equations, the construction of the causal structure on the basis of the constitutive law, which replaces the metric one uses in Maxwell Electrodynamics, the construction of the inverse of the field equations and the Puli-Jordan propagator and the classification of the classical symplectic phase space of the theory. This classical analysis then sets the stage for the construction of the quantum algebra of observables and quantum states. 

11 May 2016

Entlastung von pflegenden Angehörigen (Kurzzeit- und Verhinderungspflege)

Wo:GW 2, Raum B 3009, Universität Bremen
Wann:10:00-12:00 Uhr

11 May 2016

RTG Colloquium 

Where:University of Hannover, Room 027, Appelstr. 4
When:10:00 - 17:30 hrs
10:00 - 11:00Students´ Seminar 
Lukas Brunkhorst

"Minimal length and Hopfian Relativity"
11:00 - 11:15Coffee break
11:15 - 12:00Women´s Assembly
12:00 - 12:15Coffee break
12:15 - 13:15Journals´ Club
Stephan Reimers

"An Example of a New Type of Cosmological Solutions of Einstein's Field Equations of Gravitation", K. Gödel 
13:15 - 14:15Lunch break
14:15 - 15:15Dr. Jan Pieter van der Schaar, University of Amsterdam and Nikhef
"Probing the physics of (eternal) inflation"
15:15 - 15:45Coffee break
15:45 - 16:45Dr. Adam Michael Goldstein, NASA USRA / NASA MSFC, Huntsville, Alabama
"Fermi gamma-ray burst monitor observations of GW150914 and near-future orospects for electromagnetic follow-up of gravitational wave signals"
16:45 - 17:00Coffee break
17:00 - 17:30General Assembly

Prior to the colloquium, 17 of our phd students and postdocs will be visisting GEO600. A report on their experiences and impressions will be available soon afterwards. Please come back for this and click here

9 - 13 May 2016 

Ultracold Quantum Gases - Current Trends and Future Perspectives

Where:Bad Honnef, Germany
What:Since the first experimental realization of Bose-Einstein condensation in ultracold atomic gases in 1995, there have several substantial breakthroughs. Today, systems of bosonic or fermionic quantum gases allow for a very high level of experimental control concerning all ingredients of the underlying many-body Hamiltonian. The underlying trapping geometry can be designed to be harmonic, anharmonic or, recently, even box-like which mimics a quasi-uniform potential. Furthermore, the shape of the two-particle interaction can be modified from the short-ranged and isotropic contact interaction to the long-ranged and anisotropic dipolar interaction. In particular the possibility to tune the strength of the contact interaction to basically any attractive or repulsive value with the aid of the Feshbach resonance allows nowadays to probe quantum fluids in regimes and under conditions hitherto unavailable. Since 2011 it has even been experimentally achieved to also tune the kinetic energy of the many-body Hamiltonian by producing synthetic spin-orbit coupling. This nourishes the prospect to generate for neutral atoms abelian gauge fields, as they appear in electromagnism for charged particles, but also non-abelian gauge fields, as they occur in the standard model of elementary particle physics. Therefore, quantum gases are considered to be ideal quantum simulators, i.e. they are best capable to simulate difficult quantum problems in condensed matter physics and other fields of physics in the sense of Richard Feynman from 1982. 

more information

4 May 2016

Mutterschutz, Elternzeit, Elterngeld, Elterngeld+

Wo:GW 2, Raum B 3009, Universität Bremen
Wann:10:00-13:00 Uhr
Schwerpunkt: Fragen zum Wissenschaftszeitvertragsgesetz

April 2016

28 - 29 April 2016

11. Kosmologietag 

Where:University of Bielefeld, main building - room V2-210/216
Thursday,28.04.2016
12:30 hrsWelcome Coffee & Registration for Kosmologietag
13:10 hrsMickael Rigault
"Accurate Measurement of the Hubble Constant with Type la Supernovae"
13:30 hrsKaren Schulze-Koops
"General Relativistic Ray Optics in a Nonmagnetized, Pressureless two-fluid Plasma"
13:50 hrsGiorgia Pollina
"Cosmology with Cosmic Voids"
14:10 hrs Benjamin Javanmardi
"Near Field Cosmology with Small Telescopes: Finding Dwarf Satellite Galaxies outside the Local Group" 
14:30 hrsCoffee Break
15:00 hrsVanessa Böhm 
"A Bias to CMB Lensing Measurements from the Bispectrum of large-scale Structure"
15:20 hrsSteffen Hagstotz
"Hunting Neutrinos and Modified Gravity with Clusters of Galaxies"
15:40 hrsTommi Tenkanen
"Observational Properties of Weakly Coupled Dark Matter"
16:00 hrsCora Uhlemann
"Large-Deviation Statistics on the Cosmic Density Field"
16:20 hrsCoffee Break
16:50 hrsChristian Fidler
"Relativistic Interpretations of N-Body Simulations"
17:10 hrsStefan Oslowski
"Gravitational-Wave Cosmology across 29 Decades in Frequency"
17:30-18:30 hrsGuy Moore
"Axion Mass - Dark Matter Abundance Relation"
20:00 hrsDinner at Brauhaus Johann Albrecht
  
Friday,29.04.2016
09:00 hrsChris Byrnes 
"Inflation and the Cosmic Microwave Background Anomalies"
09:20 hrsJonathan Frazer
"Manyfield Inflation"
09:40 hrsMafalda Dias
"Inflating in a Random Landscape"
10:00 hrsCoffee Break
10:30 hrsJuraj Klaric
"Leptogenesis in GeV Seesaw Models with Large Mixing Angles"
10:50 hrsMarco Drewes
"What Can the CMB Tell about Cosmic Reheating?"
11:10 hrsGaoyuan Wang
"Vacuum Selection on Axionic Landscape"
11:30 hrsCoffee Break 
12:00-13:00 hrsChihway Chang 
"Exploring the Dark - Weak Lensing with the Dark Energy Survey and Beyond" 
13:00 hrsEnd of Kosmologietag

 

Official website

27 - 28 April 2016

Spring Workshop 

Wednesday, 27.04.2016
Where:D6-135
10:00 hrsWelcome and Coffee
10:30-12:30 hrsProf. Dr. Gerhard Schäfer, Jena
"Extraction and Estimation of the Parameters that Characterize"
GW150914
12:30-13:00 hrsLunch
13:00-14:30 hrsDr. Harald Skarke, TU Vienna & Bielefeld
"Cosmic Acceleration as an Optical Illusion" 
14:30-15:00 hrsCoffee
15:00-16:00 hrsStudent Seminar
Thursday, 28.04.2016
Where:V2-210/216
09:30 hrsCoffee
10:00-10:20 hrsOmar Contigiani
"Cosmological Alignment of Radio Sources"
10:20-10:40 hrsIsabel Oldengott
"Models of Reionization and Dark Matter Decay"
10:40-11:00 hrsCoffe break 
11:00-12:00 hrsLaura Spitler, MPIfa Bonn
"An Overview of Fast Radio Bursts"
12:00-13:00 hrsLunch break
Then we continue with Kosmologietag, starting 13:00 with registration and welcome coffe. 

22 April 2016

BREMEN-OLDENBURG RELATIVITY SEMINAR
- Field Theory, Gravity, Relativity -

Where:University of Oldenburg, W02-3-349
When:11:15 hrs
Speaker:Michael Kalisch, Friedrich-Schiller-Universität, Jena 
Title:"Pseudo-spectral construction of highly deformed non-uniform black string solutions "
Abstract:Black strings are static solutions to Einstein's vacuum field equations in spacetimes with a compactified dimension. The horizon of such an object wraps the compact dimension. I will explain in detail how we constructed black string solutions in a critical regime, in which the horizion is close to pinching off. The use of an appropiately designed pseudo-spectral scheme allowed us to obtain very accurate and unprecedented results. In particular, we observed three clearly pronounced turning points in the curves of thermodynamic quantities, resulting in a spiral curve in the black string's phase diagram. 

19 April 2016

BREMEN-OLDENBURG RELATIVITY SEMINAR
- Field Theory, Gravity, Relativity -

Where:University of Bremen, ZARM, Room 1280
When:2:30 hrs
Speaker:Dr. Maxim Eingorn, North Carolina Central University, Durham, NC, USA
Title:"All-scale cosmological perturbations and screening of gravity
in inhomogeneous Universe"
Abstract:Without exceeding the limits of the concordance cosmological model, all-scale scalar and vector perturbations of the homogeneous background are derived analytically for arbitrarily distributed inhomogeneities (discrete gravitating masses) as their nonrelativistic sources. The obtained expressions for the metric corrections are gauge-invariant, converge everywhere in voids, have zero average values, and conform to Minkowski background limit and Newtonian  cosmological approximation as particular cases. Moreover, the uniform matter distribution limit as one more crucial test is easily passed as well. It is rigorously proven that gravitational attraction between inhomogeneities is governed by Yukawa law, covering the whole space and coming up to take place of Newtonian gravitation, which is restricted exclusively to sub-horizon distances. The finite time-dependent screening length (amounting to 3.7 Gpc at present) is determined by the average rest mass density of nonrelativistic matter and provides natural estimates of the homogeneity scale, the upper limit of the cosmic structure dimension, and the bound to a spatial domain of probable structure development. The definition of Yukawa interaction range is generalized to the extended cosmological model with extra continuous perfect fluids and nonzero spatial curvature.

14 April 2016

Physics Colloqium 

Where:University of Bremen, Hörsaal H3, Geb. NW1, Otto-Hahn-Allee
Speaker:Prof. Dr. Wiesendanger, Universität Hamburg
Title:"Magnetische Knoten auf der Nanometerskala: von der Grundlagenforschung zu neuen Datenspeicherkonzepten"
Abstract:Nanoskalige Knoten in der Magnetisierung, sogenannte Skyrmionen, sind zum Gegenstand intensiver weltweiter Forschungsanstrengungen geworden, da man mit ihnen neuartige Konzepte der hochdichten magnetischen Datenspeicherung realisieren kann. Neben ihrer geringen Größe zeichnen sich Skyrmionen durch nicht-triviale topologische Eigenschaften verbunden mit einem ausgezeichneten Drehsinn der Magnetisierung aus, verursacht durch eine zugrundeliegende chirale spinabhängige Wechselwirkung, welche diese nanoskaligen magnetischen Objekte äußerst stabil werden lässt. Die Entdeckung von Skyrmionengittern und insbesondere einzelner nanoskaliger Skyrmionen in ultradünnen metallischen Schichten liefert die Basis für Anwendungen in Form von neuartigen magnetischen Datenspeichern, Logikelementen und Sensoren unter Nutzung der Technologie, welche in den vergangenen Jahrzehnten auf dem Gebiet der Riesen- und Tunnelmagnetowiderstands-Sensoren etabliert wurde. Dieser Vortrag widmet sich sowohl den grundlegenden physikalischen Aspekten dieser neuartigen nanoskaligen Magnetisierungsstrukturen in ultradünnen Schichten und Multilagensystemen als auch deren Anwendungsperspektiven.

13 April 2016

RTG Colloquium

Where:University of Oldenburg, W2 - 1 146; W2 - 1 143 
When:10:15-17:00 hrs
10:15 - 11:00 Women Assembly
11:00 - 11:15 Coffe break 
11:15 - 12:15 Prof. Dr. Joris Verbiest, University of Bielefeld
"Pulsar Timing Tests of Gravity"

Abstract
Millisecond pulsars are highly stable "Einstein" clocks that often inhabit extreme gravitational environments. In many ways, they're ideal probes of extreme gravity. Consequently, they are regularly used for tests of relativistic gravity -- and might even lead to a direct detection of nHz gravitational waves in the near future.
In this talk, I will briefly review the various types of radio pulsars that are known to exist and discuss some of the more typical (and most sensitive) gravity tests performed with these pulsars. Furthermore, I will review the current efforts at making a direct detection of gravitational waves through pulsar timing; and will clarify which types of sources could be observed and investigated with such a detection. Finally, I briefly present what can be looked forward to in the context of gravitational-wave science with pulsar timing in the coming decade. 
12:15 - 12:30 Coffe break
12:30 - 13:00 Students' Seminar
Paul Jefremov, ZARM
"Relativistic disk accretion. "Polish Doughnuts" model". 
13:00 - 14:00 Lunch break at the Cafeteria
14:00 - 14:30 hrsJournal's Club
Fech Scen Khoo, Jacobs University Bremen
"A master equation for gravitational pertubations of maximally symmetric black holes in higher dimensions"  
14:30 - 15:00 Coffe break 
15:00 - 16:00 Dr. Térence Delaste, Université  de Mons, Mons, Belgium
"Slowly rotating neutron stars in general scalar-tensor theory: The case of non minimal derivative coupling"
16:00 - 17:00 Board Meeting
Apprx. 17:30 Dinner

7 April 2016 

Theory Colloquium

Where:University of Oldenburg, W2 1-143
When:14:15 hrs
Speaker:Dr. Roman Konopolya
Title:"Detection of gravitational waves from black holes: Is there a window for alternative theories?"
Abstract:Recently the LIGO and VIGRO collaborations reported the observation of gravitational-wave signal corresponding to the inspiral and merger of two black holes, resulting into formation of the final black hole. It was shown that the observations are consistent with the Einstein theory of gravity with high accuracy, limited mainly by the statistical error. Angular momentum and mass of the final black hole were determined with rather large allowance of tens of percents. Here we shall show that this indeterminacy in the range of the black-home parameters allows for some non-negligible deformations of the Kerr spacetime leading to the same frequencies of the black-hole ringing. This means that at the current precision of the experiment there remains some possibility for alternative theories of gravity. 

March 2016

23 - 24 March 2016

Sixth Quantum Universe Symposium  

Where:University of Groningen, Netherlands
We cordially invite you for the sixth edition of our annual Quantum Universe symposium, which will take place in the Smitsborg at the Zernike campus in Groningen on Thursday, March 24. This symposium will highlight recent developments at the intersection of astronomy, (astro-)particle physics, cosmology, mathematics and subatomic physics. In particular, the special topic of this year will be the recent developments and extensions of Einstein's theory of general relativity, which was discovered 100 years ago. The keynote speakers of this year's edition include Heino Falcke, Subir Sarkar and Erik Verlinde, in addition to a number of national and local speakers. More information plus registration can be found on the website. On the day before the symposium, Vincent Icke, Aart Heijboer and Subir Sarkar will provide masterclasses specifically aimed at advanced BSc, MSc and PhD students.
You have to register separately for these classes, and there is a limited number of places available. 

Please register if you are planning to come; we look forward to having you over in Groningen! 

14 - 18 March 2016 

DPG-Frühjahrestagung

Where:Darmstadt, Germany
What:- Physik der Hadronen und Kerne
- Arbeitskreis Beschleunigerphysik

More information 

14 - 15 March 2016

Nordic String Theory Meeting 2016

Where: Jacobs University Bremen, ICC Conference Room

What: several gravity-related talks including a pedagogical introduction to Newtown-Cartan theory

Official website

11 March 2016

BREMEN - OLDENBURG RELATIVITY SEMINAR

- Field Theory, Gravity, Relativity -

Where:University of Oldenburg, Room W2 3-349
When: 12:15 hrs
Speaker:Christian Knoll, University of Oldenburg
Title:"Dirac equation in Myers-Perry black hole geometry with equal angular momenta"
Abstract:This talk is the defense of the Speakers' Master Thesis. The main result is the solution of the angular part of the Dirac equation in the geometry of the five dimensional Myers-Perry black hole with equal angular momenta. The Speaker will begin to introduce the formalism and fix the notation for the Dirac equation in curved spacetimes. After that the Speaker briefly consider the Dirac equation in the geometry of the Kerr black hole. The decoupled Dirac equation of Chandrasekhar is reproduced using a method from the literature. A minimal example is constructed and some physical interpretations are discussed. One set of special solutions to the angular equations is derived. 
Next is the Dirac equation in the geometry of the five dimensional Myers-Perry black hole with equal angular momenta. Again, the equations are decoupled using a method from the literature. A minimal example is constructed with which some physical interpretations are discussed. The angular equations are solved.
The last part involves possible future work. A possible condition for physical solutions to the complete equations considered before is discussed. The Dirac equation in the Myers-Perry black hole geometry with equal angular momenta in any uneven dimension is formulated.  

6 - 11 March 2016

80. Jahrestagung der DPG und DPG-Frühjahrestagung 

Where:Regensburg, Germany
What:- Sektion Kondensierte Materie (SKM)
- Mikrosonden
- Umweltphysik
- Arbeitskreis Chancengleichheit
- Arbeitskreis Energie
- Arbeitskreis Industrie und Wirtschaft
- Arbeitsgruppe Information
- Arbeitsgruppe jDPG
- Arbeitsgruppe Physik und Abrüstung

More information 

10 March 2016

Vortragsreihe: 100 Jahre Allgemeine Relativitätstheorie

Wo:Schlaues Haus, Oldenburg
Wann: 19:30-21:00 Uhr
Sprecher/in:Prof. Dr. Claus Lämmerzahl, Universität Bremen, Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)
Titel:"Gravitationswellen direkt nachgewiesen: Einstein wieder bestätigt"

February 2016

29 February - 4 March 2016

DGP-Frühjahrstagung

Where:Hamburg, Germany
Topics:- Sektion Materie und Kosmos (SMuK)
- Gravitation und Relativitätstheorie
- Strahlen- und Medizinphysik
- Teilchenphysik
- Theoretische und Mathematische Grundlagen der Physik
- Arbeitsgruppe Philosophie der Physik

More information 

29 February - 4 March 2016

DGP-Frühjahrstagung

Where:Hannover, Germany
Topics:- Sektion Atome, Moleküle, Quantenoptik und Plasmen (SAMOP)
- Atomphysik
- Kurzzeitphysik
- Massenspektrometrie
- Molekülphysik
- Plasmaphysik
- Quantenoptik und Photonik
- Didaktik der Physik
- Arbeitsgruppe jDPG 

More information

25 February 2016

Talks at ZARM

Where:ZARM, University of Bremen, Room 1280 
When: 11:00 am 
Speaker:by Karen Schulze-Koops
Abstract:Karen Schulze-Koops is giving a seminar talk on the results of her Diploma Thesis. The Thesis deals with general-relativistic ray optics in a plasma. In particular, the Sachs equations for light bundles in a plasma are derived and a brief outlook on possible applications to cosmology is given.

The talk will be in Englisch. Everybody is welcome. 

17 February 2016

RTG Colloquium 

Where:University of Bielefeld, Lecture Hall 10
When:11:00 - 17:15 hrs
10:30 - 11:00 Students' Seminar
Xiao Yan Chew, University Oldenburg
"On the Reproduction of Field Configurations via Retarded Green's function in de Sitter Spacetime"
11:00 - 12:00Students' Meeting
12:00 - 12:30 Journal's Club
Kris Schroven,
University Bremen
"Gas dynamics of semidetached binaries", S. H. Lubow and F. H. Shu (adsabs.harvard.edu/abs/1975ApJ...198..383L)
12:30 - 13:00General Assembly
13:00 - 14:15 Lunch
14:15 - 15:15Jun.-Prof. Annalisa Bonafede, University Hamburg 
"Magnetic fields and cosmic rays in galaxy clusters" 
Abstract
The extreme physical conditions in the intra-cluster medium of galaxy clusters are beyond anything achievable in any laboratory on Earth, and offer us a unique tool to study magnetic fields and cosmic rays on the largest scales in the Universe. A big challenge of modern astrophysics is understanding the origin of radio emission spread over the volume of some galaxy cluster. This emission is a mystery because it requires relativistic electrons moving around magnetic field lines, but both the origin of the magnetic fields and of the electrons are unknown. We are entering into a golden age to address these fundamental problems, thanks to the advent of a new generation of radio telescopes, such as LOFAR, the JVLA, and ASKAP. At the same time, the new eROSITA X-ray satellite is going to provide us with a wealth of new data on the most distant and less massive galaxy clusters and groups. In this talk, I will review our current knowledge about magnetic fields and cosmic ray particle sin galaxy clusters, and I will illustrate the potential of the new generation of radio instruments to answer the many open questions about the origin and evolution of magnetic fields an cosmic rays.  
15:15 - 15:45Coffee and discussions
15:45 - 16:45 Dr. rer. nat. Sebastien Clesse, RWTH Aachen
"Chameleon and K-mouflage models of modified gravity: cosmological, astrophysical and laboratory constraints"
Abstract 
Understanding the current acceleration of the Universe expansion is one major challenge in cosmology. Present and future experiments aim to distinguish between a cosmological constant, a dark energy fluid, and modifications of gravity. Most modified gravity models involve at least one scalar field coupled to matter. An environmental dependance eventually leads to a screening mechanism suppressing long-range fifth force effects in galaxies, in the solar system and in laboratory experiments. Three possible screening mechanisms have been proposed: chameleon (screening when the Newtonian potential is large), Vainshtein (screening when the spatial curvature is large) and K-mouflage (screening when the gravitational acceleration is large). In this seminar, I will focus on chameleon and K-mouflage models. After a description of the scalar field dynamics in different contexts, and of the linear cosmological perturbations, I will give a review of the cosmological, astrophysical, and laboratory constraints that can be set on chameleon and K-mouflage models, including constraints from Lunar Laser Ranging and from atom-interferometry experiments. 
16:45 - 17:15 Coffee and discussions
18:30Dinner

12 February 2016 

Colloquium talk 

Where: Max Planck Institute for Astrophysics, Garching 
When:16 Uhr c.t. 
Speaker:Eiichiro Komatsu

6 - 12 February 2016

Quantum Spacetime '16 Winter Workshop

More information 

9 February 2016

Olbers Sitzung der Wittheit 

Wo:Haus der Wissenschaft, Sandstraße 4/5, Olbers-Saal (1. OG), Bremen 
Wann:19:00 Uhr
Sprecher/in:Prof. Dr. Dieter B. Herrmann 
Titel:"Das Urknall-Experiment - auf der Suche nach dem Anfang der Welt"
Abstract:Im Herbst 2009 ist in Genf die "Größte Maschine aller Zeiten" in Betrieb genommen worden: Der Large Hadron Collider (LHC). Nach einer längeren Pause wurde er 2015 wieder hochgefahren - auf seine maximale Leistung. Subatomare Teilchen prallen dort mit nahezu Lichtgeschwindigkeit aufeinander. Die Forscher hoffen, damit dem "Geheimnis des Urknalls" und somit der Entstehung des Universums auf die Spur zu kommen. Wie ist das möglich?

Der Vortrag berichtet, unterstützt von faszinierenden Bildern, über die gegenwärtigen Vorstellungen von der Lebensgeschichte des Weltalls und über das Standardmodell der Mikrowelt. Auf diese Weise wird für den Hörer verständlich, welcher Art die Experimente am LHC sind und wie sie unsere Vorstellungen über unsere Welt und damit über uns selbst verändern, erweitern und bereichern können. 

8 February 2016

Vortragsreihe: 100 Jahre Allgemeine Relativitätstheorie

Wo:Schlaues Haus, Oldenburg
Wann: 19:30-21:00 Uhr
Sprecher/in:Prof. Dr. Domenico Giulini, Universität Bremen, Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)
Titel:"Quanten und Gravitation"
Abstract:Quantentheorie und Allgemeine Relativitätstheorie bilden das Fundament der modernen theoretischen Physik. Auf ihnen basiert unser Grundverständnis des Aufbaus der Materie und der Welt im Großen (Astrophysik und Kosmologie). Zusammengenommen machen diese Theorien präzise und immer wieder bestens bestätigte Vorhersagen in Dimensionen unterhalb denen eines Atomkerns bis zu kosmologischen Distanzen von Milliarden von Lichtjahren. Dabei basieren aber beide Theorien jeweils auf Grundannahmen, die gegenseitig zum Teil widersprüchlich erscheinen. Die Physiker suchen deshalb nach einer übergeordneten Theorie, die diese Widersprüche umgeht aber gleichzeitig die gut bestätigten Voraussagen mit enthält, die beide Theorien in ihrem jeweiligen Anwendungsgebiet machen. Diese Aufgabe ist zurzeit noch ungelöst. In diesem Vortrag sollen einige interessante Aspekte des noch unverstandenen Verhältnisses dieser beiden Jahrhunderttheorien beleuchtet werden.

January 2016

25 January 2016

Vortragsreihe: 100 Jahre Allgemeine Relativitätstheorie

Wo:Schlaues Haus, Oldenburg
Wann:19:30-21:00 Uhr
Sprecher/in:Prof. Dr. Heino Falcke, Radboud Universiteit Nijmegen
Titel:"Das Schwarze Loch im Zentrum der Milchstraße"
Abstract:Vor hundert Jahren formulierte Albert Einstein seine allgemeine Relativitätstheorie. Innerhalb nur weniger Monate gelang es Karl Schwarzschild damit die Raumzeitstruktur schwarzer Löcher zu beschreiben. Was ursprünglich nur ein akademisches Gedankenspiel war, wurde später zum Erklärungsansatz für viele energetische Phänomene im Weltall. Als nämlich fast 60 Jahre später die geheimnisvollen Quasare in den Tiefen des Weltalls entdeckt wurden, war es einer der großen Rätsel wie ein Objekt von der Größe eines Sonnensystems so viel Licht wie hundert Galaxien zusammen produzieren kann.Schnell richtete sich der Verdacht auf das Wirken super-schwerer schwarzer Löcher. Der beste Nachweis, dass diese mysteriösen Objekte wirklich existieren findet sich heute aber direkt vor unserer Haustür, im Zentrum unserer Milchstraße. Neue Beobachtungsergebnisse im Radio und Infrarotbereich führen uns immer dichter an den Ereignishorizont her. Dieser Horizont ist eine unsichtbare Membran, durch die alles hinein aber niemals nach draußen dringen kann. In den nächsten Jahren hoffen wir sogar mit Radioteleskopen ein erstes Foto vom Schatten dieses Ereignishorizonts zu machen und damit eine der exotischsten Vorhersagen der Einstein´schen Theorie zu testen. Der Vortrag stellt diese Fragen, die dazugehörigen Beobachtungen und astrophysikalischen Antworten allgemeinverständlich dar.

18 January 2016

Physikalisches Kolloquium

Wo:Eberhard Karls Universität Tübingen, Physikalisches Institut, Experimentalphysik II
Wann: 16:15 Uhr
Sprecher/in:Prof. em. Rudolf P. Hübener
Titel: "Die Geburt der Quantenphysik - Boltzmann, Planck, Einstein, Nernst und andere"
Abstract:Wegen des rapiden Anstiegs der künstlichen Beleuchtung am Ende des 19. Jahrhunderts bestand damals ein großer Bedarf an quantitativen optischen Daten und einem anerkannten Lichtmaß. Deshalb wurde im optischen Laboratorium der Physikalisch-Technischen Reichsanstalt in Berlin die spektrale Verteilung der Lichtintensität über einen großen Frequenzbereich genau gemessen. Diese neuen Daten konnte mit den vorliegenden Modellen nicht erklärt werden. Zwischen Oktober und Dezember 1900 gelang Max Planck die Ableitung seines berühmten Strahlungsgesetzes auf der Grundlage von Boltzmann's Wahrscheinlichkeits-Interpretation der Entropie. Als zentralen neuen Ansatz führte Planck die Quantisierung der Strahlungsenergie durch die diskreten Energie Elemente hv ein, mit der universellen Konstanten h. Während Planck die volle Bedeutung der neuen Quanten Physik fast 10 Jahre lang nicht akzeptierte, waren es Albert Einstein, der 1905 mit seinen Lichtquanten und 1906 mit seiner Quantisierung der Gitterschwingungen in Kristallen, und wenige Jahre später Walther Nernst mit seinen Messungen der spezifischen Wärme, die die neuen Ideen der Quanten Physik stark vorantrieben. 

14 January 2016 

Physikalisches Kolloquium 

Wo:Universität Bremen, Hörsaal H3, Geb. NW1, Otto-Hahn-Allee 
Wann:16 Uhr c.t. 
Sprecher/in: Dr. Jan Ingo Flege
Titel:"Four (or Five) Quarks for Muster Mark?" - Zur Existenz von Tetra- und Pentaquarks  
Abstract:Etwa 50 Jahre nach der Aufstellung wesentlicher Grundlagen des Standardmodells zum Aufbau massiver Teilchen aus Elementarbausteinen, sogenannten Quarks, herrscht in der Teilchenphysik eine neue Aufbruchsstimmung: Neueste experimentelle Ergebnisse vom Large Hadron Collider (LHC) in der Schweiz zeigen ungeahnte Einblicke in den subatomaren Mikrokosmos und erhärten die Hypothese, dass es neben den etablierten hadronischen Teilchen wie Mesonen und Baryonen, die aus je zwei bzw. drei Quarks bestehen, auch Teilchen aus einer größeren Anzahl dieser Elementarbausteine gibt. Obzwar nicht die ersten ihrer Art - erste Hinweise auf ein Pentaquark aus fünf Teilchen wurden bereits 2003 veröffentlicht - so sind die aktuellen Funde im Gegensatz zu früheren (teils voreiligen) Meldungen von dramatisch gesteigerter statistischer Signifikanz.
Im Vortrag wird zunächst der akzeptierte Wissenstand zum strukturellen Aufbau der Hadronen und ihrer Wechselwirkungen kompakt dargestellt. Aufbauend auf den sich daraus ergebenden Möglichkeiten ihrer experimentellen Untersuchung werden anschließend die jüngsten Befunde der LHCb-Experimente zum Nachweis von Tetra- [1] und Pentaquarks [2] erläutert und ein Überblick über den gegenwärtigen Stand der (sicherlich noch nicht abgeschlossenen) Diskussion um ihre Bedeutung für die Teilchenphysik gegeben.
 
[1] R. Aaij et al. (LHCb Collaboration), Phys. Rev. Lett./ *112*, 222002 (2014).
[2] R. Aaij et. al. (LHCb Collaboration), Phys. Rev. Lett. / *115*, 072001 (2015). 

13 January 2016

RTG Colloquium

Where:University of Bremen, ZARM, Rm 1730
10:30 - 13:00 General Assembly
13:00 - 14:30 Board Meeting incl. lunch (Rm 1280), Lunch for students university mensa
14:30 - 15:30 Dr. Manuel Hohmann, University of Tartu

“Parametrized post? Newtonian formalism of Horndeski´s theory of Gravity”
15:30 - 16:00 Coffee break
16:00 - 16:30 Journal´s Club
16:30 - 17:30 Dr. Gudrun Wolfschmidt, University of Hamburg
"The Einstein-Tower in Potsdam - A monument with cultural significance as well as for the history of science"
18:00Dinner

12 January 2016

Vortragsreihe Hochschule Bremen  

Wo:HS-Bremen Werderstraße
Sprecher/in:Prof. Dr. Jürgen Blum 
Titel:"Was können uns Kometen über ihre Entstehung verraten?"
Abstract:Die Erscheinung eines Kometen am Himmel ist viel auffälliger als der relativ kleine und dunkle feste Körper, der sie bei seiner Annährung an die Sonne hervorruft. Dennoch zählen Kometenkerne zu den interessantesten und wissenschaftlich wichtigsten Körpern des Sonnensystems, um dessen Entstehung zu beschreiben. Die Bilder der Raumsonde Rosetta haben uns in den letzten Monaten vielfältige Eindrücke vom nur wenige Kilometer großen Kometen Tschurjumow-Gerasimenko gegeben. Was können wir aber durch das Studium von Kometen über deren Entstehung und die Bedingung im jungen Sonnensystem lernen? Der Vortrag wird sich dieser Frage widmen und Einblicke in die aktuelle Forschung der Planetenentstehung  erlauben. Dabei kommt den Kometen eine Sonderrolle zu, denn sie zählen zu den am wenigsten veränderten Körpern des Sonnensystems, weil sie den Großteil der Zeit  seit ihrer Entstehung vor gut viereinhalb Milliarden Jahren in großer Entfernung zur Sonne verbracht haben und somit weder durch hohe Temperaturen noch durch Kollisionen prozessiert worden sind. Die Tatsache, dass sie beim Flug durch das innere Sonnensystem große Mengen an Staub auswerfen und somit für uns zu einem manchmal brillianten Schauspiel am Himmel werden, erlaubt es uns, mehrere sonst möglich Entstehungsszarien auf nur noch eines zu reduzieren: Die für uns sichtbaren Kometen müssen durch den gravitativen Kollaps einer Staubwolke aus millimeter- bis zentimetergroßen Staubteilchen entstanden sein.   

11 January 2016

Vortragsreihe: 100 Jahre Allgemeine Relativitätstheorie

Wo:Schlaues Haus, Oldenburg
Wann:19:30-21:00 Uhr
Sprecher/in:Prof. Dr. rer. nat. Hansjörg Dittus, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Köln
Titel:"Raumfahrt und Relativitätstheorie"
Abstract:Im Jahr 1915 veröffentlichte Albert Einstein seine Allgemeine Relativitätstheorie, in der er die schon 10 Jahre zuvor veröffentlichten Forderungen seiner Speziellen Relativitätstheorie zur Grundlage einer umfassenden Theorie der Gravitation machte. Obwohl schon in kurzer Zeit experimentelle Beobachtungen (wie z. B. die Drehung der Merkur-Bahn um die Sonne oder die Lichtablenkung an der Sonne) gelangen, die ihre Gültigkeit sehr nahe legten und der Theorie und ihrem Entdecker zu großer Bedeutung verhalfen, galten viele, der durch sie vorhersagbaren Effekte als unmessbar klein und ohne großen Belang für das tägliche Leben.Die Raumfahrt wandelte dieses Bild. Experimente mit uns auf Satelliten ermöglichten es, mit nie dagewesener Präzision, die Strukturen des Raums unter der gravitativen Wirkung der Sonne und ihrer Planeten zu untersuchen und zeigten bisher keine Abweichungen von der Theorie. Dennoch blieben bisher viele Phänomene und kosmische Rätsel  ungeklärt.Moderne Navigation und die hochpräzise Vermessung des Schwerefeldes sind nicht möglich ohne relativistische Korrekturen und so findet die Relativitätstheorie 100 Jahre nach ihrer Entwicklung Eingang in unseren Alltag. In diesem Spannungsfeld zwischen praktischer Anwendung und Grundlagenforschung liegen die Aufgaben der Raumfahrt.

7 January 2016

Lecture University of Oldenburg

Where:University of Oldenburg
Speaker:Dr. Ralf Lehnert 
Title:"Does Relativity Theory Hold Exactly?" 
Abstract:Relativity Theory is a cornerstone of physics. Since its conception over a centruy ago, it has been scrutinized experimentally with ever increasing precision, but no credible evidence for departures from its underlying symmetry . Lorentz invariance - has been found to date. However, recent theoretical research has established that minute violations of Lorentz symmetry can be accommodated in various approaches to physics beyond the Standard Model. This seminar provides a brief overview of our group's efforts in this research field. A variety of mechanisms for Lorentz breakdown are reviewed, the effective-field-theory test framework for the emerging low-energy effects is introduced, and a number of present-day and near-future experimental measurements in this context are surveyed. 

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